~ > ~

BiiOOi0306 Bi0929

FPDH AOQCK 05000279

PGR

EARTHQUAKEEMERGENCY PLANNING

AT DIABLOCANYON

Submitted to:

Mr.'teven M. SkidmorePacific Gas and Electric Company77 Beale StreetSan Francisco, California 94I06

September 2, I 98l

TERA CORPORATION

2150 Shattuck AvenueBerkeley, California 94704415 845 5200

Berkeley, CaliforniaDallas, TexasBethesda MarylandBaton Rouge, LoulslanaDel Mar, CaliforniaNew York, New YorkSan Antonio, TexasDenver, Coloradot.os Angekl. California

TABLEOF CONTENTS

Section Pacae

1.0 INTRODUCTION AND EXECUTIVE SUMMARY ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ I - I

2.0

I~e

. I Introduction ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

I .2 Executive Summary ..................... ~... ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

TUDY AREAS ..............................................S

I-I1-3

2-1

3.0 EARTHQUAKE EFFECTS ..................................... 3-1

3.1

3.2

General Earthquake Effects ..........3.1.1 Earthquake Description ........3.1.2 Earthquake Hazards ...........3.1.3 Characteristics and Prediction

of Strong Ground Motion .......Earthquake Effects on Transportation ..3.2.1 Background ..................3.2.2 Road Network ................

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ e ~ ~

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

3-13-13-3

3-53-93-9

3-45

4.0 EVACUATIONTIME ESTIMATES...................,............ 4-1

5.0

4.1

4,2

4.34.44.5

Main Evacuation Route Transportation Model .......S

Iimulation Approach ............................4.2.1 Preparation Time ......................; ..4.2.2 Transit Time Between Residences

and Main Evacuation Routes................4.2.3 Merging Time Onto Main Evacuation Routes ..4.2.4 Transit Time On Main Evacuation Routes.....T I I Crrraffle Control e ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ e ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Modeling Earthquake Damage.....................Summary of Results .............................

5.1

5.2

5.3

5.4

Earthquake Effects on Communications ............PGandE Communications Systems .................5.2.1 Power Plant Private Unified Telephone System5.2.2 PGandE UHF and VHF Radio Systems........5.2.3 Critical Elements ..................... ~ ~ ~ ~

Pacific Telephone Company .................... ~ ~

5.3.1 General Description .......................5.3.2 Redundancy and Seismic Criteria............5.3.3 Critical Elements .........................San Luis Obispo County Communications System ....5.4.1 General Description .......................5.4.2 Critical Elements .........................

COMMUNICATIONS............................ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

4 44-64-7

4-74-8

4-104-134-144-14

5-1

5-15-15-1

5-105-135-165-165-175-185-195-195-20

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TABLEOF CONTENTS

(CONT.)

Section Pacae

6.0

5.5 Emergency Broadcast System..........5.5. I General Description ............5.5.2 Critical Elements ..............

5.6 Early Warning System ................5.6. I General Description ............5.6.2 Critical Elements ..............

DIABLOCANYON EARTHQUAKE RESPONSE PLAN ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

5-2I5-2I5-2I5-255-255-26

6-I

6~O.I Introduc I ion ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

6.I. I

6.I.26.I.3

urpose ..........................................PRelationship to Other Plans ........................State-of-the-Art..................................

6.~O2 Operational Concepts....................................

6.2. I General..........................................6.2.2 Reporting of the Emergencies ..........'............6. 2.3 Emergency Periods.............................. ~ ~

6.2.4 Concept of Local Operations .......................6.2.5 Earthquake Damage Assessment Center (EDAC).......6.2.6 Additional Interfaces with State Earthquake

Response Plan ....................................6. 3 Special Tasks.....................'.............. ~ ~ ~ ~ ~ ~ ~-

Task ADamage Assessment of Transportation Routes and Communications .

Task BResources and Support (Repairs) ............. - ~ ~ ~ - ~ - ~ ~ ~ ~ - ~ ~ - ~ ~ ~

Task CTraffic Control .............................. ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~-

Task DProtective Actions for Nonessential Plant PersonnelTask EProtective Actions for the Public ..............................R ~Oeferences for Section 6.0 ....................................

7.0 REFERENCES CITED ........................................

6-'I6-I6-l6-46-46-46-66-66-7

6-II

6-126-l3

6-l3

6-37

6-39

6-4I

6-436-48

7- I

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LIST OF TABLES

TableNo. ~Pa e

3-I Expected Landslide Assessment Criteria .....'.......... ~.... ~ ~ ~ ~

3-2 Landslides Potential Summary by Roads.........................3-3 Expected Liquefaction Assessment Criteria..............3-4 Repair Time Estimates for Liquefaction (Two Lanes)......3-5 Liquefaction Potential Summary (By Roads) .............3-6 Best Estimate Bridge Performance Summary (By Roads)...4-I Repair Time for Seismic Damage Used in Network Analysis

4-2 Summary of Estimated Evacuation Times (Hours).........4-3A Availabilityof Crews Assumed in Evacuation Scenarios ...4-3B Reduced Resources........................... -.... - ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

4-3C Reduced Resources........................... ~ ..... ~ ~ ~ ~ ~I

5- I Major Components of the Diablo Canyon Power PlantC

~ ~ ~ommunicaiions Systems ....................... - - .. -. ~ ~ ~

5-2 PGandE Communications Capabilities by Location ...........5-3 Availabilityof Communications System Backup Power Supplies

5-4 PGandE Radio Systems ........................... 5-5 Alternate Links for the Communications Systems

3-25

3-26

3-28

3-29

3-30

3-43

4-l94-22

4-23

4-24

4-25

5-5

5-65-9

5-I25-l5

5-6

5-7

6- I

6-2

San Luis Obispo County EBS Stations ..............San Luis Obispo County Emergency Broadcast System

Bridge Performance Summary .............. ~ ~ ~ ~ ..Summary of Estimated Evacuation Times (Hours)....

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

5-23

5-24

6-27

6-47

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LIST OF FIGURES

FigureNo. Pacae

2- I General Road Network........................................ 2-63- I Median Peak Ground Acceleration.............................. 3- I I

3-2 Areas of Potential Landslide..................'................. 3-233-3

3-4

Areas of Potential Liquefaction.....................5

~ Qtate Bridges .....................................~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 3 24

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 3 39

3-5 County and City Bridges ...........................4- I Location of Entrance Nodes Used in Network Simulation

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 3 4I

Model..... 4-34- ~ ~-2 Car Speed vs. Density ........................................ 4-5

4-3 Volume of Cars vs. Density.................................... 4-56- I Earthquake Emergency Plan Response Schematic ......6-2 Protective Action Decision Matrix ............'......

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ o 6 IO

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 6 46

6-3 San Luis Obispo Area ....................................... 6- I 9

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I.O INTRODUCTIONANDEXECUTIVESUhhMARY

I. I INTRODUCTION

Traditionally the emergency planning process has focused on singular events or

categories of events to develop and organize appropriate emergency response

activities. The exigencies of each event class challenge the applicable emergen-

cy plan in unique ways —the resources required, the organizations responsible,

the time frame of interest, the geographical region impacted. But it has always

been recognized that, first, every emergency plan represents a base that can be

expanded or contracted in response to the actual emergency and second, that

~ each emergency plan establishes a response capability with a significant degree

of transferability to events other than those specifically the subject of the plan.

ln fact, a fundamental premise of planning is to avoid narrowly addressing

specific scenarios and thereby to provide the most effective overall capability.

This report expands the envelope of current emergency planning by considering

the potential interactions of a severe natural event, a large earthquake, with the

functioning of emergency plans for a radiological emergency at a nuclear power

plant. Earthquakes and radiological emergencies are individually addressed by

local, state, and federal plans and planning requirements. In addition, earth-

quakes are considered initiatory events for nuclear plant radiological plans. Not

coincidentally, the separate plans addressing each event provide a considerable

response capability for the combined events. Thus, it is expected that these

separate, "specialty" plans should remain the basic planning tools. This report

examines some of the detailed interactions of a combined event, and establishes

a framework for coordination and optimization of emergency response capa-

bility.

Several natural phenomena, including earthquakes, are specified as initiating

events for nuclear power plant emergency plans in NUREG-0654/FEMA-REP-I,

"Criteria for Preparation and Evaluation of Radiological Emergency Response

Plans and Preparedness in Support of Nuclear Power Plants." The PGandE

Emergency Plan currently considers the spectrum of possible earthquakes by

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their inclusion as initiating events for the four classes of Emergency ActionLevels. The PGandE plan also includes onsite instrumentation for monitoring ofseismic activity. Additionally, a general capability exists to respond to the most

likely and frequent levels of seismic activity (e.g., earthquakes of magnitude 5

or 6) through basic emergency planning performed by the public sector. For

example, the San Luis Obispo Seismic Elements of l974 provide basic. technical

information to describe and respond to potential earthquake damage.

For larger earthquakes discussed herein, much of the preparedness that currentlyexists due to radiological emergency planning should allow response by extension

of the basic planning. Additionally, state and federal earthquake response plans

(e.g., State of California 'Earthquake Response. Plan" reprinted April l98l and

FEMA Region IX Federal Earthquake Plan, l 979), provide a level of preparedness

to respond to the effects of the large (magnitude 7.5) earthquake postulated forthe design of the Diablo Canyon Power Plant (DCPP). Such a large earthquake,

regardless of whether a coincident radiological emergency exists, might exhaust

the resources. of local authorities, thus requiring action by both state and federal

authorities.

The study described herein was specifically prepared to respond to. the NRC

request of December l6, l980 for evaluation of the potential complications in

emergency planning resulting from an earthquake which could either initiate orfollow the initiation of accidents at the Diablo. Canyon site. As such, we

addressed three. principal subject areas identified in the NRC letter.- The firstarea involves estimating the potential ground motion within the evacuation

planning area and the resultant likely earthquake damage to transportation and

communication systems. This effort relied upon the extensive seismologicalstudies presented in the Diablo Canyon seismic hearings (Atomic Safety and

Licensing Board and Atomic Licensing Appeal Board) as well as additionalinvestigations conducted to estimate the structural damage to transportation and

communication systems that might be used in an emergency. Decisions

regarding evacuations after an earthquake would likely require consideration ofconditions differing from those presented in the PGandE Emergency Plan. Thus,

the second area involves an evaluation of the impact of a spectrum of. potential

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earthquake damage levels on evacuation time estimates..This effort utilized a

realistic simulation model of the evacuation route network including the dynamic

effects of traffic congestion and control.

The third area identifies revised planning concepts intended to facilitate the.

response of local authorities to the complicating effects of a large earthquake on

a radiological emergency. As with all planning, periodic review and upgrading of

these concepts is required to assure a dynamic planning status. In this case, we

have identified a major revision to response dictated by the combined seismic

and radiological emergencies; however, the continued development of earthquake

response plans by federal, state and local authorities will necessitate revision

and cross-reference to their respective radiological emergency preparedness

plans. Annual review and updating of radiological planning is assured by federal

requirements.

I.'2 EXECUTIVE SUMMARY

The study focused. on two areas where the most significant earthquake interac-tions would be manifested: transportation and communications. The study also

establishes a conceptual framework for an "earthquake response plan" which

addresses both the response to the complicating eFfects of damage as well as

advanced planning concepts to deal with the duality of a radiological and

earthquake emergency. The specific evaluations rest on the assumption of a

7.S magnitude surface wave located on the Hosgri fault. The specific earthquake

postulated is not considered to be particularly crucial as for the most part the

study proceeded and, in fact, endeavored to generalize the initiating events.

Due to the complexity of a combined emergency, it was important to develop a

detailed data base on earthquake-generated damage. In doing so, it is not

contended that such damage can be deterministically predicted; rather, it is to-amplify our understanding of the likely nature and extent of damage as a basis

for rational planning decisions. In recognition of the range of possible earth-

quake ground motion, the range of effects over a geographical area due to thatground motion, and the variable response of individual structures and geologic

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formations with respect to a given earthquake input, the data base was actuallytriplicated to encompass three defined damage levels. These are Level I as an

optimistic evaluation, Level 2 as a best estimate, and Level 3 as a pessimistic,evaluation. The terms minor, ~ex ected, and ~ma or are also used interchangeablyto characterize these levels. Again, the value of this tiered approach is not tobe viewed in terms of a predictive capability but in the achievement of a,

generalized and adaptive data base to be used in planning and in responding tothe event actually encountered.

e

For road systems the data base considered two principal damage mechanisms:

ground failure resulting in soil liquefaction underneath the road beds or landslid-

ing onto the roadways, and structural or settlement damage to bridges and

overpasses. Each bridge in the evacuation routes was evaluated as to its design

and the types of damage likely to be sustained. For landsliding and liquefaction,the full traverse of each highway was surveyed to locate potential liquefactionsites, and to assess the likelihood of such liquefaction and the extent ofencroachment of slide material on the highway or damage to the highway due toground subsidence. In addition, estimates were made of the expected times and

required resources to repair each item of damage and restore the road toservice.

The data base for earthquake damage also included information on the suscepti-

bilityof essential communications equipment to earthquake forces. The types ofdamage that could interrupt communications include loss of electrical power,loss of telephone lines, loss of buildings housing the equipment, loss of equipmentwithin the building and loss of antennae towers.

From a planning perspective, damage to transportation and communicationssystems reflects most directly on the selection and implementation of protectiveactions. Protective action decisions for the combined radiological/earthquakeemergency would benefit from a pre-analysis of evacuation times representativeof the degraded conditions likely to be encountered. Therefore, analyses wereundertaken using a computer simulation technique that dynamically modeled theflow of cars through the evacuation network. A flexible menu of evacuationoptions and strategies were considered to minimize the impacts of damage to the

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road system. Evacuation times were computed for the range of damage levels

contained in the data base. A matrix was then prepared (Table 4-2) correlating

evacuation times, damage levels and extent of evacuation (i.e., partial versus

total). This matrix represents a distillation of the detailed analyses performed in

the study and effectively coalesces the decision-making process for protective

action.

The final step in the study was to design a planning structure that would have at

its core the modified protective action matrix and which would implement the

various survey, assessment, and coordination functions necessary to sustain the

decision process. The plan has been formulated such that emergency functions

related to each type of event (i.e., radiological and earthquake) proceed largely

in parallel, with provisions made for (I) prioritizing actions where necessary,

(2) coordinating key organizations, and (3) synthesizing data and decisions to

adequately reflect the contingencies of each emergency.

In addition to the development of the damage data base, evacuation matrix, and

response plan, this study provided more refined insights into emergency planning

for these combined events. The conclusions able to be reached are perhaps as (or

more) important than the specific results. They are as follows:

I. Even on a pessimistic basis, a large earthquake in thestudy area would not be expected to result in totalneutralization of emergency response capabilities. This isattributable to the inherent resistance of much of thephysical equipment and structures involved and the diver-sity of capabilities provided by redundant and separatemeans of transport and communications.

2. Evacuation, as a protective action option, is availablewithin a reasonable time for most geographic areas undermost damage conditions. The availability of evacuation isenhanced considerably by pre-analyses of potential dam-age and repair resources, and the establishment of plansto survey, assess and repair damage and to utilize avail-able evacuation routes in a maximum manner.

3. Emergency planning must be considered as an evolvingprocess and in the context of other related plans andevents. The detailed assessment of earthquake effects

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and conceptual plan provided in this study are at perhapsthe leading edge of planning for these types ofemergencies. Planning resources and attention should bedistributed such that local, state and federal emergencyplanning is conducted in an integrated and harmoniousmanner.

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2.0 STUDY, AREAS

From a natural disaster viewpoint, large earthquakes are somewhat unique in

their ability to challenge simultaneously a variety of emergency responsefunctions over a wide geographic area. To provide the technical basis to developsite specific planning, we conducted a detailed study of the expected effectsthat a large earthquake occurring on the Hosgri fault would have on the areawithin about I 5 miles of the Diablo Canyon Power Plant (Figure 2- la, b).

This geographic area is called the Basic Emergency Planning Zone and was

chosen for detailed evaluation since it is the area where one expects that thecombined effects of a radiological and earthquake emergency would be encoun-tered. The effects of a large earthquake could be experienced over an extendedarea. Earthquake effects over such an extended area are addressed in state andfederal earthquake plans. Radiological emergency planning requirements focuson an approximate IO-mile zone for the radiological plume exposure pathway.Therefore, the study area was selected to envelop the most likely complicatingeffects that an earthquake would have on radiological planning.

This study of earthquake emergency planning was able to focus on a single,specified large earthquake for two reasons: (I) the specific earthquake that wasconsidered is the most logical one to be involved in a combined radio-logical/earthquake emergency and (2) the planning concepts determined to be

appropriate are not particularly sensitive to the choice of earthquake size orlocation.

There are a variety of faults within San Luis Obispo County; however, only th'reeare considered capable of generating major earthquakes (Envicom, l 974). Thelargest earthquake, of surface wave magnitude 8.0 to 8.5, is believed to becapable of occurring on the San Andreas fault, which is located approximately60 kilometers northeast of the city of San Luis Obispo and approximately80 kilometers from the Diablo Canyon Power Plant. The maximum magnitudethat has been assigned to the Hosgri fault is a surface wave magnitude of 7.5.

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This large earthquake would pose the greatest hazard to the coastal areas since

it is located offshore approximately-6 kilometers southwest of DCPP and

approximately 25 kilometers from the city of San Luis,Obispo. The Rinconada

fault trend is believed to be capable of generating a surface wave magnitude 7.0to 7.5 earthquake. Due to its location some I5 kilometers northwest of the cityof San Luis Obispo and 35kilometers from DCPP, a large earthquake on thisfault would pose the greatest hazard to San Luis Obispo and the mountainous

areas lying just northeast of the city.

For this study the postulated magnitude 7.5 earthquake on the Hosgri fault was

used as the basis for developing damage scenarios and investigating evacuation

times. This earthquake was chosen because of its use as the seismic design basis

for the Diablo Canyon Power Plant and its dominant seismic hazard to the plant.Furthermore, the use of this large earthquake was responsive to the directives ofFEMA and NRC. The hypothesized earthquakes on the San Andreas and

Rinconada faults pose a substantially lesser hazard to DCPP because the peakaccelerations from either are expected to be only 30 percent of those expectedfrom the Hosgri earthquake. Therefore, one would expect that the probability ofa concurrent radiological emergency with either of these two earthquakes wouldbe much less than that with the Hosgri earthquake.

The planning concepts identified in this study are not particularly sensitive tothe choice of the Hosgri earthquake due to the large variability in damage that is

expected from this particular earthquake. This diversity in damage compre-hensively challenges emergency plans and requires them to be extremelyflexible. In fact, the variety of damage and evacuation scenarios simulated inthis study largely envelop those expected for the other two hypothesizedearthquakes, the main difference being the relative likelihood of specificscenarios. For instance, the proximity of the Rinconada fault to US. IOI Northwould require considering an alternate evacuation to the northwest and south-west along the coast under conditions of light-to-moderate damage in the eventof this hypothesized earthquake. Therefore, since the hypothesized largeoffshore earthquake poses the greatest hazard to DCPP, is responsive to FEMAand NRC directives, encompasses the effects expected from other major

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earthquakes in the area, and does not control the development of emergency

plans, we believe that it is the only earthquake that need be considered in detail

for this study.

The principal earthquake effects considered in this study'are those on the

transportation and communication systems. Obviously, the major earthquake

postulated in this study would produce other effects of concern to local

authorities, including fire damage, potential fatalities and injuries. Mitigation ofthese other effects is the goal to which most earthquake response plans have

been directed and are therefore not repeated here.

Transportation of both emergency materials and personnel, as well as the

protective evacuation of the public, are key requirements for effective radiolog-

ical emergency response and ones which an earthquake might significantlyaffect. Disruption of the communications systems due to earthquake effects

could also prevent effective emergency response. This necessitated an evalu-

ation of both transportation and communication systems including a detailed

review of the local road network and communications equipment that would most

likely be required to function in a radiological emergency. We did not attemptto address the non-radiological preparedness that should be included in local

earthquake response planning. However, some of these data and the approaches

described herein might be useful for that purpose.

To a very large measure our evaluation of earthquake effects was not deter-

ministic, but recognized the stochastic nature of earthquake damage. Addi-

tionally, it was believed that a range of potential damage levels would be useful

to consider in developing planning concepts and guidelines. In this way, the truestochastic nature of potential earthquake effects are captured and a range ofprotective action guidelines are formulated. One should also note that such a

spectrum of damage locations and levels is not artificially imposed due toresource constraints or to satisfy planning goals. The spectrum of damage

represents our evaluation of each bridge and roadway within the study area and

consideration of their potential response to the forces of a magnitude 7.5

earthquake.

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The transportation network model developed for estimating the effect of damageon evacuation times is somewhat different from that originally developed and

used in the radiological plans. This model includes the dynamic effects of trafficcongestion and control. For the conditions included in the current radiologicalplans, we would predict similar times using similar assumptions. We have, infact, used essentially all of the input data developed by Voorhees (l980) for thoseestimates. However, in evaluating the effects of seismic damage, such as delaysdue to bridge repair or landslide clearing, transient times on individual sectionsof road becomes important. Additionally, we found it useful to consider morelimited protective actions, such as partial or staged evacuation of the populationwithin l0 miles of the plant or in the downwind directions should heavy damagebe inflicted to evacuation routes. These considerations led us to the develop-ment of a dynamic evacuation model.

Based upon the results of these studies, we developed revised planning conceptsto address combined seismic and radiological emergencies. A key revision in thisplanning is the need to survey the post-earthquake damage and allocateresources to repair communications and roadways prior to decisions on pro-tective actions. Such an approach would be useful in dealing with anycombination of natural phenomena and radiological accident.

The general properties of earthquakes, the types of hazards they create and theexpected effects from the large earthquake postulated in this study aredescribed in Section 3.1 of this report. The principal earthquake hazardsaffecting the transportation systems and the potential for ground failure andstructural failure are presented in Section 3.2. Section 4 describes the evacu-ation model developed, evacuation scenarios analyzed and evacuation timeestimates. Section 5 presents our evaluation of communication systems in thestudy area, including that of PGandE, Pacific Telephone, and the County andEmergency Broadcast Systems. Section 6 provides our recommended planningconcepts for addressing a combined earthquake and radiological accident.

Much of the detailed survey information compiled in our investigation is includedin Appendices to this report. Additional detailed description of our geologic and

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engineering evaluation methods is also provided. Several of the detailed maps,

identifying potential seismic hazard areas, might be effective for inclusion in the

procedures for damage assessment reporting and subsequent repair activities.

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SAN LUIS OBISPO AREA-Northern Section

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3.0 EARTHQUAKEEFFECTS

3. I GENERAL EARTHQUAKEEFFECTS

3.l.l EARTHQUAKE DESCRIPTION

Shallow crustal earthquakes, the type common to California, occur as a result of

a sudden break and movement of the rock in response to stress build-up in the

Earth's crust. This sudden movement generates seismic waves that propagate

through the crust and manifest at the Earth's surface as ground shaking. The

break occurs along a zone of weakness in the crust known as a fault or fault

plane. It initiates at a specific location on the fault called the hypocenter, then

propagates along the fault for some finite distance. The area of the fault plane

involved in the break is known as the rupture zone and the point on the surface

of the Earth directly above the hypocenter is referred to as the epicenter.

There are three basic mechanisms that describe the faulting process: strike-slip,

reverse (or thrust), and normal. These mechanisms refer to the relative

direction of movement of the rock on opposite sides of the fault with respect tothe orientation of the fault. This orientation is described in terms of the strike

and dip of the fault plane, the strike being the direction of the surface trace ofthe fault usually given as the azimuth, and the dip being the angle between the

fault plane and the surface of the Earth. As an example, a fault described as

striking N45oW and dipping 85o refers to a fault whose surface trace is oriented

in a northwest-southeast direction and whose fault plane is nearly vertical.

A strike-slip mechanism is faulting in which the rocks on opposite sides of the

fault move horizontally with respect to one another in the direction of the strike

of the fault. Most major faults in California, including the San Andreas, are of

this type, with the l979 Imperial Valley earthquake being a recent example of

this type of faulting. The other two mechanisms refer to faulting in which the

relative movement of the rocks on opposite sides of the fault is in the direction

of the dip of the fault plane, which is generically referred to as dip-slip

movement. In this respect, a reverse (or thrust) mechanism refers to dip-slip

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movement in which the opposite sides of the fault move towards one another,

with one side overriding the other in response to compressional forces. The I 97l

San Fernando earthquake was an example of this type of faulting. A normal

mechanism refers to dip-slip movement in which the opposite sides of the faultmove away from one another in response to extensional forces. The Foothill

fault system, located along the western edge of the Sierra Nevada Mountains, is

representative of this type of faulting, with a recent example being the l975

Oroville earthquake. Faulting in which relatively equal amounts of strike-slip

and dip-slip motion occur is referred to as oblique-slip movement. Geological

evidence indicates that the predominant movement of the Hosgri fault is strike-

slip, similar to faults of the San Andreas system.

Earthquakes commonly occur in clusters called earthquake sequences. The

'argestor outstanding earthquake of the sequence is known as the mainshock.

Although not so common to California, multiple mainshocks of nearly the same

size and separated by hours, days, or sometimes weeks may occur. Foreshocks

usually precede the mainshock by several days to several months. Relatively few

in number, they tend to cluster in a few isolated areas within the eventual

rupture zone, the largest concentration usually occurring in the immediate

vicinity of the hypocenter. Immediately following the mainshock, a large

number of smaller earthquakes called aftershocks occur. Depending on the size

of the mainshock, aftershock sequences can last as long as several months to

several years; however, as time goes on, both their size and their number

diminish. Although not as large as the mainshock, foreshocks and aftershocks in

many cases can cause as much damage locally as the mainshock. Aftershocks

are especially serious, since manmade structures, as well as natural deposits thathave been weakened by the mainshock, are highly susceptible to further damage.

There are various-measures available that characterize the size of an earth-

quake. The most common of these is earthquake magnitude, a standard measure

related to the logarithm of the amplitude of ground motion resulting from an

earthquake. For smaller earthquakes in California, local Richter magnitude (ML)is used as the standard measure of magnitude and is the value generally reported

by the seismographic stations at Berkeley and Pasadena. For larger earthquakes

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worldwide, surface wave magnitude (M ) is generally used as the standard.smeasure of magnitude. As a general rule, magnitude values exceeding 6.8 to 7.0

represent surface wave magnitude due to limitations of the other magnitude

scales. For the. purposes of this study a surface wave magnitude 7.5 earthquakewas postulated to occur on the Hosgri fault with the center of the rupturelocated offshore approximately six kilometers from DCPP.

Other measures of the size of an earthquake include epicentral intensity, area ofthe rupture zone and seismic moment. Epicentral intensity is a measure of thelargest degree of damage sustained during the earthquake (the intensity scale is

discussed in a later section). This zone of greatest damage is usually confined tothe vicinity of the rupture zone and, hence, the term epicentral intensity has

been historically used to refer to the observed maximum intensity. The area ofthe rupture zone can vary from as little as several square meters for very small

earthquakes to as large as several thousand square kilometers for the largestearthquakes that can occur in California. Seismic moment is a measure of theearthquake size that depends only on the physical mechanism of the source. It is

related to the overall energy or force of the earthquake.

3.1.2 EARTHQUAKEHAZARDS

The primary natural hazards from an earthquake are ground shaking and groundrupture along the surface trace of the fault rupture zone. Secondary naturalhazards are ' result of the above-named hazards and include landslides,

liquefaction, settlement, tsunamis, seiches, lurching and'round shaking. The

interaction of these natural hazards with manmade structures generates thepotential for structural hazards. These include the collapse or destruction ofbuildings, bridges, towers, smoke stacks and piers; the failure'f retainingstructures such as dams, reservoirs, tanks, pipelines, canals, dikes, earthretaining walls and sea walls; and the failure or movement of equipment such as

pumps, valves, electrical equipment, machinery, piping, and furniture.

The natural seismic haza'rds,of major concern to radiological emergency planningin the study area are 'ground shaking, landslides, liquefaction, settlement and

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tsunami. The most widespread hazard affecting the study area is ground shaking.

Although the characterization of this hazard, is, discussed in the next section,

some fundamental properties are discussed here. Ground shaking results from

seismic waves that are generated by the sudden movement of rock along opposite

sides of'the fault. As the waves travel away from the rupture surface, their

amplitude decays (i.e., attenuates) due to the energy absorption properties of

rock and soil through which they travel and the dispersion of the energy with

area., Since the waves originate at all points along the rupture zone of the fault,

the distance most appropriate for characterizing the amplitude of the seismic

wave or ground shaking at a specific location is the shortest distance between

the site and the rupture zone.

Strong ground motion refers to ground shaking of sufficient amplitude to be

considered important to the performance and safety of manmade structures.

The instrument used to record strong motion is the accelerograph.. It was

designed to measure and 'record the time history of the acceleration of the

ground, called an accelerogram, because of the use of acceleration by engineers

in the design of structures. They are nominally set to start recording when

accelerations exceed one percent of gravity (.Ol g), although strong motion is

commonly thought to be ground motion in excess of five percent of gravity(.05 g). The accelerograph records acceleration time histories in three directions

called components. Two components are oriented to record motion in the

horizontal plane, orthogonal to one another, while the third component is

oriented to record motion in the vertical plane. The three components taken

together serve as a three-dimensional description of ground motion.

Due to the hilly topography of the study area, landslides are a major potentialhazard for evacuation, especially during the rainy season. The actual number

and location of landslides expected to occur along evacuation routes throughout

the study area during a major earthquake on the Hosgri fault is discussed in

detail in Section 3.2 and the appendix on ground failure. Due to the dominance

of the strike-slip mechanism of faulting expected on the Hosgri, large areas of

tectonic settlement are not expected to occur. The greatest hazard forsettlement comes from artificial fills, especially thick bridge abutments and

road fills, which tend to compact and spread laterally under seismic shaking.

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Liquefaction is a term used to describe the loss of strength of a saturated soil

deposit due to an increase in pore water pressure caused by ground shaking. This

loss in strength can result in ground failure such as landslides and lateral spreads

or result in a loss. of foundation support for manmade structures. Due to the

large number of water crossings and the presence of soil deposits with shallow

water tables along evacuation routes, liquefaction has been identified as a majorpotential'azard affecting the safe evacuation of the study area. Specificdetails regarding the number and location of liquefaction areas along evacuation

routes throughout the study area during a major earthquake on the Hosgri faultmay be found in Section 3.2 and the appendix on ground failure.

A tsunami is a tidal wave which is generated by rapid vertical displacement ofocean water either from tectonic movements associated with faulting or bysubmarine landslides. The strike-slip mechanism of faulting expected on the

Hosgri would preclude the tectonic generation of a tsunami since the horizontalmovement of the ocean floor associated with this type of faulting would not

displace ocean water. (Note that the most recent analysis reported in

Section 2.4 of the FSAR conservatively postulates for design basis purposes a

vertical displacement of 7.33 feet on the Hosgri fault leading to the generation ofa tsunami. The very conservative assumptions contained in the FSAR were not

considered to be applicable for planning purposes.) There is, however, a remote

possibility of a tsunami generated by a submarine landslide triggered by the

earthquake. Large submarine landslides, however, have been observed togenerate only relatively small, local tsunamis presumably due to their failuremechanism, their poor efficiency in generating tsunami energy, and the rela-.tively small amount of potential energy available for tsunami generation (Wiegel,

l975). The effects of such a tsunami, therefore, would be expected to be

relatively localized with waves sufficiently small so as not to interfere with theevacuation of the study area.

3.I.3 CHARACTERISTICS AND PREDICTIONOF STRONG GROUND MOTION

The accelerogram, while providing a complete description of strong motion, is

extremely difficult and expensive to use in design, since it requires complex

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mathematical models and procedures. Therefore, design engineers over the

years have developed techniques that rely upon certain parameters characteris-

tic of the actual acceleration time histories. The parameters most commonly

used are peak ground acceleration (PGA) and response spectral ordinates.

Peak acceleration is simply the maximum acceleration value recorded by the

accelerograph and is usually reported as three peak values,'ne for each

component. Response spectral ordinates are somewhat more complex in nature,

but similar in principle to PGA. 'A response spectral ordinate is the maximum

response of a single-degree-of-freedom system (e.g., a pendulum), having a given

natural frequency and damping, to a specific acceleration time history input atits base. The response of the system is commonly described in terms of a

velocity time history,- more specifically, the velocity at the top of the system

relative to the velocity at its base. When these spectral ordinates are computed

for a suite of single-degree-of-freedom systems of various natural frequencies,

all having the same damping, and plotted as a function of frequency, the result is

what engineers refer to as a response spectrum.

Two other parameters typically used by engineers are intensity and duration.

Intensity is a non-instrumental measure of the earthquake effects at a particularlocation given in terms of the response of humans, manmade structures and the

natural environment. By its very nature, it serves as a subjective measure of the

severity of the ground motion at a specific location. Its usefulness stems fromits non-instrumental source, which allows the quantification of the severity ofground motion in areas lacking accelerographs, and in many cases is a more

accurate measure of the level of damage than are some instrumental measures

of ground motion. The standard measure of intensity in the United States is

Modified Mercalli intensity, a twelve-level scale specified in ter'ms of Roman

numerals I,through XII, with XII being the most severe level of earthquake

effects.

Duration is a measure of the length of time over which strong motion is

observed. It is an important characteristic of ground motion when considering

time-degrading systems subject to strain softening or fatigue. Examples of such

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systems are natural soil deposits, soil structures and manmade structures subject

to nonlinear behavior. Although several measures of duration exist, one of the

most simple and common measures is bracketed duration. It represents the time

over which the first and last occurrence of a specified level of acceleration,

ysually five percent of gravity (.05 g), is observed.

Peak acceleration and duration were the two strong-motion parameters used in

the evacuation study, so the prediction of these parameters will be discussed

briefly. Due to the proximity of the source of the design earthquake to the study

area, a relationship for predicting near-source acceleration's recently developed

at TERA Corporation (Campbell, l980; l98I) was used to predict the level of

peak acceleration to be expected at specific locations.

This relationship was developed from strong-motion data recorded within 50 kilo-meters of the rupture zone from selected worldwide earthquakes of magni-

tudes S.O to 7.7. The data base used in the study was assembled using criteriadesigned to select only consistent and quality data in the range of magnitudes

and distances of interest for most design applications. It consists of 229 horizon-

tal components (I l6 records) of peak acceleration from 27 earthquakes, including

the October I S, I 979, Imperial Valley earthquake. A weighted, nonlinear

regression analysis was used to establish 'the relationship, where weights were

used to control the effects of well-recorded events such as the l979 Imperial

Valley and I 97 I San Fernando earthquakes.

The relationship resulting from the regression analysis is given by the following

equation:

PGA = .Ol 59 Exp (.868M) R + .0606 Exp (.700M)

where PGA represents the mean of the peak acceleration values from the two

horizontal components from each recording in fractions of the acceleration of

gravity (g), M is magnitude, and R is closest distance to the fault rupture zone in

kilometers. Magnitude is defined as local Richter magnitude (ML) for magni-

tudes less than 6.0 and surface wave magnitude (M ) for magnitudes of 6.0 ors

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greater. Peak acceleration was found to be lognormally distributed with a

standard error representing a 45-percent increase in the median estimate as

given by the above equation. Predictions from Equation I were found to be valid

for both soil and rock.

Bracketed duration, based on a threshold of .0.05g, was predicted from an

expression developed by McGuire and Barnhard (l979). They used 50strong-

motion records from earthquakes of local Richter magnitude (ML) 4.5 to 7.2,

recorded at distances of 6 to 2l8 kilometers, to establish a relationship between

bracketed duration and magnitude, distance, geology type and component type.

Distance was defined as either closest distance to the rupture zone when

available or epicentral distance. Their equation for the duration of the

horizontal component is given by

D = .000452 Exp (2.0M+.20S) R (2)

where D is duration in seconds, M is local Richter magnitude (ML), S is 0.0 for

rock and l.0 for alluvium and R is distance in kilometers. The duration expected

at San Luis Obispo, located on alluvium some 25kilometers from an M 7.5

(roughly equal to ML 6.9) earthquake on the Hosgri fault, would be about

IOseconds using this expression. This value would be reduced by about

l 8 percent for rock at the same distance. Using Equation l, this same site would

be expected to experience a peak horizontal acceleration of roughly 0.2 g. Sites

located about 10 kilometers from the fault would be expected to experience a

peak acceleration of approximately 0.4g and a duration on alluvium of approxi-

mately 30 seconds.

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3.2 EARTHQUAKE EFFECTS ON TRANSPORTATION

In this section we analyze the potential effects on transportation of an earth-

quake of surface wave magnitude 7.5 occurring on the offshore Hosgri fault. The

earthquake-induced effects considered are landslides, liquefaction, bridge dam-

age or failure, and flooding from dam failure or tsunami that might reduce the

traffic capacity of highways.

3.2.1 BACKGROUND

3.2.I. I EARTHQUAKE LOADING

A magnitude 7.5 earthquake on the Hosgri fault would result in widespread

ground shaking of long duration (over IO seconds) in the study area. Such an

earthquake would generate a fault rupture of over 60 km with such a large area

of energy release that the ground shaking would attenuate inversely in proportionwith distance to the linear trend of the ruptured area of fault. The ground

motion model used to predict peak ground acceleration throughout the region is

based on previous work by TERA (Campbell, l980; l98l) specifically developed

for such applications.

From a planning viewpoint, one must expect that the damage patterns resulting

from even a major earthquake, such as the magnitude 7.5 postulated here, could

vary significantly within the study area. A contour map of expected peak ground

acceleration, based on Equation I, for a magnitude 7.5 earthquake on the Hosgri

fault is presented in Figures 3-la and 3-lb. A large amount of uncertainty is

associated with the'level of ground motion and duration for any given earthquake

and, correspondingly, the potential damage resulting from its occurrence. This is

not only because the amplitude of ground shaking is systematically decreasing

with distance from the fault, but because observed ground motion, at the same

distance from an earthquake fault, can vary by as much as 45 percent or more.

Therefore, three levels of damage have been modelled to more realisticallyaccount for these uncertainties, and to provide for the greater flexibility in

planning options that these uncertainties require. Level I corresponds to an

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optimistic estimation of the damage and can be considered as a lower bound ofthe expected damage from a magnitude 7.5 earthquake. Level 2 is a best

estimate, while level 3 represents a pessimistic damage estimate. We also use

the terms "minor," "expected," or "major" to describe these damage estimates.

Therefore, the three damage levels represent a spectrum of possible damage thatcould occur, even though the systematic effects of attenuation of PGA withdistance and localized damage potentials (e.g., individual bridge designs) have

been considered.

In general, we have identified two major damage mechanisms that could affectthe road network in the study area: 'I) ground failure resulting in soil

liquefaction underneath the road beds and landsliding onto the roadways, and

(2) structural and settlement damage to bridges and overpasses. The procedure

for damage assessment is presented in the following sections.

In a later section of this report, we briefly discuss possible earthquake-induced

flooding damage from either dam failures or tsunami. It was not possible withinthe scope of this study, nor necessary from the planning concepts presented, toconduct detailed damage assessments from these causes.,The potential damage

areas are localized to the areas downstream of the dams, and most likely the

damage would have the same net effect on transportation routes as one of the

three damage levels discussed below.

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SAN LUIS 08ISPO AREA - Northern Section

Figure 3-loMEDIAN PEAK GROUND ACCELERATION GENERATED

BY AN EARTHQUAKE OF SURFACE WAVE MAGNITUDE 7.5OCCURRING OF THE HOSGRI FAULT

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3.2.1.2 DAMAGEDUE TO GROUND FAILURE

Landslides - Overview

Earthquake-induced landslides differ from conventional landslides by their geo-

metry, failure mechanism, and type of sliding. Conventional landslides are

caused by water infiltrating a slope after rainfall which reduces the shear

strength (i.e., cohesion and friction) of weathered rock and soil material. In

addition, the water increases the weight of the slide mass and decreases the

confining effects at. the toe of the slope. Once the shear strength of the

material is exceeded, the slide mass moves downward in response to gravity.

Earthquake-induced landslides are trigger'ed by energy developed by the earth-

quake in the form of ground shaking.. The shaking, depending on its intensity and

duration, weakens and eventually loosens rock and soil materials, resulting in

downslope movement. These landslides are mostly confined to surficial failures

and result in rock falls, rock slides, soil falls, and soil debris. Very few deep-

seated rotational block glides or slump failures have been observed as a result ofearthquake shaking.

The controlling factors needed to trigger landslides are the intensity and

duration of the ground shaking and the steepness of the slope. The potential is

increased when steep slopes are underlain by low density, weathered, weakly

cemented soils and/or highly fractured bedrock. There are indications that rain

saturation has little or no additional adverse effect on slopes that would

otherwise be susceptible to earthquake-induced failures (Harp, I 98 I).

Seismic-induced landslides normally occur with the initial shock of an earth-

quake. However, in some cases the initial shock may only loosen or weaken rock

or soil material on a slope, while subsequent aftershocks may eventually cause

failure. To compound the problem, heavy rain following a major earthquake

might cause failure of slopes that were originally weakened by the initial shock.

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Studies by Wilson (l978) of the August l3, l978, Santa Barbara earthquake

(M = 5.I) showed that artificially cut slopes are significantly more prone toseismically induced landslides than natural slopes in the same geologic material.

Based on work by Harp (l98I), slopes greater than 35 (I.5:I slope ratio) where

rock is exposed are prone to rock'falls and rock slides. This is considered

conservative since statistics indicate a 40-to-45 lower limit. The higher thedegree of fracturing or jointing of the rock, the higher the probability of failure.Soils or colluvial materials have a tendency to fail on slopes of 25 (2:I slope

ratio) or greater (Harp, l98 I). Research has shown that soils most susceptible tofailure are granular and nonorganic. Slopes which comprise artificial fillalso areprone to seismic-induced failures. The geometry of the fill(e.g., slope ratio and

slope height) and consistency of the soil materials will control its stability orlack of stability. Fills're known to fail by either slumping or debris slide.

Poorly compacted, low-cohesive fill materials on slopes in excess of 25 aresubject to earthquake-induced failure.

Landslides - San Luis Obis o Area

Numerous landslides have occurred in the study region (Envicom, l974). The

type and distribution of failure were probably functions of specific bedrock

conditions, namely: bedding, jointing and fracturing, and steep slope. These

slides-were most likely triggered by water infiltrating the slopes and were notrelated to earthquake activity. None of the mapped landslides near theevacuation roads and highways are known to be active, and the majority of thelarger features are considered quite old, possibly having moved during a much

wetter climate (e.g., over I l,000 years ago).

Where ear thquake-induced slides are likely to occur in the study area, they wouldin most cases fall onto highways rather than below them. Materials falling on

the roadways will cause at least partial blockage. The slides that occur below

(downslope from) a roadway could sever one or more lanes, rendering themimpassable.

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The quantities of materials generated at the toe of a slope from any one slide

will vary depending on the dimension of the slide. Most of the shallow slides that

occurred during the I 97 I San Fernando earthquake had lengths of I 5 to

300'meters and thicknesses of 0.2 to I meter (Morton, l97l). Based on the

survey of mapped landslides, we assumed the average width of these slides to be

about one-third of the length, and the average thickness to be I meter.

Quantities ranged between 45 and 300 cubic meters of displaced debris. It is

estimated, based on similarity of relief, that similar quantities could be

developed from slides occurring in the study area. Slides might occur adjacent

to each other and form coalescent slide masses.

The removal time to clear a road blocked with slide debris depends on the

amount of materials to be removed, the number and type of heavy equipment

available, access to the site, and distance to a suitable disposal or borrow area.

The most practical types of heavy equipment for expediting road repair work are

rubber-tired loaders and tractor bulldozers. Normally, a loader of the type

owned by CALTRANS can excavate'300 cubic yards of loose, unconsolidated

material per hour'. Such loaders are available at the CALTRANS maintenance

stations and could be onsite within 30 minutes. A bulldozer (e.g., D-7

Caterpillar) would be able to move more yardage per hour. However, the only

one'wned by CALTRANS in this area is stationed on Highway I north of Morro

Bay and would require a long time to reach most sites. Local contractors would

be able to provide such equipment with a delay of two to four hours. In order to

obtain clearing time estimates for our study, we have assumed that once onsite,

front end loaders would be able to clear the road at the rate of 200 ft/hour per

lane. This implies that no hauling is required and the debris is l2 feet wide with

an average thickness of 3 feet. All the estimates have been made assuming that

only one loader is working on any given road.

Because roads are long linear structures, multiple failure can occur any place

along them, creating several blockages. In this case, the blockages may have to

be removed one at a time from each end unless equipment is available at

intermediate points. As an alternative, for emergency purposes a road can be

reopened after a major landslide by grading a road over the top of the slide mass

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or by passing it around the perimeter of the mass. This would certainly be time-

saving; however, caution must be exercised when people or equipment are

working in an area of potential active sliding. Roads severed or heavily damaged

by a slide located below the road may be difficult to repair within a reasonable

time frame. Such occurrences would have to be dealt with on a case-by-case

basis.

Assessment of Landslide Potential

The number of technical reports on earthquake-induced landsliding is verylimited. Much of the state-of-the-art work is presently being conducted by the

U.S. Geological Survey through their Earthquake Hazard Reduction Program.

Criteria for assessing earthquake-induced landslides for this study were devel-

oped primarily from the criteria established by the U.S. Geological Survey.

Using these criteria (ABAG, l980-8l) to determine seismic-induced landslide

potential, all slopes analyzed within the study area fall into. an "unstable

condition" for both summer and winter conditions. However, based on distance

from the fault, the intensity of ground shaking will vary from strong to very

strong to occasionally violent (Table 2- I presented in the Ground Failure

Appendix). On the Modified Mercalli scale, intensities will range from Vll.to IX.

According to the definition given to the scale, earthquake landsliding has been

known to take place within this range of intensities.

Basically, there are four main factors that control earthquake-induced landslid-

ing: (I) strong ground motion, (2) slope inclination, (3) surface geologic and

engineering parameters, and (4) conventional landsliding susceptibility (water-

induced failures). Aerial photographs (Fairchild, l978), geologic and topographic

maps, and a field inspection were used to collect information on those slopes

suspected of potential landsliding. Field data sheets prepared for each siteduring our field investigation, and a summary of the pertinent data for each site,are shown in the Appendix.

Only slopes that trend immediately adjacent to or near the roads or highways

were considered in this study. All slopes (natural slopes, cuts, and fills) were

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excluded from this study unless they exceeded the lower limits of the criteriapresented in the Appendix. No deep-seated potential slides were suspected or

recognized along the roads surveyed. Fill slopes normally are difficult to

analyze by inspection since their stability is in part related to how well theyI

were constructed (e.g., compacted). Usually new road fills have been construct-ed to adequate standards, though there are exceptions. Old road fills or newer

ones with slope ratios in excess of 2:I (horizontal-to-vertical) were considered

zones of likely failure.

Based on the assessment criteria, many slopes along the evacuation routes have

been categorized as landslide zones (Figure 3-2), potentially capable of failingunder seismic shaking. Since the current state-of-the-art required a conserva-

tive approach to formulating the assessment criteria, one does not expect thatall slopes so judged would fail. It is expected that the number of failures willdecrease rapidly with distance from the fault, based principally on the attenua-tion of acceleration. In order to estimate the expected number of slides and thecorresponding clearing times, the criteria pr'esented in Table 3- I were developedfor three damage levels. These criteria reflect engineering judgment based on

geological data and past earthquake experience. For a potential landslide

located in a given acceleration zone, the expected footage of failure wasI

obtained by multiplying the total potential footage by the percentage corre-sponding to the selected damage level.

A summary of expected footage failure and clearing time is presented in

Table 3-2 for each road surveyed.. This represents clearing time for two lanes oftraffic for the major evacuation routes. As the volume demand is less forsecondary routes, the clearing time is for only one lane on these roads.

Li uefaction - Overview

Under certain soil and ground water conditions, ground failure by liquefaction

may occur during an earthquake. Liquefaction is defined as the transformationof cohesionless water-saturated material, such as sand, from a solid state to a

fluid state. The cause of cyclic mobility or liquefaction in sands is the build-upof excess hydrostatic pore pressure due to the application of cyclic shear

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stresses. The shear stresses are generated in a soil deposit during ground

shaking. As a consequence of the applied cyclic stresses, the structure of the

undrained soil tends to become more compact. If the sand is loose, the pore

pressure increases rapidly to a value equal to the confining pressure, and the soil

layer may undergo large deformations and be in a state of extreme liquefaction.If the sand is more compact, it will undergo limited deformation and partialliquefaction. Any structure, fillor embankment located on a liquefying soil willundergo some deformation varying from minor settlement to complete sinking.The goal of a liquefaction potential analysis is to differentiate between those

situations where liquefaction can cause damage and those situations where

liquefaction, per se, may not cause significant damage.

Three major factors are conducive to liquefaction: ground shaking, shallow

water table, and sandy material. Generally, low-lying areas mantled by young,

unconsolidated, weil-sorted sand and/or silty sand (clay free) materials are themost susceptible to liquefy. In addition, some minor topographic relief, such as

stream banks or gentle to steep slopes, is normally needed to cause liquefactionground failure. However, some ground failure can occur on flat ground if the

liquefiable materials are unevenly loaded, as in the case of road fills.

Li uefaction - San Luis Obis o Are'a

Several of the evacuation routes travel through areas susceptible to liquefactionin the event of a major earthquake. However, no known historic liquefaction has

occurred in the study area. The areas susceptible to liquefaction could

experience accelerations between O. I2 and 0.50 g for an event of magnitude7.5'ccurring

on the, Hosgri fault. According to Youd, et al. (I978), the lower limitfor liquefaction to occur is about an acceleration of 0.2 g. This suggests thatalmost all locations within the study area have the potential to liquefy. The

resulting damage at each site will depend upon the specific soil and groundwaterconditions.

Those areas most capable of liquefaction damage to roads and highways arelocated on valley floors, river channels, estuaries, and low-lying coastal areas.

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These are areas that have been flooded historically or within the recent geologic

past. The most recent flooding may have deposited very young, loosely-packed

granular sediments. Generally, the continuous ground water table is shallow in

these areas though it may fluctuate seasonally or over a period of time. Salt

water (intrusion) is reported to underlie the Morro Bay and other coastal sections

south'f Pismo Beach (DWR, l97 I and I 972).

The degree of damage to a road or highway caused. by liquefaction is difficulttoassess. Liquefaction may cause surface cracking, settlement, or lateral spread-

ing. During the process of high pore pressure generation, water is caused to flow

upward to the ground surface where it emerges in the form of sand boils.

Formation of cracks is associated with the initial emergence of water from the

ground. Such effects probably will not cause impairments to roads or highways.

With regard to roads and highways, liquefaction induced settlement and slope

failure of artificial fills may be the most common and most damaging effects.The increase in pore water pressure in the fill or the underlying materials can

reduce the shear strength of the materials, causing failure by differential,laterial flow, settlement'and/or slope failure. This may occur especially in the

case 'of high narrow fill slopes where there is a lack of lateral confinement.

Laterial spreads are defined as large masses of material that move laterally on

liquefied sand or silt. This can cause sections of road to rotate or subside. This

type of failure usually occurs along high steep bluffs, though it has been known

to occur in low relief areas such as along flood plains and deltas (Youd, l98 I).

Damage from liquefaction to roads and highways may be minor to severe.

Flexible pavement, such as asphalt, may be able to withstand minor differentialsettlement, cracking, and lateral spreads without disruption of traffic flow.

Concrete roadways may crack, causing portions of the surface to heave or

separate several inches to several feet and rendering the road impassable. Road

embankment materials may slump or settle, partially removing one or more

lanes, or the total fillmay fail.

Remedial repairs may require only filling in cracked pavement or constructing

earthen ramps over areas that have been vertically displaced. Major lateral

B-8 I-269 3-I9

TERA CORPORATION

displacements can probably be easily and quickly repaired by importing fillmaterials and regrading the displaced portion of the road. It is doubtful, though

possible, that a major settlement could cause flooding by surface or groundwater. Depending on the severity of the damage, it could be temporarilyrepaired by importing fill and placing it in the flooded area,to reestablish

continuity of the roadway.

Li uefaction Potential Assessment

Criteria developed by the U.S. Geological Survey were used to assess potentialliquefaction areas in the San Fernando Valley, California (Youd et al., l978). In

l979 the U.S. Geological Survey (Helley et al., l979) used techniques similar to,but more refined than, those used by Youd for the San Francisco Bay area. The

Seismic Safety Element for San Luis Obispo County (Envicom, l 974) has

delineated areas which have a potential to liquefy; however, their techniques forclassifying liquefied areas did not include the more recent techniques developed

by the U.S. Geological Survey. When boring logs and standard penetration testsare available, more refined methods may be used to determine the liquefactionpotential, the most common one being the technique developed by Seed and Idriss

(I 97 I) and Seed (I 979) which is presented in the Appendix.

For this study topographic soil and geologic maps, aerial photographs, and ground

water studies were used to delineate low-lying areas where younger sedimentshave been deposited and where ground water may be shallow (i.e., less than

I5 meters below the ground surface). A field reconnaissance was made to verifyor characterize the relief, types of surficial sediments, and their consistency.No subsurface exploration was performed to determine the types and consisten-cies of subsurface soils below a particular site. The subsurface conditions wereestimated using mapped and reported data and geologic projection techniques.The criteria used in the study are similar to those used by the U.S. GeologicalSurvey (Youd et al., I 979, and Helley et al., l 979).

In addition, boring logs at bridge locations were obtained from state and countytransportation departments to determine the local subsurface conditions and

B-8I-269 3-20

TERA CORPORATION

apply the procedure developed by Seed and Idriss (l97I) and Seed (l979). This

was possible for about 50 percent of the zones for which a'potential forliquefaction exists.

Using the ground data provided by topographic and geologic maps and the point

data at the bridges, the zones of potential liquefaction along the highways and

roads were localized and classified in terms of low or high susceptibility

(Figure 3-3). The low susceptibility areas include those underlain by young age

(Holocene) alluvial materials that are estimated to contain appreciable amounts

of sand and silt layers or lenses and where ground water is within 50 feet of the

ground surface. The high liquefaction susceptibility areas have the same

characteristics as the low susceptibility areas, except that these zones eitherlack lateral confinement, have gentle slopes, or are differentially loaded

(artificial fills). In each case, accelerations are in excess of 0.2 g. Maps and

tables describing these zones in greater detail are presented in the Appendix.

Based on the assessment criteria, many areas along the evacuation routes have

been categorized as potential liquefaction zones, capable of failing under

excessive seismic shaking. Since there is a reasonable amount of conservatism

built into the assessment criteria, not all areas considered are expected to

liquefy. The number of liquefaction zones will decrease rapidly with distance

from the rupture, based principally on the attenuation of acceleration. More-

over, as explained in the previous section, there is a difference between

liquefaction, per se, and damage. In order to estimate the expected number ofliquefaction zones and the corresponding clearing times, the criteria presented in

Table 3-3 were developed for three damage levels. These criteria are based on

considerations such as topographic and geologic conditions, soil profile charac-

teristics (sand and silt layers, presence of clay or gravel layers, depth to waterlevel), level of earthquake shaking (PGA), and liquefaction potential assessment

using Seeds (l979) criterion. Engineering judgment played an important role in

this evaluation, especially in the areas where subsurface conditions were not

known. Each high liquefaction potential area was assigned a susceptibility level

ranging from I to IV. Level I corresponds to a low potential for damage to roads

and highways (i.e., very small deformation with little or no impairment to the

B-8 I-269 3-2I

TERA CORPORATION

road). Level IV would correspond to large deformation, settlement, slope failure

and/or lateral spreading. In this case the road would be impassable in some

sections and significant repair would be necessary. Levels II and III are interme-

diate between these two. The susceptibility level was decreased by one unit forthe adjacent low potential zone. For a potential liquefaction area located in a

given acceleration zone, the expected footage of failure was obtained by

multiplying the total potential footage by the reduction factor for the selected

damage level. To estimate the repair time, it was assumed that each major

deformation would require a fixed amount of time depending upon the damage

level assumed plus an additional amount of time depending upon the degree ofliquefaction. Both of these time estimates are functions of the liquefaction

susceptibility and damage levels. They are presented for two lanes of repair in

Table 3-4.

A summary of expected footage failure and clearing time is presented for each

road surveyed in Table 3-5. This represents clearing time for two lanes for themajor evacuation routes and for one lane for the secondary roads.

B-SI-269 3-22

TERA CORPORATION

SAN LUIS OBISPO AREA - Northern Section

Figure 3-2a

AREAS OF POTENTIAL LANDSLIDE

ATASCADERO

EES

CAYUCOS 4IQse

Io

Ester o

Bay

'L

A

, ~ E

'r".EE

''Ei

~ A

SANTAMARGARITA

MORRP

INero „.,:8

SAN SASEL

s:R" ROAD

ioi

A C

SantaNorgarita

Lake

I 0 I 2

SCALE IN MILKS

PointBaohon

LOS OSOSOSOS

~ "0nocto6IIII ~S

A <os

Sos

S~

OAD WJR

K'OID

SANTAaopa

go+ g+

III "$ O~

LEGEND

DREARY EVACIHTIOII RDAD

EECOHDARY EVIICDATICH ROAD

OTHER RECCE

$$ POTENTIAL LANDSLIDE AREA

Po'ntBudian

~ LOS OSOS

r

~ ~O

Lososos

0<a(os

~os

+(~ROAO

RO.

I-IIIla>

I(lI

@@~~ ~) 00

SAN LUIS OBIS

SAN LUIS OBISPO AREASouthern Section

Figure 5-2bAREAS OF POTENTIAL LANDSLIDE

ANN FARIA

Diablo Canyon'.+POSER PLANT

::.VILABEAC

Son Luis Obispo Boy '- '.SHELLBEACH

Opco,p

.::" C~+p.

OO

~o

z: o+

Cy4v

O

Loper;Ciwyon

'ibscrvoir:.

I 0 I 2 3

SCALE IH IllLES

LEGEND

l%llQRY EVACUATION ROAD

SECONDARY EVACUATION ROAD

OTHER ROADS

QR POTENTIAL LANDSLIDE AREA

PISMOBEACH

GROVERCITY cr''~

e

GRANO

EANO

GRA

CS

II/

ROYONDE

Qoi+o

OI

SAN LUIS OBISPO AREA -Northern Section

Figure 3-3aAREAS OF POTENTIAL LIQUEFACTION

ATASCADERO

CAYUCOS4I

058

LEI+L

r,

A

EVEv

Esfero

Boy

SANTAMARGARITA

MORRP

'AA,A

INorroBoy .„H.p.:

SAN SABEL

ROAD

". Err

Ioi

SonfoNorgorifo

Luke

I 2 3

FbinfBucfIOFI

~ . ~ r

LOS OSOS gps 0 P ~~A:.:"0JAM.

e@au

(Pe0

-!I "Y4~

C@ROAD

IY

RO lD:, SANTA

pe+ q+

'40 'gSCALE IN MILKS

LEGEND

ARNNIY EVACUATION ROAD

EECOHDAIIY 'VACUIITIDN ROA.D

DTHER ROADS

5% HIGH POTENTIAL LIOUEFACTION

mama Low PoTENTIAL LIGUEFAOTIoN

<. LOS OSOS

i

'-E:UW,.CRACE.EOG "os '""". '""""

D"'>o~'..O~„. ~'„OIO

?" 4Cog .

'':: ~+SAN LUIS OBIS

SAN LUIS OBISPO AREASouthern Section

Figure 5-3bAREAS OF POTENTIAL LIQUEFACTION

Prin8uchon e

EeQgo

ALLEY ROADV

pOW

I

A SAVUCR UUw

0+c~

Pp,

Diablo Canyon+POSER PLANT

AVILABEAC

~gO S5

..'O~qI A„U <0

/E

OgCg

+o~o~.'p

Lope;Canyon

"

Rwarvofr:,

San Luis C8ispo Bay .. SHELLBEACH

O

Q 5Cy

O'AU

I 0 I 2

SCALE N MILES

LEGEND

ARUARY EVACUATIOII ROAR

RRXVIOARI EVACUATICR ROIUI

OTHER ROADS

PISMOBEACH

Ut

GROVERCITY

ao>e~ A ROYO

GRANDE .

(, GRANDUS UU'IA d

W,.A

EANO

GOI

Qg HIGH POTENTIAL LIOUEFACTIOM

LOW POTENTIAL LIOUEFACTIOM

TABLE 3-I

EXPECTED LANDSLIDEASSESSMENT CRITERIA

PGA (g)

Percentage'f

Failures

Damage Level

I 2 3

Suscep-tibility

O.IO — 0.200.20 - 0.300.30 - 0.400.40 - 0.50

.50

0 5 10IO I5 2020 25 3030 40 5050 65 85

Very LowLowModerateHighVery High

3-25

TERA CORPORATION

TABLE 3-2

LANDSLIDES POTENTIAL SUMMARYBY ROADS

RoadNo. Rood Name

TotalNo. of Length ofLanes Potential

Blocked Failure(ft)

Expected TotalAffected Length (ft)

Damage Level

Expected RepairTime (hours)

Damage Level

I 2 3 I 2 3

Route IOI North(Northbound)

Route 101 North(Southbound)

Route IOI Central(Northbound)

Route 101 Central(Southbound)

Route 101 South(Northbound)

Route IOI South.(Southbound)

4 Route I North

5 Route I South

6 Route 41

7, 8 Orcutt Rd. 8 Lopez Dr.

Route 227(Marsh St. (SLO) to Edna)

10 Price Canyon Road

I I Son Luis Bay Road

12 Avi la Road

13 South Plant Road

14 North Plant Road

I 1,350 0 68 135 0 .3 .72 4,150 20 228 435 .2 2.3 4.4

I 3,000 20 170 320 .I .9 1.62 1,900 0 95 190 0 1.0 1.9

NoneI

I I,IOO IIO 165 220 0.6 0.8 I.I2 0 0 0 0 0 0 0

I 0 0 0 0 0 0 02 1,300 130 195 260 1.3 2 2.6

I 0 0 0 0 0 0 02 70 40 60 80 0.2 0.3 0.4

I 800 80 120 160 '.4 0.6 0.82 2,000 200 300 400 2 3 4

I 1,300 30 95 160 .2 .5 .82 0 0 0 0, 0 0 0

I 2,400 240 360 480 1.2 1.8 2.42 600 60 90 120 0.6 0.9 1.2

I

2None

I 800 80 120 160 0.4 0.6 0.82 1,500 150 225 300 1.5 2.3 3.0

I 200 40 50 60 0.2 0.3 0.32 0 0 0 0 0' 0

I 0 0 0 0 0 0 02 6~700 I ~340 I ~ 675 2~010 6 8 8 4 10

I 0 0 0 0 0 0 02 9,600 2,655 3,520 4,380 13.3 17.9 22.4

I 70 2! 28 35 .I .I .22 5~800 1~740 2~320 2f900 8 7 II 6 15

B-81-269

3-26

TABLE 3-2

(CONT.)

RoadNo.

ISl617I8l9

Road Name

Higuero StreetMadonna RoadFoothill Blvd.Crand AvenueTonk Farm Road

Expected TotalAffected Length (ft)No. of Length of

Lanes Potential D ma eLeveBlocked Failure

2

None

Expected RepairTime (hours)

Damage Level

I 2 3

20 South Bay Boulevard

2I Main St. 8 Country Club Dr.22 Halcyon Rood23 Valley Road

I 3002 300

None

30 45 60 0.2 0.2 0.330 45 60 0.2 0.2 0.3

24 Los Berros Road

Avila Road (Port San Luisto Plant Entrance)

I 900 90 l35 I80 0.5 0. 7 0.92 I,500 ISO 225 300 .8 I.I I.S

I 2,500 500 625 750 2.5 3.2 3.82 2,500 500 625 750 2.5 3,2 3.8

See Canyon and PrefumoValley Roads

I 0 0 0 02 27~ I IS 'i 7I0 4i070 5 420

0 0 0I3.6 20.3 27. I

27 Los Osos Valley Road

28 Corbit Canyon Road

None

I 0 0 0 0 0 0 02 400 40 60 80 .2 .3 .4

29 Route 227(Edna to Lopez Drive)2 O O O O O O O

30 Oak Park 8 Noyes Roads3 I 'rintz Road None

B-8I-2693-27

TERA CORPORATION

TABLE 3-3

EXPECTED LIQUEFACTIONASSESSMENT CRITERIA

PercentageDeformation

Percentage ofLiquefaction

Damage Level

I 2 3

Suscep-tibility

0- 5

5- I 5

I 5-.30

30

0 5 IO

10 20 30

30 40 50

50 75 IOO

I Low

II Moderate

III High

IV Very High

3-28

TERA CORPORATION

TABLE 3-4

REPAIR TIME ESTIMATESFOR LIQUEFACTION

(TWO LANES)

LiquefactionSusceptibility""

Damage Level Percentage ofFootage RequiringAdditional Repair+

0 hr

0.25 hr

0.5 hr

0.5 hr

I hr

2 hr

I.O hr

2 hr

4 hr IO

. Repair rate assumed at 200 ft/hour/lane."" No areas of Category IV liquefaction potential were found in the study area.

B-SI-269 3-29

TERA CORPORATlON

TABLE 3-5

LIQUEFACTIONPOTENTIALSUMMARYBy Roads

RoadNumber Road Name

Total AffectedLength (ft.)

Dama e Level

Total RepairTime (hours) '-

Dama e Level

Route 101 - NorthRoute 101 —CentralRoute 101 - South

Route I - North(SLO to Main St. & Morro Bay)

Route I - North(Main St. to Route 41)

Route I —South

023101900

10049202600 .

200 0 1.27520 4 3.1/1.9 +10.5/6.53290 3.2 6.6

350 '860 3300 1.6 13.8

1670 3000 4330 I.l 3.4

1850 4335 6810 2.8 11.6

3.2+20.1/13.7

11.4

36

26,

678 8

9

10II12

Route 41 350Orcutt and Lopez Roads 0Route 227 (Edna to SLO) 140

Price Canyon Road 0San Luis Bay Road 270Avila Road (IOI to Avila Beach) 1620

1110380

1155

280440

2240

1810 2.9 13.8750 0 3

2170 .3 4.1

520 0 2.5610 .5 1.7

2890 . 2.4 6.5

31.99Il.l7.53.2

12.2

Left column = NorthboundRight column = Southbound

B-81-269

TABLE 3-5 (CONT'D)

LIQUEFACTIONPOTENTIALSUMMARYBy Roads

RoadNumber Road Name

Total AffectedLength (ft.)

Dama e Level

Total RepairTime (hours)

Dama e Level

ISl6l7

l9202I

222324

252627

282930

Higuera StreetMadonna RoadFoothill Boulevard

Tank Farm RoadSouth Bay BoulevardMain St. and Country Club Drive

Halcyon RoadValley RoadLos Berros Road

Avila Road (W of Avila Beach)See Canyon and Prefumo RoadsLos Osos Valley Road

Corbit Canyon RoadRoute 227 (Edna to Lopez Drive)Oak Park and Noyes Roads

370 I 445 24800 2IO 4200 290 560

470 II60 I850900 I340 I780

2'400 3200 4000

30 95 I6030 230 430

l20 240 360

. 600 800 IOOO

20 60 90IIO I580 3IOO

0 I70 3200

,I80 370

0 20 40

.300

.3I

l.5

0.I.I

I.3.I.6

2.4.5

I

l.33.42.6

.3

.8

.6

. 2.4.8

4.6

I

l.3.3

B-8I-269

3.2. I.3 BRIDGES

A standard method for evaluating the seismic vulnerability of bridges is not

presently available. The problem can be addressed using one of several

approaches.

The first approach involves performing a dynamic analysis in order to predict the

forces and displacements generated in the bridge as a result of an earthquake.

These forces and displacements are then compared with allowable forces and

displacements and a judgment is made as to the likelihood and extent of damage.

There are some uncertainties with respect to the accuracy of the predicted

forces and displacements and the corresponding allowable values. Even though-

quantitative results are obtained from this approach, prediction of earthquake

damage is still very much an art and must rely heavily on engineering judgment

if reasonable answers are to be obtained.

The second and more subjective approach to bridge seismic evaluation consists of

classifying different types of bridges and bridge components based on their

performance in past earthquakes. From this classification, a judgment can be

made regarding the probable performance of similar bridges and bridge compon-

ents in future earthquakes. This approach is far less expensive and time

consuming than the first approach and in general will yield reliable results. This

type of approach has been used by the California Department of Transportation

in deciding which bridges should be strengthened to resist earthquake loads.

The second approach was selected for this study. Guidelines for evaluating

bridges were specifically developed for this study based on experience with

bridge failures in past earthquakes. These guidelines are included in the

Appendix of this report. Each bridge was field inspected and photographed.

Drawings were obtained from the state and county departments of transporta-

tion, and a study of each bridge was performed following the guidelines. The few

secondary bridges for which drawings were unavailable were assessed from field

inspections. The following paragraphs discuss in general the basis for the

development of certain provisions in these guidelines.

B-8I-269 3-32

ERA CORPORATION

The primary concern of this part of the study is to assess the ability of bridges to

serve as effective components on the evacuation routes. As such, the predicted

structural damage was classified into one of three categories. The first category

involves little or no damage and results in little delay to traffic using an

evacuation route. Minor settlements in the abutment fills of approximately 4 to

5 inches are not considered obstacles to traffic since fillcan be added to smooth

the roadway. Likewise, minor structural damage to bridge bearings, columns,

and abutments are not considered an obstruction. For evacuation routes which

pass under a structure, only total collapse will result in traffic delays.

A second category of damage involves a delay to traffic of less than four hours.

In this case damage will occur that renders the bridge unusable by traffic, and

repair is necessary to make it usable for evacuation. The repair time should be

less than four hours. In assigning bridges to this category, no attempt was made

to anticipate the demand on personnel and materials for other purposes. Only

the physical time restraints for repairing the individual bridge were considered.

The third and final category of damage involves the total loss of the bridge as a

component of the proposed evacuation route. Repair is considered physically

impossible within a period of four hours regardless of the commitment of men

and material to the task.

Although the performance of a bridge is based on the interaction of all of its

components, it has been noticed in past earthquakes that four bridge components

are most vulnerable to damage. These are the bearings, columns or piers,

abutments, and foundations. Therefore the following guidelines were developed

around the evaluation of each of these components.

~Bearin s

Bearings are used at superstructure/substructure interfaces as well as at in-span

joints. For the purpose of evaluation, bearings are considered to include

restraints provided at these locations, including shear keys, restrainer bars, etc.

Bearings may be "fixed" bearings which do not provide for translational move-

B-81-269 3-33

TERA CORPORATION

ment, or expansion bearings which do. A bearing may provide for translation in

one orthogonal direction but not in the other.

There are basically four types of bearings used in bridge construction. First is

the rocker bearing, which is constructed of steel and which rocks to provide for

translational and/or rotational movement. It is the most vulnerable of bridge

bearings because it becomes unstable after a limited movement. The second

type is the roller bearing, which is also constructed of steel. It is. usually a fairlystable bearing during an earthquake except that it can become misaligned and

eventually displaced. Third is the elastomeric bearing pad, which has become

very popular in California. It is constructed of an elastomer and relies on the

distortion of this material to provide for movement. It is very stable during an

earthquake, although it has been known to "walk-out" under severe shaking. The

final bearing type is the sliding bearing, which may consist of anything from

asbestos sheet packing between two concrete surfaces to sophisticated teflon

and stainless steel bearings. I

Transverse restraint of some type is almost always provided at the bearings,

which usually consists of concrete shear keys, keeper plates, or anchor bolts. It

has been noticed that certain bearing applications have always performed well in.past earthquakes. Therefore, some structures may be considered nonvulnerable.

In vulnerable structures, failure is usually related to the relative transverse or

longitudinal movement at the bearings. The expected movement at a bearing is

dependent on many factors and is not easily analyzed. In the development of

Seismic Design Guidelines for Highway Bridges, the Applied Technology Council

(ATC) developed ari empirical formula for required support length at a bearing.

Since it is very difficult to predict relative movement, evaluation of bearing

vulnerability for the purpose of this study uses the ATC formula as the basis for

checking the adequacy of longitudinal and transverse support lengths. The ATC

formula is assumed to represent an upper bound for movement at the bearing.

Transverse restraining devices are assumed to fail at various peak ground

accelerations depending on the type of restraint provided. These assumptions

are based on past performance of these devices plus engineering judgment.

B-8I-269 3-34

TERA CORPORATION

Rocker bearings have proved to be the most vulnerable in past earthquakes and

are assumed to topple at various combinations of skew and peak ground

acceleration. If bearings topple, the guidelines require that some basic minimum

seat dimensions exist to prevent collapse. These are based on geometric

considerations and are considered necessary to keep the bearing from falling offthe seat.

A limitation is also placed on the amount of longitudinal movement that could

occur in a non-skewed bridge. Movement is limited to the maximum expected

opening at the expansion joints (twice the nominal opening) plus a factor to

account for loss of support effectiveness resulting from impacting at the joints.

The settlement of a span due to a bearing toppling is assumed to be a minor

problem easily solved by ramping with asphalt fill, etc. Only total loss ofsupport will result in Category 3 damage.

Columns and Piers

Columns have failed in past earthquakes due to lack of proper transverse

reinforcement and poor structural details. Excessive ductility demands have

resulted in a degradation of column strength in shear and flexure. In the most

serious failures in past earthquakes, the column eventually failed in shear

resulting in severe vertical settlements or its total disintegration. Another typeof column failure observed in the San Fernando earthquake was the pull-out oflongitudinal reinforcing at the footing. Fortunately, serious bridge column

failures usually do not occur except at fairly high ground accelerations.

During the San Fernando earthquake, all the damaged columns had insufficienttransverse reinforcement. There appeared to be a correlation between column

damage and the ratio of shear capacity to maximum shear force. The maximum

shear force is related to the flexural capacity of the bridge column. Therefore itis possible to calculate the shear capacity to maximum shear force ratio fromthe dimensions and reinforcement in the column. By making some simplifyingassumptions, a parameter was developed which reflects the vulnerability of the

B-8I-269 3-35

TERA CORPORATION

column to damage. This parameter was tested on bridges which failed in the San

Fernando earthquake. Critical values for the column vulnerability parameter.

were identified by observing the extent of damage that occurred. These values

were then adjusted using judgment to reflect'damage at different force levels.

More information about the development of this parameter is included in the

Appendix.

The guidelines also require that high single column bents be checked for possible

pull-out of the longitudinal reinforcement. None of the bridges within the study

area appear to be vulnerable to this type of damage.

Abutments

Abutment failures during earthquakes do not usually result in total loss of the

bridge. This is especially true for earthquakes of the intensity expected within

the study area. Therefore, the abutment guidelines were developed with the goal

of predicting damage that would temporarily prevent access to the bridge.

One of the major types of problems observed in past earthquakes has been the

settlement of fillat the abutment. Elms (l979) reports that in past earthquakes

of this magnitude th'ese settlements have been on the order of IO-l5 percent of

the fill height. However, observations of damage during the San Fernando and

other California earthquakes suggest far less settlement. Bridges within the

damage area of the San Fernando earthquake experienced average fill settle-

ments on the order of 3-5 percent. This was assumed to be due to superior

construction of fills, the absence of water, and the generally wider and better

retained bridge approaches. Based on judgment, an upper limit of l0 percent fillsettlement was considered possible in the study area. This value was then scaled

down for cases with lower ground accelerations, absence of water, and wide or

well-retained fills. The resulting predicted fill settlements are approximate but

give a good indication of the type of damage that can be expected.

Additional abutment fill settlements are considered likely in the event of

abutment failures due to excessive seismic earth pressures or seismic forces

B-8 l-269 3-36

TERA CORPORATION

transferred from the superstructure. Some simple rules were developed to

identify abutment types that could be vulnerable to this type of damage. These

rules were based on engineering judgment and the performance of abutments in

past earthquakes.

Foundations

For the purpose of this study, only foundation failures due to liquefaction were

considered. Because of the many water crossings within the study area, the

potential for this type of failure is considered high. A special study was

conducted to determine the potential for liquefaction at each of the bridge sites

on the major evacuation routes using boring logs and the procedure of Seed and

Idriss (l97I) and Seed (l979). Four different levels of liquefaction were

predicted.

The classification of bridge damage is based on the liquefaction potential and the

susceptibility of different types of bridges to liquefaction-induced ground move-

ment. The vulnerability of different bridge types was determined by studying

bridge liquefaction failures during the l964 Alaskan earthquake as reported byRose et al. (I 973), and various Japanese earthquakes as reported by Iwasaki et al.

It was observed in these earthquakes that bridges with continuous super-

structures and supports that were capable of large translational deformations

usually remained serviceable with minor repairs in the case of large liquefactionmovement. However, bridges with discontinuous superstructures and/or brittlesupporting members usually were rendered useless. Therefore, this observation

was taken into account in determining the damage category for the various

bridges in the study area.

The guidelines are generally written to consider the effect of the failure of one

component on the failure of the entire structure. Therefore, the final damage

category is usually the maximum category chosen for any one of the fourcomponents. It is still necessary to look at the total damage and use engineering

judgment to determine ifbridges should be classified in a higher or lower damage

B-8 I-269 3-37

TERACORPORATION

category. Often a bridge will be such that its exact damage category is

questionable. 'This is taken into account by using engineering judgment to

establish the best estimate of total bridge damage due to the anticipated

earthquake. Figures 3-4 and 3-5 present the locations of the state and county

bridges considered in the analysis. Table 3-6 presents a summary of the bridge

damage by roads. Detailed bridge review is presented in the Appendix.

B-8I-269 3-38

TERA CORPORATION

SAN LUIS OBISPO AREA -Northern Section

Figure 3-4aSTATE BRIDGES

ATASCADERO

CAYUCOS

I$ NcL

TORO CREEK49»05

RTE I 4 I SEP

41 ATASCADERO49-51

ATASCADERO4~

058

MORRO CREEK49-ISI

ATASCADEROCRKI4M9

Eslero

Boy

M

'I

. ~ 'IO'S I

NMORROBAYVC2l9-109

5 MORRO BAY49-l08

BAYWOODPK49-I 77

BUENA VIS49-94

CRAM)AVEVC 2i3SANTA

M

RTESB IOI SEP49-I 58

ST MARGARITA49%7

MORRP

".:.„:., R

Mero;:. Boy

SAN

,-.s 'OAD

CHORRO CR OH 2i3

5N BRpsu7o Eo v49-ISS

SAN BERNARDO C4~RTE I IOI SEP I49 l4l

CALIFBLVDUP49-l47

CALIFBLVDOC49-79

STEPS'REEK49-I 23

CUESTA OVERH2(3

Qoi

ACACIACREEK49-I 17

SAN L CBISPO C49-52

SAN L OBISPO C49-57

SantaNargorila

Lake

I 0 I 2 3

SCALE MI ISLES

FaintBrjahcs7

6NM. ~S~I

'S

A

LOS OSOS

SLOBI4ILSS

MARSH ST SEP.4948

MADOISIARD OC49 l90 I,

I.OsOSOs

ROAD

CHORRO ST UC

4~'os

OS

DAD

<c

EI+

''GCL'j

CG

X

Is A

gong+

+o

LEGEND

RRRAIIT SVACQITIOR ROaD

STOORDARV RVaOOaaloll ROAD

OTRRR ROADS

0 STATE BRIDGE

SROGE NAME

avaa~»s ~EXPECTED CAMAGE

SRDGE NMMSER

TERACORPORATION

0

A3. LOS OSOS

STEI883449-123

RTE I IOLSEP49-144

I.DSOSDS

leap~

0 gg;»ih

SAN LUIS OBISPO AREASouthern Section

Figure 5-4bSTATE BRIDGES

SAN L 0815PO49«52

Paint8ua/Ian

CHORR0 ST UC4IL39

MARSH ST SEP4948

p LLEar ROAD

eceoT,O

MADOMAARD OC49 190 Sp~

a~4

IMlMIIL'

MI 0

ANILFARIA

RD.

0~o

CALIFBLVDOC49-79

5 L OBISPO CRKl9-58

ACACIACREEK49-117

E FK SLO CREEK49-116

SAN L OBISPO4947

'BUENA VISTA49-94

GRAM)AVEUC 2/349M

CALIFBLVDUP49-147

5 L 085PO CRK2/3

AVILAROAD49 191'/3

Diablo Conyon+POWER PLANT

LOS 0505 RD OC49-185

SANTA FE UC49-115

N AVILAROAD OCl9-192

AYILABEAC

~peG

W COR D PDR CR49-204

E CORRI. PIEDR49-103

E FK P5MO CRKI49-112

N EDNA OH49-220

Og

+e~

~o

Lopar'anyon

Absmefr "..

0 I 2 3

SCALE iN MILES

LEGEND

VRIIIRT EVEDDETER RaaD

EEDOROIJIV EVIOOITIOR ROaD

OTHER ROADS

O STATE BRIDGE

BROGE NAME

'«'~» I «EXPECTED CAMAGE

SROGE NUMBER

QKLLBEACH UC49 189 I 2

NORTH PISMO'9

184

WADSWORTH AV,49-183

PISMO ST PUC,49-139

VtLLACREEK

HIM35 AVE OC49-130

PIQAO CREEK49-15

PIQAO OVERIKAD49 16

PIQAO OAKSOC'9-156

AKPARKRDOCIl9 155

BR5CO RD UC49-154

on rs isloo oy

E3

SHELLMA'EACH

GROVEC

OCEANO OH49-12

AROYO CRAM3E'49-19

eo+R~ A ROYO

GRANDEND /

O

MI

OS

oe

LOS BERROS CRK

4vCT

Rp.

CORBIT CAN CR49 I IO

CROWN HLLPOC49-201

CORBETT CAN CR49-77

VALLEYROAD OC I49-174

BRIDGE ST UC49 173R

ARRYO CRAM7E49-175

CRAM3 AVE SEP49-176

!

SAN LUIS OBISPO AREA-Northern Section

Figure 5-5aCOUNTY AND CITY BRIDGES

ATASCADERO

QI

CAYUCOS 4IQss

'\ ~

Es/ero

8oy.. ~ E

'>TEE ~

ITIORRP

SOUTH BAYBLVDATCHORRO CR49C-242

SOUTH BAYBLVDATCHORROCR I/249C-2 4 I

LOS OSOS - MORRO BAYRBRIDGE AT LOS OSOS CRK /3I3027< I

PEDESTRIAN U C ONSOUTH BAYBLVD

MO CANYONVERT BR2

49C-

PREFUM0 ONRD CULVER49C-227

PREFUMO CANYONRD CIA.VERT BR449C-226

SANTAMARGARITA MILLST BR ovER

S P RAILROAD

S P BR AT MONTEREY ST49C 299

Point8oo/7orr

Norro.. 8oy '.:

SAN ABEL

.T" ROAD

QI

LOS OSOS VALLEYRDLOS OSOS CREEK 249C-233

ososos

ROAD

'

PECHO VALLEYRD ATISLAYCR

eEqu

LOS OSOS

~ "AO

BIIN e%

os

PREFUMO CANYONRD COVERT BRS49C-223

VALLEYRDAT PERFUMO CANCR496%9

R( AD SANT'v ROP'IA

OSps

l~ROA p.

IOI

O~

+o

STEPPER CR BR490466

Son/oNorgori/o

Loke

S P BR AT 3O494MN AVE4~7

I 0 I 2

SCALE DI MILES

LEGEND

TRIIARY EVACOATHH ROAD

EECCHDAAY EVACOATIOH ROAD

OTHER ROACH

O COUNTY OR CITY BRIDGE

BRIDGE NALIE

EXPECTED CAMAGE

BRXXIE NUMSER

o LOS OSOS

~ . ~+ LOS OSOS VALLEYRD~ o LOS OSOS CREEK

o+ 49C-238

PECHO VALLEYRD ATISLAYCR I/2

MILLST BR OVERSPRALROAD-<Os

OSno40

<OS

+oI

V LEY RDAT MO CANCR4

'R% UT. QNO

I

UIS

SAN LUIS OBISPO AREASouthern Section

Figure 3«5bCOUNTY AND CITY BRIDGES

Point8ud/on

PREFUMO CANYON IRD CULVERT BR249C-229

PREFUMO CANYONRD CLLVERTBR349C-227

PREFUMO CANYONRD CULVERTBR449C«I26

VALLEY ROAD

L3

MIIEI

ILO

ANKFA IA

0

549C-

+o0

5 P BR AT MONTEREY STI 49C-299

ORCVTT ROADCVLERT BR$213008-52

ORCVTT ROADCLX.VERTBR B IA1300881

ORCVTT RD CIAVERT'RIDGE 549C-113

Diablo Canyon~POWER PLANT PREFVMO CANYON

RD CLX.VERTBRS49C-223

AVILACVTT~RDSEE CANYONCR BR49C-150

s>54

Agg.A nO

AVILABEAC

~:..'. r '"i... QIO

AT 3019eON AVE1 o ~

ORCVTT RD CLAVERTBRIDGE 449C-114

O gg+e,

+0~o

E«A

~ E

Lopez '.

CL2nyon.

/IIFSCFVNI'

I 0 I 2 3

SCALE W MILES

LEGEND

~UIIUIYEvaEUaTENI RoaD

EONNIDARY EhaOUATIUU ROAD

OThER RDAOE

0 COUNTY OR CITY BRIDGE

8140CE LIAME

~«*«hovET ~EXPECTE00AMACE

88OCE MCMSEIL

HARTFORD CR BRIDGEO AVILABEACH49C427

AVILACUT~ RDSLO CREEK BR49C-ISI

ONTARIO ROAD BRSAN LUIS 085PO CREEK49C-191

2/3

2/3

PRICE CANYONRDCORRAL DE PIEDRA CR49C-330

2/

CORBIT CANYONOVER CRI /249C 155

TRAFFIC WAY BRON ARROYO CRAM3E CR49C-318

VALLEYROAD ATLOS BERROS CR49C852

2/3

S n Luis Obispo Bay

L3

PRICE CANYONRDOVERtEAD49D829

SHEEAC

ISMOBE H

GROVERCITY

E

N

E

ROYONDE

Os

~o'~+

e~ AGRA

GRAND I

O5

o+

oe

«U'RCVTTRD CLLVERT

BRIDGE I I49C-117

ORCUIT RD COVERTBREXZ 2 I49C 115

ORCUTT RD CULVERTBRIDGE 3 I

IQ 49C I I 5

+O

RD.

e

TABLE 3-6

BEST ESTIMATE BRIDGE PERFORMANCE SUMMARY

BY ROADS

RoadNo.

US. IOI, NorthU5. IOI, CentralUS. IOI, SouthRoute I, NorthRoute I, South

TotalNumber

ofBridges

91014104

Number of Bridgesin Damage Category"

I 2 3

7 (7) 2 (0) 0 (2)7 (7) 3 (I) 0 (2)

10 (8) 4 (4) ~ 0 (2)5 (5) 5 (3) 0 (2)2 (2) 2 (I) 0 (I)

TotalRepairTime"

(hours)

12 (56)16 (120)2 (81)5 (85)2 (10)

. 6'789

10

Route 41Orcut t RoadLopez DriveRoute 227 (Marsh St. SLO to Edna)Price Canyon Road

4II

None42

3IO

30

I 0I 0

I 02 (I) 0 (I)

0 (2)I (4)

I

9 (74)

II121314!5

1617181920

San Luis Bay RoadAvila RoadSouth Plant RoadNorth Plant RoadHiguera Street

Madonna RoadFoothill Blvd.Grand AvenueTank Farm RoadSouth Bay Boulevard

2I

NoneI

None

0 2 00 I (0) 0 ( I )

I (0) 0 (I) 0

2 (I) 2 (I) 0 (2)

2 (5)4 (72)

0 (I)

4 (80)

2122232425

Main St. and Country Club DriveHalcyon RoadValley RoadLos Berros RoadAvila Road (West of Avilo Beoch)

0 0 I (2)

2627282930

31

See Canyon and Prefumo Valley RoadLos Osos Valley RoadCorbit Canyon RoadRoute 227Oak Park Road and Noyes Rood

Printz Road

42I6

None

4 0 0I I 0I (0) 0 (I) 0 (0)6 0 0

0I (4)0'I)0

" When the best estimate is expressed as a ronge, both bounds are given. fhe numbers in parentheses present theestimate of most damage.

B-81-2693-43

3.2. I.4 DAMAGEDUE TO FLOODING

Dam Failure

Three major dams are located in the vicinity of the study area. The Salinas dam

has its valley located totally outside the study area and is not considered herein.

The Lopez dam, built in l 968, is an earth-filled zoned dam owned by the SanLuis'bispo

County Flood Control Department. The Whale Rock dam, built in l96I, is

a rock-filled dam with a clay core and is under the jurisdiction of State Dams

Operation and Maintenance in Sacramento. Both dams have had a "National Dam

Inspection Report." They are considered safe for the storage of water; however,

both are underlain by alluvium, and a liquefaction potential exists. The owners

have been asked to study the problem. The Whale Rock dam is presently being

studied for its seismic safety by Converse, Ward, Davis, Dixon and Associates.

Their preliminary findings indicate that the foundation is not susceptible to

liquefaction (Babbit, I 98 I).

It is outside the scope of this study to assess the seismic safety of these dams.

However, their potential failures are a major threat to life and property as well

as to important evacuation routes. The Lopez Canyon Reservoir would flood the

Arroyo Grande Valley, damaging Arroyo Grande, Grover City, Pismo Beach, and

Oceano, thereby closing Routes IOI and I south. The failure of Whale Rock dam

would flood Cayucos and close Route I north of Route 4I.

Tsunami

Tsunamis are tidal waves generated by rapid vertical displacements of ocean

water either from tectonic movements of the ocean floor associated with

faulting or by major submarine landslides. Since the Hosgri fault is of the strike-

slip type, it is very improbable that it can generate a tsunami. There is a remote

possibility of a seismically-induced submarine landslide; however, its effects

would be expected to be localized with waves sufficiently small so as not to

interfere with the safe evacuation of the study area. Therefore, tsunamis were

not considered as a potential seismic hazard in this study.

B-81-269 3-44

TERA CORPORATION

3.2.2 ROAD NETWORK

The evacuation route network consists of the following three major radial

highways:

o Route I 0 I crossing the mountains north of San LuisObispo;

o Route IOI south of San Luis Obispo passing through theurbanized region along the south coast; and

o Route I from San Luis Obispo to Morro Bay and passingalong the coast to the north.

To supplement these interregional highways, four other routes have been

identified:

Route 4 I from the intersection with Route I in Morro Bayto Route IOI in Atascadero;

Orcutt Road from San Luis Obispo via Lopez Drive to theintersection with Route I 0 I in Arroyo Grande;

Route 227 to Price Canyon Road and then to the inter-section with Route IOI in Pismo Beach; and

Route I from the interchange with Route I 0 I on thenorthern outskirts of Pismo Beach south along the coastand out of the study area.

In addition, a number of city streets and secondary roads will be used to access

the major highways.

In the following sections, each major highway is reviewed in order to assess the

potential damage to the evacuation network that might result from the earth-quake under consideration. Detailed tables are presented in the Appendix.

B-SI-269 3-45

TERA CORPORATION

3.2.2. I ESTIMATED DAMAGE TO MAJOR EVACUATIONROUTES

Route IOI North (road length: 8.0 miles)

From the junction with Route I in San Luis Obispo, Route IOI follows the

general alignment of El Camino Real. Within the city, it is constructed to

freeway standards; however, some features, such as shoulder and median widths

and spacing and design of interchanges and ramps, do not conform to current

practice. On the outskirts of the city, the ascent to Cuesta Pass begins, and the

design standard is reduced to expressway, although there are few intersecting

roads and practically no tributary traffic. As the'grade steepens to 7'h percent,

the shoulders and median narrow, and a median barrier has been installed to

prevent cross-median accidents. A number of openings are provided in the

barrier which would allow median crossing if need be. In this section and

continuing on the descent to Santa Margarita, the overall roadway (pavement and

shoulders) is too narrow to accommodate disabled vehicles without impeding

traffic. At the bottom of the grade, the highway enters a rollirigvalley, and the

design changes to freeway standards, with full control of access and normal

shoulder widths.

Ground Failure

The California Department of Transportation reports continued fill settlement

and ground water problems in this area. Because natural slopes and cut-and-fill

slopes are over-steepened due to the existing settlement problems, some

blockage is anticipated even though the expected ground acceleration is low

(~0.20 g). Many rockfalls may occur, along with some rock slides and debris

slides, which could close the two northbound lanes in several areas. The higher

fills will probably settle down and out, severing the two southbound lanes locally

and possibly all lanes. Wet weather would certainly increase the damage.

Slumps and debris slides may occur on the westerly facing fill slopes. The total

road lengths where potential blockages of one and two lanes were identified are

5,500 feet for the northbound direction and 4,900 feet for the southbound

direction. Bounding expected blockages for damage levels I and 3 respectively

B-8I-269 3-46

TERA CORPORATION

vary between 0 and 920 feet (northbound) and 20 and 200 feet (southbound). No

significant liquefaction is expected on this road.

Bridge Failure

Several bridges present potential problems in this area leading to potential

closure of IOI North and requiring the use of alternate routes and bypasses.

o The Pacific Railroad California Boulevard Overcrossing(49-79) is expected to fall off its bearing, but not tocollapse on the road; this would not affect the roadtraffic.

o The Grand Avenue Undercrossing (49-84) might sustain aloss of „support at span 4 resulting in partial collapse andclosure to traffic. City streets would have to be used tobypass this bridge.

o The Pacific Railroad Cuesta Grade Overcrossing (49-60)might sustain a loss of support at the expansion joints. Ifno collapse occurs, the span might be shored, resulting ina traffic delay of one-half to one day. The collapse of thespan would effectively result in the closing of IOI North,since the bypass to this bridge is a one lane dirt road.

o The Route 58/IOI Separation Bridge (49-l58) might po-tentially collapse, although this is doubtful at the lowacceleration levels expected at its location. A directofframp bypass is available.

Route IOI Central between junction of Route I and Avila turnoff (road length:8.9 miles)

Running south from the intersection with Route I in San Luis Obispo, Route I 0 I

follows the gently rolling San Luis Obispo Creek Valley before it turns southeast

along the coast. The entire route to the study area boundary and beyond is offreeway design construction, although the portion within San Luis Obispo is

below today's standards.

B-8 I-269 3-47

TERA CORPORATION

Ground Failure

A 400-foot road cut section is susceptible to failure (onramp northbound IOI

from Avila); this could cause total closure of this onramp due to rock falls and

rock slides. Rock falls might close the southbound lane over an estimated

I,I00 foot section of cut slopes. Bounding lengths of expected blockages vary

between I IO and 220 feet.

Liquefaction is a major concern through the San Luis Obispo Creek area (l7,000

feet discontinuous). Lateral spreading and fill settlement may remove one or

more lanes where the highway either crosses the creek or parallels the creek.

Groundwater is very high, near the surface, with numerous fills along the

highway. Bounding estimates of the lengths of damaged roadways vary between

2,300 and 7,500 feet mainly'in the northbound direction.

Bridge Failure

Two bridges present potential problems to this section of the highway. The San

Luis Obispo Creek Bridge (49-I4) is in a highly liquefiable zone. While the

northbound lane has been retrofitted to improve its earthquake performance, the

southbound lane has not been upgraded, making it most vulnerable. However,

both lanes might undergo extensive damage forcing the closure of the bridge.

The bypass is involved since it requires the use of San Luis Bay Road and Avila

Road, because the truss bridge on the frontage road (49C-l97) is expected to

collapse. Both bridges on the bypass road (49C-IS I and 49C-l50) might undergo

some settlement resulting in minor to moderate traffic delay. The Avila Road

Undercrossing (49-l9l) might also undergo severe deformation due to liquefac-

tion, requiring shoring with a traffic delay of at least 8 hours.

Route IOI South from Avila turnoff to I.4 miles south of Los Berros turnoff4: 144

This stretch has 'intermittent frontage roads on both sides of the highway, and

access ramps are spaced from one-half to two miles apart. This route has

B-8I-269 3-48

TERA CORPORATION

moderate grades and curves, and ample space for disabled vehicles outside the

traffic lanes.

Ground Failure

A number of soil and rock falls, over l400 feet of the roadway, might be

anticipated l.2 miles north of Los Berros Road, north of Pismo Beach and near

Gragg Canyon. Bounding lengths of expected blockage vary between l30 and 260

feet in the northbound direction and are negligible in the southbound direction.

One main area of liquefaction is expected in the 5,000 lineal feet of fills across

the Price Canyon drainage area. This would result in lateral spreads and

settlement to fills, closing all four lanes in several locations. Liquefaction could

also take place at the Avila Beach - U.S. IOI interchange across Gragg Canyon

drainage, where fills might be susceptible to settlement. The estimate of the

length of damaged roadway varies between l,900 and 3,300 feet.

Bridge Failure

Structural damage is not expected to affect traffic on IOI South in this area,

although some overcrossings might be closed to traffic. The Bridge Street

Undercrossing (49-l73R) will probably topple off its bearings and possibly lose

spans I and 3, thereby closing IOI to northbound traffic.

Route I North (road length: I5.3 miles)

Route I, known as the "Coastal Highway," is a designated primary state route.

The segment of interest originates on Santa Rosa Street at the Route IOI

overpass structure and terminates l.9 miles north of the Route 4I intersection.

lt is developed as a four-lane urban arterial, changing to expressway standards

near Foothill Boulevard. Through the rural area between San Luis Obispo and

Morro Bay, the route is a four-lane, divided expressway with limited access and

at-grade intersections. Through the southern portion of Morro Bay, Route I is

constructed to freeway standards, with four full interchanges. North of the

B-SI-269 3-49

TERA CORPORATION

Route 4I interchange, the highway reverts to expressway standards. Outside the

study area, and beyond the town of Cayucos, Route I becomes a two-lane

highway. Both horizontal and vertical alignment of this highway are good and

there are no serious roadside restrictions. Full shoulders provide ample space for

disabled vehicles. The median is usually at grade without fences or barriers,

which would allow easy access between the south and northbound lanes.

Ground Failure

No landslides are anticipated along this portion of Route I, since both cut and

fillslopes are not expected to fail.

Fourteen zones of variable length along the road, for a total of l2,500 feet, have

been found susceptible to liquefaction, lateral spreading, and fill settlement.

Significant damage might be expected in fills constructed over stream channels

or where the road parallels stream channels. Due to the width of the highway

and relatively low slopes, it is unlikely that all four lanes would require repair in

more than a few areas, the most susceptible being those close to the sea coast

due to higher predicted accelerations. Bounding lengths of expected damage for

this road vary between 2,000 and 7,500 feet.

Bridge Failure

The Chorro Creek Overhead (49-63) is expected to undergo some settlement and

possibly complete closure in the event of liquefaction. The northern bypass

consists of a four-mile, one lane road. No other bridges are expected to sustain

structural damage, but all four bridges north of the south Morro Bay Undercross-

ing could potentially undergo 6- to I 2-inch fillsettlement.

B-8I-269 3-50

TERA CORPORATION

Route I South from Pismo Beach to Valley Road (road length: 4.4 miles)

Ground Failure

The road fills constructed over the railroad tracks (Oceano Overhead) are

susceptible to settlement and debris slides possibly closing the outside lanes.

Total closure is not anticipated by failure of the road fills. Bounding estimates

vary between 80 and l60 feet for damage to one lane and between 200 and

400 feet for damage to two lanes.

Moderate to major damage can be expected by liquefaction along an 8,000-foot

discontinuous section near Meadow Creek (Lagoon area) and over stream

crossings in Pismo Beach, Grover City, and Arroyo Grande Creek. Fill settle-

ments and lateral spreads are likely. The bounding estimates of the lengths of

damaged roadways vary between I,800 and 6,800 feet.

Bridge Failure

The Oceano Overhead (49-l2) might topple off its bearings and undergo some

settlement requiring minor ramping. Liquefaction might produce large deforma-

tions in the bridge across Villa Creek (49- I 0) and necessitate bent shoring.

Route 4I (road length: 5.0 miles)

This route provides a connection between the Morro Bay urbanized area and

Route IOI North at Atascadero. The route is two-lane, built to mountainous

terrain standards, with steep grades, sharp curves, and narrow shoulders. Traffic

capacity is correspondingly low and, therefore, Route 4I should be regarded as a

limited alternative for light damage scenarios, to be used primarily by vehicles

originating in the Morro Bay area, with the preferred evacuation route being the

Route IOI North corridor.

B-8I-269 3-5 I

TERA CORPORATION

Ground Failure

Debris and rock slides may be severe over the I.5 miles of roadway which passes

through the steep hilly area. Total closure might occur to both lanes but is notexpected due to the low peak ground accelerations. Bounding lengths ofexpected blockages vary between 60 and 200 feet for one lane.

Nine zones of potential liquefaction are found on this five-mile stretch. Lateral

spreads and minor fill settlements are anticipated over stream channels.

Bounding estimates of the lengths of damaged roadways vary between 350 and

I,800 feet.

Bridge Failure

The four bridges on the road to Atascadero are expected to sustain only minor

damage with no traffic delay.

3.2.2.2 ESTIMATED DAMAGE TO SECONDARY EVACUATIONROADS

Orcutt Road (road length: I5.4 miles)

The Orcutt Road route provides an alternative to Route IOI South that may be

used by vehicles originating in San Luis Obispo and preferring to evacuate to thesouth or by vehicles from the Arroyo Grande and Grover City regions heading

north. This route may become particularly important if prevailing winds should

cause early exposure of the south coastal area to a radiological release. OrcuttRoad originates in San Luis Obispo and is maintained by the county throughoutmost of its length. The road traverses rolling terrain and has fair alignmentwithout any long steep grades.'n the southern end, the route follows LopezDrive and State Route 227 into and through the city of Arroyo Grande.

B-8I-269 3-52

TERA CORPORATION

Ground Failure

Minor landsliding with one lane closure could be expected near the Southern

Pacific Railroad overpass at Johnson Avenue. On the Lopez Drive section, five

locations of potential rock fall and debris slides extend discontinuously over

2,200 feet. The bounding estimates of blockage vary between 240 and 480 feet

for one lane and 60 and l20 feet for both lanes.

Liquefaction may occur at the intersection of San Luis Obispo Creek and Johnson

Avenue and at the various Corral de Piedra Creek crossings, resulting in lateral

spread and minor filldisplacements. On the Lopez Drive section, three areas of

potential liquefaction extend discontinuously over l,200 feet. The bounding

estimates of the length of damaged roadway vary between zero and 750 feet.

The potential for liquefaction in the road fill, traversing the. reservoir near

Lopez Drive, is considered remote due to the low acceleration level.

Bridge Failure

The bridges on this road are of the small culvert type. Minor damage is expected

due to settlement, requiring no repair with the possible exception of Bridge

49C-I I3, which is located in a zone of high liquefaction potential. The bridges

on Johnson Street (49C-367 and 49C-366) are not expected to undergo traffic-delaying damage.

Route 227 and Price Can on Road (road length: I I.5 miles)

This route is generally parallel to Orcutt Road and would serve a similar

function. The evacuation route originates in San Luis Obispo and follows

Route 227 to its intersection with Price Canyon Road, continuing over the

county-maintained Price Canyon Road, terminating at Route IOI in Pismo

Beach. This route avoids not only a section of Route 227 with poor vertical and

horizontal alignment but also the congested urban business district of Arroyo

B-8 I-269 3-53

TERA CORPORATION

Grande. This route has a relatively wide pavement (including paved shoulders on

Price Canyon Road) that could permit two-lane traffic in the principal evacua-

tion direction in extreme circumstances.

Ground Failure

No landslides are anticipated on Route 227. On Price Canyon Road, one

discontinuous section (three cuts) approximately 800 feet long is susceptible torock falls. Another major l,500-foot section of potential rock falls and rock

slides is located l.3 miles north of Route lOI and may block both lanes. The

bounding estimates of the length of road blockage vary between 80 and l60 feetfor one lane and l50 and 300 feet for'both lanes.

Four zones of potential liquefaction are recognized for a total length of3,200 feet on Route 227. On Price Canyon Road, a major 2,000-foot section near

Edna and two small zones (200 feet each) at stream crossings have been

identified. Minor fill settlement and lateral spreads are anticipated. The

bounding estimates of the length of damaged roadway vary between l40 and

2,700 feet.

Bridge Failure

No damage is expected to bridges on this section of Route 227. The bridge over

San Luis Obispo Creek on Marsh Street (49-58) may undergo bearing failurerequiring minor ramping. On Price Canyon Road, the Price Canyon Road

Overhead (49C-329) is expected to undergo moderate settlement and liquefac-tion requiring ramping. The bridge over Corral de Peidra Creek (49C-330) mightbe closed to traffic due to severe liquefaction. Both bridges can be easily

bypassed on the old Price Canyon Road.

B-8l-269 3-54

TERA CORPORATION

3.2.2.3 ESTIMATED DAMAGE TO PLANT ACCESS ROADS

San Luis Ba Road (road length: I.4 miles)

Ground Failure

One oversteepened fill 200 feet long is susceptible to settlement and possible

slumping on both sides of the road. Damage would result in partial closure to

both lanes, leaving the road center open to traffic. The estimate of the length

of road blockage is about 50 feet.

One 400-foot section across the See Canyon drainage may fail due to liquefac-

tion, lateral spreads and minor fill settlement. Significant damage may be

anticipated for both lanes. Another l,200 feet of road crosses an area of low

liquefaction potential. The bounding estimates of the length of damaged

roadways vary between 250 and 600 feet.

Bridge Failure

The bridge over San Luis Obispo Creek (49C-ISI) is expected to undergo

moderate settlement requiring minor ramping, while the bridge over See Canyon

Creek may be damaged by liquefaction and require more significant ramping.

Avila Road from Route IOI to Marina (road length: 4.6 miles)

Ground Failure

There is a potential for major landsliding along 5,000 feet of oversteepened cut

and natural slopes which could result in the closing of both lanes. Some failures

presently exist. The bounding estimates of the length of road blockage vary

between l,300 and 2,000 feet.

Major liquefaction damages are expected along 7,300 feet (discontinuous) of the

road with closure of both lanes. The fill area at the public pier and the road

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from the bridge over San Luis Obispo Creek east to below the storage tanks have

the highest susceptibility to damage. The bounding estimates of the length of

damaged roadway vary between l,600 and 2,900 feet.

Bridge Failure

The Harford Drive Bridge (49C-327) is expected to be damaged by settlement

and shifting at the bearings requiring moderate ramping. If the severe

liquefaction potential in the area materialized, the structure would likely lose a

span.

PGandE Access Road from Avila Road to Diablo Canyon (road length: 7.0 miles)

Ground Failure

Natural slopes are oversteepened, and 5,000 to 6,000 feet of roadway are

susceptible to debris slides and rock falls, which could result in the closure of

both lanes. Fourteen steep, high fills have been placed across the major

southwest flowing drainages. There is much evidence (tension cracks and repair

patching) that the fills are presently settling. Slumping and debris slides are

expected on some of these fills resulting in the closure of both lanes. The

expected length of blockage of both lanes varies between 700 and l,000 feet.

No liquefaction is anticipated along this road.

Bridge Failure

There are no bridges on this road.

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North Plant Road. Northern Access to the Plant. Fields Ranch Road and PechoValley Road from Diablo Canyon to intersection of South Bay Blvd. and Los OsosRoad (road length: IO. I miles)

Ground Failure

Surficial debris flows and possible slumping can be expected in the deep fillacross Diablo Canyon. Natural oversteepened slopes some 4,500 feet in length

are susceptible to debris slides resulting in potential closure of the road. The

problem is compounded by the relatively high acceleration expected in the area.

The expected length of blockage of both lanes varies between l,700 and

2,900 feet.

No liquefaction is anticipated along this road.

Bridge Failure

The bridge over Islay Creek (49C-239) is expected to undergo some moderate

settlement and possible shifting of the deck, but could handle light trafficwithout repair.

3.2.2.4 ESTIMATED DAMAGEDTO OTHER ROADSWITHINTHE SIX-MILEZONE

Port San Luis Road from Plant Entrance to Lighthouse (road length: I.4 miles)

Ground Failure

The road is in poor condition, narrow, with numerous steep slopes. The first mile

is susceptible to debris slides and complete failure at many points. No

liquefaction is anticipated on this road and no bridges exist.

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See Can on and Prefumo Can on (road length: 12.1 miles)

Ground Failure

Extremely steep natural slopes and manmade cuts are nearly continuous along

See Canyon's westerly side. Numerous debris slides are anticipated along a four-

mile section. There are several steep, high cuts discontinuous-about 6,000 feet

in the upper reaches of See Canyon and central portions of Prefumo Canyon

which are susceptible to failure. Many slides are expected, resulting in total

closure of both canyon roads.

Some minor liquefaction may occur at the intersection of Davis Canyon.

Bridge Failure

No damage is anticipated on the four bridges in Prefumo Canyon.

South Ba Boulevard (Morro Bay) (road length: 3.9 miles)

Ground Failure

A 600-foot cut adjacent to Black Hill is susceptible to rock falls and possible

rock slides that would close at least the southbound lane and possibly both lanes.

The fills placed across Los Osos Creek and the bay inlet area between Black Hill

and Cerro Cabrillo Hill are very susceptible to lateral spreads and fill settle-

ment. Both lanes could be anticipated to be closed at several locations.

Bridge Failure

The bridges over Turri and Chorro creeks are located in high potential liquefac-

tion areas. Some settlement is expected and collapse is possible.

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Main Street and Countr Club Drive (Morro Bay) (road length: 2.9 miles)

Ground Failure

No landslides are anticipated in this area. Liquefaction ground failure and

lateral spreads are likely to occur over a 7,000-foot continuous section of road

adjacent to the bay. A large portion of this section may be damaged by lateral

displacements, resulting in the closure of both lanes.

Bridge Failure

There are no bridges on this road.

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1

4.0 EVACUATIONTIME ESTIMATES

Evacuation time estimates are an important ingredient in emergency planning.

They provide a key input to the protective action decision making process by

indicating whether sufficient time is available to conduct a partial or total

evacuation of the population within the plume exposure zone. Where earthquake

damage has impacted the evacuation road system, decisions regarding evacuation

become more complex. Also it is desirable, if not necessary, to consider a

variety of evacuation options in order to provide the greatest protection to the

most people. Therefore, it was determined that protective action decisions

could benefit from pre-analysis of evacuation times representative of post-

earthquake conditions. Such analyses were performed in this study for the Basic

Emergency Planning Zone (BEPZ) surrounding the Diablo Canyon Power Plant for

specified evacuation zones and earthquake damage levels.

The evacuation of part or all of the population around the Diablo Canyon Power

Plant was simulated using a computer model of the evacuation process. This

model dynamically simulates the distribution and flow of cars through the

evacuation road network. For each evacuation scenario, distributions can be

obtained for various quantities of interest, such as total time to evacuate, total

time spent on the road in an evacuation, and the density and velocity of cars at

various points in the evacuation road network (Figure 4- l).

\

The evacuation process is initiated when the affected populace is notified of the

need to evacuate. Once this notification is issued, the process of evacuating

from a given area for any given individual is modeled by a sequence of activities,

or steps. An example of such a sequence is:

o Become aware of the notification

o Prepare to leave work

o Drive home

o Prepare to evacuate from home

o Drive from home to a main evacuation route

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o Merge onto the main evacuation route

o Drive out of the evacuation zone on the main evacuationroute.

The time required to evacuate from a given area-equals the sum of the times

taken to complete whatever individual activities are required.

The September 1980 PRC-Voorhees report, "Evacuation Times Assessment forthe Diablo Canyon Nuclear Power Plant," obtained distributions for the times

needed to complete the steps leading up to a person leaving his or her residence

and entering the transportation network. These time distributions were then

combined to derive an overall distribution for the times at which evacuees can

be expected to enter the transportation network with the purpose of directlyexiting the evacuation zone. The following types of evacuees.were considered in

the Voorhees analysis: (I) students attending California Polytechnic State

University, (2) visitors to Pismo Beach State Park, and (3) everyone else includ-

ing workers who must drive home from work before evacuating, and spouses and

children at home who will wait until the other spouse arrives home before

evacuating.

In this report, the last three basic steps in the evacuation process were modeled,

namely:

0 Transit between a person's residence and a main evacua-tion route

Merging onto the main evacuation route

Transit from the point of entrance onto the main evacua-tion route to the evacuation zone boundary.

The times required to complete these three activities were calculated using

TERA's evacuation simulation model. The results were combined with the

distributions given in the Voorhees report for the three types of evacuees. This

yielded an overall evacuation analysis which explicitly described the timecomponents involved in the various steps in an evacuation, from the time atwhich notification is given to the affected populace until the evacuation is

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LOCATION OF ENTRANCE NODESUSED IN NETWORK SIMULATIONMODEL

4-3 TERA CORPORATlON

4.1 MAINEVACUATIONROUTE TRANSPORTATION MODEL

The principal dynamic characteristic of the evacuation process is the flow ofvehicles along the evacuation routes. To compute the transit times associated

with the flow of vehicles, a general model of vehicle flow was used. In this

model, car speed (S) over a given section of roadway is assumed to be a function

of the density of cars (p) and the capacity of the given section of roadway. The

density of cars is merely the number of cars per unit of highway length, and the

roadway capacity is a direct function of the type of road (e.g., limited access

freeway) and the number of lanes. At low densities, cars can travel relativelyfast, but the volume of traffic or throughput, v (which equals p.s), moving past a

given point is relatively small. As the density of cars increases, speed decreases,

and throughput is increased until an "optimum" density (popt) is attained. Atthis density, the corresponding speed (Sopt) Is such that throughput (which equals

popt Sopt) is maximized, and the maximum capacity of the road is attained. As

the density increases past poptp car speed continues to decrease, and throughput

decreases until the density equals approximately I.7 times the optimum density.

At this point, both car speed and throughput are effectively reduced to zero. A

graphical representation of this model is given in Figures 4-2 and 4-3.

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S(CAR SPEED)

Sopt

I

I

I

I

Popt 1.7 x Popt P (DENSITY)

FIGURE 4-2

CAR SPEED VS. DENSITY

V(VOLUMEOF CARS)

Vopt

Popt I 7 x Popt P (DENSITY

FIGURE 4-3

VOLUMEOF CARS VS. DENSITY

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4.2 SIMULATIONAPPROACH

The simulation technique used in computing evacuation time estimates utilized a

network model of the main evacuation routes leading from the Basic Emergency

Planning Zone. The network consists of points of entrance onto the main

evacuation routes, "nodes," and the sections of roadway between entrances,

"links." Evacuation times were computed by simulating the flow of trafficthrough the network model.

Because of the large number of vehicles that would be involved in an evacuation,

vehicles having similar simulated characteristics were grouped into units called

"entities." Each entity represented 25 vehicles having a common origin, destina-

tion, and type of evacuee. Therefore, the flow of 55,000 vehicles from the

evacuation zone was simulated by sending 2,200 (55,000/25) entities through the

network. The fact that one entity represents 25 vehicles was reflected in allcalculations.

In cases where a given network node corresponds to a main evacuation route

entrance which is close to other entrances not represented by nodes, it was

assumed that the given node represented these nearby entrances as well. Thus,

the number of cars (as represented by entities) which were routed to each

entrance node in a given evacuation scenario represented the number of cars

which would be entering any of the entrances represented by that node. Also, at

each node which represents more than one actual entrance, the merge time foreach entity was reduced by a factor corresponding to the number and type ofnearby entrances. This reflects the fact that cars would be entering the main

evacuation routes from all possible entrances.

At the time the first notification to evacuate is issued, in any given evacuation

scenario, each entity under consideration is identified as to the type of evacuee

it represents and labeled with the number of the node wheie it will be entering

the main evacuation network. The evacuation process is then modeled in the

network by calculating a sequence of time components that each entity

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experiences before it has exited from the network. These components are

discussed below.

4.2.I PREPARATION TIME

The first time component that an entity experiences is the time required to

complete all of the steps necessary before a person is ready to leave his or her

'residence in an evacuation. For this time component,.each entity is assigned a

time taken from the PRC-Voorhees distributions corresponding to the type ofevacuee specified.

4.2.2 TRANSIT TIME BETWEEN RESIDENCESAND MAINEVACUATIONROUTES

The second time component that an entity experiences is the time required for a

person to drive from his or her residence to an entrance of a main evacuation

route. This time generally contributes only a small increment to the totalevacuation time. However, because the distance to a suitable evacuation route

varies considerably for some population concentrations, there are significantdifferences in travel time among various segments of the population. Very short

travel times occur in San Luis Obispo,'orro Bay, and the Five Cities area

because of the proximity of the designated evacuation routes to these concen-

trated populations. For communities that are comparatively remote from the

main evacuation routes, such as Los Osos, Baywood Park, and Cuesta-By-The-

Sea, local travel times are greater. In addition, zones that have relativelydispersed populations have greater variability of travel times.

A distribution of times for this part of the evacuation process was-obtained foreach emergency planning zone as given in the Voorhees report. This involved

obtaining travel times from three points in each zone: a modal or average timefor trips originating near the centroid of the zone's population; a maximum timefor trips from the most remote residences in the zone; and a minimum time fortrips originating on the roads or streets nearest to the evacuation routes. The

estimate of travel time in each case was based on the travel distance and the

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assumed travel speed, which was a function of roadway type and condition.

Generally, top speeds of 25 mph on rural roads and l5 mph on city streets were

used, recognizing that congestion during evacuation would be greater than usual

and that these are trip averages rather than preferred driving speeds.

4.2.3 MERGING TIME ONTO MAINEVACUATIONROUTES

The third time component that an entity experiences is the time which is

required to merge onto the main evacuation route. This part of the evacuation

process is important because the rate at which cars enter a section of roadwayaffects the density of cars on that roadway. This in turn affects the speed oftraffic and throughput on the main evacuation routes, and therefore the totalevacuation time.

Capacity at the entry points to the evacuation network depends in part on thegeometry of the ramp or intersection and the characteristics of traffic controls.However, when the highway is operating at or near maximum capacity, theoverriding consideration is the density and speed of highway traffic approachingthe entry point and, hence, the frequency of opportunities for cars to merge intothe traffic stream. At freeway ramps during heavy traffic, opportunities resultbecause of the irregularity of intervals between cars and because upstream cars

tend to move to the left-hand traffic lane in order to avoid conflict withentering cars. As the density increases, fewer opportunities for merging occur.At intersections with traffic signals, opportunities to enter the traffic streamdepend on the signal cycles and the relative proportions of traffic light greentime allocated to entering streets. In these cases, congestion is likely to limitentry severely if traffic tie-ups cause blockage of intersections. At unsignalizedsurface intersections, right-turn entry opportunities depend on the occurrence ofgaps in the through traffic stream, much as they do at freeway ramps. Left-turnopportunities depend on breaks in on-coming traffic and, therefore, may be

virtually impossible unless the on-coming traffic flow is very light (as may wellbe the case in the return direction during an evacuation) or manual trafficcontrol is provided. When opportunities to cross the opposing traffic are

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plentiful, the merge into the traffic stream is similar to that for right-turn

traffic.

The following simplified expression was developed to describe the volume of cars

entering the evacuation network at each entry node:

K l l l'7 t S t for 0 — < l.7 (I)P P

p t opt opt ~opt

for ) l.7P

~opt

where: e = entering traffic volume (cars/hour)

p = actual density of cars (cars/mile)

and

p t— density of cars at maximum capacity (cars/mile)

optS t

— speed at maximum capacity (miles/hour)opt

~ = a constant depending on the type of intersection and thenumber and type of nearby entrances.

These equations are consistent with the nomographs given in Figures 8.2 and 8.8

in the Highway Capacity Manual-l965 (HCM) for ramp capacities on four-lane

highways and with the graphs (Figures 6.8 and 6.9) of surface street intersection

capacities when through traffic is moving freely at less than possible capacity.

(The HCM is a publication of the Highway Research Board that is widely

regarded as the standard reference on practical analytical methods for determin-

ing traffic capacity and predicting traffic performance.) The equations also

conform to the general constraint that "if the demand volume exceeds the

capacity, the bottleneck will be critical and queueing and speed reduction can be

expected either on the ramp or on the through freeway lanes, or both" (HCM,

p. 197). The controlling variables in these equations are the relative density of

traffic and the traffic capacity (which equals p ~ S ) for the evacuationopt opt

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route. Thus, if traffic is very light, a steady stream of cars can enter; however,

as the route approaches saturation few, if any, cars will be able to merge intothe traffic stream.

When a car arrives at an entrance to a main evacuation route, there may be

other cars waiting to merge. Thus, the total time taken for a car to merge ontoa main evacuation route equals the time that it must spend waiting while othercars are merging plus its own merging time (which on average equals I/e). In theevacuation simulation, when an entity arrives at an entrance node into the

network, it is held in a queue (if necessary) while any preceding entities merge.When the entity reaches the head of the queue it computes its own merging timefrom the equation:

entity merging time = 25 ~ (I/e)

where e is computed from expression (I). The factor of 25 reflects the fact thatone entity represents 25 cars, each of which takes approximately I/e (hours) tomerge onto the main evacuation route.

4.2.4 TRANSIT TIME ON MAINEVACUATIONROUTES

The last time component that an entity experiences is the time required totravel on the main evacuation route out of the evacuation zone. This timedepends on the speed at which cars can travel, which in turn is largely dependent

on the capacity of the roadway and the density of cars on the roadway.

The capacity of a highway to carry traffic (usually expressed as vehicles per hour

or vehicles per lane per hour) is a physical quantity that depends on certainrecognized geometric characteristics of the roadway. Among these characteris-tics are vertical and horizontal alignment (the frequency and sharpness of curves

and grades, usually subsumed under aggregate measures such as safe operatingspeed or average highway speed) and percentages of the roadway mileage having

adequate sight distances for passing other vehicles. Other geometric character-istics that directly affect capacity are roadway or lane width and the width of

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shoulders or distance from the road to obstructions, such as trees, bridge

abutments, and parked vehicles. The length and steepness of grades has littledirect effect on traffic capacity for passenger automobiles, but does affect the

treatment of trucks and buses in terms of car equivalents. Thus, a heavy truck

such as a five-axle semi-trailer combination, which on a good highway in level or

lightly rolling terrain is equivalent to two passenger cars, may displace more

than l00 cars on sections of roadway with long, steep grades. These and many

similar relationships have been determined quantitatively by observation ofactual traffic and are reported in the HCM.

Throughout the HCM, the authors use the basic relationship between operating

speed and traffic volume to illustrate how speed changes as the number of

vehicles on the road changes. In general, traffic is known to proceed at the

average highway speed, or safe operating speed, when traffic volumes are very

.Iow. Speed declines gradually, but at an increasing rate, as volume increases.

When the peak capacity is approached, movement rates become unstable and

speed may decline precipitously as a result of either an incident that disrupts

flow or the addition of a small number of cars to the stream. If traffic increases

beyond this point, throughput of the highway declines. These relationships are

the speed versus traffic volume analogs to the speed versus density relationships

described previously. On all highways the maximum capacity occurs at rela-

tively low speeds, usually about 25 to 30 mph in rural areas or on urban highways,

and l5 mph on urban arterial streets.

For the simulation of traffic over the main evacuation route network, the basic

relationship between operating speed and traffic volume has been converted to a

speed versus density relationship (Figure 4-2). For most types of highway, a

nearly linear relationship exists between speed and density, although there are

minor irregularities in the region of maximum capacity where traffic flow tends

to be unstable. For purposes of simulation a conservative linear equation has

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been assumed which effectively describes the conditions that will prevail during

an emergency evacuation.

S 2P

p popt

Pfor 0 < —< l.7

opt(2)

for —) I.7P

opt

where: S = actual speed (mph),

S t— speed at maximum capacity,

p = actual density (cars/mile)

po t— density at maximum capacity.

In the. evacuation simulation, the time required for an entity to transit the

network is determined as follows:

I. Upon entering a link of the network (representing asection of a main evacuation route), the density of carstraversing that link is computed and substituted intoexpression (2).

2. If S is positive, a transit time for the link is computed bydividing the length of the link by S. The entity is thenrouted to the next node of the network where it repeatsStep I unless it has arrived at an end node of the network(representing the boundary of the evacuation zone).

In this case, the entity has completed the last step that itmust undergo in its "evacuation process" and so its arrival-time is recorded and used as one data point in anempirical distribution of evacuation completion times.Such a distribution is computed for each end node and theentire network.

3. If S = 0, the entity waits in a line behind other entitieswhich have computed a 0 value for S. When an entityleaves the link, the first waiting entity is allowed to enterthe link with a speed (and thus transit time) correspondingto

P1.7.

~opt

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Each subsequent entity which leaves the link allows onewaiting entity to enter the link (with the same speed)until there are no more entities waiting. After an entityenters a link, it is routed to the next node (after theappropriate transit time) where Step I is repeated (if it isnot an end node) as in Step 2.

Step 3 corresponds to a traffic-jam situation in which cars must come to a stop

and wait because the density of cars on the road has become too great. This

condition persists until cars farther up the road have moved forward, allowing

the waiting cars also to move forward.

Thus the time required for an entity to traverse a link equals its waiting time

(representing the time a car may spend sitting in a traffic jam) plus its transit

time once it has begun moving. The time required for an entity to exit from the

evacuation zone once it has entered a main evacuation route equals the time the

entity takes to traverse all of the links which it must pass through before it has

left the evacuation zone.

4.3 TRAFFIC CONTROL

As described previously, the volume of cars which can pass through a given

section of roadway is maximized when the density of cars (p) equals poptp which

in turn yields an average car speed of Sopt. Thus the goal of a traffic control

program should be to guarantee that the density of cars on a roadway does not

exceed popt. Such a program could be implemented by traffic control personnel

at the major entrances to the main evacuation routes.

ln the simulation, this type of traffic control was modeled by not allowing an

entity to join the moving stream of entities on a main evacuation route link if by

doing so it would cause the density of cars on that link to exceed popt.

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4.4 MODELING EARTHQUAKEDAMAGE

In the scenarios where damage was assumed to occur to the highway system,

(e.g., bridge damage, landslides, or liquefaction), damage repair times were

modeled as follows:

I. Estimates were made of the time needed to repair eachoccurrence of damage on each section of roadway corres-ponding to a link in the network.

2. An estimate was made as to the number of crews whichwould be available to repair damage on each section ofroadway, and from this an estimate of the total timeneeded to repair each link in the network was computed.

3. If a bypass existed around the damaged area, the capacityof the link was lowered to the capacity of the bypass forthe duration of the repair time. If no bypass existed, noentities were allowed onto the link for the duration of therepair time.

4. In addition to the above steps, it was assumed that carswould not travel at speeds greater than So t (i.e., thecapacity maximizing speed). This speed equals about one-half of the speed which would be expected if the roadwaywas uncongested and no damage had occurred. In caseswhere traffic control was assumed, traffic was assumedto be moving at a speed of Sopt since the purpose oftraffic control is to assure that maximum capacity ismaintained on the evacuation routes.

4.5 SUMMARYOF RESULTS

Evacuations of population in several geographic regions were modeled using the

simulation approach described above. Four types of evacuation were considered:

I. Total - the entire Basic Emergency Planning Zone (BEPZ)

2. Partial (Northern) - the region north of the plant whichcontains Morro Bay and Baywood Park

3. Partial (Eastern) - the region east of the plant whichcontains San Luis Obispo

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4. Partial (Southern) - the region south of the plant whichcontains Avila Beach, Shell Beach and the Five Citiesarea.

The number of cars which were assumed to be involved in each of these

evacuations was derived from the number of cars expected to be involved from

each of the evacuation zones (I through XVIII) of the September l980 PRC-

Voorhees report.

For each of the four types of evacuation, four earthquake damage levels were

modeled:

I. No damage

2. Light damage

3. Moderate damage

4. Heavy damage.

The repair times that were computed for each link in the network for each of

these damage levels, along with the number of crews which would be required to

attain these repair times, are given in Table 4- I.

For each combination of evacuation type and damage level, a rough optimization

of the routing of the evacuating cars was performed. The goal of this

optimization process was to distribute and route the cars on the main evacuation

routes such that the Basic Emergency Planning Zone (i.e., the end node of each

of these routes) was cleared at approximately the same time. The distributions

and routing of cars which resulted from this process are given in the Appendix.

Should there be a different evacuation objective —for example, to clear the

IO-mile radius as quickly as possible —a different distribution and routing of cars

may be appropriate.

The estimated evacuation times for the BEPZ for the l6 possible combinations of

evacuation types and damage levels are given in Table 4-2. It was assumed in

obtaining these estimates that the type of traffic control described above was in

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effect and that there were sufficient resources available to repair all of the

occurrences of damage within the time interval required to repair the worst

occurrence of damage for each link. The effect of assuming a more limitedavailability of resources is discussed below. Also listed are the times required toclear a IO-mile radius around the plant. These represent entities which have

been routed to clear the larger radius (BEPZ) in the optimal time and, therefore,do not necessarily represent an optimal !0-mile evacuation time.

Total Evacuations

The evacuation time estimated to clear the entire evacuation zone ranges from

6.5 hours if no damage is assumed to I0.5 hours if heavy damage is assumed.

Partial Evacuations

The time estimated to clear the 10-mile radius in an eastern evacuation is threehours for all four damage levels. The constant time estimates are a product ofthe very few residents within IO miles of the plant in this direction and the

evacuation model which does not include any main evacuation routes within this

area. Thus the time to clear the region in the model simply equdls the time for

people in the region to leave their homes (which is assumed to be less than orequal to three hours in the PRC-Voorhees report) plus the transit time on local

roads past the IO-mile radius (approximately 5-IO minutes). The three-hour

estimate for people to leave their homes and exit the IO-mile zone is based upon

use of private automobiles with little delay in reaching the main evacuation

route. From the damage estimates given in Section 3.2.2.3, forms of egress fromthe Avila Beach area other than private automobile may be necessary due to the

potential for road damage. For example, walking around the damage to

Highway IOI and then being transported by buses or cars out of the BEPZ may be

required if the Avila Beach Road is heavily damaged. This could require some

additional time beyond the three hours even though the distance is not great (less

than three miles).

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The time estimated to clear the IO-mile radius in a southern evacuation equals

three hours for the light, moderate, and heavy damage levels which is less than

the 3.5 hours for the no-damage case. The reason for this lies in the assumed

routing of cars for the damage versus no-damage scenarios. In the damage

scenarios a bridge failure was assumed to occur on Route IOI between Avila

Road and San Luis Bay Road. Because of this, in these scenarios no traffic was

routed from Shell Beach and the Five Cities area onto Route IOI going north'.

This allows the traffic from the Avila Beach area to enter and exit from the

section of Route IOI which is within the IO-mile radius with almost no delay.

Thus, the time to clear the IO-mile radius essentially equals the time taken by

people in the region to leave their homes (less than or equal to three hours, per

PRC-Voorhees, l980). In the no-damage case, however, traffic which is routed

from the Shell Beach and Five Cities area on to Route I 0 I going north interferes

with the Avila Beach traffic which is attempting to clear the IO-mile radius.

This results in the time required to clear the IO-mile radius being longer in this

case than in the three damage scenarios.

Effect of Available Resources on Evacuation Time Estimates

The evacuation time estimates above were based upon the assumption thatsufficient resources would be available to repair the damage to all sections of

the roadways simultaneously and the only delay that would result in longer

evacuation times was that due to lower capacity bypasses and the time to repair

the worst link on a given section of roadway. These repair times and resources

are presented in Tables 4- I and 4-3A.

Since it is not possible to know ahead of time the level of resources (equipment

and labor) that would be available, we have estimated the incremental increase

in evacuation times that would result from limitations on these resources.

Table 4-3B is a tabulation of the reduced resources which would result in a delay

of less than one hour for light damage level, less than two hours for moderate

damage and less than four hours for heavy damage. If the available resources

were less than those shown in Table 4-3A, but greater than or equal to those

shown in Table 4-3B, one would add these incremental times to the evacuation

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TERA CORPORATION

time estimates shown in Table 4-2. Similarly, Table 4-3C provides resource

levels which would result in delays of two, four and eight hours for the three

damage levels. If the available resources were less than those shown in

Table 4-3B, but greater than or equal to those shown in Table 4-3C, one would

add these incremental times to the evacuation time estimates shown in

Table 4-2.

tn Table 4-3A we have tabulated the availability of crews which were assumed

for the various evacuation scenarios and upon which the results in Table 4-2 are

based.

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TABLE4- I

REPAIR TIME FOR SEISMIC DAMAGEUSED IN NETWORK ANALYSIS

Minimum Time to Clear Damaged Areas

Link LightDamage

ModerateDamage

HeavyDamage

Hours Crews" Hours Crews" Hours Crews

l2 to I I

I I to IOIOto 99 to 88 to 7

7 to 6

6 to 4

.4 to 3

3 to 22 to End

Route

0.20.40.3040.8I

0.81.2

0I.I00

I 0 I, Southbound

I 0.7I 0.72 .60 0

I Br 82 2.4

I Br 8I l.8I 2.1

0 I

I 20 00 0

Lane

I

220

I Br2

I BrI

I

I BrI

00

l.3I.5l.20

724.5

483I

3.543.30I

I

220

i Brl2

I Br2I

I Br3I

2 BrI

0I Br4

l7 to l6

l6 to l4

l4 to l2l2 to I I

I I to IOIOto 9

Route

0.2

0.30.20.20.2

IOI, Northbound Lane

I 4 I BrI 3

0 8 I Br0.3 2

I I 2I 07 I

2 0.7 22 0.6 3

82

48.8

2I.3I.5l.6

I Br53

I Br622I

22

End to 32

32 to 30

30 to 2929 to 27

2 I I

2 2

0 0 05 I.2 8.4

Route I, North or Southbound Lanes

.7 2 I I BrI.8 2

0.6 Br

23.34I

3.202.2

I Br72

I Br8I Br920

II

""BR" beside the number of crews indicates a bridge crew, with thecorresponding times for the repair of bridges only. The next line wouldindicate times and number of crews for road crews only.

Other footnotes explained on last page of table.

4-19B-8 I-269

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TABLE4- I

(CONT.)

Minimum.Time to Clear Damaged Areas

Link LightDamage

ModerateDamage

HeavyDamage

Hours Crews Hours Crews" Hours Crews"

Route

27 to 26 I

26 to 25 025 to 23 0

(Merger of Route

I, North or Southbound Lanes (Cont.)

I Br 2 I Br 72 I Brl0.5 4 l.5 4

0 .5 2 I.5 20 .5 2 I.5 2

I with Route I 0 I between SLO and Pismo Beachsummarized under Route I 0 I)

22 to 20

20 to l9

l9 to End

42 to End

0.6

0.8

I. I

.3

0 I

3 2. I

0 I

2 I.3I I.5

Los Berros Road

4 2.3

Orcutt Road

I Br4

I Br42

84.222.42

I Brll4

I Brl242

SLO to 3636 to 35

35 to 2

I .6I I

1.7

0 .5

2I Br3

1.6 2I Brl3

8 (S49) I

2.2 6I.S I

Price Canyon Road, Northbound or

39to38 0 0 .538 to 37 .3 I I.I37 to 4 I I Br 8

.6 I I

.9

Southbound

I

4I BrI Br4

Lanes

l.52. I

722l.5

I

5I Brl4I Brl53

''BR" beside the number of crews indicates a bridge crew, with thecorresponding times for the repair of bridges only. The next line wouldindicate times and number of crews for road crews only.

Other footnotes explained on last page of table.

. B-8I-269 4-20

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TABLE4-l

(CONT.)

FOOTNOTES,

BRIDGE BYPASSES

I 49-I42 49 I9I3 49-I894 49- I 755 49-606 49-847 49-I828 49-I8I9 49-I09

10 49-63II 49-IOl2 49 l2I3 49-CI I3I4 49-C330I5 49-C329

parallel roads for southbound and northbound.interchange ramps, northbound and southbound.

interchange ramps, northbound and southbound.

Traffic Way northbound and southbound.

none, northbound and southbound.

city streets, northbound and southbound.

interchange ramps, northbound and southbound.

Frontage Road, northbound and southbound.

ramps, northbound and southbound4-mile bypass northbound, 7-mile bypass southbound.

Cypress Street, northbound and southbound.Railroad Road, northbound and southbound.none.Old Price Canyon Road, northbound and southbound.

Old Price Canyon Road, northbound and southbound.

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TABLE 4-2

SUMMARYOFESTIMATED EVACUATIONTIMES

(HOURS)

Type ofEvacuation

ZoneCleared

Da'ma e LevelNone Light Moderate Heavy

Total(Basic EPZ)

I 0 mile

BEPZ 6.57 5+

l0.5

Partial I 0 mile(Southern Area) BEPZ

3.54.5

3 3

4.5 6

Partial I 0 mile(Eastern Area) BEPZ l0.5

Partial I 0 mile(Northern Area) BEPZ

3.5 4 5

4.5 5.5

The time given is an upper bound on the time required to evacuatethe Baywood Park area. The Avila Beach area clears the IO-mileradius in less than 3.5 hours in all four damage scenarios.The beach transient population on a summer weekend couldincrease these evacuation time estimates. For the no-damage andmoderate-damage levels, we estimate an increase of aboutI.S hours.

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TABLE 4-3A

AVAILABILITYOF CREWSASSUMED IN EVACUATIONSCENARIOS (TABLE 4-2)

Evacuation Scenario

Light Moderate HeavyDamage Damage Damage

Number of Crews

Northern Evacuation (Partial)Route I North

Total2B+ 42B+ 4

3B+ 43B+4

Eastern Evacuation (Partial)Route IO I SouthboundRoute IO I NorthboundRoute I NorthPrice Canyon Road 6 Route 227Lopez Drive & Orcutt Road

Total

I

I

IB+ 9IB+222B+ I5

IB+ I

IB+33B+ 209IB+ 66B+ 39

3B+ I

IB+ 32B+ 239IB+ IO7B+ 46

Southern Evacuation (Partial)Route IOI SouthboundRoute I 0 I NorthboundRoute I NorthRoute I SouthPrice Canyon Road Bc Route 277Los Berros Road

Total

28IB+ 93IB+ 242B+ 28

IB+ 2IO3B+ 20IB+ 6925B+ 49

4B+ 292B+ 23IB+ 6927B+ 51

Total Evacuation

Route IOI SouthboundRoute I 0 I NorthboundRoute I NorthRoute I SouthPrice Canyon Road 6 Route 227Lopez Drive Bc Orcutt RoadLos Berros Road

Total

29IB+ 96IB+ 2242B+ 34

IB+ 2IB+ l53B+ 202B+ IO9IB+ 628B+ 64

4B+ 2IB+ l42B+ 232B+ IO'

IB+ IO2

IOB + 70

One crew is the equipment and labor equivalent to a front loader withoperator that can clear 300 cu. yds. of loose, unconsolidated material perhour.

2 One bridge crew (B) would contain engineering supervision and constructioncrew and equipment. Different equipment and labor skills would be requiredfor repair of bridges over the earth moving and road grading equipment andskills for landslide and liquefaction repair.

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TABLE4-3B

REDUCED RESOURCES

0

Light Moderate Heavy. Damage Damage Damage

Increases evacuation time if availableresources are greater or equal to those (I hour (2 hours (4 hourslisted for the following scenarios

Northern Evacuation (Partial)Route I North

Total21 IB2+ 3

2 IB+32B+ 3''2B+ 3

Eastern Evacuation (Partial)Route IOI SouthboundRoute I 0 I NorthboundRoute I NorthPrice Canyon Road & Route 227Lopez Drive & Orcutt Road

Total

Southern Evacuation (Partial)

I IB+ I 2B+ I

I IB+ I IB+ I

IB+ 4 2B+ IO 2B+ I I

IB+ I 4 5I IB+3 IB+5

2B+ 8 5B+ l9 6B+ 23

Route IOI SouthboundRoute I 0 I NorthboundRoute I NorthRoute. I SouthPrice, Canyon Road & Route 227Los Berros Road

'otal

Total EvacuationRoute I 0 I SouthboundRoute I 0 I Northbound

,Route I NorthRoute I SouthPrice Canyon Road & Route 227Lopez Drive & Orcutt RoadLos Berros Road

Total

22

IB+ 4. 3

IB+ I

22B+ l4

22

IB+ 45

IB+ I

I

2

2B+ l7

IB+ 24

2B+ IOIB+ 4

42

4B+ 26

IB+ 2IB+ 3

2B+ IOIB+ 7

4IB+ 3

2

6B+ 3I

2B+ 24

2B+ I I

IB+ 352

5B+ 27

2B+ 2IB+ 3

2B+ I I

2B+ 45

IB+ 52

8B+ 32

4-24

B-8l-269TERA CORPORATION

TABLE 4-3C

REDUCED RESOURCES

Light Moderate HeavyDamage Damage Damage

Increases evacuation time if availableresources are greater or equal to those g2 hours (4 hours 48 hourslisted for the following scenarios

Northern Evacuation (Partial)Route I North

Total

Eastern Evacuation (Partial)Route I 0 I SouthboundRoute I 0l NorthboundRoute I NorthPrice Canyon Rd. & Route 227Lopez Drive & Orcutt Road

Total

Southern Evacuation (Partial)Route IOI SouthboundRoute I 0 I NorthboundRoute I NorthRoute I SouthPrice Canyon Road 8 Route 227Los Berros Road

Total

Total EvacuationRoute I 0 I SouthboundRoute I 0 I NorthboundRoute I NorthRoute I South

~Price Canyon Road & Route 227Lopez Drive 8 Orcutt RoadLos Berros Road

Total

I IB+ 2 IB+ 2'IB+ 2 IB+ 2

I IB+ I IB+ I

I IB+ I IB+ I

IB+ 2 IB+ 5 IB+ 6IB+ I 2 3-

I IB+2 IB+32B+6 4B+ I I 4B+ l4

I IB+ I IB+ I

I 2 2IB+ 2 IB+ 5 IB+ 6

2 IB+2 IB+ I

IB+ I 2 3I I I

2B+ 8 3B+ l3 3B+ l4

I IB+ I IB+ I

I IB+ 3 IB+ 3IB+ 2 IB+ 5 IB+ 6

2 IB+4 2B+3IB+ I 2 3

I IB+2 IB+3I I I

2B+ 9 5B+ I8 6B+ 20

4-25

B-8 I-269TERA CORPORATION

5.0 COMMUNICATIONS

5. I EARTHQUAKE EFFECTS ON COMMUNICATIONS

As with transportation systems, a magnitude 7.5 earthquake on the Hosgri faultcould damage communications systems within the study area. For example, in

the l97l San Fernando earthquake, substantial damage was reported to the com-mercial telephone system, generally due to a lack of restraint or support to

'revent equipment from falling over. The type of damage that could interruptcommunications within the study area includes loss of electrical power, loss oftelephone lines, loss of buildings housing the equipment, loss of equipment withinthe building and loss of antennae towers. Additional factors that could furtherimpede communications include the high volume of transmissions expected aftersuch an earthquake, both from within the damaged area and from concernedindividuals outside of the area.

In our investigation, we examined the susceptibility of essential communicationsequipment to earthquake forces. This investigation was based upon our evalua-tion of the critical elements of each system reviewed which might be sensitiveto seismic forces; Some elements, for example, automobile portable radios,were not examined since they should not be damaged by an earthquake. Afterthe critical elements were identified, the location, mounting and emergencypower for each were reviewed, generally during an onsite inspection.

5.2 PACIFIC GAS AND ELECTRIC COMPANY COMMUNICATIONSSYSTEMS

5.2.l POWER PLANT PRIVATE UNIFIED TELEPHONE SYSTEM

PGandE" has a private dial telephone system which provides voice communica-tions among all company facilities. The Diablo Canyon Power Plant is served bytwo independent microwave systems: the primary link, Coast Valley MicrowaveSystem and the alternate link, West Valley Microwave System. The system is

designed to allow plant telephone access to any other company facility.Telephones are located at various locations throughout the plant, including the

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Control Room, Hot Shutdown Panels, Technical Support Center, Operational

Support Center, and the offsite Emergency Operations Facility. In addition,

there are phone jacks located at strategic operating points throughout the plant

such as the Control Room, which enable a portable telephone unit to communi-cate with any other telephone in the power plant.

The plant telephone system is a combination of an existing private Automatic

Branch Exchange (PABX) and a Computerized Branch Exchange (CBX). In this

system the telephones connected to the PABX are limited to intra-company

telephone communications, code calling, and conferencing capabilities. Directaccess to the Pacific Telephone System is not available to telephones on this

exchange. The Computerized Branch Exchange (CBX) is a computer-based,

software-controlled telephone exchange and is connected to the PABX via ten

tie trunks..

The CBX telephone system standard features include call transfer, call waiting,conferencing, call forwarding and toll restriction in varying degrees. The CBX

allows telephone sets to be programmed to have various levels of priorityrelative to trunk, line, or feature availability. This capability allows thetelephone system to serve the needs of its users in terms of need or importancerather'than on a first-come first-served basis. Certain CBX telephone sets

serving the key centers will have, in addition to standard CBX station features,an executive override feature which allows the calling party to place'a call toany other CBX telephone, even if the called station is in use. In this instance,

the called party will hear a tone; then the calling party is connected in a fewseconds.

The CBX has been programmed to allow high priority telephone sets to service

the Technical Support Center, Control Room, Operational Support Center,

Emergency Operations Facility, Corporate Incident Response Center and other

key locations. These sets have sole access to the critical telecommunications

lines which interconnect these centers and the Pacific Telephone System dial

network. All other telephones, served by the CBX and utilized for administra-tive or other purposes, will be restricted from using these critical lines when the

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priority sets are being used. Calls from'either intra-company telephones or thePacific Telephone System which are calling high priority telephones will be

answered by an At'tendant's Console, thereby screening calls not critical to the

handling of an emergency, but allowing important calls to be'extended to high

priority telephones by the individual operating the Attendant s Console.

V

The power plant telephone'system provides a code call feature which can be

initiated by dialing the appropriate code from any power plant telephone. This

sounds code bell units located throughout the plant.'ode numbers are assigned

to key members of the plant staff. A person can acknowledge his code and

communicate with the person initiating the code call by picking up any companytelephone in the plant and dialing his acknowledgement code. The planttelephone system has several built-in conference call features. One seven-phone

conference feature is set aside for emergency use and is normally initiatedfollowing the sounding of the emergency signal or the fire alarm. The controloperator enters the conference call with a pushbutton on the control console.

The next six persons who pick up a company phone and dial a special conferencecall number will be included in the 'call. Four other independent conference callsystems are available, each having a capacity of four in-plant phones plus one

phone from offsite. These conference circuits are available to any grouprequiring this service.

During normal plant operations, all calls into the plant's PGandE Private DialSystem will be via the l8 trunk circuits. In addition, l2 one-way tie trunks willprovide direct dial access to the Private Branch Exchange (PBX) in theCorporate Headquarters in=San Francisco. These tie trunks bypass normal dialtraffic and can only be accessed by high-priority telephones; this ensures thatthe high-priority telephones can call the Corporate Incident Response Center and

the Corporate Offices and also provides an alternate access to the PacificTelephone System through San Francisco if the local Pacific Telephone Exchangein San Luis Obispo were congested due to heavy use during an emergency. The

Corporate Headquarters and Corporate Incident Response Center are providedwith l6 Off-Premises Extensions which allow unrestricted access by eliminatingthe need to have calls come through the San Francisco PBX.

B-Sl-269 5-3

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Direct-dial access to locations outside the company system will be available on

selected CBX telephones via 20outgoing Pacific Telephone System trunks.

These telephone locations will include the Control Room, Technical Support

Center, Operational Support Center, and other designated key plant personnel.

All incoming calls will be via 20 incoming Pacific Telephone System trunks. The

plant will also have four separate special-purpose lines. One line will be

mounted on the" Senior Control Operator's desk in the Control Room and willprovide a means of calling out from the Control Room in the event of an

emergency. This number will be completely unlisted, not even on the dial, toensure that is will not be tied up by persons trying to reach the plant in the event

of any emergency. A second line will be to a telephone in the Plant

Superintendents office. A third line will be to a telephone in the Security

Supervisor's office, and a fourth line. will be dedicated to the Central Alarm

Station (CAS) and the Secondary Alarm Station (SAS) for security use. These

numbers also will be unlisted.

All critical equipment is securely braced and anchored to prevent sliding,

overturning, or striking other equipment or the building. Experience has shown

that when equipment frames are thus restrained, the components within are

capable of withstanding considerable earthquake vibration. All critical telecom-

munications equipment has been strengthened and braced. This includes equip-

ment racks, battery racks, antennae and supports. All equipment evaluated willsurvive the 7.5M Hosgri earthquake loading.

The major components of the PGandE communications systems are presented in

Table 5-I. The PGandE communications capabilities listed by location are

presented in Table 5-2. The power and backup-power supplies for the compo-

nents of the Plant PGandE telephone system, along with information PGandE

radio communications systems, are presented in Table 5-3.

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TABLE 5-I

MAJOR COMPONENTS OF THE DIABLOCANYONPOWER PLANT COMMUNICATIONSSYSTEMS

I. Pacific Gas and Electric Company Private Dial System

Two independent microwave systems

o primary - Coast Valleys Microwave Systemo alternate - West Valley Microwave System

2. Site Telephone Systems

Private Automatic Branch Exchange (PABX)Internal Telephone System

Computerized Branch Exchange (CBX)'nternal andPacific Telephone System Access

3. Dedicated Special Purpose Pacific Telephone SystemLines (4)

4. Data Communications System

5. NRC Communication Lines

6. UHF and VHF Radio Systems

3 UHF Systems

o Plant Operationso Securityo Health Physics

I VHF System

o Los Padres District Commercial Operating Network

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TABLE 5-2

PGandE COMMUNICATIONSCAPABILITIESBY LOCATION

CONTROL ROOM

Tele hone Communications

Dedicated tie lines to:

o State Office of Emergency Services, Sacramento

o NRC Headquarters, Bethesda, Maryland

o San Lyis Obispo County Emergency Operations Center

o All NRC-Region V Power Plants and Region V Headquarters

o Plant Technical Support Center (PGandE system)

o Plant Operational Support Center (PGandE system)

o PGandE Emergency Operations Facility, San Luis Obispo

Other lines to:

0 Midway Gates Morro Bay - 3 dedicated dispatch tie lines (PGandE)

PGandE Energy Dispatch Control CenterSan Francisco General Office - 2 dedicated dispatch tie lines(PGandE)

PGand E San Luis Obispo Dial Exchange - I Off-Premise Extension

PGandE Power Plant Exchange - IO lines

Radio Communications

o Plant Operations Emergency Radio System

o Security Emergency Radio System

o Health Physics - Voice Communications Emergency Radio System

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TABLE 5-2 (Cont.)

TECHNICAL SUPPORT CENTER

Tele hone Communications

Dedicated tie lines to:

o NRC Headquarters, Bethesda, Maryland

o PGandE Emergency Operations Facility, San Luis Obispo

o Plan Control Room (PGandE system)

o Plant Operational Support Center (PGandE system)

Other lines to:

PGandE San Luis Obispo Dial Exchange - I Off-Premise Extension

Pacific Telephone System - I line

ATC - Attendant's Console (PGandE system)

0 PGandE Power Plant Exchange - 25 lines

Radio Communications

o Plant Operations Emergency Radio System

o Security Emergency Radio System

o Health Physics

Emergency Radio Systems (voice comm'unications and datacommunications)

B-SI-269 5-7

TABLE 5-2 (Cont.)

OPERATIONAL SUPPORT CENTER

Tele hone Communications

Dedicated PGandE system tie lines to:

o Plant Control Room

o Plant Technical Support Center

Other line to:

o PGandE Power Plant Exchange - I line

EMERGENCY OPERA'TIONS FACILITY(EOF) AND COUNTY EMERGENCYOPERATIONS CENTER (EOC)

Tele hone Communications

County EOC: 3-way Pacific Telephone System dedicated tie to PlantControl Room and Plant Technical Support Center

PGandE EOF:

3-way Pacific Telephone System dedicated tie line to Plant ControlRoom and Plant Technical Support Center

5 Pacific Telephone System lines

IO PGandE Power Plant Exchange lines.

Radio Communications

County EOC/Sheriff's Office

o Plant Operations Emergency Radio System

PGandE EOF

o Plant Operations Emergency Radio System

o Health Physics - Emergency Radio System

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TABLE 5-3

AVAILABILITYOF COMMUNICATIONSSYSTEMBACKUP POWER SUPPLIES

o PGandE Private Microwave System

Mountaintop repeaters: DC powered with ACpowered battery chargers and automatic enginegenerator

o Site PABX and CBX

Battery-battery charger arrangement, with AC fromredundant vital sources, one from Unit I and theother from Unit 2

o UHF and VHF Radio Systems

I) Base stations powered by battery-batterycharger arrangement, with reliable AC powersupply

2) Mountaintop repeaters powered by battery-battery charger arrangement

B-81-269 5-9

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5.2.2 PACIFIC GAS AND ELECTRIC COMPANY UHFAND VHF RADIO SYSTEMS

The plant maintains three UHF radio systems which will be used in the event ofan emergency to establish and maintain point-to-point communications between

the plant Control Room, the Morro Bay Switching Center, the PGandE Informa-

tion Center, the Port San Luis guardhouse, the San Luis Obispo County Sheriff's

Office Emergency Operations Center, the plant Technical Support Center, the

, PGandE Emergency Operations Facility, the Security Department, and several

mobile and portable radio sets. The radio system equipment provided includes

base stations or radio control consoles at the locations listed above, mobile units

in several of the plant vehicles, numerous hand-held walkie-talkie units, and

mountaintop repeaters (see Table 5-4). The three UHF radio systems are used

for Plant Operations, Security, and Health Physics. The Health Physics system

has two separate modes, one for voice communications and the other for data

transmission. The Health Physics voice communication channel will be used by

field monitoring teams.

All three UHF radio systems are two-frequency systems. The two channel

capability increases the flexibilityof each system for both normal and emer-

gency uses. One channel has short-range onsite coverage, and the other provides

long-range coverage. The short-range channel provides direct radio-unit toradio-unit communications around the plant site, independent of the telephone

system. The use of the long-range radio channels requires all radio transmissions

to be rebroadcast by a mountaintop repeater. The long-range coverage extends

north to Cambria, south to Santa Maria, and east to San Luis Obispo. All the

UHF radio systems have similar short-range and long-range coverage.

The plant radio systems can be used in conjunction with paging devices tocontact onsite personnel who are out of range from other paging systems (i.e.,

the plant intercom). This paging capability can also be used to contact offsitekey plant personnel during offshift hours.

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The VHF radio system is the company's Los Padres «District Commercial

Operating Network, providing coverage from King City in the north to Solvang in

the south. The Districts radio-equipped vehicles are normally dispatched

through this system by one of several base stations in this network. The Control

Room radio station, the Technical Support Center communications console,'he

Emergency Operations Facility and the mobile stations in the Plant Manager'

and Security Supervisor's automobiles will have the capability to enter and

dispatch through this network if required during an emergency.

Marine and aeronautical radio communications capabilities are considered part

of the Security Emergency Radio System. Access to these radio frequencies willbe available at key plant locations: the Control Room, the Technical Support

Center, the Central Alarm Station and the Secondary Alarm Station.

n

The radio equipment is securely braced and anchored in the same manner as

previously discussed for the PGandE telephone system. All of the PGandE radio

communication systems are powered by battery-battery charger arrangements;

the chargers are supplied by reliable A'C power sources.

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TABLE 5-4I

PGandE RADIO SYSTEMS

Radio Control Console Locations

Plant Control RoomPlant Technical Support CenterSan Luis Obispo County Sheriff's Office/County

Emergency Operations CenterPGandE Emergency Operations FacilityPlant Security Department (CAS & SAS)Morro Bay Switching CenterPGandE Information CenterPort San Luis GuardhousePower Plant Hot Shut Down Panels Unit I and Unit 2

Base Station Locations

Plant Communications Room Unit 2Plant Meteorological BuildingPlant Security BuildingPGandE Emergency Operations Facility

Mobile Units

Plant Superintendent's automobileSeveral plant radio-equipped vehiclesNumerous portable units

Mountaintop Base Radio/Repeater Locations

Davis PeakTepusquet PeakTassajera Peak

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5.2.3 CRITICALELEMENTS

While the PGandE communications system is obviously very complicated, our

evaluation indicated that for emergency purposes there are three major redun-

dant and diverse methods of communications for each of the three important

information channels, between the plant and EOF. Communications within the

plant are much less vulnerable to seismic damage. The three major methods ofcommunications, in addition to the "normal" Pacific Telephone System, are:

(I) Off-premise dial telephone lines on the plant exchange using dedicated

'Pacific Telephone lines which are routed both north and south, (2) Dedicated

Pacific Telephone tie lines from the Control Room and the TSC to the PGandE

EOF, and (3) UHF radio transmission from the plant (and portable radios) to the

Davis Peak base/repeater radio and the base radios on Tassajera Peak and

Tepusquet Peak, and VHF radio transmission from the plant to base stations

located on Tassajera and Tepusquet Peaks. The three important radio/telephone

channels of information which are expected at the EOF are the Plant Operations

channel from the Control Room and TSC, the voice Health Physics from the

Control Room and TSC, and the data Health Physics for dose assessment.

For each of these methods, we examined the location and mounting of equipment

and backup power at the plant, at Davis Peak and at the EOF. All the PGandE

communications equipment appears to have been installed -following strictseismic criteria. All the equipment is placed in frames bolted to the floor and

braced to the ceiling. Emergency power is provided by batteries mounted on

seismically designed racks. Backup diesel. generators are available at the plantand at Davis Peak. The microwave antennae are designed to resist !00-mph'wind velocities comparable to seismic loading. The buildings housing 'the

equipment are seismically resistant structures at the plant. The building atDavis Peak has not been analyzed in detail, but it appears to be in a sound

location and capable of withstanding the type of acceleration expected at thatstructure. The temporary trailer housing the equipment at the EOF needs strongfoundation anchoring. In the past, trailers have reacted very poorly duringearthquakes, usually being thrown off their supports. This could sever

all the underground and above ground electrical connections necessary for

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communications and power supply. A permanent EOF is planned and will be

located near the County Sheriff s office. This facility will be designed to meet

seismic criteria. ~"Considering the redundancy of the communications system (Table 5-5),.it is

expected that communications could not be rendered totally inoperable by an

earthquake. Since all three communications channels can use each of the threemajor methods, we would expect that there is a high probability all threecommunications channels would be available to the EOF. Even if one channelwere unavailable, the two remaining channels could be used successfully eventhough the data channel for the dose assessment might require voice relay ofresults from the plant.

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TABLE 5-5

ALTERNATELINKS FOR THE COMMUNICATIONSSYSTEMS

I. PGandE Private Dial System is backed-up by thePacific Telephone System.

2. Onsite communication over the Plant PABX isbacked-up by the PGandE Radio Systems.

3. Plant CBX is backed-up by the PABX and PGandE"Private Dial System, with its capability to accessPacific Telephone lines remote from the plant.

4. Dedicated Special Purpose Pacific Telephone linesare backed-up by the PGandE Radio Systems.

5. NRC communication lines are backed-up by thePGandE Private Dial System (remote access toPacific Telephone lines).

6. Data Communication lines are backed-up by fieldmonitoring teams who can radio in data from offsitestations.

7. Plant Radio Systems are backed-up by PacificTelephone lines and the PGandE Private Dial Systemfor communications between the plant controlroom/TSC and the PGandE EOF.

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5.3 PACIFIC TELEPHONE COMPANY

5.3.l GENERAL DESCRIPTION

The Pacific Telephone Company provides telephone service in the San Luis

Obispo area. A Central Office is located in the city of San Luis Obispo, and thearea's associated Community Dialing Offices/Central Offices are located in

Avila Beach, Morro Bay and Pismo Beach. Pacific Telephone serves the DiabloCanyon Power Plant from both the Avila Beach and Morro Bay offices, with each

office providing the plant with 20 trunk lines.

The carrier to Central Offices consists of cable pairs either above or under-

ground; both are present in the study area. Central Offices or switching stationsreroute calls either locally through cable pair. or long distance to another centraloffice. The San Luis Obispo Central Office equipment is presently of themechanical type, but is scheduled to b'e replaced with new electronic equipmentby the end of the year. The equipment at Avila Beach, Morro Bay and PismoBeach offices are the mechanical type. All Central Offices use commercial DC

power, with batteries in line that can provide backup power for 3 to l2 hours.Diesel generators are also available to provide system electricity and to chargethe batteries.

In the study area, all long distance calls must go through the San Luis ObispoCentral Office before being rerouted either north to San Jose, south to the Los

Angeles Basin, or east to Bakersfield.

The carriers between Central Offices are either underground coaxial cables ormicrowave transmitters, or both. Small repeaters are placed underground alongthe coaxial cables and are powered by the cable itself. Depending on the line, a

signal enhancer is necessary every 30 miles or so. It is placed above ground in a

small 8' IO'tructure and uses commercial AC power with the same backuppower as a Central Office. Microwave installations'ccount for a smallpercentage of the carriers. Microwave repeaters have the same role and

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characteristics as coaxial signal enhancer equipment. Microwave dishes are

mounted on towers or small buildings.

The routing of calls on dedicated lines is similar to that used for normal calls,except that they always have a free carrier reserved for their use and thereforeare unaffected by the traffic on the system. However, they are susceptible tothe same type of system failure.

5.3.2 REDUNDANCYAND SEISMIC CRITERIA

All the equipment in Central Offices and repeater stations has redundant

backups, except the emergency power generators. The equipment has alarmsystems indicating equipment failure. The company buildings are seismicallydesigned to meet or exceed Uniform Building Code criteria. All the equipmentin Central Offices is set in frames that are bolted to the floor, braced and tiedtogether. Older equipment also is braced to the ceiling vertically with 45 anglesteel braces. New electronic equipment has the tops of the frames braced to thestructural columns in the building. Batteries are stored on seismic racks, and theemergency generators are mounted on springs with locking pins. Microwavedishes and towers are designed for high wind speeds comparable to seismic

loadings.

Pacific Telephone equipment has come through recent California earthquakes

without damage or service disruption. In January l980, two earthquakesoccurred, both centered north of Livermore and both registering greater than 5.0

on the Richter scale. A third, the October l979 El Centro Imperial Valleyearthquake, was over 6.3 on the Richter scale, and the epicenter was onlyI4 miles from the company's Central Office. While these earthquakes did notresult in loss of telephone services past experience has shown above-ground linesto be very resistant to earthquake damage and underground lines to be affectedonly by severe shear movement (fault crossing).

The Pacific Telephone Company has emergency plans for natural and human-

caused service disturbances. The plans include the procedures to be followed in

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the event of.a major earthquake. Emergency capabilities of Pacific Telephone

include:

o Operations Report Center to collect and compile reportsof damage.

o Two emergency centers, one in San Francisco and theother in Sherman Oaks, where managers collectively as-sess damage and direct restoration of service.

o Priority service can be provided to essential customers,-including police, fire, ambulance, doctors, civil defense,and selected federal, state, and city agencies and mostcoin telephones.

o ~ Within hours of,,a major earthquake, telephone employeesfrom outside the area can be mobilized and sent to theaffected area to assist in the assessment of damage andthe restoration of service. This can be done becausetelephone equipment is standardized.

5.3.3 CRITICALELEMENTS

The critical elements of the Pacific Telephone System consist of the power

supply for Central Offices and repeater-enhancer stations, the cable pairs and

coaxial cables, the equipment at the Central Offices and repeaters, the micro-wave tower, and the buildings housing the equipment.

In view of the seismic criteria and the redundancy of the system, it should

survive an earthquake of magnitude 7.5. The most likely failure modes ofcommunication between PGandE and Pacific Telephone consist of losing an

underground cable between the site and either the Morro Bay or Avila Beach

Central Office due to landslides. Other more unlikely modes of failure includethe complete loss of the Central Offices at Morro Bay, Avila Beach and San LuisObispo. Pacific Telephone communications at the plant would not be lost unless

both the Morro Bay and Avila Beach offices were lost. The loss of the San LuisObispo Central Office would disable long-distance calling in the area.

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5.4 SAN LUIS OBISPO COUNTY COMMUNICATIONSSYSTEM

5.4. I GENERAL DESCRIPTION

San Luis Obispo County is currently evaluating the County's emergency com-

munications requirements. The County Emergency Response Plan addresses the

use of the existing law enforcement, radio communications and teletype services

including the state Public Safety Microwave System, along with the use of new

dedicated tie lines, paging devices, emergency monitoring devices, and radio

equipment. The new emergency communications system configuration is ex-

pected to be finalized in the near future.

The San Luis Obispo County Emergency Operations Center (EOC) will be co-

located in the County Sheriff s Office and will use the Sheriff's radio communi-

cations during an emergency. The County Sheriff's Department has 70-80 radio-

equipped vehicles including patrol cars, vans, and four-wheel drive vehicles, and

40-50 portable radio sets operating on the three different frequencies designated

blue, yellow, and red channels. The radio system mountaintop repeaters are

located on Davis Peak; Rocky Butte, Black Mountain, and Cuesta Peak. The

system has simulcast communications over all four repeaters. The simulcast

system enhances the voice communications quality and operates in a loop

arrangement with the Sheriff's Office Communications Center, from where allcommunications are rebroadcast. Communications between radio-equipped vehi-cles can be accomplished over a separate white channel for limited distances up

to three miles.

The repeaters for the County Local Government frequency and the County

Medical Communications (Med Com), for ambulance dispatching, are co-located

with the Sheriff's mountaintop repeaters; The County Engineering Department

operates on the local government frequency. A base station for the county 'fire

departments is also located at each repeater site.

The mountaintop installations have backup power, liquid petroleum generatorswith 450-gallon tanks..The switchover to backup power takes only a few

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seconds. Batteries provide the backup power for the Sheriff s Office Communi-

cations Center.

The county will be able to notify simultaneously all law enforcement agencies

via the California Law Enforcement Teletype Service, which operates over

leased telephone lines coming from Santa Barbara. The California Office ofEmergency Services (OES) can provide additional communications capability over

the state Public Safety Microwave Radio System. This multichannel system

enables the OES to talk to San Luis Obispo area local police, sheriff, and

California Highway Patrol offices, as well as local government offices. The

radio system base station is located on Mount Lowe, northeast of the city of San

Luis Obispo.

5.4.2 CRITICALELEMENTS

The critical elements of the county communications systems consist of the

mountaintop repeaters and the radio-equipped vehicles. The communications

center at the Sheriff s Office is needed to provide simulcast communications. Ifthe communications center were lost, each repeater would have to be manually

switched to operate in the general repeater mode. The quality 'of the

transmission would decrease but the communications system would be opera-

tional. However, the base stations for the fire department would be lost since

the communications center transmits to the base stations.

A number of portable transmitters.and repeaters are available to replace any

major failure of one system's components.

The facilities at the Sheriff s Office and Davis Peak were visited. The building

housing the equipment at the Sheriff's Office appears to be of marginal

earthquake resistance, although no analysis has been made. The equipment is

bolted to the ground but lacks ceiling bracings. These would greatly improve the

equipment stability. At Davis Peak, the equipment is housed in the PGandE

building; here again it is bolted to the floor but not braced to the ceiling even

though a top railing is provided in the building.

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5.5 EMERGENCY BROADCAST SYSTEM

5.5.I GENERAL DESCRIPTION

San Luis Obispo County/cities have established an Emergency Broadcast SystemPlan to be used in the event of an emergency situation, such as a natural disaster

or a major accident/explosion. The Emergency Broadcast System (EBS) is

available to disseminate emergency information and warnings to the general

public at the request of designated local, state and federal officials. The countyplan presents the objectives of the EBS, which include providing the public withaccurate information in an expeditious manner and controlling rumors withtimely release of information.

The operation of the EBS relies on primary EBS stations to monitor a Common

Program Control Station (CPCS) for emergency alerting and programming. Allother EBS stations are considered primary stations. The County EBS Plan

identifies three radio stations to be Common Program Control Stations (CPCSs),although only one will function as the CPCS at any time. The three stations areKVEC (CPCS-I), KSLY (CPCS-2) and KATY (CPCS-3). The operating CPCS

sends emergency programming to all primary EBS stations, following theactivation of the EBS for an emergency. Primary EBS stations rebroadcast localemergency programming only on a voluntary basis. The procedure for state ornational emergencies is slightly different and primary stations are required torebroadcast emergency programming.

5.5.2 CRITICALELEMENTS

The radio transmission towers and their telephone links are critical to theoperation of the EBS system and are vulnerable to earthquake damage. Anotherconsideration is backup power; the CPCS-I station, KVEC, is the only stationwith backup power for the transmitter and studio. At the present time thestation is not on the air 24 hours a day. The earthquake resistance of the EBS

communications equipment is in question, because the stations reviewed reportedthat the stations'arthquake resistance has not been previously evaluated.

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The activation of the EBS system relies on communications to the CPCS station

over Pacific Telephone lines. The emergency message to be broadcast is also

delivered over the telephone. Activation of the EBS and delivery of the message

could be performed by a messenger or by radio.

One would not expect that all of the EBS stations would sustain damage

rendering them inoperable following an earthquake. The County EBS Plan has

provisions ensuring the operation of the EBS to provide emergency informationto the public. For that purpose, the radio station designated CPCS- I is equipped

with backup power for both the studio and the transmitter to ensure its operation

following the loss of commercial power. In addition, the CPCS-I station has the

capability to arrange to transmit directly from the transmitter site, should the

telephone lines to the transmitter be unavailable. This transmission arrangement

will require that a technician and special equipment be sent to the transmittersite. If the CPCS- I station is not operating, one of the two backup stations

(CPCS-2 or CPCS-3) would assume the role of the operating CPCS. Should it be

necessary, an airborne public address system could be used to complete thenotification of the public.

A list of participating San Luis Obispo County EBS radio and television stationsis presented in Table 5-6. Descriptive information on the three CPCSs is

provided in Table 5-7.

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TABLE 5-6

SAN LUIS OBISPO COUNTY EBS STATIONS

KATY - radio

KBAI - radio

KCBX - radio

KCPR - radio

KIQO - radio

KKAL - radio

KPGA - radio

KPRA - radio

KPRL - radio

KSBY - television

KSLY — radio

KUNA - radio

KVEC - radio

San Luis Obispo

Morro Bay

San Luis Obispo

San Luis Obispo

Atascadero

Arroyo Grande

Pismo Beach

Paso Robles

Paso Robles

San Luis Obispo

San Luis Obispo

San Luis Obispo

San Luis Obispo

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TABLE 5-7

SAN LUIS OBISPO COUNTY EMERGENCY BROADCAST SYSTEM

Call: KVEC EBS Classification CPCS- I

Studio

Location: 820 Walnut, San Luis ObispoBackup power: diesel generator

Transmitter

Location: Off Highland Drive, on hill near California Polytechnic State Univ.Height: 250 ft., free-standingBackup power: bottled gas generator

Communication between studio and transmitter: 2 separate Pacific TelephoneSystem telephone lines.

Call: KSLY EBS Classification CPCS-2

Studio

Location: 2895 South Higuera St., San Luis ObispoBackup power: none

Transmitter

Location: On hill above studio, San Luis ObispoHeight: 175 ft., guy-wiredBackup power: none

Communication between studio and transmitter: 2 separate Pacific TelephoneSystem telephone lines.

Call: KATY EBS Classification CPCS-3

Studio

Location: I I46 Montgomery St., San Luis ObispoBackup power: none

TransmitterLocation: S. Higuera Street Near Meisner RoadHeight: I52 ft., guy-wiredBackup power: none

Communication between studio and transmitter: I Pacific Telephone Systemtelephone line.

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5.6 EARLY WARNING SYSTEM

5.6.l GENERAL DESCRIPTION

The Early Warning System (EWS), an area-wide siren system, will be installedwithin the state Basic Emergency Planning Zone to alert the public promptly in

the event of a major accident at the Diablo Canyon Power Plant. The county is

responsible for sounding the EWS and providing emergency information and

instructions to the public. The initial sounding of the EWS will notnecessarily'ean

that an evacuation is ordered; it will serve to alert the public to tuneradios or televisions to an Emergency Broadcast System station for emergencyinformation and instructions.

The EWS siren system consists of a network of approximately 75 area-type sirensof various sizes designed to attain the desired radius of coverage. The sirens will

I

be installed on existing structures in the PGandE electric distribution system. In

addition, the EWS has a number of sirens used to notify individual houses inremote areas outside the range of area sirens. Indoor warning devices orprocedures will be used in large buildings that may not allow the area sirens tobe heard. Buildings in this category include hospitals, schools, detentionfacilities, factories and large office buildings.

The EWS sirens will be tone-activated through a radio system. Activation of thesiren system is planned to be over the San Luis Obispo County local frequencyI58.805 mHz. This radio network consists of three remote mountaintop trans-mitters linked by microwave to the Sheriff's Office. With this arrangement a

tone encoder is installed at the Sheriff's Office which will activate the threemountaintop transmitters via the county microwave system. Each siren'sactivation signal will be provided by at least one of the three remote mouritain-top transmitters, located at Davis Peak, Rocky Butte and Cuesta Peak.

Backup control of the sirens will be provided by installing necessary encoders on

transmitters located at the Morro Bay, San Luis Obispo, and Pismo Beach city

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police or fire departments and designated Zones I, II and III, respectively. These

transmitters willoperate independently of each other.

The Sheriff, upon receiving authorization as stipulated in the San Luis ObispoCounty Emergency Response Plan, will activate the EWS. Security provision toprevent inadvertent operation of the EWS will be built into the system.

5.6.2 CRITICALELEMENTS

We did not conduct a detailed seismic assessment of the EWS. It has no backuppower supply to the normal AC power. The purpose of the EWS system is toalert the public.to turn on their radios for information in the event of aradiological emergency. This system would not be required to notify people ofthe occurrence of a magnitude 7.5 earthquake in the study area. Such anearthquake would be felt for many miles and the strong shaking in the study areawould be sufficient to alert at least as many people as the EWS, and therebyalert people to turn on their radio for further information.

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6.0 DIABLOCANYON EARTHQUAKERESPONSE PLAN

6. I INTRODUCTION

The planning approach described in this section provides a conceptual frameworkfor dealing with the occurrence of a large earthquake and radiological accident

in the vicinity of the Diablo Canyon Power Plant (DCPP). The existing siteradiological emergency plan for DCPP incorporates many of the planningactivities and interfaces appropriate for handling any type of emergency. In

addition, plans exist at the local, state and federal levels for responding to'

major earthquake. The intent of this plan is to supplement and expand, where

necessary, the guidance and planning base in existing plans to specificallyconsider a combined earthquake/radiological emergency. Consistent with the

approach for radiological emergencies, a spectrum of potential earthquakeeffects is considered in terms of specified damage levels. By not limiting the

plan to consideration of specific scenarios, it should be possible to provide a

broad and flexible planning base that can be readily adapted to the exigencies ofthe actual event.

6.I.I PURPOSE

The purposes of the Diablo Canyon Earthquake Response Plan are as follows:

I. Enhance, through the use of specialized operational con-cepts and emergency actions, the overall preparednessand capability of responsible organizations to respond tothe compounding effects of an earthquake on the imple-mentation of radiological emergency plans;

2. Identify the scope and nature of potential earthquakeeffects on critical elements of the DCPP emergency planand actions to ameliorate these effects.

3. Provide suggested operational concepts to be followed bythe responsible organizations to respond to earthquakeeffects and minimize their impact on the radiologicalemergency plans.

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4. Provide a planning base for the development of detailedStandard Operating Procedures and interorganizationalagreements.

6.I.2 RELATIONSHIP TO OTHER PLANS

I. State of California Earth uake Res onse Plan

The state Earthquake Response Plan is the basic plan for responding to a majorearthquake within California. It sets forth the operational concepts and

responsibilities for such emergencies and is the primary source of earthquake-related planning. It provides guidance for each level of emergency response

(Local, Operational Area, Mutual Aid Region, and State) and outlines procedures

by function (Direction and Control, Fire and Rescue, Law Enforcement and

Traffic Control, Medical and Health, Emergency Welfare, and Resources and

Support).

The DCPP Earthquake Response Plan is designed to interface the state plan withradiological emergency plans and provide supplemental guidance for the unique

potentiality of a combined emergency.

2. San Luis Obis o Count Nuclear Power Plant Emer enc Res onse Plan

The county plan establishes organizational responsibilities and actions requiredto minimize radiation exposure in the event of a radiological emergency at theDCPP. It is supplemented by Standard Operating Procedures covering emer-

gency notification, mobilization of emergency personnel, dissemination of infor-mation, responsibilities and authorities, interfaces with other agencies, and

resource listings.

3. DCPP Emer enc Res onse Plan

Pacific Gas and Electric Company has prepared a facility emergency plan toaddress potential accidents or severe natural phenomena occurring at the plant.The plan is, directed at actions necessary to be undertaken by PGandE to

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minimize the course of the plant'emergency and to assess the future course of

events and recommended protective actions.

4. State of California Nuclear Power Plant Emer enc Res onse Plan

The state plan describes the responsibilities of state organizations in responding

to a nuclear plant emergency.

5. California De t. of Trans ortation Emer enc Plan (CALTRANS)

The state CALTRANS emergency plan outlines the response of CALTRANS to

peacetime and war emergencies, including earthquakes. This plan ensures that

actions are taken to (I) restore and maintain the state transportation system in

effective operating condition, (2) assist local governments to restore and

maintain their transportation systems in effective operating condition, and (3)

provide engineering and communications support to the state Office of Emer--

gency Services (OES), the CHP, and other agencies. Under the plan CALTRANS

maintains inventories of various equipment including aircraft for emergency

operations support. In implementing the plan CALTRANS will provide highway

damage assessment data and assistance in clearing and repairing major trafficarteries.

6. California De t. of Trans ortation District 5 Emer enc Plan (CALTRANS)

The District 5 CALTRANS plan for the San Luis Obispo area is the local

counterpart of the state CALTRANS plan. It provides for the establishment. of a

District Emergency Planning Officer and for liaison with local agencies and OES

Regional Managers.

7. Federal Plans

The Federal Emergency Management Agency (FEMA), Department of Energy

(DOE), and Nuclear Regulatory Commission (NRC) would all assist the primaryresponse organizations in the event of a radiological emergency at the DCPP. In

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addition, FEMA would have the lead federal agency role for other natural

disasters, such as a severe earthquake.

6. I.3 STATE-OF-THE-ART

The state of planning for a radiological emergency in the same frame ofreference as the occurrence of a major earthquake is still an ongoing and

evolving process. Radiological emergency planning has received constant

attention for many years as part of the federal licensing requirements for

nuclear power plants. The current plans, in fact, represent a new generation of

complexity and sophistication as a result of the experience gained during the

Three Mile Island accident. The decision to explicitly overlay the effects of an

earthquake on the functionability of the radiological plan is most recent and

mandates a synthesis of analysis, planning concepts, and responsibilities not

previously envisioned. Compounding this is the fact that detailed earthquake

planning is still evolving in this country and, for a major event, transcends the

authority, responsibility and capability of a single utility or local governmental

entity.

The approach taken in this plan reflects the developmental nature of this unique

type of planning and the organic character of emergency planning in general. As

for all types of emergencies, the planning process does not focus on the conse-

quences of the events. Rather, in the event that those consequences ever come

to be, it assures that plans are in place which have anticipated and made

provisions for a suitable response.

6.2. OPERATIONAL CONCEPTS

6.2. I - GENERAL

The combined occurrence of a large earthquake and a radiological emergency at

DCPP represents a new challenge to emergency planners. Fortunately reason-

able planning has been accomplished for each event occurring individually. This

plan attempts to bridge the existing planning structure for the separate events,

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leaving intact those elements of each plan that are essentially independent and

providing additional plans for those aspects of a combined. event that present

new or unique problems. It is recognized that more detailed planning, par-

ticularly in terms of implementation, is required.

There are two emergency activities that are of particular concern for this plan:

protective actions for plant personnel and the general public, and the capability

to maintain communications systems relied upon to implement emergency plans.

With regard to the former, evacuations are ordinarily considered as either pre-

impact or post-impact of a given disaster. Pre-impact evacuations are accom-

plished when there is sufficient warning of an event, such as may be the case forfloods or dam failures. Post-impact evacuations, on the other hand, generally

are oriented toward reconstruction or rehabilitation of an already damaged area.

Radiological accidents would normally fall in the pre-impact evacuation cat-

egory while earthquakes, due to the general lack of predictive capability, usually

involve a post-impact evacuation. It is clear that when an earthquake is

considered in common with a radiological emergency, an evacuation could be a

hybrid, serving multiple purposes such as hazard avoidance and rescue. The

decision-making process outlined in this plan is directed at the potential need forevacuation due to a release of radioactivity from the DCPP. It is recognized

that other valid, independent reasons compelling evacuation could arise (e.g., the

potential for a dam failure following an earthquake) and that decisions under

these circumstances would be made on more general criteria applicable topeacetime disasters.

Another general operational concept of relevance here is the inverse pyramid ofresources described in the state Earthquake Response Plan. That is, when a

major earthquake occurs, the initial response and resources must come fromlocal authorities to the extent possible. If these resources are exhausted,

additional assistance may be requested from the Mutual Aid Region and from the

state. Ultimately for large disasters, federal assistance may be required tocontend fully with all aspects of the emergency. It appears that this concept ofoperations is, if anything, even more applicable to the very severe disaster thatan earthquake .and radiological accident would effect. This plan offers

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appropriate guidance for the initial authorities that would be involved in the

response, i.e., PGandE and San Luis Obispo County. It is expected that where

conditions require additional assistance and resources, they would be obtained

from the appropriate state and federal agencies in the manner described in other

plans.

6.2.2 REPORTING OF THE EMERGENCIES

The occurrence of an earthquake within the State of California would be

reported to the state Office of Emergency Services (OES) by one or more of the

following means:

o The National Earthquake Information Service (USGS)

o Local authorities that experience substantial earthquakeeffects

o Field units of state agencies that experience substantialearthquake effects

o Pacific Gas and Electric Company: for the Diablo Canyonsite PGandE would notify local, state, and federal offi-cials of the occurrence of earthquakes in accordance withthe emergency action levels specified in Reference 3.

The report and confirmation of a major earthquake will precipitate a number ofactions at the state level as described in Reference I, Part II E.

6.2.3 EMERGENCY PERIODS

The state Earthquake Response Plan describes three phases of an earthquake

generated emergency:

o Phase I - Immediate Emergency Phase

o Phase II - Sustained Emergency Phase

o Phase III - Recovery/Rehabilitation Phase

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The activities 'uniquely associated with a combined radiological emergency and

earthquake would fall into the first phase.'ubsequent response under Phases II.

and III would need to be caveated so that activities taking place in the DCPP

Radiological Emergency Planning Zones would be modified as appropriate to

account for any radiological release.

Somewhat analogously, the utility,county and state radiological emergency plans

for the DCPP specify the sequence of activities for that category of events. If

earthquake effects are superimposed on these plans, the major interactions are

again found in the assessment and protective action functions. Other emergency

activities would need to take account of any direct earthquake effects but would

otherwise be essentially unchanged.

6.2.4 CONCEPT OF LOCAL OPERATIONS

As indicated in the San Luis Obispo County Nuclear Power Plant Emergency

Response Plan, the organizational form of the county and city governments

within the area does not require major changes in the no'rmal lines of authority

to conduct effectively the various actions outlined in the Plan. For an

emergency condition encompassing several political jurisdictions,.the San Luis

Obispo County/Cities~Basic Plan for Peacetime Emergencies and supporting

emergency ordinances at the county and city level provide for a coordinated

emergency preparedness organization with the county assuming the key coordi-

nating role.

As stated in the county plan, county departments participating actively in

responding to an emergency are classified into four groups, according to

function:

o Direction and Control Group

o Response Group

o Support Group

o Assessment Group.

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Figure 6-I=provides a schematic for the local response activities associated with

a combined earthquake and radiological emergency. In concept it provides for

parallel activation and implementation of earthquake response plans and radio-

logical emergency plans. In addition, it specifies areas requiring coordination

and joint assessment. A principal element would be an Earthquake Damage

Assessment Center (EDAC) to evaluate the impact of a combined event on the

emergency response activities that would otherwise be prescribed for the

individual events. In addition, the Unified Dose Assessment Center (UDAC)

would evaluate radiological releases from DCPP and recommend the appropriate

radiological protective actions for emergency workers and the public.

The earthquake is taken as the triggering event for the earthquake emergency

plan. If a radiological event had already been in progress at the time of an

earthquake, the only change would be that the radiological emergency plans

would have been previously activated. In either event, the experience of an

earthquake would trigger earthquake response plans (state and local) and would

also activate radiological plans since seismic events are included under each

emergency action level (the action level being a function of the earthquake size).

While the activation of each plan will precipitate a number of response

activities, a timely assessment of damage both at DCPP and within the Basic

Emergency Planning Zone is necessary to establish any synergistic effects.Damage assessment within the Basic Emergency Planning Zone would focus on

primary evacuation routes and communications systems. Damage assessment atthe DCPP would consider any short-term or long-term degradation of plant

systems, onsite evacuation routes, and communications equipment. At this

point, decisions will be made as to the need to continue emergency plansin'ffect.If the earthquake was minor and caused essentially no damage, this

finding would be transmitted to the EDAC (described below) and the earthquake

plans phased out. If significant earthquake damage was experienced, damage

assessment and repair activities would be undertaken and, in the longer term, the

Phase II and III activities of the state Earthquake Response Plan would be

required.

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In a parallel path, a negative finding of damage to the DCPP itself would be

reported to the EDAC and, in accordance with the radiological plans, emergency

preparedness activities would be phased down. If there was significant damage

reported at the DCPP, appropriate damage assessment activities would be

undertaken. The damage'evaluation would be passed on to EDAC to allow an

integrated assessment of earthquake damage and to UDAC for development of a

dose assessment prediction.

Upon determination that there had been more than slight earthquake damage and

that a potential for a radiocictive release from the DCPP existed, an integrated

protective action assessment would be established. The UDAC would provide

input as to the likelihood and timing of any radioactive release and the

advisability of implementing any protective action. Concurrently, the EDAC

would provide their evaluation of the integrity of communications systems and

evacuation routes and the feasibility of implementing various protection actions.

This input would be made available to the county Direction and Control Group

for a determination of the protective actions to be followed. The range of

protective actions and the protective action guidelines would be identical to

those currently found in the radiological emergency plans. The basis for

selection of protective actions would also be'essentially the same, only the data

base on evacuation. times will have been adjusted to account for the effects of

the earthquake. Where an evacuation is determined to be the appropriate

protective action, the actual implementation options available will be more

numerous and flexible to minimize any earthquake-related impediments.

The specific tasks involved in damage assessment and protective action assess-

ments are described in detail in Section 6.3.

B-8I-269 6-9

TERA CORPORATION

EARTHQUAKEEXPERIENCED

EARTHQUAKE RESPONSEPLANS ACTIVATED

RADIOLOGICALPLANSACTIVATED

SIGNIFICANT DAMAGETO AREA?

NO NO SIGNIFICANT DAMAGETO DCPP?

YES YES

DAMAGE ASSESSMENT EDAC DAMAGE ASSESSMENT

REPAIR ACTIV I TIES

PROTECTIVEACTION CAPABILITY

ASSESSMENT

UDAC DOSEASSESSMENT

PHASE II, III RECOVERYACTIVITIES

PROTECTIVEACTION

OTHER RAD.EMERGENCYACTIVITIES

FIGURE 6-I

EARTHQUAKEEMERGENCY PLANRESPONSE SCHEMATIC

6-IO

TERA CORPORATION

6.2.5 EARTHQUAKEDAMAGE ASSESSMENT CENTER (EDAC)

In contemplating the combined effects of an earthquake and radiological

emergency, it is important to provide the capability for an integrated assessment

function of earthquake damage to the extent that it could impact on emergency

activities. To provide this capability, an Earthquake Damage Assessment Center

(EDAC) will be established. The EDAC will receive reports from damage survey

teams deployed to inspect primary evacuation routes and communications

systems. PGandE would still input plant status and damage to the UDAC but, in

addition, damage to plant transportation routes and communications systems

would be reported to the EDAC.

Based on the damage reports the EDAC will:

(I) Provide an assessment of the availability of,communica-tion links, including EWS and EBS.

(2) Provide an overall evaluation of damage to the evacuationroad network (i.e., no, light, moderate or heavy damage).

(3) Specify the available evacuation routes and alternaterouting if necessary, and approximate capacities at anytime.

(4) Update the. assessments as more detailed reports arereceived or repairs are effected.

Prioritize allocation of repair resources to damaged sys-tems.

The EDAC will comprise representatives of the county, PGandE, CALTRANS,

and Pacific Telephone. These individuals will have the requisite expertise in

highway/bridge design and repair and communications systems.

B-8I-269 6-II

TERA CORPORATION

6.2.6 ADDITIONALINTERFACES WITHSTATE EARTHQUAKERESPONSE PLAN

6.2.6. I EMERGENCY CONDITIONS

Section II of the state Earthquake Response Plan defines five emergency

conditions, A through E, as the basis for planning and response. Condition A is a

general preparedness, or standby, condition based on the assumption that a

serious earthquake will occur in the future. Conditions B, C, D, and E describe

situations prevailing after an earthquake has occurred. The conditions are as

follows:

Condition A - Pre-Emergency

Condition B - Distant from Damaged Area

Condition C - Close to Damaged Area

Condition D - Damaged

Condition E - Evacuation

The operation of this Earthquake Response Plan would only arise under condi-

tions C, D and E. These same emergency conditions can still be used to describe

the earthquake-related status in interfacing with state and other agencies, withone modification. As currently envisioned by the state plan, condition E would

effectively arise only when there existed a risk of dam failure subsequent to an

earthquake. For the DCPP Emergency Planning Zone there could also be the

potential need to evacuate due to a radiological emergency.

6.2.6.2 COORDINATION OF OPERATIONS

Under the state Earthquake Response Plan,

Operational Area. At the next level there

Regions, the DCPP being located in Region I.

local and state resources, these area and

each county is designated an

are six designated Mutual Aid

As a basis for coordination of

region designations should be

B-8 I-269 6- I 2

TERA CORPORATION

maintained to the extent possible under a combined earthquake/radiological

emergency.

The state plan also provides an outline of state, federal, and military operations

that would be responsive in the event of a major earthquake. These conceptual

plans provide a reasonable basis for response by these organizations. Since these

same agencies also have responsibilities under radiological emergency plans forthe DCPP, the individual agencies may want to provide additional guidance forresponding to a dual emergency.

6.3 SPECIAL TASKS

This part identifies those special tasks that might have to be performed

following a major earthquake and radiological emergency. The focus is on those

tasks that require special attention due to the uniqueness of a combined event.

Tasks that would be required to respond to each event independently are assumed

to be performed in accordance with applicable'plans. Where various organiza-

tions are assigned tasks, it is expected that implementing plans and procedures

will be developed accordingly.

TASK A DAMAGE ASSESSMENT OF TRANSPORTATION ROUTESAND COMMUNICATIONS

I. ~Pur ose

To establish policies and objectives and assign general responsibilities for the

following activities:

a.

b.

Early conducting of a reconnaissance of the Basic Emer-gency Planning Zone to determine the nature, extent, andlocation of damage to primary evacuation routes andcommunications sytems.

Follow-up assessment activities to monitor repair andrestoration activities and update evacuation routes andcommunications availability.

B-8I-269 6-l3

TERA CORPORATION

co Assessment of damage reports for input to protectiveaction decisionmaking, allocation of repair resources, andrequirements for alternate means of transport or com-munications.

2. Conce t of 0 erations

Following an earthquake, field units of local government and state agencies will

promptly conduct a rapid reconnaissance of the affected areas to determine the

extent and nature of damage (see References I, 5 and 6). For the Basic Planning

Zone described in Reference 2, particular attention will be given to the condition

of the primary evacuation routes. Reports of damage to these routes will be

channeled to an Earthquake Damage Assessment Center (EDAC) for assessment

and use by the county, Direction and Control Group. In addition, communications

systems availability will be determined by actual usage and system checkouts.

Where specific problems are enc'ountered, damage teams will be dispatched as

appropriate (e.g., to Davis Peak). Other forms of general earthquake damage

assessment will be conducted and reported in accordance with the requirements

of the state Earthquake Response Plan.

3.

~Sifts*

T k

A. DAMAGE RECONNAISSANCE

Following the occurrence of a major earthquake, an immediate area reconnais-

sance of the Basic Emergency Planning Zone will be undertaken. The survey

would normally be conducted as follows:

(I) Roads and overpasses for the primary evacuation routeslisted below are surveyed to determine the extent andlocation of damage.

o Route I from San Luis Obispo to Morro Bay andalong the coast to the north;

o Route IOI north and over the mountain range fromSan Luis Obispo;

B-8I-269 6-I4

TERA CORPORATION

Route IOI south from San Luis Obispo and throughthe urbanized region along the south coast;

4

Route 4l, from the intersection with Route I inMorro Bay to Route IOI in Atascadero;

o Orcutt Road, from San Luis Obispo via Huasna Roadand Route 227, to the intersection with Route IOI in

'rroyo Grand;

o Route 227 to Price Canyon Road and hence to theintersection with Route IO I in Pismo Beach; and

o Route I, from the interchange with Route 10l onthe northern outskirts of Pismo Beach, along thecoast and out of the EPZ.

(2) The. damage surveys should identify any failures or dam-age to bridges/overpasses and the occurrence of anylandsliding or ground subsidence. Locations of damageshould be given by bridge number and highway mileagemarker. Figures 6-3a through 6-3h indicate the locationsof bridges and potential areas for landslides and liquefac-tion. The following damage characterizations should beobserved.

~Brid ee

o No observable damage

o Light damage, bridge passable at reduced speed

o Moderate damage, bridge temporarily impassable upto four hours, repairs required

o Heavy damage/failure, bridge impassable and notrepairable within four hours.

Landslides

Estimate number of feet and depth of encroachment ofslide on road shoulder and pavement.

Subsidence

Where subsidence is observed, categorize as light, mod-erate or heavy in a similar manner as described underbridges.

B-8 I -269 6- I 5

TERA CORPORATION

(3) Where moderate or heavy bridge damage or road subsi-dence occurs, or significant encroachment due to slidingis observed, survey the availability of alternate routing.A list of alternate routes for critical highway bridges isincluded in Table 6-l.

(4) Damage assessment should also be performed for all vitalcommunications links relied upon in the'adiologicalemergency plans. These are listed below. Generalassessments can be made'hrough the continued usage andavailability of normal communications channels. Forspecial systems such as EWS and EBS or where specificproblems are encountered;,damage survey teams will bedispatched to the scene (e.g. Davis Peak). If all EBSstations are unavailable, other commercial radio stationswill be surveyed to identify those capable of transmittingemergency instructions. Alternate means will be estab-lished to convey the messages to the station for broad-cast. Reports should be made to the EDAC.

Pacific Gas and Electric Company

o PABX

o CABX

o Coast Valley Microwave System

o West Valley Microwave System

o UHF- Radio System

o VHF Radio System

o Early Warning System

San Luis Obispo County"

o Telephone Lines to EOC

o 'HF Radio

o VHF Radio

Pacific Telephone and Telegraph

o PGandE Interface

o Telephone Lines

Radio/Television Stations

B-SI-269 6-l6

TERA CORPORATION

o EBS

(5) Local damage reconnaissance will usually be accomplishedthrough ground surveys using local agency emergencyvehicles.

(6) Aerial reconnaissance will be utilized where capabilitiesand conditions permit. To the extent practicable, thesesurveys will be initiated by San Luis Obispo County usinglocally available aircraft. Flights will be coordinatedwith and additional equipment requested from the stateOES Mutual-Aid Region (see Appendix A of Reference I

and References 5 and 6).

(7)

(8)

All damage reconnaissance missions will be coordinated,or be a part of, the general damage reconnaissancemissions conducted pursuant to the state EarthquakeResponse Plan.

Where no damage to evacuation routes or communicationssystems is observed, negative reports are to be made toEDAC to establish completeness of reconnaissance.

B. DAMAGE ASSESSMENT

(2)

Following the submission of damage reports from the fieldreconnaissance teams, the EDAC will evaluate the dataon evacuation route and communications systems damage.

An overall assessment will be made as to the damagesustained by the evacuation road system in accordancewith the four categories defined below:

(3)

o Essentially no damage

o Light damage

o Moderate damage

o Heavy damage.

An overall assessment of the damage to communicationssystems will be made with findings as to capability forvoice and data transmission from the plant to the EOFand EOC; capability for communications between ele-ments of the county emergency organization; and theoperability of the EWS and EBS.

Estimates will be made of the resources required to repairprimary evacuation routes and communications systems.

B-8I-269 6-l7

TERA CORPORATION

The resource requirements will be compared to resourceavailability and a priority agenda will be prepared

for'onductingrepairs. Time estimates for the restoration ofservice will then be determined and made available todecisionmakers.

(5) Periodic updating of the damage assessments will be madeto include progress of. repairs and more detailed damagesurveys.

C. ORGANIZATIONS AND RESPONSIBiLITIES

~DSPGandE: Access road to Port San Luis

Gate and northern routethrough Montana de Oro StatePark.

CALTRANSCounty EngineerCounty Sheriff's OfficeCalifornia Highway PatrolLocal Police Departments

Pacific TelephonePacific Gas and ElectricCounty Sheriff's Office

Offsite Primary EvacuationRoutes

Communications Systems

B-8I-269 6-I8

TERA CORPORATION

SAN LUIS OBISPO AREA-Northern Section

Figure 6-3a

AREAS OF POTENTIAL LANDSLIDE

ATASCADERO

CAYUCOS 4IQss

Estero

8ay EU ~

SANTAMARGARITA

VIDRRP

Nero8oy

SAM 'rSABEL

'ROAD

ioi~ A

SanlaNorgari la

Lake

0 I 2 3

SCALE N ISLES

Point8rlchon

LOS OSOS r,oO>OS:"O

ROAD$ yg

Eeu

ee'ossos

ROAD

pc&

C~ic

ROAD Q Oq

SANTAROPA

go+ q+

LEGEND

PNMNIY EVACUAYION ROAD

SECONDARY EVACUAYICN ROAD

OYIIER ROADS

%% POTENTlAL LANDSLIDE AREA

TERA CORPORAllON

Punt8udion

o LOS QSOS<OS

OSOs

ohio<os

so

yALLET ROADI-IEI

ANKFAR|A

0+c~

P~

SANTAROSA ST.m ~"

I

4Y

SAN LUIS OBIS

SAN LUIS OBISPO AREASouthern Section

Figure 6-3bAREAS OF POTENTIAL LANDSLIDE .

E V

- „.„~Diablo CanyonPOWER PLANT

E

I 0 I 2 3

SCAI.r. III MII.SS

LEGEND

-4;AyiLABEACrLVV.A LM

0

~IOE ~

San Luis Obispo Boy SHELLBEACH

PISMOBEACH

GROVERCITY

LO

e~ A

GRAND I

ROYOGRANDE

dIL

ILI

+o~o

= o~

ISA

oeAY'

E

Loper ."

Canyon"

Abscrvul -'.

YHMARY EYACIIATHH RDAO

SHXHDAIIY EYACDATEH RDAD

OTIIER ROADS

8I rmeNmAL uwosuoE ~A

D ~OI

osQIOI

+o

0

SAN LUIS OBISPO AREA-Northern Section

Figure 6-3C

AREAS OF POTENTIAL LIQUEFACTION

ATASCADERO

I ~

CAYUCOS

r$ gglL

L ~

4lQss

Estero

8oy

'V,E 1

I" SANTAMARGARITA

C)

MORRP A ".

IOFI .

E 'I; vAATE

V

'Irr, 'E

Narro8oy

SAN TSABEL

ROADr....'~<

I~

LOS OSOS gpDODS... %",gear.0

OIE'rI rrrE

~op

0

ROADA ":„. SANTA

+0 cj

Qoi

SontoNargorito

Loke

I 2 3

SCALE IH NLES

LEGEND

THHART EVIIOOATIOH ROAD

EEHHDAIH EVAOOATIOH IHVID

Point8riohur

VALLEY

4(ROAD

+o

OTIIER RDAIHIi HIGH P0TENTIAL LICVEFAcTNN

Nm Iow P0TENTIAL LICUEFAGTNN

PrintBudIon

I LOS OSOS '-AV,vga'~~

~8$ 'h Kos .,~,os""jpo,

'l'os-.'::::>os,:,,

'''(eyALLEY ROAD

I-4lILI

+

SAN LUIS OBIS

SAN LUIS OBISPO AREASouthern Section

Figure 6-3dAREAS OF POTENTIAL LIQUEFACTION

sg~Cq

Diablo Canyon+POSER PLANT

yl A<

AVILABEAC .,';.;,:.,:...

OpCg

+elp

0~~'o~

Lope;:Conyon;

'incrvoir:.1h

Son Luis C5ispo Boye

1

SHELLBEACH

O

I 0 I 2 3

SCALE W MILES

LEGEND

PRIIAIIYEVACIUITKNI IIOAD

SECONDARY EVACUATION ROAD

OTHER ROADS

@5 HICH POTENTIAL LIOUEFACTION

LOW POTENTIAL LIOUEFACTNN

PISMOBEACH

\A

~IGROVER

CITY

+ e. +o~~+R~ A ROYO

GRANDE,CjRAND I

QIOI

oe

+~RD.

TERACORPORAllON

SAN LUIS OBISPO AREA-Northern Section

Figure 6-SeSTATE BRIDGES

ATASCADERO

220

IEIPL

CAYUCOS TORO CREEK49-68

RTE I 4 I SEP

4I ATASCAOERO49-5 I

ATASCAOERO CRKI

4'58MORR0 CREEK49-I 8 I

ATASCADERO CRKI

Estero

8ay

c NMORROBAYVC49-109

5 MORRO BAY49-l08

BAYINOOOPK49-I 77

BUENA VIS49 94

CRAMBO AVE VC 2pSANTA

RTE 58 I0 I SEP49-158

ST MARGARITA4947

COSTA OVERH

NOTCRP

iIrtorroBay:.;-:~

?', SARI YSABE

''ROAD

LOS OSOS I.os"a

6IIII 0QSLOBI49-58

SN BRI8IDO EO II19-188

SANBERNAROOCI4546

osos7IOAD

RTE I IOI SEP49-l44

CHORRO ST VC4~

<os

CHORR0 CR OH p49-63 CAUF BLVDLS'9

I47

CALFBLVDOC49 79

STEER CREEK49 l23

OAD N A

OI

SAN L OBISPO C4S42

5AN L OBISPO C49-57

ACACIACREEK49-ll7

SantoNorgorita

Lake

Ic'A

I 2 5

SCALE IN LGLES

LEGEND

NIIIIART ETACIIATICR IIOAD

ERXWDIUIT ETACUATRU ROAD

PointBeet?cv7

MARSH ST SEP49kB

AAOOA94ARO OC49 I90

sos OTHER ROUN

0 STATE BRIDGE

8800K NAME'~ ~~

D ~EXPtCTTOOAUAGESRCGE NUMBER

lERACOAPORAIIOITI

j LOS OSOS

RTE I 101. SEP49-144

(OSOSOS ~+o~o

o,

OiRD. RK ST.

IOo

SAN LUIS OBISPO AREASouthern Section

Figure 6-3fSTATE BRIDGES

SAN L 085PO4942

Print»o/ton

49M

MARSH ST SEP4949

VALfSY ROA

0gE

<+

PIJSSII

IlO

MADOIItIARD OC49-190 I

SE

Cg

I.OS 0505 RD OC49-185

SANTA FE VC49-1 IS

5 L OBISPO CRK2/349-14

NAVILAROADOCIl9-192

AVILAROAD49-191 2/3

AVILABEAC

Diablo Canyon+POWER PLANT

r

tto

QO

ANKFARIA

W COR D PDR CR49-204

Q7

E CORRL PIEDR49 103

E FK P5MO CRK49-112

0lO

CALIFBLVDOC49 79

SAN L OBISPO49-57

5 L OB5PO CRK4948

49-94

N EDNA OH49-220

ACACIACREEK49-1 i7

GRAMS AVE V4944

LopezCanyon

'ibsttrttot/',Op

0~rir

CALIFBLVD45l49-147E FK SLO CREEK

49-116

0 I 2

SCALE Ot IlllfS

LEGEND

~rIIIrIIYEVIrIIrTICH ROID

SECONDARY EVACUATION ROAD

OTHER ROADS

Q STATE BRIDGE

8ISOSE NAllE

~~~ I ~EXPECTED OAMASE

8ISOCE NUllSEA

SIKll.BEACH VC49-189 I 2

NORTH PISMO49-184

n c.rtts Obispo Boy

WADSWORTH AV49-183

PISMO ST PVC49-139

H1NDS AVE OC49-130

PISMO OVERtEAD49-16

P5MO OAKS OC49-156 OAK PARK RD OC

49-155

BRISCO RD VC49-154

2/3 'ISMOCREEK49 10 49-15 2/3

SHELL 4al

BEACH4.

GROVEC

OCEANO OH49-12

AROYO GRAtCE49-19

o.

e~+e A Rg(O

GRANDEND t

CS

lAI

O

u CORBIT CANCR49-110

o~ CROWN tELLPOC49-201 I

CORBETT CANCR49 77

VALLEYROAD OC I49-174

BRIDGE ST VC 2/349-173R

ARRYO GRANDE49-ITS

GRAM)AVE SEP49-176

~ ~osQIOI

o~

67889r~

LOS BERROS CRKI

SAN LUIS OBISPO AREA-Northern Section

Figure 6-Sp

COUNTY AND CITY BRIDGES

ATASCADERO

CAYUCOS4I

Qss

I$ /IL

SOUTH BAYBLVDAT CHORRO CR49C-242

Estero

MORRP RO 7

IiVorloBoy

SAN Y ABEL

LOS OSOS MORRO BAYBRE7GE AT LOS OSOS CRK.I3027&l

/3

PEDESTRIAN U C ONSOUTH BAYBLVD

SOUTH BAYBLVDATCHORRO CR I/249C-24 I

MO CANYONVERT BR2

49C

PREFUMO ONRD CIA.VER49C<27

PREFUMO CANYONRD CILVERTBR449C-224

PREFUMO CANYONRD COVERT BRS49C-223

VALLEYRDAT PERFUMO CAN CR4~

SANTAMARGARITA

IOI

MILLST BR OVER5 P RAILROAD

S P BR AT MONTEREY ST49C-299

STBPKR CR BR49G36S

S P BR AT~ AVE49G367

SantaNorgori to

Lake

''ROAD'4,

C ~ ~

'VLOS OSOS

LOS OSOS VALLEYRDLOS OSOS CREEK49C-238

Ososos

ROAD

os

Osos

ROAD SANTROKER

I - 0 I 2 3

SCALE MI WLES

LEGEND

OOIIIIIVEV4CU4TOU ROOD

EECCUDIRT EVICU4TIOR RO4D

OTIIOI RECCE

PointBvchan

PECHO VALLEYRD ATISLAYCR

E

Efue9

3~Cg

ROA + OqO~

G~

+o

0 COuNTY OR CITY BRIDGE

BRIOCE NAME

EXPECTED CAMACE

SROGE NVMSER

e, I~OS OSCS

LOS OSOS VALLEYRDLOS OSOS CREEK49C 238

PECHO VALLEYRD ATERLAY CR I/2

MLLST BR OVER5 P RALROAO

O'DS oogo

(ossos

AT MO CANCR I4

SANTAROSA ST.

IQIO

UIS

SAN LUIS OBISPO AREASouthern Section

Figure 6-Sh

COUNTY AND CITY BRIDGES

gantL7oJ/on

PREFVMO CANYON;RD CLLVERT BR249C-229

VALLEY ROAD

b

IIRILRJ

ILIrrI

ANKFA

0

5 CRBR4

ORCVTT ROADCVLERT BR52I 300$ 42

5 P BR ATMONTEREY STI 49C-299

R

PREFVMO CANYONRD COVERT BR349C-227

PREFVMO CANYONRO CLAVERTBR449C-226

Diablo Canyon'<i OWER PLANTr

~R

PREFVMO CANYONRD CULVERTBRS49C-223

AVILACLAT~RDSEE CANYONCR BR49C-I 50

+o~o

LL3SSB+"SP4

ATJOFB40N AVE7 I

ORCVTT ROADCLA.VERTBR 8 IAI300$8 I

ORCUTT RD CLAVERTBRIDGE 549C-I I3

ORCUTT RD CLA.VERTBRIDGE 449C ll4

rRr.. rR

Loper;Canyon

/ibssrvofr '~V

Aqg 0 'O

AVILABEAC

':r„L QIQ

S n Luis Obispo Boy SHE I

EAC22

I 0 I 2 3

SCALE LN MLLES

LEGEND

RRIRRRV RVRRRRVRR RRRR

SECONDARY EVACUATION ROAD

OTHER ROADS

0 COUNTY OR CITY BRIDGE

BRIDGE NAME

I~ EXPECT C0 DAMAGE

BRDGE NUMBER

HARTFORD DR BRIDGEQ AYEABEACH49G327

2/3

AVILACUT~ RDSLO CREEK BR49C.I 5 I

ONTARIO ROAD BRSANLUISOBISPO CREEK 2/349C-l97

PRICE CANYONRDOVERHEAD4~

CORBIT CANYONOYER CR49C-I 55

TRAFFIC WAY BRON ARROYO GRAICE CR49G3 IB

VALLEYROAD ATLOS BERROS CR496452

2

I/2

ISMOBE H

R

4 ~

GROVERCITY

CI'r~4r

e~ A

GRAIID /

RIR7.

ROYOGRANDE

CL

IRrI

osIO

ORCUTT RO CLA.VERTBRIDGE 349C-I IS

o~

RD.

ORCUTT RD CULVERTBRIDGE I I49C-IIT

ORCVTT RO CLLVERTBRIGE 2 I49C-I I6

TABLE 6-1

BRIDGE PERFORMANCE SUMMARY

State Route 101 (South to North)

Sheet I of IO

Bridge Ho.

49-173R

Description

Bridge StreetUndercrossing

PGA

(9)

.22

Structure

Damage

Soil

Possible collapse ofspans 153; probabletoppling of bearings

No soil failureanticipated

Effecton Traffic

Typeof Repair

Traffic over struc- Ramping atture delayed or bearings;stopped; traffic possibleunder unaffected total loss

RepairTime(Hrs.)

1/72

FullCapacity

(vph)

3790

Bypass Description

NB:*Frontage RoadSB: Not needed (no

structure)

49-174 Valley RoadOvercrossing

22 No damage affectingtraffic under bridge

No soil failureanticipated thatwill affect trafficunder structures

None Nonerequired

3790 NBASB: Adjacent streets

49-175L/R Bridges AcrossArroyo GrandeCreek

.22 No damage antici-pated

Minor fill settle-ments 5"t

Traffic may have to Ramping toslow to 15-20 mph butment

ay speedtraffic

0/1 3790 NB8SB: Traffic way

49-176

49-154

49-155

49-156

Grand AvenueOvercrossing

Brisco RoadUndercrossing

Oak Park RoadOvercrossing

Pismo OaksOvercrossing

.23 Ho damage antici-pated; trafficnder bridgenaffected

.24 o damage antici-pated

~ 25 Ho damage antici-pated; trafficunder bridgeunaffected

.24 Sheared keeperplates; trafficunder bridgeunaffected

Moderate liquefac-tion will notaffect traffic underthe structure

Minor fill settle-ment 2"a; possibleliquefaction

Moderate 1 iquefac-tion should notaffect trafficunder the structure

Moderate liquefac-tion should notaffect trafficunder the structure

None

Hone

None

Hone

onerequired

onerequired

Nonerequired

oneequired

3580

3580

3580

3580

NB8SB: Inter change ramps

NB: Interchange rampsSB: Frontage Road

NBSSB: Interchange ramps

NBSSB: Interchange ramps

49-16L/R Pismo Overhead .25 No structuraldamage anticipated

Moderate groundmovements due toliquefaction

Traffic delayed Ramping toabutments

0/2 3580 NB!5B: Adjacent streets

49-1 5L/R/C

49-130

Pismo CreekBridge (VillaCr.)

Hinds AvenueOvercrossing

.25 Possible columndamage resultingfrom liquefaction

.26 No damage antici-pated; trafficunder bridgeunaffected

Moderate to severeground movementsdue to liquefaction

Moderate liquefac-tion will notaffect trafficunder the structure

Traffic delayed; ifliquefaction issevere only leftbridge may bereopened

Hone

Ramping toabutment;possiblebentshoring

onerequired

1/4 3580

3880

NB: Parallel streetsSB: Frontage Road

NBSSB: Frontage Road

* I ~ Northbound

I ~

I ~ ~ I

~ ~

I ~ I. I ~

I

~,~

I ~

I ~ ~

~ I

~ ~

~, '

I I ~

muggm~~gg ~'

~ I

I ', ~',, ~

I ~ ~ I ~' I I ~ ~ I '

~ I

', ~ I, ~

~ ~ ~ ~ ~, ~ ~ ~ ~ ~ ~ I ~

I ~ ~'

~'

~ ', I I

~ ~

~ ~ ~~ ~

I ' I

I ~

I ~ I ~

~ I

~ I I

~ ~

I ' ~

I ~ I ~ I I ~

~ I I ~

~ I I ~, ~ ~ ~ I ~ I

~ I

~, ~ I ~ ~ ~ I ~ ~

I

~ ~ ~

I ~

I '~ ~ ~

I

~ ~ ~

I . ~

~ ~ ~, I ~ I ~

I, '~ ~ 'I

~ ~

I '

I ', I

I ~ ~

~, ~ ggggg:

TABLE 6-1BRIDGE PERFORMANCE SINMARY

State Route 101 (South to North) - Cont'dhect 3 of 10

Bridge No. Description PGA

(9) StructureDamage

SoilEffect

on TrafficType

of Repair

RepairTime(Hrs.)

FullCapaci ty

(vph)Bypass Description

49-185

49-190

Los Osos RoadOvercrossing

Madonna RoadOvercrossing

.23

.22

No damageanticipated

Ko damageanticipated

Moderate liquefac- Nonetion will not affecttraffic understructure

Moderate liquefac- Nonetion will not affecttraffic understructure

Nonerequired

onerequired

3880

3780

NB: Parallel RoadSB: Interchange Ramps

NB: Interchange RampsSB: Blocked

49-08 L/R

49-146

Marsh StreetSeparation

Stenner CreekCulvert

.22

.21

No damageanticipated

No damageanticipated

Minor fill settle-ment 3"a

Possible moderateliquefaction - notraffic delay

None Nonerequired

Traffic may have to oneslow to 25-30 mph equired

3780 NB: Interchange RampsSB: Blocked

3780 NB&58: City Streets

49-39 L/R

49-144

Chorro StreetUndercrossing

Rte. 1/101Separation

.21

.21

No damageanticipated

No damageanticipated

Minor fill settle-ment 2"x

Minor fill settle-ments 2"x

None

None

Honerequired

Honerequired

3780 NB&SB: City Streets

3780 NB&SB: City Streets

49-79 California Blvd.Overcrossing

.21 No damageanticipated

Ho soil failureanticipated

None onerequired

3780 NB&SB: City Streets

49-147 California Blvd.Underpass

.21 No damage antici-pated that willaffect traffic

No soil failureanticipated

None oneequired

3780 NB&SB: City Streets

49-84 R/L Grand AvenueUndercrossing

.20 Loss of supportat Span 4 - PartialCollapse

No soil failureanticipated

Closed to traffic dd new

temporarypan-a ileyridge

8/48 3780 NB&58: City Streets

49-94 Buena Vista Ave.Overcrossing

.20 No damageanticipated

Ho soil failureanticipated

None oneequired

3550 NB&58: City Streets

49-60 Cuesta GradeOvercrossing

.18 Loss of support atexpansion joints-Possible partialcollapse

No soil failureanticipated

Traffic Delayed-Possibly closed totraffic

horing ofidspanxpansionoints

4/8 3550 NB&58: None

TABLE 6-1BRIDGE PERFORNNCE SINNARY

State Route 101 (South to North) - Cont'dSheet 4 of 10

Bridge No. Description

IPGA

(g) Structure

Damage

SoilEffect

on TrafficType

of Repair

RepairTime(Hrs.)

FullCapacity

(vph)Bypass Description

49-07

49-158

Santa HargaritaCreek Bridge

Route 58/IOISeparation

.18 No damageanticipated

.17 Not probable atthese force levels;collapse at higherlevels

No soil failureanticipated

No soil failureanticipated

Mone Nonerequired

Probably none, but Probablycould close road to onetraffic for'higherforce levels

3550 HBSSB: Hone

3780 NB: Frontage Road, ramps

s ~

~ ~ t ' I ~s I ~ . I . I ~

~ I

~'

I I, I IHRW ~ ~

\~

~ ~ I ~,, 'I

~ ' I s '~ ~

I ~ . I I - -.s ~ ~ I '

~ ~ ~

~ ', '

~ ~ I I

~ I ~ ~ I I

~ I ~ ~ I ~

~, I ~

I ' '~

~ I I '~ I

~ I ~ II

t ~

s slI~ I ~

I I

I .. s

I ' ~ II''~ I'

I ~ I

I ~

~ I

I ', ~ ~

I ~ I I I ~'

~ I

I I I ~

I ~ I

~,, I

s I s

I ~

~ ~

I ~

~ ~

~ ~ ~

I

~ ~

~ ~ ~

~ t

~ I ~ ' t

~ ~ I ~ ~

mm

~ 'I

I ~ ~

~, I

I ~ 'I ' I

I '

~ ~

~ ~

t ~

I ~

~ ~

RAHU~ggmtN

I I ~

WRil

I '

~ '

~ ~ I ~

~, ~ ~

~ ', ~

~'

~'

I I

TABLE 6-1BRIDGE PERFORNNCE St@MARY

Route 1 (South to North) - Cont'dSheet 6 of 10

Bridge No.

49-68 L

Description

Bridge AcrossToro Creek

PGA

(9)

.32

Structure

o damageanticipated

Damage

Soil

Hoderate fillsettlements - 12"+

Effecton Traffic

Traffic delayed

Typeof Repair

amping atbutments

Repair Full

(Hrs.) [vph)Time CaPaci ty "'ypass Description

3940I/2 KB558: Use CypressHountain Or aroundMhale Rock Reservoir

TABLE 6-1BRIDGE PERFORMANCE SINHARY

Route 227 (South to North)Sheet 7 of 10

Bridge No. Description PGA

(9) StructureDamage

SoilEffect

on TrafficType

of Repair

Repair FullTime Capacity(Mrs.) (vph)

Bypass Description

49-77 Corbit CreekCanyon

.22 No damageanticipated

No soil failureanticipated

None Nonerequired

1260 NB: Left on Hason St thenright 9 LePoint Stto 227 (.5 mi)

SB: Right 9 LePoint St,left 9 Hason St to227 (.5 mi)

49-201 Branch StreetPedestrianOvercrossing

.21 No damage antici-pated .that wouldaffect traffic

No soil failure Noneanticipated thatwill affect trafficunder the structure

Nonerequired

1260 NBKSB: Use Crown Stparallel to 227(on the north side)(.3 mi)

49-112

49-103

49-204

49-220

49-116

East Fork PismoCreek Bridge

East Corral dePiedra Creek Br.

Mest Corral dePiedra Creek Br.

North EdnaOverhead

East Fork SanLuis OpispoCreek Bridge

.21

.21

.21

.21

.21

No damageanticipated

No damageanticipated

No damageanticipated

No damageanticipated

No damageanticipated

Hinor fill settle-ment 2"+

No soil failuresanticipated

Hinor fill settle-ment 1$ "+

Hinor fill settle-ment - 4"

Hinor fill settle-ment - 3"

None

None

None

Traffic may have toslow to 20-25 mph

Traffic may have toslow to 25-30 mph

onerequired

oneequired

oneequired

Nonerequired

Nonerequired

1490

1490

None

None

None

None

None

49-117 Acacia CreekCulvert

.21 No damage, anticipated

Settlements will not Noneresult in roadway

~ discontinuities

oneequired

1490 None

49-58 Bridge AcrossSan Luis ObispoCreek

.21 Possible bearingfailures resultingin vertical offset

Low liquefactionpotential

Traffic delayed amping atbutments

1490 NB(MB): Higuera to HadonnaSB(EB): Hadonna exit on

101 to Higuerato 227

TABLE 6-1BRIDGE PERFORNNCE SlÃQRY

Route 41Sheet 8 of 10

~rldge No. Description PGA

(9) Structure

Damage

SoilEffect

on TrafficType

of Repair

Repair FullTime Capacity(Nrs.) (vph)

Bypass Description

49-49 Bridge AcrossAtascadero Creek

.18 No damage antici.- No soil failurepated because of low anticipatedforce levels

None Nonerequired

1310 Use parallel dirt road

49-50 Bridge AcrossAtascadero Creek .18

No damage antici- Ho soil failurepated because of low anticipatedforce levels

None Nonerequired

1310 Use parallel dir t road

49-51 Bridge AcrossAtascadero Creek

.18 No damage antici- No soil failurepated because of low anticipatedforce levels

Hone onerequired

1310 None

Route 101/41Separation

.17 No damage antici- Low to moderatepated because of low liquefactionforce levels

Possible trafficdelay

amping tobutments

0/2 1310 Frontage Rd or 9th St

TABLE 6-1BRIDGE PERFORMANCE SDMHARY

County Roads

Sheet 9 of 10

Bridge No. Description PGA

(9) Structure

Damage

SoilEffect

on TrafficType

of Repair

RepairTime(Hrs.)

FullCapacity

(vph)Bypass Description

49C-151 Avila Cut-off RdSLO Creek Bridge

.31 No damageanticipated

Moderate fillsettl ement 7"+

Traffic delayed Ramping toabutment

None

49C-150 Avila Cut-off RdSee Canyon CreekBridge

.31 Minor abutmenttilting

Minor fill settle- Traffic delayed .ment 5"+;severe liquefaction

Ramping toabutment

I/4 None

49C-327 Harford Dr. Bridg9 Avila Beach

.33 Superstructureshifted at bearings;collapse possible

Moderate fill Possibly closed to Supplemen-settlements; traffic tary bents;severe liquefaction span re-

placement

4/72 Dirt road and light dutyroad

13027-81 Los Osos-Horro BayRd.-Bridge at .LosOsos Creek

.30 Possible loss ofsupport andcollapse

Moderate fillsettlements

Possibly closed totraffic

Ramping atbutments;ossib'le

span re-lacement

I/72 None

49C-238

49C-197

Los Osos Valley RdLos Osos Creek

Ontario Rd Bridge,San Luis ObispoCreek

.31

.29

No damage antici-pated except due toliquefaction

Collapse of approachspans; shear failurein columns

Minor fill settle- Traffic delayedments 6">;severe liquefaction

Moderate fill Closed to trafficsettlement 6">;severe liquefaction

amping tobutment

upplemen-ary bents;pan re-lacement

1/4

72

None

None

49C-11714008-81

49C-11614008-82

Orcutt Rd. Culvert-Bridge 1

Orcutt Rd. Culver-Bridge 2

.19

.20

No damageanticipated

No damageanticipated

Minor fill settle-ment 2"+

Minor fil'i settle-ment 2">

None

None

one

None

1260 .

1260

*NB: Left on Tiffany RanchRd, north on CorbitCanyon Rd to 227 NB,right 9 Biddle(total 5 mi)

SB: Right 9 Biddle, southon 227, left 9 CorbitCanyon Rd, left 9Tiffany Ranch Rd(5 mi)

Same as 49C-11714008-B1

49C-11514008-B3

Orcutt Rd. Culver-Bridge 3

.20 No damageanticipated

Minor fill settle-ment 2"+

None one 1260 Same as 49C-11714008-Bl

*Alternate route

TABLE 6-1

BR1DGE PERFORMANCE SUMMARY

County Roads - Cont'd

Sheet 10 of 10

Bridge No. Description PGA

(9) Structure SoilEffect

on TrafficRepair

Type Timeof Repair (Mrs.)

FullCapacity

(vph)Bypass Description

49C-11414008-84

49C-11314008-85

13008-B1

13008-52

49C-229C2085-82

49C-227C2085-B3

49C-226C2085-B4

49C-223C2085-85

49C-329.

Orcutt Rd. Culvert .20 No damage-Bridge 4 anticipated

Orcutt Rd. Culvert .21 No damage-Bridge.5 anticipated

Orcutt Rd. Culvert .22 No damage-Bridge 81A anticipated

Price Canyon Rd.Overhead

.21 No damageanticipated

Orcutt Rd. Culvert .22 No damage-Bridge S2 anticipated

Prefumo Canyon Rd. .27 No damageCulvert - BR2 anticipated

Prefumo Canyon Rd..26 No damageCulvert - BR3 anticipated

Prefumo Canyon Rd. .26 No damageCulvert - BR4 anticipated

Prefumo Canyon Rd. .25 No damageCulvert - BR5 anticipated

Hinor fill settle-ment 2"+

Minor fill settle-ment; severeliquefaction

Minor fill settle-ment 2"+

Hinor fill settle-ment 2">

Hinor fillsettlement

Minor fillsettlement

Minor fillsettlement

Hinor fillsettlement

Moderate fillsettlement - 7"+;moderateliquefaction

None

Traffic delayed

None

None

None

None

None

None

Traffic delayed

None

Ramping toabutments

None

None

None

None

None

None

Ramping toabutment

1/2

1260

1260

1260

*NB: No direct bypass; useLopez Dr 8 Pozo NB oruse NB 227 B CorbitCanyon Rd

SB: Right turn 9 TiffanyRanch Rd, 6 SB onCorbit Canyon Rd

Same as 49C-11414008-B4

*NB: Left turn on Biddle,then NB on 227, rightturn 9 Orcutt (5 mi)or continue NB

SB; from Johnson Av rightturn 9 Orcutt, SB on227, left turn 9Biddle (5 mi) orcontinue SB

Same as 13008-Bl

None

None

None

None

NBSSB: Old Price CanyonRd

49C-330

49C-352

Price Canyon Rd.Corral de PiedraCreek

Valley Road aterros Creek

.21 No damageanticipated

.23 No damageanticipated

Severe 1 iquefaction

Hoderateliquefaction

Closed to traffic

Traffic delayed

entshoring;span re-lacement

amping tobutment

8/72

1/2

NB!LSB: Old Price CanyonRd

None

*Alternate route

TASK B RESOURCES AND SUPPORT (REPAIRS)

~Pur ose

To establish policies and objectives and assign general responsibilities for the

following activities:

a. Conduct emergency repair and/or restoration of essentialstreets, roads, highways and related bridges, overpasses,underpasses and tunnels.

b. Clear debris. from access routes, evacuation routes, andother vital roads, streets, and highways, to include that onboth public and private property.

Ce Coordinate, with appropriate law enforcement agencies,the barricading of areas which must be cordoned off inthe best interest of public safety.

d. Procure and allocate required transportation resources(air and surface).

2. Conce t of 0 erations

Following an earthquake, there would be heavy demands placed on emergency

manpower and essential supplies, equipment and services. This might include:

skilled workers, transportation, fuels, heavy equipment, food, potable water, etc.

Consequently, government at all levels must be organized accordingly and be

prepared to respond expeditiously to, and meet, the many demands that will be

placed on resources required to support emergency operations. Coupled with the

above would be the immediate requirements for clearance of debris from firelanes, access routes, pre-planned evacuation routes, and main traffic arterials.

Engineering/public works agencies, and segments of the private sector would be

in great demand for this activity.

For a combined earthquake/radiological emergency it will be most essential toestablish priorities for those resources required to maintain or re-establishevacuation capabilities. This objective will not be inconsistent with the more

8-SI-269 6-37

TERA CORPORATION

general need to reopen transportation arteries and communications links to

recover from an earthquake independent of a radiological event. As discussed

under Task A, the EDAC will evaluate damage reports, estimate repair resources

and prioritize the implementation of repairs. The purpose of this task is toeffect those repairs.

3. ~S*i i* T

ao For bridge-type damage, repairs will consist of restoringthe roadway to a level and adequately supported condi-tion. Where the damage has resulted from abutmentsettlement or rocker bearing failure, ramping with anappropriate fill material will be required. Where thedamage has resulted in the loss of support columns (butnot collapse of the span) shoring will be required.

b. For roadway impairments due to subsidence, regradingwill be required to return serviceability.

c. For landslides leading to road blockage, clearing of slidematerial willbe required to reopen the route.

4. Or anizations and Res onsibilities

CALTRANS

County Engineer/Public Works

B-8 I-269 6-38

TERA CORPORATiON

TASK C TRAFFIC CONTROL

~Pur ose

To establish policies and objectives and assign general responsibilities for the

following activities:

a.

b.

Provide traffic and crowd control in accordance withevacuation plans.

Provide law enforcement and crowd control support tomultipurpose staging areas and other major operations.

Ce Survey and report damage and other vital information.

2. Conce t of 0 erations

If the protective action selected by the county Direction and Control Group is to

implement a partial or total evacuation, traffic controls will have to be applied.

These controls will channel traffic to the appropriate evacuation routes, control

access to major arterials to maximize flow, and block off damaged road areas or

hazards and provide rerouting. The county Direction and Control Group will

initiate plans to establish traffic control during the evacuation (see Section Il.7.5

of Reference 2). Various law enforcement agencies will have responsibilities for

implementing traffic controls. Additional assistance will be procured from

Mutual Aid Regions and state and federal agencies in accordance with

Appendix C of Reference I.

3. ~5e T k

In addition to those tasks specified in Section ll.7.5.B of Reference 2, the

following should be performed:

a. Coordinate with the county Direction and Control Groupto confirm the sequence of evacuation and routes. Theroutes may differ significantly from the pre-designatedevacuation routes established in the county plan for a

B-8I-269 6-39

TERA CORPORATIONl

radiological emergency. The routing will be a function ofearthquake damage and the restoration of damagedroutes.

b. Install traffic controls and barricades. Earthquake dam-aged sections of road and bridges will need to be blockedoff and traffic rerouted as necessary. If the availableevacuation routes have been significantly reduced, addi-tional traffic controls will be required to maximizetraffic flows.

4. Or anizations and Res onsibilities

CALTRANS

Country Engineer

County Sherif f's

CHP

B-8 I-269 6-40

TERA CORPORATION

TASK D PROTECTIVE ACTIONS FOR NONESSENTIALPLANT PERSONNEL

~Pur ose

To establish an approach and assign general responsibilities for the following

activities:

a. The integrated evaluation of emergency data as a basisfor decision making.

b. Determination of the appropriate protective actions fornonessential plant personnel taking into consideration theeffects of earthquake damage.

2. Conce t of 0 erations

In the event of a coincident earthquake and radiological emergency, the response

plan described in Section 2 of this plan would provide the framework forcoordination of key tasks. From a protective action perspective, it will be

essential to obtain two types of information: (I) the status of the plant and the

likelihood and timing of any onsite release of radioactivity, and (2) the status of

evacuation routes from the site. Under this plan the type (I) information willcontinue to be provided by the onsite emergency organization in a manner

essentially unchanged from a purely radiological emergency (see Section 6 of

Reference 3). The type (2) information would also be provided by the onsite

emergency organization. Four options exist for the evacuation of onsite

personnel:

o Evacuation south via the access road to the Avila BeachGate

o Evacuation north through Montana de Oro State Park

o Evacuation via air (helicopter)

o Evacuation via water.

8-8I-269 6-4 I

TERA CORPORATION

The land evacuation routes will be surveyed for earthquake damage and revised

transit time estimates made in accordance with Task A. Availability of

helicopter or water transport will be determined on a continuing basis. The Site

Emergency Coordinator will be responsible for deciding the appropriate protec-tive actions. The selection of protective action will be made on the basis of

minimizing personnel exposures to radiation.

The determination of the most effective protective actions to be taken would be

conducted as follows:

ao Initially a determination will be made as to the ability toevacuate personnel along either the northern or southernland routes. This decision will be based on the timeavailable before a release of radioactivity onsite and thetime required to transit the evacuation route. Evacuationon foot would also be considered if, by doing so, a furthermitigation of the radiological hazard is assured.

b. An ongoing assessment should be made of the availabilityand capacity of helicopter and'boat transport. Thesemodes of evacuation would normally be considered asbackups to a land evacuation.

4. Or anizations and Res onsibilities:

Pacific Gas and Electric Assessment of plant status, availability of helicoptertransport.

U.S. Coast Guard Availabilityof water transport.

B-8I-269 6-42

TERA CORPORATION

TASK E PROTECTIVE ACTIONS FOR THE PUBLIC

I. ~Pur ose

To establish an approach and assign general responsibilities for the following

activities:

a. Integrated evaluation of emergency data as' basisfor'ecisionmaking.

b. Determination of the appropriate protective actions forthe public taking into consideration the effects of earth-quake damage.

2. Conce t of 0 erations

In the event of a coincident earthquake and radiological emergency, theresponse'lan

described in Section 6.2 of this plan would provide the framework for

coordination of key tasks. From a protective action perspective, it will be

essential to obtain two types of info'rmation: (I) the likelihood and probable

timing of releases of radioactive materials offsite from the DCPP and (2) the

continued viability of various protective action options. Under this plan, the

type (I) information will continue to be provided. by the Unified Dose Assessment

Center (UDAC) in a manner essentially unchanged from a'urely radiological

emergency (see Section l.6 of Reference 2 and Section 6 of Reference 3). The

type (2) information will be supplied by the Earthquake Damage Assessment

Center (EDAC) and will indicate a damage-level characterization for the

evacuation road system, the locations of specific damage and alternate routing

around the damage, and the status of emergency communications systems. With

these data the county Direction and Control Group will be able to make an

integrated evaluation of the overall emergency situation.. It should be noted

(reference Figure 6-I) that this dual evaluation will only arise where there has

been non-negligible earthquake damage in the Basic- Emergency Planning Zone

and where there exists a coincident potential for an offsite release of radioactiv-

ity from the DCPP site. If either element is not present, emergency planning

B-8I-269 6-43

TERA CORPORATION

activities will be governed by the appropriate earthquake response plans or the

DCPP Emergency Plan.

The fundamental criteria that would trigger protective action would remain the

Protective Action Guidelines (see Section l.4 of Reference 2.and Section 6 of

Reference 3). The types of protective actions that are available would also be

substantially the same as those indicated in the San Luis Obispo County Nuclear

Power Plant Response Plan:

o initial precautionary actions

o Selective evacuation

o General sheltering

o Relocation

o ~ General evacuation

o Selective sheltering

o Administering of radioprotective drugs

o Ingestion pathway isolation.~ .

Emphasis, however, will be placed on a flexible evacuation menu that minimizes'ny

impacts resulting from earthquake damage.'.

~5ifi*T

The determination of the most effective protective actions to be taken would be

conducted as follows (see Figure 6-2): I

ao Initially, a determination yvill be made as to the ability toconduct a general evacuation of the Basic EmergencyPlanning Zone. This decision will be based on the timeavailable before the arrival of radiation offsite and thetime required to conduct a general evacuation. Theevacuation time will be a value keyed to the level ofearthquake damage sustained by the evacuation roadsystem. Representative evacuation times for four levels

B-8I-269 6-44

TERA CORPORATION

of earthquake damage have been precalculated and areprovided in Table 6-2. The availability of sufficientcommunications equipment to effect the evacuation willalso be a factor in the decision to evacuate.

b. If a general evacuation is not considered advisable, selec-tive and/or staged evacuations of the public would beconsidered. Two additional inputs of data will be utilized:the wind direction and the specific locations of earth-quake damage in the evacuation road system.

(I) A selective evacuation would involve movement ofpeople only out of certain areas and would result ina partial evacuation of the Basic Emergency Plan-ning Zone. Normally the objective would be toevacuate the areas downwind of the release.

(2) A staged evacuation would involve a progressiveevacuation in several stages or steps. It wouldresult in a total evacuation of the Basic EmergencyPlanning Zone. Normally this approach would beemployed where the damage to evacuation routeswas such that a sequential ordering of areas to beevacuated would result in a more efficient (faster)use of the available roads and, therefore, a fasterevacuation.

(3) Table 6-2 provides representative evacuation timeestimates for staged and selective evacuations forfour wind directions. This data will provide a guidefor decisionmakers to tailor an appropriate evacua-tion plan.

co In those instances where evacuation is not the preferredprotective action, other protective actions such as shel-tering will be implemented.

4. Or anizations and Res onsibilities:

a. Release times:Meteorology

UDAC

b. Earthquake damage level: EDACDamage locations

c. Protective Actions: San Luis Obispo County> Direction and ControlGroup

PGandE

B-SI-269 6-45

TERA CORPORATION

TIMING OFRELEASE

EARTHQUAKEDAMAGE LEVEL METEOROLOGY SPECIFIC

DAMAGEDATA

GENERAL EVACUATIONPOSSIBLE?

NO SELECTIVE OR STAGEDEVACUATIONPOSSIBLE?

YES YES NO

IMPLEMENTEVACUATION

IMPLEMENTEVACUATION

'

SELECTALTERNATEPROTECTIVE

ACTION

IMPLEMENTALT. PA

FIGURE 6-2

PROTECTIVE ACTIONDECISION MATRIX

1

6-46

TERA CORPORATION

TABLE 6-2

SUMMARY OFESTIMATED EVACUATIONTIMES

(HOURS)

Type ofEvacuation

ZoneCleared

Dama e LevelNone Light Moderate Heavy

Total(Basic EPZ)

IO mile

BEPZ 6.5

7. 5+

l0.5

Partial I 0 mile(Southern Area) BEPZ

3.54.5

3 3

4.5 6

Partial I 0 mile(Eastern Area) BFPZ l0.5

Partial l0 mile(Northern Area) BEPZ

3.5 4 5

4.5 5.5

The time given is an upper bound on the time required to evacuatethe Baywood Park area. The Avila Beach area clears the IO-mileradius in less than 3.5 hours in all four damage scenarios.The beach transient population on a summer weekend couldincrease these evacuation time estimates. For the no-damage andmoderate-damage levels, we estimate an increase of aboutl.5 hours.

B-SI-269 6-47

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REFERENCES FOR SECTION 6.0

I. State of California Earthquake Response Plan, California Office of Emer-gency Services, reprint, April I 98 I.

2. San Luis Obispo County Nuclear Power Plant Emergency Response Plan,Revision 3, June l5, l98I.

3. Diablo Canyon Power Plant Emergency Plan, Revision 3, September l98I.

4. State of California Nuclear Power Plant Emergency Response Plan, Revi-sion 3, June l5, l98I.

5. State of California Department of Transportation (CALTRANS) EmergencyPlan, August l979.

6. State of California Department of Transportation (CALTRANS), District 5,Emergency Plan, October l980.

B-8 I-269

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7.0 REFERENCES CITED

Applied Technology Council, l98l, "Guidelines for the Evaluation of HighwayBridges, ATC-b, Final Draft Report," Applied Technology Council,Berkeley, California.

Association of Bay Area Governments (ABAG), l980-8I, "A Guide to ABAG'sEarthquake Mapping Capability," Berkeley, California.

Babbit, D., l98I, personal communication, August 25, l98l, California Dept. ofWater Resources, Div. of Safety of Dams, Sacramento.

Bailey, E. H., Irwin, W. P. and Jones, D. L., l964, "Franciscan and Related'ocksand their Significance in the Geology of Western California,"

California Div. of Mines and Geology, Bulletin I83, Sacramento.

Blanc, R. P. and Cleveland, G. B., l968, "Natural Slope Stability as Related toGeology of the San Clemente Area, Orange and San Diego Counties,California," California Div. of Mines and Geology, SR-98, Sacramento.

Borchardt, G. A., l 977, "Clay Mineralogy and Slope Stability", California Div. ofMines and Geology, SR-I33, Sacramento.

California Dept. of Water Resources, l954, "San Luis Obispo County Investi-gation," DWR Bulletin 18, Sacramento.

California Dept. of Water .Resources, l97I, "Water Well Standards, ArroyoGrande Basin, San Luis Obispo County," DWR Bulletin 74-7, Sacramento.

California Dept. of Water Resources, l972, "Sea Water Intrusion, Pismo andGuadalupe Areas," DWR Bulletin 63-3, Sacramento.

California Dept. of Water Resources, l972, "Sea Water Intrusion, Morro BayArea, San Luis Obispo County," DWR Bulletin 63-6, Sacramento.

California Dept. of Water Resources, l979, "Ground Water in the Arroyo GrandeArea," District Report, Sacramento.

California Dept. of Water Resources, l979, "Morro Bay Sandspit Investigation,"District Report, Sacramento.

California Div. of Mines and Geology, l978, "Geological Map of California, San

Luis Obispo Sheet," Sacramento.

Campbell, K. W., l980, "Attenuation of Peak Horizontal Acceleration within theNear-Source Region of Moderate to Large Earthquakes," TERA Corpora-tion, Technical Report 80-I, Berkeley, California.

B-8I-269 7-I

TERA CORPORATION

Campbell, K. W., l98I, "Near-Source Attenuation of Peak Horizontal Accelera-tion," Bulletin of the Seismological Society of America, Vol. 7 I (in press).

Campbell, R. H., l980, "Landslide Maps Showing Field Classifications, Pt. DumeQual., California," U.S. Geological Survey, MF-I l67, Menlo Park, Cali-fornia.

Eckel, E. B., ed., 1958, "Landslides and Engineering Practice," Highway ResearchBoard, Special Report 29 (NAS-NRC Publication 544), Washington, D.C.

Elms, D. G. and Martin, G. R., l979, "Factors Involved in the Seismic Design ofBridges," Proceedin s of a Worksho on Earth uake Resistance of Hi hwaBrid es Januar 29-3l l979 Applied Technology Council, Berkeley, Cali-fornia sponsored by the National Science Foundation).

Envicom Corporation, l974, "Seismic Safety Element, San Luis Obispo County,California," San Luis Obispo.

Fairchild National, Inc., l978, "Stereo Aerial Photographs, May l978," Scotts-dale, Arizona (total 30 photos).

Goodwin, M., personal communication, June 25, l98I (Water Conservation-Ground Water), San Luis Obispo, California.

Hall, C. A., l973, "Geology of the 'Arroyo Grande Quadrangle, California,"California Div. of Mines and Geology, MS-24, Sacramento.

Hall, C. A., l973, "Geologic Map of the Morro Bay South and Port San LuisQuadrangles, San Luis Obispo County, California," U.S. Geological Survey,MF-SI I, Menlo Park, California.

Hall, C. A. and Prior, S. W., l975, "Geologic Map of the Cayucos - San LuisObispo Region, San Luis Obispo County, California," U.S. GeologicalSurvey, MF-686 (2 sheets), Menlo Park, California.

Hall, C. A. et al., l979, "Geologic Map of the San Luis Obispo - San SimeonRegion, California," U.S. Geological Survey, I-l097 (3 sheets), Menlo Park,California.

Harp, E. L., l98l, personal communication, June l5, l98I, U.S. GeologicalSurvey, Menlo Park, California.

Harp, E. L., l978, "Earthquake-Induced Landslides," U.S. Geological Survey,National Earthquake Hazards Reduction Program, Summaries of TechnicalReports Vol. Vll, pp. 210-2I2, Menlo Park, California.

Harp, E. L., l979, "Earthquake-Induced Landslides," U.S. Geological Survey,National Earthquake Hazards Reduction Program, Summaries of TechnicalReports Vol. Vill, Menlo Park, California.

B-8I-269 7-2

TERA CORPORATION

Harp, E. L., l980, "Earthquake-Induced Landslides,"~U.S. Geological Survey,Open-File Report 80-6, pp. I82-I83, Menlo Park, California.

Harp, E. L, l980, "Earthquake-Induced Landslides," U.S. Geological Survey,Open-File Report 80-842, pp. 295-296, Menlo Park, California.

Harp, L. H., l978, "Earthquake-Induced Landslides: Investigation of PredictionCriteria," U.S. Geological Survey, Open-File Report 79-387, pp. 35-36,Menlo Park, California.

~ Harp, L. H., Keefer, D. K. and Wilson, R. C., l980, "Artificialand Natural SlopeFailure, the Santa Barbara Earthquake of August l3, l978," California~Geolo, California Div. of Mines and Geology, May 1980, pp. 102~05.

Hart, E. W., l976, "Basic Geology of the Santa Margarita Area, San Luis ObispoCounty, California," California Div. of Mines and Geology, Bulletin l99,Sacramento.

Helley, E. J. and LaJoie, K. R., l979, "Flatland Deposits of the San FranciscoBay Region, California - their Geology and Engineering Properties andtheir Importance to Comprehensive Planning," U.S. Geological Survey,Professional Paper 943, Menlo Park, California.

Iwasaki, T., Penzien, J. and Clough, R. W., 1972, "An Investigation of theEffectiveness of Existing Bridge Design Methodology in Providing AdequateStructural Resistance to Seismic Disturbances," Federal Highway Admin-istration, Office of Research and Development, Report FHWA-RD 73-I3,Washington, D.C.

Keefer, D. R., l978, "Ground Failures Caused by Historic Earthquakes," U.S.Geological Survey, National Earthquake Hazards Reduction Program, Sum-maries of Technical Reports Vol. Vill,pp. 2 I4-2 I 7, Menlo Park, California.

Keefer, D. R., l979, "Ground Failures Caused by Historic Earthquakes," U.S.Geological Survey, National Earthquake Hazards Reduction Program, Sum-maries of Technical Reports Vol. Vill,pp. 2I9-22I, Menlo Park, California.

Keefer, D. R. et al., l979, "Preliminary Assessment of Seismically InducedLandslide Susceptibility," U.S. Geological Survey, Circular 807, pp. 49-60,Menlo Park, California.

Keefer, D. R., l980, "Ground Failures Caused by Historic Earthquakes," U.S.Geological Survey, Open-File Report 80-6, pp. I84-I85, Menlo Park, Cali-fornia.

Keefer, D. R., l980, "Ground Failures Caused by Historic Earthquakes," U.S.Geological Survey, Open-File Report 80-842, pp. 297-299, Menlo Park,California.

B-8 I-269 7-3

TERA CORPORATION

Leighton, B. F. et al., l978, "Surficial Landslides Triggered by Seismic Shaking,San Fernando Earthquake of I 97 I," U.S. Geological Survey, NationalEarthquake Hazards Reduction Program, Summaries of Technical ReportsVol. Vll, pp. 2I8-2 I 9, Menlo Park, California.

Leighton, B. F., l978, "Surficial Landslides Triggered by Seismic Shaking, SanFernando Earthquake of I 97 I," U.S. Geological Survey, Open-FileReport 79-387, p. 36, Menlo Park, California.

McGuire, R. K. and Barnhard, T. P., l979, "Four Definitions of Strong MotionDuration: their Predictability and Utility for Seismic Hazard Analysis,"U.S. Geological Survey, Open-File Report 79-15 I 5, Denver, Colorado.

Morton, D. M., 197 I, "Seismically Triggered Landslides in the Area above the SanFernando Valley," U.S. Geological Survey, Professional Paper 733, pp. 99-l04, Menlo Park, California.

Pacific Gas and Electric Company, l970, "Final Safety Analysis Report, DiabloCanyon Power Plant," Geology and Seismicity Chapter and Appendix 2.5(prepared by Earth Sciences Associates, Palo Alto, California).

Rogers, T. H. and Williams, J. W., l974, "Potential Seismic Hazards in SantaClara County, California," California Div. of Mines and Geology; SR-I07,Sacramento.

Ross, G. A., Seed, H. B. and Migliaccio, R. R., l973, "Performance of HighwayBridge Foundations, the Great Alaska Earthquake of I 964," NationalAcademy of Sciences, Washington, D.C.

San Luis Obispo County, Engineering Dept., l 974, "Groundwater Seasons l970-7I,l97I-72, County of San Luis Obispo," San Luis Obispo, California.

San Luis Obispo County, Office of Emergency Services, l98I, "San Luis ObispoCounty/Cities Emergency Broadcast System Plan (EBS)," San Luis Obispo,California.

Seed, H. B., l979, "Soil Liquefaction and Cyclic, Mobility Evaluation for Groundduring Earthquakes," Journal of the Geotechnical Engineering Division,

",. *

ASCE, l05.

Seed, H. B. and Idriss, I. M., l97l, "Simplified Procedure for Evaluating SoilLiquefaction Potential," Journal of the Soil Mechanics and FoundationsDivision, ASCE.

U.S. Soil Conservation Service, l977, "General Soil Map, San Luis Obispo County-Coastal 'Part" (including text of soil descriptions), USDA (unpublished;'available at SCS Santa Maria office).

Voorhees, A. M., 1980, "Evacuation Times Assessment for the Diablo CanyonNuclear Power Plant," Alan M. Voorhees & Associates, Berkeley, Cali-fornia.

B-8 I-269 7-4

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Wiegel, R. L., l970, "Tsunamis," in Earth uake En ineerin R. L. Wiegel, ed.,Prentice-Hall, Inc., Englewood Cliffs, New Jersey, pp. 53-306.

Wilson, R. C., l978, "Interaction between Ground Motion and Ground Failure,"U.S. Geological Survey, National Earthquake Hazards Reduction Program,Summaries of Technical Reports Vol. Vll, pp. 222-225, Menlo Park, Cali-fornia.

Yen, B. C., I 978, "Seismically Induced Shallow Hillside Failures," U.S. GeologicalSurvey, National Earthquake Hazards Reduction Program, Summaries ofTechnical Reports Vol. Vll, pp. 226-228, Menlo Park, California.

Youd, T. L. et al., l979, "Liquefaction Potential Map of San Fernando Valley,California," U.S. Geological Survey, Circular 807, pp. 37-48, Menlo Park,California.

Youd, T. L., l98I, personal communication, July l3, l98I, U.S. GeologicalSurvey, Menlo Park, California.

B-8 I-269 7-5

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>e.4

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APPENDIX

GROUND FAILURE

TABLEOF CONTENTS

Section ~Pa e

I.O OVERVIEW OF CRITICALROUTES .............. ~ ~ ~ ~.... ~ ~ ~... I-I

Ie ~.I Introduction ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ I-I

l.2 Field Reconnaissance Maps............................... I -2

0000

Table of Roads Surveyed ...................Map of Roads Surveyed ....................Quadrangle Names vs. Map Numbers.........Field Reconnaissance Maps.................

~ ~ ~ ~ ~ ~ ~ ~ ~ I-3~ ~ ~ ~ ~ ~ ~ ~ ~ I-5~ ~ ~ ~ ~ ~ ~ ~ ~ I-6~ ~ ~ ~ ~ ~ ~ ~ ~ I-7

l.3 Road Summary Sheets of Landslide and Liquefaction Hazards . I-l7

2.0 LANDSLIDEPOTENTIAL ..................................... 2- I

2.I2.22.32.4

Overview and Methodology ...................Summary of Landslide Potential by Road .......Summary of Landslide Potential by Site ........Detailed Field Survey.................;... ~ ..

2- I

2-l42-222-26

0

00

Reference Table - Landslide Site NumbersCritical.Routes .......

Pictures of Potential Landslide Sites......Field Data Sheets ......................

for~ ~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

2-272-292-42

3.0 LIQUEFACTIONPOTENTIAL.................................. 3- I

3. I Overview and Methodology ...................3.2 Summary of Liquefaction Potential by Road ....3.3 Summary of Liquefaction Potential by Site .....

3-I3-I33-l7

B-8I-227

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I.O OVERVIEW OF CRITICALROUTES

I. I INTRODUCTION

This section contains maps, tables and summary sheets which provide an

overview of the evacuation routes and plant access roads discussed in the report.This section should be used as reference for the location of roads and sites ofpotential ground failure.

A table of roads surveyed is presented providing a uniform numbering system

used in subsequent sections, and a description of the sections of the roads

considered. This is followed by a map of the roads which should be referred tofor their locations, as the field reconnaissance maps do not contain thisinformation.

The color field reconnaissance maps contain a detailed view of potential sites ofground failure in relation to the critical routes, topography, population and

cultural features. The site numbering systems defined by these maps are

referred to in subsequent sections.

The "Road Summary Sheets" presents a summary of potential ground failureproblems for each of the critical routes.

B-8I-227

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I.2 FIELD RECONNAISSANCE MAPS

0

0

0

0

Table of Roads Surveyed

Map of Roads Surveyed

Quadrangle Names vs. Map Numbers

Field Reconnaissance Maps

B-8I-227 I-2

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TABLE OF ROADS SURVEYED

RoadNo.

2 ~,

3-

4.

5 ~

6 ~

Road Name

Major Evacuation Routes

Route 101 - North

Route 101 - Central

Route 101 - South

Route 1- North

Route 1- South

Route 41

Portion of Road Surveyed

North of San Luis Obispo

San Luis Obispo to Avila turnoff

Avila turnoff to Los Berros turnoff

San Luis Obispo to Route 41

Pismo Beach to Valley Road (Oceano)

Horro Bay to five miles northeastof Route 1

MapNumber

6-7-9

6-3

3-2-1

6-5-10

3-1

10

7 ~

Secondary Evacuation Routes

Orcutt Road Harsh Street (SLO) to Lopez Drive 6-7-2

8.

9.

10.

,Lopez Drive

Route 227,

Price Canyon Road

Plant Access Roads

Orcutt Road to Route 101 (ArroyoGrande)

2-1

Marsh Street (SLO) to Edna 6-2

Edna to Route 101 (Pismo Beach) - 2-3

12.

13.

14.

San Luis Bay Road

Avi la Road

South Plant Road

North'Plant Road

Route 101 to Avila Road

Route 101 to Plant Entrance

Avi la Road to DCNPP

3-4

~ 4

Pecho Valley Rd. and Fields Ranch Rd. 5-4(Los Osos to DCNPP)

San Luis Obispo

15. Htguera Street

16. Madonna Road

17- Foothill Road

18. - Grand Avenue

19. Tank Farm Road

Route 101 to Santa RosaStreet (Route 1)

Los Osos Valley Road to Route 101

Los Osos Valley Road to Route 1

Cal. Poly. to Route 101

South Higuera Street to Route 227

1-3

3-6

RoadNo.

20.

21.

Road Name

~Morro Ba

South Bay Blvd.

Main Street andCountry Club Drive

Five Cit Areas

TABLE OF ROADS SURVEYED (CONT'D)

Portion of Road Surve ed

Los Osos Valley Road to Route 1

Route 1 to South Bay Blvd.

MapNumber

22.

23

24.

25.

26.

„29.

30.

31.

Ha 1 cyon Road

Valley Road

Los Berros Road

Other Roads

Avila Road

See Canyon and PrefumoValley Roads

Los Osos Val ley Road

Corbit Canyon Road

Route 227

Oak Park Road andNoyes Road

Printz Road

Route 101 to Route 1

Route 101 to Route 1

Valley Road to Route 101

Point Sqn Lui's. to I'lant Entrance

San Luis Bay Road toLos Osos Valley Road

Route 101 to South Bay Blvd.

Route 227 to Route 227

Edna to Lopez Drive

Route 101 to Route 227

Route 227 to Noyes Road

3-4-5-6

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PISMOBEACH

GROVERCITY

ARROYOGRANDE

EANO O~ Q

MAP OF ROADS SURVEYED

1-5

TERA CORPORATION

QUADRANGLE NAHES VS; HAP:NUHBERS

Quadran 1 e Name

Oceano

Arroyo Grande, NE

Pismo Beach

Port San Luis

Horro Bay South

San Luis Obispo

Lopez Hountain

Santa Hargarita

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1-6

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l.3 ROAD SUMMARYSHEETS OF LANDSLIDEAND LIQUEFACTIONHAZARDS

B-8 I-227 1-17

TERA CORPORATION

San Luis ObispoLopez Mtn.,Atascedero Quads

ROAD SUMMARY SHEET

ROAD LENGTH

Road No.: 1

Road Name (stretch): Route 101 - North (from northern city limits of SLO to theSanta Margarita turnoff)

8.0 miles NO LANES 4 1 anes (narrow)

LANDSLIDING (REF. NO. 1 thru 11 ) This is the Questa Grade-consideredmountainous. Cal Trans reports continued fill-settlement and ground water problemsin this area. Acceleration in this area are 0.2 or less - this being the lowerlimit for slides to occur. However because natural, cu't and fill slopes areover steepened and due to existing problems blockage is anticipated. Many rockfallswill occur, and some rock slides and debris slides. Closing the 2 northbound lanes(No 1, 3, 4, 5) The higher fills (No. 8) will probably settle down and out, severingthe two southbound lanes locally and possibly all lanes. Slumps and debris slides mayoccur on the westerly facing fill slopes.

LIQUEFACTION: None anticipated.

1-18

Pismo BeachSan Luis Obispo Quads

ROAD SUMMARY SHEET

Road No.: 2Road Name (stretch): Route 101 - Central (from Avila turnoff to SLO limits)ROAD LENGTH 8. 9 mi 1 es NO. LANES 4+

LANDSLIDING (REF. NO.35-36-52 ) A 400 foot road cut section issusceptible to failure (onramp northbound 101 from Avila) " this will cause totalclosure of this onlamp w/ rock falls and rock slides. At cut slope slide areas35 and 36 (est. 1,100 feet) rock falls may close the outside lane - southboundlane only - NOT total impairment.

LIQUEFACTION is a major concern through the SLO creek area (17,000 feet discontinuous).Lateral spreading and fill settlement may remove one or more lanes discontinuously,where the highway either, crosses the creek or parallels the creek. Water is very high(near surface) and numerous fills were constructed along the highway.

1-19

ROAD SUMMARY SHEET

Oceano, ArroyoGrande 6 PismoBeach Quads

Road No.: 3Road Name (stretch):

ROAD LENGTH 14.4 mi les

Route 101 - South (Avi la turnoff to 1/4 mile south nfLos Berros turnoff)

NO. LANES 4+

LANDSLIDING (REF. NO. 43"37-51 ) 1 a2 mi les north of Los Berros .Rd.(Northbound lanes only) cuts both sides may fail with soil falls, debris slides,=and possible slumps total closure not anticipated (1 lane northbound anticipated)No. 43. No. 37 north of Pismo Beach in center between north and south bound lanes.Rock falls would be expected to close both southbound lanes. High steep cutsnear Gragg Cyn. (No. 51) may close both northbound lanes and offramp to Avila

1 Southbound lane with rock falls, rock slides, and slumps.

LIQUEFACTION One main area of 1 iquefaction is expected in fills across the Price Cyn;-drainage (5,000) foot section. It would result in lateral spreads and settlement to .fills. This could close all four lanes both north and south bound in several locations.Liquefaction also could take place at the Avila Beach/U.S. 101 interchange across CraggCyn. drainage; fills would be susceptible to settlement. e

1-20.

ROAD'UMMARY SHEET

San Luis ObispoMorro Bay No, 8 So. quads

Road No.: 4Road Name (stretch): Route 1

- North (SLO to 1.9 mi1es north of Route 41)

ROAD LENGTH NO. LANES 4 (AC and concrete)

LANDSLIDING (REF.. NO.'ortion of State l. ) No 1 ands 1 ide anticipated along thi s

L>QUEFA<T>ON There are 14 zones (varying in length) along the route for a total of,500 feet susceptible to liquefaction. Lateral spread and fill settlement. Sig'nificantmage most likely in fills constructed overstream channels or where the road parallels

stream channels. See map for the locations.

1-21

Oceano/Pismo Beach Quads

ROAD SUMMARy SHEET

Road No.: 5

-Road Name (stretch): Route 1- South (Pismo Beach to Valley Road)

ROAD LENGTH 4.4 mi les 2-4NO. LANES

LANDSLIDING (REF. NO. 41 ) The road f ills and bridge constructedover the railroad tracks (Oceano - near airport) are suscepti ble to settlement and

debris slides possibly closing the outside lanes of the 4- lane road. Total closureis not anticipated by failure of the road fills.

LIQUEFACTI'ON Moderate to major damage is anticipated by liquefaction along a8,000 foot discontinuous section near Meadow Creek (Lagoon area) and over streamcrossings in Pismo Beach and Grover City and Arroyo Grande Creek. Fill settlementand lateral spreads are likely.

~,

1-22

Morro Bay North Quad

ROAD SUMMARY SHEET

Road No.: 6.Road Name (stretch): Route 41 (Morro Bay to 5 miles NE of Route 1)

ROAD LENGTH 5.0 mi les NO. LANES

LANDSLIDING (REF. NO. 34 ) Near the16 of T29S and RllE rock slides can be expected in only(1 lane closure). Debris and rock slides may be severeSections 1, 2, and 3. (T29S RllE) — 1.5 mile section.to both lanes.

Section corner (Western) 9 andthe northbound lanein the steep hilly area ofTotal closure can be expected

LIQUEFACTION Nine zones of potential liquefaction exist from State 1 to about sect.10 (T29S, Rll ). Lateral spreads and minor fill settlements, anticipated in fillsover stream channels. (See map for the 9 locations).

1-23

Arroyo Grande, LopezNtn 8 San Luis Obispo quads

ROAD SUMMARY SHEET

Road No.: 7Road Name (stretch): Orcutt Road (from Marsh St. in SLO to Lopez Drive)

ROAD LENGTH 10.4 NO. LANES 4 - 2

LANDSLIDING (REF. NO. 48 ) t1inor'landsliding With one lane closure(southeast bound) near Southern Pacific RR overpass 6 Johnson Avenue. Not totalclosur'e.

L>QUEFACTXON Liquefaction may occur at San Luis Obispo Creek and Johnson Avenue (SLO)'~and Biddle Ranch Road and West Corral de Piedra Creek crossings. Lateral spread and mino~fill displacements. The potential for liquefaction in the road fill that traverse thereservoir near Upper Arroyo Grande 'Road is considered remote.

1-24

Arroyo Grande 8 Oceano Quads

ROAD SUMMARY SHEET

oad No.: 8Road Name (stretch): Lopez Drive (from Route 101 northeast to Orcutt Road)

ROAD LENGTH 4.9 mi les NO. LANES 2

LANDSLIDING (REF. NO. 49/50 ) Feature No. 49 near Biddle Ranch'oad intersection is a dam embankment, seich could cause breaching of embankment,

however, acceleration level is below 0.2 g. Five locations of potential rockfalls and debris slides (total 2,200 feet discontinuous) on west side of road.Two slide areas are below the 0.2g threshold level (See map). Total closure ofboth lanes not anticipated - only northeast bound lane.

LIQUEFACTION Road fill in reservoir (Biddle Ranch Rd) south of 731/32S. Township lineot likely to liquefy due to "g" level of 0.18 g. Three other potential liquefaction areas1,200 feet total " discontinuous) may fail w/lateral spreads 6 fill settlements.

1-25

Arroyo Grande, Pismo Beach,San Luis Obispo quads

RQAD sUMMARy sHEET

Road No.: 9Road Name (stretch): Route 227 (from Marsh St. in SLO to intersection of Corbit Canyon

Road, Edna).ROAD LENGTH 6.7 miles NO. LANES 2

LANDSLIDING (REF. NO. ) t/one anticipated

LIQUEFACTION Four zones of potential liquefaction anticipated for a total of3,200 feet of potential closure. Two zones are located near the county airport Q

stream crossings another 9 the railroad (Los Ranchos School) crossing and the fourthnear intersection w/Price Canyon Road. Minor fill settlement and lateral spreads areanticipated.

1-26

Arroyo Grande 8 Pi smoBeach Quads

ROAD SUMMARY SHEET

Road No.: 10Road Name (stretch): Price Canyon Road (from Route 101 north to Route 227)

ROAD LENGTH 4.8 miles NO. LANES 2

LANDSLIDING (REF. NO. 46 and 47 ) One discontinuous (3 cuts) sectionapproximately 800'ong are susceptable to rock falls, 0.3 to 0.8 miles north ofTimber (RR siding), and a major 1500'ection of potential rock falls, rock slidesabout 1.3 miles fiorth of U.S. 101 may blockboth lanes. Feature flo. 47 has anexisting landslide (cut area) that covered both lanes.

LIQUEFACTI'ON Lateral spreads and minor fill settlements due to liquefaction may~ e

occur along a 2,000 foot section near Edna (Southwest of State 227) and two small(200 feet long - each) stream crossings 1.5 and 1.9 miles north of U.S. 101.

1-27

Pismo Beach Quad

ROAD SUMMARY SHEET

Road No.: 11

Road Name (stretch): San Luis Bay Road (from Route 101 west and south to Avi la Road)

ROAD LENGTH 1.4 mi les NO. LANES 2

LANDSLIDING (REF. NO. 24 ) One oversteepened fill is susceptibleto settlement and possible slumping on both sides of road. The 200 foot section islocated about 0.3 miles west of U.S. 101 across a minor drainage. Damage will resultin partial closure to both lanes - leaving the road center (1 lane) open to throughtraffic.

LIQUEFACTION One 400 foot section across the*See Canyon drainage may.fail due to .

liquefaction lateral spreads and minor fill settlement. Significant damage may beanticipated for both lanes.

'0

1-28

ROAD SUMMARY SHEET

Pismo Beach andPort San Luis

. Road No.: 12Road Name (stretch): Avila Road (Route 101

ROAD LENGTH 4.6 mi les

to plant entrance)

NO. LANES 2

LANDSLIDING (REF. NO. 17,18,19,20,21 ) Major landsl iding (rocksl ides, rockfalls and slumps) is anticipated along both cut and natural slopes, all of whichare oversteepened and some failures presently exist. Over 5000 feet of both laneclosures are anticipated both east and west of Avila Beach community.

LIQUEFACTION Major liquefaction damage (lateral spreads of fill settlement) areexpected along 7,300 feet (discontinuous) of the road w/total closure of both lanes)

n several locations. The fill area at the Public Pier and the road from the bridgeover SLO Creek east to below the storage tanks have the highest susceptability ofdamage.

1-29

Port San Luis Quad

ROAD SUMMARY SHEET

Road No.: 13Road Name (stretch): South Plant Road (PG6E access road from Avila Road to DCNPP)

ROAD LENGTH 7.0 mi les NO. LANES 2

LANDSLIDING (REF. NO. 12, 13, 14, 15 ) Natural slopes (No. 12) are over-steepened and 5,000 to 6,000 feet of roadway may have disconti,nuous debris slidesand rock falls. Closure would be expected to both lanes. Rubble Fill (rip rap)slopes above the road Q 3 locations each about 50+ feet wide will fail closingboth lanes (No. 14). These are areas of instability and the rubble fill has beenplaced to help stabilize erosion. Fourteen steep high fills have been placed acrossthe major SW flowing drainages. There was much evidence (e.g. tension cracks andrepair patching) noted that the fills are presently settling. Slumping and debrisslides are expected on these fills resulting in closure of both lanes. Slide areaNo. 15 will result in rock falls and slides and slumps.

LIQUEFACTION - doubtful if any will occur along this road section.

1-30

Morro Bay South andPort San Luis Quads

ROAD SUMMARy SHEET

oad No.: 14Road Name (stretch): North Plant Road (Pecho Valley and Fields Ranch Road from Los Osos

to DCNPP)

ROAD LENGTH 10.1 mi les NO. LANES 1 s 2 gravel/AC

LANDSLIDING (REF. NO. 27,28,29,30,31,32) See map for locations. No. 27 is adeep steep fill across Diablo Cyn. - settlement surficial debris flows and,possibleslumping can be expected. Also flooding (breaching-washout) is possible if thereservoir fails upstream in the PG8E complex. Natural oversteepened slopes (No. 28and 29) 4,500're susceptible to debris slides and total closure should be expected.Three major landsl ides (ancient) traverse the road. These appear old, deep, and shallowfailures and presently in a stable state. Reactivation is considered remote. No. 30and 31 are minor cut slopes that could close portions of the road but still remainpassable. No. 32 is a small fill which appears unstable and may settle, closing 1 lane.

" None anticipated along this road section.

1-31

San Luis Obispo 6Pismo Beach Quads

ROAD SUMMARY SHEET

Road No.: 15Road Name (stretch): Higuera Street (Route 101 north to Santa Rosa St. / Route 1)

.~

ROAD LENGTH 4m 3 mi les NO. LANES 2 and 4

LANDSLIDING (REF. NO.anticipated.

) Low relief area - No landsliding

LIQUEFACTION Approximately 4,300 feet (discontinuous) in three zones susceptable. toiiquefaction. These zones (See map) are adjacent (paraiiei) existing drainages '

water is very shallow in area. Moderate to heavy damage may occur to'all lanesin these areas.

1-32

San Luis Obispo Road

ROAD SUMMARy SHEET

Road No.: 16Road Name (stretch): Madonna Road (Los Osos Valley Rd. to Route 101)

ROAD LENGTH 1.2 miles NO. LANES 2 "4

LANDSLIDING (REF. NO. ) No landsliding anticipated

LIQUEFACTION Minor damage may occur to over 600 foot section n'ear the Southeastern end of Laguna Lake.

1-33

San Luis Obispo Quad

ROAD SUMMARY SHEET

Road No.: 17Road Name (stretch): Foothill Road (Los Osos Valley Road to Route 1)

ROAD LENGTH 3.0 miles NO. LANES 2

LANDSLIDING (REF. NO. ) None anticipated

LIQUEFACTION Moderate liquefaction problems may be expected in two zones total ling1,600 feet (See map). Water is very shallow in area. Totai ciosure to both lanes may ~occur in the valley floor area over stream crossings (fill).

1-34

Oceano Quad

ROAD SUHHARY SHEET

Road No.: 18Road Name (stretch): Grand Avenue (Cal Poly to Route 101)

ROAD LENGTH 2.7 miles NO. LANES 4+

LANDSLIDZNG (REF. NO. ) None anticipated

L1QUEFACTI'ON None anti ci pated

1-35

Pismo Beach Quad

ROAD SUMMARy SHEET

Road No.: 19Road Name (stretch): Tank Farm Road (South Higuera St. to Route 227)

ROAD LENGTH 1.8 miles NO. LANES

LANDSLIDENG (REF. NO. ) None anticipated due to v. low relief.

Moderate 1iqufaction problems may occur due to fill settlement andlateral spread through a long section adjacent to the large tank farm. Groundwateris very shallow in this area.

1-36

Morro Bay South Quad

ROAD SUMMARY SHEET

Road No.: 20Road Name (stretch): South Bay Boulevard (Los Osos Valley Road north to Route 1)

ROAD LENGTH 3.9 mi les NO. LANES 2 to 4

LANDSLIDING ( REF . NO. 33 ) A 600 foot section (cut) adjacent~ to Black Hill is susceptible to rock falls and possible rock slides. This will

close at least the southbound lane w/possible northbound lane too.

OU CTION F> 1 ls placed accross Los Osos Creek and the bay inlet area between,Black Hill and Cerro Cabrillo Hill are very susceptible to lateral spreads and fillettlement. Both lanes anticipated to be closed at several locations.

1-37

Morro Bay So. Quad

ROAD SUMMARY SHEET

ROAD LENGTH

tRoad No.: 21Road Name (stretch): Hain St. and Country Club Drive (starts south of Black Hill at

intersection with South Bay Road (Mt. View) then southaround campgrounds to Rte. 1

- includes 5th St. in city of2.9 miles NO. LANES 2 Horro Bay)

LANDSLIDING (REF. NO. ) No landslides anticipated this area.

LIQUEFACTION '.Liquefaction ground failure and lateral spreads are likely to-occurover'a 7,000 foot continuous section of road adjacent to the bay. A large portion ofthis section may be damaged by lateral displacements with the cl'osure of both lanes.

1-38

t

ROAD SUHHARY SHEET

Oceano Quad

Road No.: 22Road Name (stretch): Halcyon Road (from Route 1, Arroyo Grande Ave., north to Rte, 101)

ROAD LENGTH 1.7 miles NO. LANES 2-4

LANDSLIDING (REF. NO. ) None anticipated

LIQUEFACTION - Potential damage to a 1,000 foot section located immediately north ofArroyo Grande Avenue and adjacent to Arroyo Grande Creek. Damage is expected to be moderate.

Oceano Quad

ROAD SUMHARY SHEET

Road No.: 23

Road Name (stretch): Valley Road (from Route 1, Arroyo Grande Ave., north to'te." 10'i)

ROAD LENGTH 2.6 miles NO. LANES 2

LANDSLIDING (REF. NO. 40 ) A 2,000'iscontinuous sectionlocated on the river bluff slope above Clenega Valley. Both north and south lanesclosed from cut and fill failures. Rock and soil falls are anticipated with settle-ment to fill areas.

LIQUEFACTION At intersection of vally Avenue and Los Berros - Arroyo Grande Rd., moderatedamage to both lanes over a 200 foot section anticipated.

1-40

Oceano Quad

ROAD SUNMARY SHEET

Road No.: 24Road Name (stretch): Los Berros Road (Valley Road to Route 1)

ROAD LENGTH 5.5 mi les NO. LANES 2

LANDSLXDZNG (REF. NO. 38, 39 6 42 ) 1,500 feet (discontinuous) rock fallsand small slumps on the southeast bound lane and, possibly into northwest bound lane

near Nipomo Hill. 300 feet of rock and soil falls onto southeast bound lane near

U.S. 101. Two potential slide areas 500 feet long are located southeast of U.S. 101

where rock falls'and rock slides are anticipated.

L>QUEFA<T>ON 1,000 foot section near intersection with Valley Road, moderatedamage both lanes from lateral spreads and minor fi 1 1 set'tlement.

1-41

Point San Luis Quad

ROAD SUMMARY SHEET

Road No.:'5Road Name (stretch): Avila Road (from Point San Luis Plant Entrance)

ROAD LENGTH 1.4 miles NO. LANES 1 gravel dirt AC

LANDSLIDING (REF. No. 16 ) The road is in poor condition, narrow withnumerous steep slopes. These slopes do show signs of instability and would be verysusceptible to debris slides and rock falls. The first mile south is susceptible tocomplete failure at many points. Small fills may also fail. Very steep slopes onboth sides of road and moderately high acceleration.

LiQUEFACTiON None anticipated "~

1-42

ROAD SUHHARY SHEET

Pismo BeachPort San Luis 6San Luis Obispo Quads

Road No.: 26Road Name (stretch): See Canyon and Prefumo Roads (San Luis Bay Road to Los Osos

Valley Road)

ROAD LENGTH 12.1 mi les NO. LANES 182 (narrow gravel 8 AC)

LANDSLIDING (REF. NO. 25 - 26 ) Extremely steep natural slopes andmanmade cuts are nearly continuous along See Canyon westerly side. Numerousdebris slides are anticipated 4 mile section. There are several steep high cuts(about 6,000 feet-discontinuous) in the upper reaches of See Cyn and central portionsof Prefumo Canyon that are susceptible to failure. Nany slides are expected withtotal closure of both canyon roads. See map for location of slide areas.

L~QUEFACT1ON: No liquefaction is anticipated 'though some minor fill settlement andateral spread could occur at Davis Canyon crossing in See Cyn.

4

1-43

IROAD SUMMARy SHEET

Morro Bay SouthSan Luis Obispo andpi.smo Beach, Quads

Road No.: 27Road Name (stretch): Los Osos Valley Road (from South Bay Blvd. east to Route 101)

ROAD LENGTH 9.4 mi les NO. LANES 2 and some 4

LANDSLIDING (REF. NO. ) No landsl iding anticipated alongthis stretch - all relatively flat low lands.

LIQUEFACTION Nine zones totaling 1,800 feet may be subject to lateral spreads andminor fill settlement. The zones are located near stream crossings usually where shallfil)s have'been placed.

1-44

Arroyo Grande Quad

ROAD SUMMARY SHEET

Road No.: 28Road Name (stretch): Corbit Canyon Road (Route 227 to Route 227)

ROAD LENGTH 6.1 mi les NO. LANES 2

LANDSLIDING (REF. NO. 44 ) Two 200 foot sections of both lanes

may be blocked due to rock falls. Sites are located about .4 to e5 miles northof Township line (T31/32S).

LIQUEFACTION Three 600 foot sections may be susceptible to lateral spreads andfill settlements indicated by liquefaction. Locations are 0.2, 0.6 and 1.6 milesorth of 731/32S Township line. Damage is expected to be moderate.

gs) e ~

P

1-45

Arroyo Grande

ROAD SUMMARY SHEET

Road No.: 29Road Name (stretch): Route 227 (Carpenter Canyon Section from Edna to Lopez Drive)

ROAD LENGTH 4.8 miles NO. LANES 2

LANDSLIDING (REF. NO. 45 ) A 3,000 foot discontinuous section is susceptibleto rock falls only in the Southeast bound lane and small portion of the Northwestbound lanes. Slide locations are 0.3 to 1.0 miles south of T/31/32S township line.

LiQUEFACTION Lateral spreads and fill settlement may close both lanes at theCanada Verde Creek crossing (approximately 200 foot section) .

1-46

Arroyo. Grande Quad

ROAD SUHHARY SHEET

Road No.: 30Road Name (stretch): Oak Park and Noyes Roads (Southeast from Noyes Road to Route 227)

ROAD LENGTH 3.2 miles NO. LANES 2 (narrow)

LANDSLIDING (REF. NO. ) None anticipated

LIQUEFACTION Minor to moderate damage may be sustained at the Canyon No. I

stream crossing.

'-47

Arroyo Grande Quad

ROAD SUMMARY SHEET

Road No.: 31

Road Name (stretch): Printz Road (SE from Noyes Road to Route 227)

ROAD LENGTH 1.3 NO. LANES 2 (narrow)

LANDS LI DI NG (REF. NO. ) None anticipated

LlQUEFACTION None anticipated

1-48

2.0 LANDSLIDES

2. I OVERVIEW AND METHODOLOGY

Landslides - Overview

Earthquake-induced landslides differ from conventional landslides by their geo-

metry, failure mechanism, and type of sliding. Conventional landslides arecaused by water infiltrating a slope after rainfall. The water has a tendency tosignificantly decrease the shear strength (e.g., cohesion and friction) of wea-thered rock and soil material. In addition, the infiltrated water increases theweight of the slide mass and decreases the confining effects at the toe of theslope. Once the shear strength of the material is exceeded, the slide mass movesdownward in response to gravity.

Earthquake-induced landslides are triggered by energy developed by the earth-quake in the form of ground shaking. The shaking, depending on its intensity andduration, weakens and eventually loosens rock and soil materials, forcing themdown the slope. These landslides appear to be mostly confined to surfacefailures and result in rock falls, rock slides, soil falls, and debris slides. Very fewdeep-seated rotational block glides or slump failures have been observed as a

result of earthquakes. Approximately 90 percent of the failures will be eitherrock falls, rock slides, soil falls or debris slides. Only IO percent will form deep-

I

seated rotation, block glide or slump types of failures (Harp, l981). During thel97l San Fernando earthquake most of the failures were only I. meter thick andhad average length-to-depth ratios of 3I-to-I to a maximum of 80-to-I (Yen,I 978).

The factors controlling the triggering of landslides are the intensity and durationof ground shaking and steepness of the slope. The potential for landslides isincreased when steep slopes are underlain by low density, weathered, weaklycemented soils and/or highly fractured material. There are indications that rainsaturation has little or no additional adverse effect on slopes that wouldotherwise be susceptible to earthquake-induced failures (Leighton, I 974, Harp,

B-8!-227 2-I

TERA CORPORATION

l98I). Since this has not been proven, and for the purposes of this study, we

have considered the worst possible condition which would be the combined effectof water-saturated slopes and simultaneous excessive ground shaking at a site.

Seismic-induced landslides normally occur with the initial shock of an earth-quake. However, in some cases the initial shock may only loosen or weaken rockor soil material on a slope, while subsequent aftershocks may eventually cause

failure. To compound the problem, heavy 'rain following a major earthquakemight cause failure of slopes that were originally weakened by the initial shock.

Studies by Wilson (l978) of the Santa Barbara (M = 5.I) earthquake of August l3,l978 showed that artificially cut slopes are significantly more prone to earth-quake induced failure than natural slopes of the same geologic material.

Rock falls and rock slides are most common on steep slopes devoid of a soilcover. Broken rock in steep road cuts is very susceptible to falls or slides. Soil

falls generally occur along very steep (near vertical) natural slopes or on man-made cuts where blocks of unconsolidated materials become detached and fall.

Based on work by'Harp (l98l), slopes greater than 35o (I'h:I slope ratio) whererock is exposed are prone to rock falls and rock slides. This is considered

conservative since statistics indicate a 40-to-45o lower limit. Furthermore, thehigher the degree of fracturing or jointing of the rock, the higher, is theprobability of failure. Other discontinuities such as bedding or foliation,'nlessadversely oriented out of slope, appear not to be a major issue with regard toseismically-induced rock falls or rock slides (Harp, I 98I). Debris slides usuallyoccur on moderate-to-steep natural slopes and include only loose soil or colluvialmaterials above the bedrock. Usually very steep slopes are devoid of a soil coverand bedrock is exposed which is subsceptible to failure. Soils or colluvialmaterial have a tendency to fail on slopes of 25o (2:I slope ratio) or greater(Harp, 198I). Research has shown that soils most susceptible to failure

are'ranular

and nonorganic.

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TERA CORPORATION

Had the l978 Santa Barbara earthquake been any larger, a number of severe

failures would have resulted. In a study of earthquake-induced landslides of I5

major earthquakes throughout the world, cut failures were very common whilefill failures were less frequent (Wilson, l.978). However, slopes comprisingartificial fillalso are prone to seismic induced failures. The geometry of the fill(i.e., slope ratios and slope heights) and consistency of the soil materials willcontrol its stability or lack of stability. Fills are known to fail either byslumping or by debris slide. Poorly compacted, low cohesive fill materials on

slopes in excess of 25o are subject to earthquake-induced failure.

Landslides - San Luis Obis o Area

Numerous landslides have occurred in the study region (Envicom, l974). The

type and distribution of failure probably reflect specific bedrock conditions,namely: bedding, jointing and fracturing, and steep slope. These slides weremost likely triggered by water infiltrating the slopes and were not related 'toearthquake activity. None of the slides near the evacuation roads and highwaysare known to be active and the majority of the larger features are consideredquite old, possibly having moved during a much wetter climate (i.e., over I l,000years ago).

Where earthquake-induced slides are likely to occur in the study area, they wouldin most cases fall onto highways rather than occur below them. While materialsfalling on the roadways would cause at least partial blockage, the slides thatoccur downslope from a roadway could sever one or more lanes, rendering themimpassable.

The quantities of materials generated at the toe of a slope from any one slidewill vary depending on the dimension of the slide. Most of the shallow slides thatoccurred during the l97l San Fernando earthquake had lengths of IS to 300

meters and thicknesses of .2 to I meter (Morton, l97I). Assuming average widthof these slides to be about one-third of the length and average thickness to be

I meter, quantities ranged between 45 to 300 cubic meters of displaced debris.It is estimated that similar quantities could be developed from slides occurring in

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TERA CORPORATION

the study area. Slides might occur adjacent to each other and form coalescing

slide masses.

The removal time to clear a road blocked with slide debris depends on theamount of materials to be removed, the number and type of heavy equipment

available, access to the site, and distance to a suitable disposal or borrow area.

The most practical types of heavy equipment for expediting road repair work are

rubber-tired loaders and tractor bulldozers. Normally, a loader of the typeowned by CALTRANS can excavate 300 cubic yards of loose unconsolidated

material per hour. Such loaders are available at the CALTRANS maintenance

stations and could be on site within 30 minutes. A bulldozer (e.g., D-7

Caterpillar) would be able to move more yardage per hour. However, the onlyone owned by CALTRANS in this area is stationed on Highway I north of Morro

Bay and would require a long time to bring to most sites..Local contractorswould be able to provide such equipment with a delay of 2 to 4 hours. In order toobtain clearing time estimates for our study, we have assumed that once on site,front loaders would be able to clear the road at the rate of 200 ft/hour per lane.

This implies that no hauling is required and the debris is l2 feet wide with an

average thickness of 3 feet. All the estimates have been made assuming thatonly one loader is working on any given road.

Because roads are long linear structures, multiple failure can occur any place

along them, creating several blockages. In this case, the blockages may have tobe removed one at a time from each end unless equipment is available at

tintermediate points. As an alternative, for emergency purposes a road can be

reopened after a major landslide by grading a road over the top of the slide mass

or by passing it around the perimeter of the mass. This would certainly be time-saving; however, caution must be exercised when people or equipment areworking in an area of potential active sliding. Roads severed or heavily damaged

by a slide located below the road may be difficult to repair within a reasonable

time frame. Such occurrences would have to be dealt with on a case-by-casebasis.

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TERA CORPORATION

Assessment of Landslide Potential

The number of technical reports on earthquake-induced landsliding is verylimited. Much of the state-of-the-art work is presently being conducted by theU.S. Geological Survey through their Earthquake Hazard Reduction Program.

The criteria established by the Geological Survey have been used for an earth-quake-induced landslide study of San Mateo County, California (in press).Geologic conditions in San Mateo County are in part similar to those in this studyarea. The Association of Bay Area Governments also have used the GeologicalSurvey's criteria for developing landslide assessment maps in the greater San

Francisco area. The California Division of Mines and Geology has procured a

seismic hazard study of Santa Clara County, California (CDMG, 1974), thoughthe criteria used for their "Relative Seismic Stability Map" (Plate 6) were notdiscussed. The Seismic Safety Element of San Luis Obispo County (Envicom,1974) includes a "Landslide Risk Map" (Plate 2B); however, the criteria used inthat study appear to be antiquated.

Criteria for assessing earthquake-induced landslides for this study were de-

veloped primarily from the criteria established by the U.S. Geological Survey.Tables 2-1, 2-2, and 2-3 summarize the criteria developed by the U.S.Geological Survey for studies in the San Francisco Bay area. Tables 2-2 and 2-3have been modified slightly to take into account local geologic conditions. Usingthese criteria (ABAG, 1980-81) to determine seismic-induced landslide potential,all slopes analyzed within the study area fall into an "unstable condition" forboth summer and winter conditions. However, the intensity of ground shakingwill vary from strong to very strong to occasionally violent with distance fromthe fault (tables presented in Appendix). On the Modified Mercalli scale,intensities will range from Vll to IX. According to the definition given to thescale, earthquake landsliding has been known to take place within this range ofintensities.

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Basically, there are four main factors that control earthquake-induced landslid-

ing: I) strong ground motion, 2) slope inclination, 3) surface geologic and

engineering parameters, and 4) conventional landsliding susceptibility (water-

induced failures). Aerial photographs (Fairchild, l 978), geologic and topographic

maps, and a field inspection were used to collect information on those slopes

suspected of potential landsliding. Field data sheets were prepared for each site,'nd a summary of pertinent data for each site is given later in the Appendix.

Only slopes that trend immediately adjacent to or near the roads or highways

were considered in this study. All slopes (natural slopes, cuts, and fills) were

excluded from this study unless they exceeded the lower limits of the criteriapresented in Table 2-4. No deep-seated potential slides were suspected or

recognized along the roads surveyed. Fill slopes normally are difficult toanalyze by inspection since their stability is in part related to hoyr well theywere compacted during construction. Usually new road fills have been con-

structed to adequate standards, though there are exceptions. Old road fills or

newer ones with slope ratios in excess of 2:I (horizontal-to-vertical) were

considered zones of likely failure. Table 2-5 summarizes the relative suscepti-

bility to seismically-induced landsliding for each of the slope areas investigated

in this study.

Based on the assessment criteria, many slopes along the evacuation routes have

been categorized as potential landslide zones, capable of failing under seismic

shaking. Since the current state-of-the-art requires a conservative approach toformulating the assessment criteria, one does not expect that all slopes so

identified will actually fail. It is judged that the number of failures- willdecrease rapidly with distance from the fault, based principally on the attenua-tion of acceleration. In order to estimate the expected number of slides and the

corresponding clearing times, the criteria presented in Table 2-6 were developed

for three damage levels. These criteria reflect engineering judgment based on

geological data and past earthquake experience. For a potential landslide

located in a given acceleration zone, the expected footage of failure was

obtained by multiplying the total potential footage by the percentage corres-

ponding to the selected damage level.

B-8I-227 2-6

TERA CORPORATION

A summary of expected footage failure and clearing time is presented in the

table, "Summary of Landslide Potential by Road" (Section 2.2). tn this table,each road was divided according to the range of expected ground accelerations itwas expected to experience (PGA zone). For each hypothetical demand level,the number of expected failures, number of lanes affected, and the. totalaffected footage are summarized. The estimated repair times for each damage

level is summarized first by number of affected lanes, by PGA zone, and finallyby the total repair time estimate for the road. For roads 13-3l, those notconsidered main evacuation routes, we have summarized the clearing time foronly one lane of traffic, as this was considered sufficient clearance for thoseroads under emergency conditions.

Section 2.3 presents detailed summary data concerning each landslide potentialsite. The times for clearance referenced in. that section represent timeestimates obtained from the field survey. Section 2.4 presents detailedinformation from this field survey.

B-8I-227 2-7

TERA CORPORATION

TABLE 2-I

ACCELERATION/INTENSITYRELATIONSHIPS

Modified

Mercali

Intensity

Average

Peak

Acceleration

(g = gravity)

Peak

Velocity

(cm/sec)

San Francisco

Intensity

IVV

Vl

VllVill

IX

XXI

XII

O.OI5 — 0.020.03 — 0.040.06 - 0.07

O.IO — O.I50.25 — 0.300.50 - 0.55

0.600.600.60

I-22-55-8

8-l220-3045-55

60+60+60+

Weak (E)Weak (E)Weak (E)

Strong (D)Very Strong (C)Violent (B)

Very Violent (A)Very Violent (A)Very Violent (A)

Bolt, B. A., l978, "Earthquake Primer," Appendix C, W. H. Freeman& Co., San Francisco, California.

2ABAG, l 980-8I (see references).

B-8I-227

TERA CORPORATION

TABLE 2-2

MATERIALSCATEGORY

(DEFINITIONS)

I Cohesive rock types: well-cemented, indurated,intact massive with few structural discontinui-ties (e.g., open close fracturing and jointing),high integrity.

II Relative cohesionless rock and soil units: poorlycemented coarse-grained rock types, loose sandysoils and slope wash, numerous discontinuities(e.g., open fractures and joints closely spaced),low integrity.

III Clay rich rock and soil units: fine-grained clayrich bedrock (e.g., siltstone, shale and mud-stones), including clayey slope wash, soil andartificial fill.

I Modified by TERA after ABAG I 980- I 98 I (seereferences).

2-9

TERA CORPORATION

TABLE 2-3

RELATIVESUSCEPTIBILITY OF ROCK/SOIL UNITSVS. SLOPE RATIO TO SEISMIC)LLY-

INDUCED LANDSLIDES

MaterialCategory

Slope Ratio (horizontal to vertical)

2:I I6:I I:I I:I

where:

I =

2 =

Stable all year.

Stable in summer, intermediate stability in win-ter.

3 = Intermediate stability in summer, unstable in win-ter.

4 = Unstable all year.

Modified by TERA after ABAG, I 980- I 981 (see references).

2-IO

TERA CORPORATION

TABLE 2-4

LOWER LIMITCRITERIAFOR SLOPE SELECTION

SLOPES

o Rock falls and rock slides can occur on man-made ornatural bedrock slopes in excess of I6: I (35 ) slope ratio.

o Soil falls and soil debris slides can occur on man-made(e.g., fills) or natural slopes in excess of 2: I (25 ) sloperatio.

o Slumps, rotational or block glides can occur on any slopeinclination angle above IO . This type of sliding is mostdependent on bedrock structure, geometry and engine-ering parameters.

MATERIALS(GREATEST SUSCEPTIBILITY)

o Soils: Soils that are granular, non-organic, have littlecohesion (i.e., less than 5II psi) and have low frictionalstrengths (i.e., less than 25 angle of interval friction) aresusceptible to failure.

o Rock: Bedrock that is highly fractured or jointed orwhich displays any other type of discontinuity, especiallyif planes are open, is susceptible to failure.

ACCELERATION

Any site that is estimated to exceed 0.20 g (MM Vll toVll+ intensity) can produce displacement on the order of5cm, which can cause a slope to fail. If slopes wereconsidered overly critical for other reasons, accelerationas low as O.I2 g was considered the lowest limit necessaryto produce failure.

CONVENTIONALLANDSLIDING

Any slope that shows outward signs of distress (e.g.,hummocky relief, tension cracks, etc.) or a potentialinstability due to geologic structure or rock type andwater infiltration could fail under the combined effects ofheavy precipitation and severe ground shaking. Anyknown active landslide may temporarily accelerate duringseismic shaking.

B-8 I-227 2-II

TERA CORPORATION

TABLE 2-5

LANDSLIDES

FeatureNo.

SanFranciscoIntensity

MaterialsCategory

RelativeSuscepti-

bilityFeature

No.

SanFrancisco

. Intensity

Materials Relative

Category.l I

I

2345

6789

IO

IIl2l3l4l5

l6l7I8202I

2324252627

CCDDD

DDQDD

CBC-BC-BC-BC-BC-BC-BC-BC-BC-BC-BC-BC-BB

IIIIIIIIIII

lllllIIIIIII

IIIIIIIIIII

IIIIIIIIIIII

I 8 IIIIIIIIIIIIIII

44

4

4

444

4

43'-4

4

44444

3-4444

2829303l32

3334353637

3839404I42

4344454647

'484950Sl52

BBBBB

CCCCC

CCCCC

C-DCCC

DC-DC-BC-B

IIIIIlllIIIII-III

IIIIIIIIIII

IIIIIIIIII

IIII-IIII-IIII-IIIIII

ItIIII-IIIIII-II

44

44

44

4

4

444

44444

44'

44

B-8I-227

TABLE 2-6

REPAIR TIME ESTIMATESFOR LIQUEFACTION

(TWO LANES)

LiquefactionSusceptibility

Damage Level Percentage ofFootage RequiringAdditional Repair+

0 hr

0.25 hr

0.5 hr

0.5 hr

I hr

2 hr

1.0 hr

2 hr

4 hr IO

+ Repair rate assumed at 200 ft/hour/lane.

B-8 I-227 2- I 3

TERA CORPORATION

0

2.2 SUMhAARYOF LANDSLIDEPOTENTIALBY ROAD

2-l4

TERA CORPORATION

SUHHARY OF LANDSL1DE POTENTlAL

By Road

Sheet 1 of 7

RoadName and(Number)

U.S. 101

PGAZone(g)

DamageLevel

LanesB locked

Number

ofPotentialFailures

Footageof

PotentialFailures

1350

0

PercentageFa i lureExpected

Numberof

ExpectedFa i lures

Footage Expectedof Time

Expected To ClearBlockage (Hours)

TotalClearing

Timein PGA Zone

(Hours)

.0

TotalClearing

Timefor road

H r

North

(Northbound)

(1)

Northbound

(cont.)

U.S. 101

North

(Southbound)

(i)

Southbound

(cont.)

1-.2

~ 2 ~ 3

.1-.2

~ 2- 3 2

0,

1350

0

1350

3950

0

200

200

0

200

2800

1900

2800

1900

2800

1900

200

0

200

0

200

0

10

10

15

20

10

10

15

20

.2

0

0

.1

.15

0

.2

0

.2

0

.4

.15

0.20

68

198

135

395

0

20

0

30

0

40

140

95

280

190

20

30

0

~ 3

2

~ 7

4.00

.2

.3

0

.4

~ 7

1.0

1.4

1.9

.1

0

0

2.3

4.7

.2

.3

.4

1.7

3 3

.2

.2

2.6

4.11

1.9

3 '

SUHHARY OF LANDSLIDE POTENTIAL

By Road

Sheet 2 of 7

RoadName and(Number)

PGAZone(g)

DamageLevel

LanesB locked

Number

ofPotentialFailures

Footageof

PotentialFailures

PerceritagFai lureExpected

Kenberof

ExpectedFailures

Footage Expected Totalof 'Time Clearing

Expected To Clear TimeBlockage (Hours) ln PGA Zone

Tote IC'I ear ing

Timefor road

Hour

Route 101

Central

(Northbound)

(2)

~ 2 ~ 3

10

15

20

0'

Route 101

Central

(Southbound)

(2)

2 i3 .2

1100

0

1100

0

1100

0

10

15

20

~ 2

.4

0

110

0

165

0

220

0

.6

.8

.6 .6

Route 101

South

(Northbound)

(3)

~ 2 03

0

1300

0

1300

0

1300

10

15

20

0

.2

~ 3

.4

0

260 2.6

130 1.3

0

195

1.3

2.0

2.6

1.3

2.0

2.6

Route 101

South

(Southbound)

(3) '

2 3

1

2

0

70

0

70

0

70

10

15

20

0

.15

.20

14

0

.1

SUHHARY OF LANDSLIDE POTENTIAL

By Road

Sheet 3 of 7

RoadName and(Number)

Avila Road

N. Bound

Onramp

to Route 101

Route I

PGAZone(g)

~ 2 ~ 3

DamageLevel

LanesB locked

Number

ofPotentialFailures

Footageof

PotentialFailures

400

0

400

400

0

800

2000

PercentageFailureExpected

10

15

20

10

Nunberof

ExpectedFailures

.'15

Footageof

ExpectedBlockage

40

0

60

0

80

0

80

200

Expected TotalTime Clearing

To Clear Time(Hours) in PGA Zone

.2

0

0 3

.4

2.4

Tota IClearing

Timefor road

2.4

South

(5)

Route 41

(6)

Route 41,

(Cont.)

.2- 3

.2 ~ 3

.1-.2

I

2

26'002000

800

2000

300

0

300

0

300

0

1000

1000

1000

0

15

20

10

15

20

10

.4

1.2

.I0

.2

0

.2

~ 3

0

120

00

160

400

30

0

0

60

0

50

0100

0

.6

.8

4

.2

~ 2

~ 3

0

.3

1.0

0

3.6

4.8

02

1.0

3.6

4.8

.2

.5

1.3

SUHHARY OF LANDSLIDE POTENTIAL

By Road

Sheet 4 of 7

RoadName and(Number)

Orcutt Road

and Lopez Drive

(7 and 8)

Route 227

(9 and 29)

Price Canyon

(lo)

San Louis Bay

Road

PGAZone(g)

~ 2 ~ 3

2- 3

~ 2- 3

.3- 4

DamageLevel

LanesBlocked

Number

ofPotentialFailures

4

3

Footageof

PotentialFailures

2400

2400

600

2400

6oo

3000

0

3000

0

3000

0

Soo

1500

Soo

1500

Soo

1500

200

0

200

0

200

0

PercentageFa I lureExpected

10

15

20

10

15

20

10

15

20

20

25

30

Humberof

ExpectedFailures

~ 2

~ 3

.4

.4

0

.6

0

.8

0

~ 3

.I

.2

.2

Footageof

ExpectedBlockage

240

36o

90

48o

120

300

0

45o

0

600

So

150

120

225

160

300

4o

50

0

6o

ExpectedTime

To Clear(Hours)

1.2

1.8

.9

2.4

1.2

1.5

2 3

0

3.0

0

I ~ 5

.6

2 '

3.0

~ 3

~ 3

TotalClearing

T imeln PGA Zone

Hours

1.8

2.7

3.6

1.5

2 '

3.0

1.9

2.9

3.8

Tota I

ClearingTime

for roadHours

1.8

2 '

3.6

1.5

2 3

3.0

1.9

2.9

3.8

~ 3

SUNNARY OF LANDSLIDE POTENTIAL

By Road

Sheet 5 of 7

RoadName and(Number)

Avila Road

(12)

South Plant

Road

(i3)

South PlantRoad

(cont.)

North PlantRoad

(i4)

PGAZone(g)

.3-.4

.4-.5

.3-.4

.4-.5

DamageLevel

LanesBlocked

Number

ofPotentialFailures

0.

6

10

10

10

Footageof

PotentialFailures

0

6700

0

6700

0

6700

0

7325

0

7325

0

7325

0

2275

0

2275

70

2275

70

800

70

5800777

5800

PercentageFailureExpected

20

25

30

30

40

50

20

25

30

30

40

50

'Numberof

ExpectedFailures

0

1.2

. 0

1.6

1.8

0

2.7

0

3.6

4.5

2.6

3 '0

3 '~ 3

1.8

2.4

.5

3.0

Footageof

ExpectedBlockage

0

1340

0

1675

2010

2200

2950

0

3700

0

455

0

570

0

680

21

1 40

28

2320

352900

ExpectedTime

To Clear(Hours)

0

6.7

10

15

0

19

0

2 3

0

2.90

3.4

.I11.6

.215

Tota I

Clear ingTime

ln PGA ZoneHour

c

8.4

10

15

19

2 '

2.9

3.4

8.8

11.7

15.2

Tota IClearing

Timefor road

Hours

6.7

8.4

10

13 '

17 '

22.4

8.8

11.7

15.2

SUHHARY OF LANDSLIOE POTENTIAL

By Road

Sheet 6 of 7

RoadName and(Number)

PGAZone(g)

DamageLevel

LanesBlocked

Number

ofPotentialFailures

Footageof

PotentialFailures

300

00

PercentageFa I lureExpected

10

Numberof

ExpectedFailures

Footageof

ExpectedBlockage

30

0

Expected TotalTime Clearing

To Clear Time(Hours) ln PGA Zone

.2

Tote I

Clear lngTime

for roadHours

.4

South Bay

Boulevard

(20)

Los Berros

Road

(24)

Avila Road

(25)

See Canyon

and Prefumo

Valley Road

(26)

~ 2-.3

02 .3

.3-.4

~ 2- 312

0

12

300

300

300

300 „

900

1500

900

1500

900

1500

2500

2500

2500

2500

2500

2500

2/i 1

0

2 115

15

20

10

20

20

25

30

10

15

20

.15

.15

.20

.20

.4

~ 3

.6

~ 5

.8

.6

.2

~ 3

~ 3

~ 3

0

1.8

0

2.4

45

45

60

60

90

150

135

225

180

300

500

500

625

625

750

750

2 11

0

4060

0

420

.2

.2

~ 3

~ 3

~ 5

.8

~ 7

1.1

~ 9

1.5

2.5

2.5

3 2

323.8

3.8

0

1.60

20.

0

2 .1

.6

1.3

1.8

2.4

6.4

7.6

13.6

20.3

27.1

1.3

1.8

2.4

6.4

7.6

13.6

20.3

27.1

SUHNARY OF LANDSI.IDE POTENTIAL

By Road

Sheet 7 of 7

RoadName and(Number)

PGAZone(g)

DamageLevel

LanesBlocked

Number

ofPotentialFailures

Footageof

PotentialFailures

PercentageFai lureExpected

Numberof

ExpectedFa i lures

Footageof

ExpectedBlockage

ExpectedTime

To Clear(Hours)

Tota IClearing

Timeln PGA Zone

Tote IClearing

Timefor road

Corbit Canyon

Road

(28)

.2-.3

0

400

0

400

0

400

10 ~

15

20

.2

.4

0

40

0

60

0

80

0

.2

0

~ 3

0

.4

2.3 SUMMARYOF LANDSLIDEPOTENTIALBY SITE

2-22

TERA CORPORATION

AREAS OF LANDSLIDEPOTLNTIALSUMMARYSHEET BY SITE NO.

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TERA C RPORATION

AREA OF LANDSLIDEPOTENTIALSUMMARYSHEET BY SITE NO.

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TERA CORPORATION

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TERACO ( RATION

2.4 DETAILEDFIELD SURVEY

o Reference Table - Landslide Site Numbersfor Critical Routes

o Pictures of Potential Landslide Sites

o Field Data Sheets

B-8I-227 2-26 ~

TERA CORPORATION

LANDSLIDE S ITE NUMBERS FOR CRITI CAL ROUTES

RoadNumber. Road Name Landslide Zones Included

4

10

12

13

14

15

16

17

18

Route 101 — North

Route.101 - Central

Route 101 - South

Route 1— North

Route 1- South

Route 41

Orcutt Road

Lopez Drive

Route 227 (Edna to SLO)

Price Canyon Road

San Luis Bay Road

Avila Road (101 to Plant Entrance)

South P.lant Road

North Plant Road

Higuera Street

Madonna Road

Foothill Boulevard

Grand Avenue

1-2-3"4-5-6-7-,8"9"10"11

35-36

37-43-51

None

40-41

34

48

49-50

None

46-47

24

18-20-21 ( 52 on ramp to 101)

1 2-1 3-14-1 5

27-28-29-30-31-32

None

None

None

None

19

20

21

22

23

24

Tank Road

South Bay Boulevard

Hain Street and Country Club Drive

Halcyon Road

Valley Road

Los Berros Road

None

33

None

None

None

38-39-42

25 Avi la Road 2-27 16

oadNumber Road Name Landsl ide Zones Included

26

27

28'9

30

31

See Canyon and Prefumo Valley Road

Los Osos Valley Road

Corbit Canyon Road

ORoute 227 (Edna to Lopez Drive}

Oak Park Road and Noyes Road

Printz Road

25-26

None

44

45

None

None

2-28

r

/''

'c „~

(

Ggh4 . I

Site

I

No. It y,

. ~ I IÃSII

1 I

Site No. 2L

I,

, I

, i~

Site No. 3

4'",

1

Site No. 4

4

gt c

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Site No. 5

Z

*

Site No. 6

S

lI

v'

1

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I

Site No. 7 Site No. 8

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A

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Site No. I I

(

Site No. l2 Site No. l2

J

/

I

I

/

I

, I

P

Site No. l3

'E

~

! jf -I ).' ',,I „g... i'

Site No. I 6

S>te No. IS Site No. 20

Site No. 2P

Site No. 24 Site No. 26

Site No. 28 Site No. 28

'4C

Site No 29

f;

' Site No 30l

co < Cl

','P

I'

I

/

Site No. 3I

*

4 r~J ~C It

I'I

~4"v ~

~ ', - g h

Site No. 32L==- =-m"

EF

4-

A,:F

Site No. 33 Site No. 34

Site No. 35 Site No. 36

Site No. 37

..J..

b.

,~ ~

s

Site No. 38

Site No 39 Site No. 40

FA<

Site No. 4l Site No. 42

Site No. 43 Site No. 44

Jg C~

li f.

f

Site No. 45 Site No. 46

Site No. 47 Site No. 48

Site No 49 Site No. 50

Site No. Sl Site No. 5I

Site No. 52

p. 1

Slopes:NaturalCutFill

LiquefactionSettlement

Field Data Sheet

Potential Unstable Conditions(Roads and Highways)

Site Ref. No.

By - CMPDate: 6/22/81

Highway/Road: 101 Nor th Elev.: 350'uad.: San Luis Obispo

T: '30S R: 12E Sect.:25, NW4-NEk Sur face: AC Width: 70' lanes

Bearing: N55E Slope/Rd. Relationship:Slope BearingN55E Slope Height: 50 '75 'imensions: 200+ Q toe

Slope Inclination: 56 Terrain: Cut surface very irregularDrainage: Sheetwash Cover: None (few reeds)

Erosion: None (New cut) Uncon. Surf. Material: None

Thickness: . NA Consistency: NA

Soils: Granular: Organic: Cohesive: Strength Factor:Bedrock Type: Serpentinite JR - UltrabasicsWeathering: Moderate Hardness/Cementation: Hard

Consistency: very dense Structure (Type/Attitudes) - v. sheared andfractured. 'andom-6" to 12" open (tight) near vert.foliation parallel to road

Bedrock Engr. Characteristics: Mod, strengthGround Water (Evidence/Depth): gal y — dry above. numerous seeps throughout face, dslower 1/2

Unstable Conditions (Evidence) Minor raveling (gravel size) g toe - new cut estimated.one to two years.

Exist. Retaining Struct.: None

Site Est. Max. Accel.: .21 g Est. Damage/Blockage: Rock fal ls - couldclose both Northbound lanes with possible rockslide estimated to 1,000 yards.

Remedial'epairs: Loader - dump in to North, Southbound lanes O.K.

Est. Time To Repair: Several hours + 5

Remarks/Conclusions/Recommendations:One bench cut about 40'bove, road - estimated 16'ide.,Cut above 35'+ est

Natural slope 14:1 thick brush few trees

See 1" = 300'cale map

2-42

p 1 Field Data Sheet By: CHP ~

'ate:6/22/81Potential Unstable Conditions

(Roads and Highways)Site Ref. No. 2

Slopes:NaturalCutFill X

iquefactionSettlement X

Highway/Road: 101 Northbound Elev.: 430+ Quad.: San Lui s Obi spo

T: 30S R: 12E Sect.: 24 SE4, SE4 Surface: AC Width: 70'ectionBearing: N-70E Slope/Rd. Relationship: Ent i re road i s a fi 1 1 in

Slope BearingN-70E Slope Height: 30'-35'imensions: 550

Slope Inclination: 36 1$ :1 Terrain: Smooth

Drainage: Slope wash Cover: thick grass

Erosion: Hinor to none +Uncon. Surf . Material: Gravel-f i 1 led

Thickness: Fi 1 1 35'+Consistency: Firm/Hedium Dense i it soil and sandy silt.Soils: Granular: X Organic: Cohesive: Strength Factor:Bedrock Type: Underlane by KJT = interbedded clay, shale, and sandstone

Weathering: ? Hardness/Cementation:Consistency: Structure (Type/Attitudes): Unknown mapped

bedding Station N10-15 E 6 35 NW

Bedrock Engr. Characteristics:Ground Water (Evidence/Depth):

Unstable Conditions (Evidence)

Est. 30'elow fillNone - probably none under fill

No cluster to roadOversteepened slope over 30'igh

Exist. Retaining Struct.: None

Site Est. Max. Accel.: 0.19 g. Est. Damage/Blockage: Possible minorsettlement - 2 Northbound lanes {Southside)lateral spreading

Remedial RePairs: F i 11 i n cracksEst. Time To Repair: Hinor crack f i 1 1 ing - 2 hrs.Remarks/Conclusions/Recommendations:Hinor lateral spreading {settlement) anticipated

occur to south " Lateral spread.

Down/and out toward eastSee 1" = 300'cale Topo

No way of telling how the fill was placed - Normally it is 24'nto subgrade watered.

The older alluvium/col luviumis estimated to be 5 to 10'hick under fill. Doubtful ifcolluvial materials are saturated. Fill is abuted in north side by iow hill - Fail may

2-43

p. 1

Slopes:NaturalCut xFill

LiquefactionSettlement

Field Data Sheet

Potential Unstable Conditions(Roads and Highways)

Site Ref. No.

By -. CMpDate: 06/21/91

Highway/Road: 101 Nor th Elev.: 1185 Quad.:Lopez Mountain San Luis Obispo

T: 30S R: 13E Sect:: 7 SWk, NEk, NW4 Surface: AC Width:70'earing:

N28 o W Slope/Rd. Relationship: S 1 ope above Wes t facing

Slope Bearing N2S o W Slope Height: 40'imensions:Slope Inclination: 42 Terrain: smooth./med texture

Drainage: Sheetwash Cover: Grass

Erosion: Negl i gable Uncon. Surf. Material:Thickness: NA Consistency: NA

I

Soils: Granular: - Organic: - Cohesive: - Strength Factor:Bedrock Type: Si1tstones sandstone (massive) probably KJF or KJT Toro Fm (Graywacke

and sandstone)Weathering: med. Hardness/Cementation:Consistency: blocky Structure (Type/Attitudes) - Bedding into

slopeN 20 W 40 NE laminated, very fractured, sandstone massive w/joints

2'-6'edrock

Engr. Characteristics: V. high unconfined-

Ground Water (Evidence/Depth): None

Unstable Conditions (Evidence) Large boulder 9 toe of slope 3'X6'sandstone)

Exist. Retaining Struct.: None — Smal 1 berm

Site Est. Max. Accel.: ~8 9 Est. Damage/Blockage: Large block sandston~Rock falls - block 1, possible 2 Northbound lane

Remedial Repairs: pozer-to move to side of road

Est.. Time To Repair: 2 hours

Remarks/Conclusions/Recommendations:Large out crop of sand stone at top of 40'ut, irregular, steep could be broken

loose with intense shaking.

gW ~ ~

sgNpswgF

p. lSlopes:

Natural

fSettlement

="ield Data Sheet

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 4

By: CMP

Date; 06/21/81

Highway/Road: 101 North Elev- - 1250-1450Quad. - San Luis Obispo

T: pOS R: 12F Sect:: 6 tgg of [~J Surface: AC ~ Width: 70

Bearing- N15E Slope/Rd. Relationship: Cut above highway west facingabove

Slope Bearing N15E- Slope Height: Up to 150'Dzmenszons: 2000'+ (overal 1)+15Q natural. above

Slope Inclination: 45W Terrain Lugnsurrace

Drainage: Sheetwash Cover: grass low brush

Erosion: None apparent Uncon. Surf. Material: Sandy s iltabove cut

Thickness: 3'+ est Consistency: loose

Soils: Granular: x Organic: Cohesive: x Strength Factor: low

Bedrock Type: Si 1 tstone/sandstoneWeathering- Mod to very Hardness/Cementation: Hard to mod hard

Consistency: Dense/loose at surface . Structure (Type/Attitudes): bedding intohill cut, intensely to very fractured and looseat surface.

Bedrock Engr. Characteristics: Low to moderate strength

Ground Water (Evidence/Depth): None observed

Unstable Conditions (Evidence) Oversteepened soi 1 above cut. No bedding plainprob 1 em

Exist. Retaining Struct.:Site Est. Max. Accel.: 0.18 g Est. Damage/Blockage - Rock S 1 i des 6

possible larger slumps crossing bedding "if wet" - both northbound lanes

Remedial Repairs: Several 1000's yards possibleEst. Tzme To Repair: Southbo'und cleared in 10 hours-20 hours, Northbound longerRemarks/Conclusions/Recommendations:

Entire section is oversteeped for rock or soil - the rock varies from ratherincompetent siltstone which breaks easily into 1/2+ in. fragments Q surface tomore block sandstone. If these materials were wet at the same time of an earthquakenearly continuous skin Mi.lurz could occur. Natural slope (soils) abovecuts could also fail. At least the northbound lanes would be blocked and possiblyinto So. bound. Cut is immediately adjacent to road.

2-45

pi 2Field Data Sheet

Site Ref. No. 4

Highway/Road: 101 North

Field Sketch

mls Cbl.LOVIOM'

HhTORAL

~YP>MI SECTi A

2-46

p. 1 Field Data Sheet By: CNpDate: 6/22/81

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 5

Bedrock Engr. Characteristics- Low strength surface material due to fracturingGround Water (Evidence/Depth): None observed

Unstable Conditions (Evidence) Haterial s on surface will (are) ravel ing easily

Slopes:NaturalCut X

Lique factionSet tlementHighway/Road:101 North Bound Elev.:1,450 Quad.: San Luis Obispo

T: 30S R: 12'ect.:SWP of NEP of NPP Surface: AC Width: 70 >

Bearing:N40oW Slope/Rd. Relationship: Cut above road SW facing

Slope Bearing N40oW Slope Height- Est. 40'imensions- 200't toe

Slope Inclination: 45o Terrain: I r regu.l a rDrainage: Sheetwash Cover: Grass and nothing

Erosion: Sloughing, ravel ing minor gul 1 eys Uncon. Surf. Material:Thickness: Consistency:Soils: Granular: Organic: Cohesive: Strength Factor:Bedrock Type: Ultra Basic

Weathering: Very to intense Hardness/Cementation: Nod to Nard

Consistency: Breaks into fragments Structure (Type/Attitudes) - I ntense 1 yeas i ly. fractured

Exist. Retaining Struct.: None

Site Est. Max. Accel.: 0.] 8 g. Est. Damage/Blockage - Debri s/rock

Slides - probably thin - Block both Northbound lanes - Few 1,000's cubic yards

Remedial Repairs: Loader — 5+ hrs.Est. Time To Repair: 5+ hrs.Remarks/Conclusions/Recommendations:Would soften where wet!See 1" + 300'opo

2-47

Fie'.3 Data Sheetp. l CMPDate: 6/23/81

Potential Unstable Conditions(Roads and Highways)

Site Ref. No.

Bedrock Engr. Characteristics:Ground Water (Evidence/DePth): None obv ious

Slopes:NaturalCut x

LiquefactionSettlementHighway/Road - 101 Southbound Elev.: Quad- - San Luis Obispo

T R: Sect:: Surface: AC 'Width: 80< est.Bearing: N40W Slope/Rd. Relationship- Cut above Road West Side

Slope Bearing NOHOW Slope Height: 10 to 30'imensions: 600'+ feetSlope inclination: 60-75 Terrain - I rregu 1 a r s 1 ope

Drainage: Sheetwash Cover'- Minor grass on slope-V heavy

Erosion: not excess i ve Uncon. kurz.'fazerxaf.: si 1 ty clay

Thickness: to 6> Consistency: Med dense/f i rm

Soils: Granular: Organic: Cohesive: x Strength Factor: Mod

Bedrock Type- Dia base/basalt 'intrusiveWeathering: Very/to i ntense 1 y Hardness/Cementation:Consistency: B locky/loose and Structure (Type/Attitudes): 1 ntense1 y

occasionally soft fractured sheared and altered - N 65 W near Vert.

Unstable Conditions (Evidence) On natural slope - Creep trees downslope.Raveling common - 4" fragments - minor popouts

Exist. Retaining Struct.: None

Site Est. Max. Accel.: 0.18g Est. Damage/Blockage: Rock fal 1 s in cutand possible debri's slides natural above (if wet)

Remedial Repairs: Loader

Est. Time To Repair: 4-6 hours

Remarks/Conclusions/Recommendations:1 6 possibly two south bound lane closures

2-48

p. l Field Data Sheet By ~ CMPDate: 6/23/81

Cover,: Minor grassUncon. Surf. Material: NA

Thickness: - Consistency:Soils: Granular: Organic: Cohesive: Strength Factor:Bedrock Type: Siltstone minor sandstone and shale

Weathering: S 1 i ght to Mod Hardness/Cementation: Sof t-Med. HardIntenselyConsistency: Structure (Type/Attitudes):fractu

Bedding N80o W 45+ SW W/some out of slope components (undulatory-cadorted)'

Bedrock Engr. Characteristics:Ground Water (Evidence/Depth): I6 hydrangeo pipes at toe 30'+ spacing not wet

at this time.oversteppedUnstable Conditions (Evidence) Hydrager pipe drains overs teepened-minor raveling

Slopes: Potential Unstable ConditionsNatural (Roads and Highways)

Site Ref. No. 7FillLiquefactionSettlementHighway/Road: 101 South(top of Elev.: San Luis Obispo

grade)T: ~ R: Sect:: Surface: Irregular rough Width: 70 i

Bearing: N30 W Slope/Rd. Relationship:Slope above East facing 20'ide service roa

Slope Bearing N30o W Slope Height: 6p'imensions: 3pp't toe

Slope Inclination: 1:1 45o Terrain:Drainage: Sheetwash

Erosion: V. minor

Exist. Retaining Struct.: None except service roadSite Est; Max. Accel.: 0.18 g Est. Damage/Blockage: service roadand possible outside lane of southbound. Rock slide/possible slump

Remedial Repairs: Loader

Est. Time To Repair: 8 hrs. w/loader - Dump to South

Remarks/Conclusions/Recommendations:

rock slides - fragmented si'ltstone/shale. Most likely failure is if wet precedingearthquake.One bench cut 9 30' 10'ide.

2-49

p. lSlopes:

NaturalCut

LiquefactionSettlement

Field Data Sheet

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 8

9 Separate Fills

By: CMPDate: 6/23/81

Highway/Road: 101 Southbound Elev.: Quad.: San Luis Obispo

T: R: Sect.: Surface: AC Width: 70' lanes

Bearing: Slope/Rd. Relationship:Slope Bearing Slope Height: 30-]Ops Dimensions: 2pp'+Slope Inclination: 1 g:1+ Terrain: Smooth

Drainage-.Sheetwash Cover- Grass coveredErosion:Thickness:

None

Consistency:Uncon. Sur f . Material: - Fi 11 fragmentedand disintegrated sandstone siltstone

Soils: Granular: Organic: Cohesive: Strength Factor:Bedrock Type: Variable (Beneath)Weathering: 'Hardness/Cementation:Consistency: Med dense/firm Structure (Type/Attitudes):

Bedrock Engr. Characteristics:Ground Water (Evidence/Depth):

NA

Reported problems by Cal Trans

Unstable Conditions (Evidence) Occasional tension cracks in lane nearest slope

steep high - old fills.Exist. Retaining Struct.:Site Est. Max. Accel.: p.l8settlement, debris slides and major slumps

Repa>rs - Major effort to repair - several days to several weeks gradingEst. Time To Repair: Several days to weeks

Remarks/Conclusions/Recommendations:

Est. Damage/Blockage: One to al 1 lanes

Probably are old fills - One built over another. Fill composed of excavated sedimentary

debris - siltstone shale/sandstone minor. These could settle down and out taking one or

more (all) lanes. Most of these have been constructed across swales and valleys and in

excess of 100 feet. No benching. Cal Trans reports excessive settlement of these fillsand water problems.

2-50

p~ lSlopes:

NaturalCut XFill

LiquefactionSettlement

Fir'd Data Sheet

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 9

By: CMPDate: 6/23/ 81

R: Sect::Highway/Road - 101 South Elev.: Quad- - Lopez Mtn

Surface: AC Width: 70'lanesSlope/Rd. RelationshiP - Above Rd. Eas t fac i ng

Slope Height: 70> Dimensions:400'5'errain:

New Cut

Bearing: N25E

Slope Bearing N25E

Slope InclinationDrainage: Gu 1 1 ey

Erosion - Ravel.l y

Cover:Uncon. Surf. Material:

Thickness: Consistency:Soils: Granular: Organic: Cohesive: Strength Factor:Bedrock Type: Serpintinite and diabaseWeathering: Mod to very Hardness/Cementation- Soft to Mod hard

Consistency: pi s integrated/decomposed Structure (TyPe/Attitudes) - N20W Vert.Occassional blocky Slicked sheared intensely fractured fabric

Bedrock Engr. Characteristics:Ground Water (Evidence/Depth):

Weak to Mod

None

Unstable Conditions (Evidence) Smal 1 slump - est. 20-30 yds in lowest partof cut

Exist. Retaining Struct. None wi thin 20'f highwaySite Est. Max. Accel-- 0.18 g Est. Damage/Blockage: S 1 umps

Could block 2 lanes southboundRemedial Repairs - Remove wi th loaderEst.. Time To Repair: 2 days

Remarks/Conclusions/Recommendations:

Rock falls - rock slides of possible slumps

2-51

p. l Field Data Sheet By - CMPDate: 6/23/81

Slopes:NaturalCut XFill,.

LiquefactionSettlementHighway/Road:

R:101 South

Sect::

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 1O

Elev.: Quad. - San Luis Obispo/ Lopez Mtn.Surface: AC Width: 7O~

Bearing: N S Slope/Rd. Relationship: Cut above Road

Slope Bearing N-S Slope Height: 3O>-1OO> Dimensions:Slope Inclination: 1:lf p:1 Terrain:Drainage: Sheetwash

Erosion: 2

Thickness: Consistency:

Cover: None

,Uncon. Surf. Material: N/A

Bedrock Type:Weathering: Hardness/Cementation- Hard/Mod Hard

Structure (Type/Attitudes) - Fract Mod 2

Mod

Consistency: Blocky

Soils: Granular: Organic: Cohesive: Strength Factor:Serpentinite

Bedrock Engr. Characteristics:Ground Water (Evidence/Depth):

Blocky-serpentinite 2

None observed

Unstable Conditions (Evidence) Over steepened cut slope

Exist. Retaining Struct,.:Site Est. Max. Accel.: O 18

None

Est. Damage/Blockage:'Rock falls - probably small popouts

Remedial Repairs: Loader

Est. Time To Repair: few hours to 1 day - plus 6 hrsRemarks/Conclusions/Recommendations:

I was unable to stop because of busy traffic, road repairs, and lack of parking.

2-52

p. l Field Data Sheet By - CHP

Date: 6/23Potential Unstable Conditions

(Roads and Highways)Site Ref No. 11

Cover None

Uncon. Surf. Material: NAErosion: HinorThickness: Consistency:Soils: Granular:. Organic: Cohesive: Strength Factor:Bedrock Type: Serpent ini teWeathering: Mod.

Consistency: very blocky

Hardness/Cementation: Hard

Structure (Type/Attitudes): fractured random

Slopes:Natural

(Icut x

LiciuefactionSettlementHighway/Road: 101 South Elev.: Q«d- - San Luis Obispo

T R: Sect.: Surface: AC Width:70'earing:

N70E Slope/Rd. Relationship- Cut above east faceSlope Bearing N70E Slope Height: 40> Dimensions- 200'st.Slope Inclination: 52-55 Terrain:Drainage: Shee twas h

Bedrock Engr. Characteristics:ound Water (Evidence/Depth):

Strong except for blocky characterNone

Unstable Conditions (Evidence) Ninor ravel ing oversteepened

Exist. Retaining Struct.:Site Est. Max. Accel.: 0.20g

Remedial RePairs: LoaderEst. Time To Repair: +4

Remarks/Conclusions/Recommendations:

Est. Damage/Blockage: Outs i de I I aneSouthbound

Rock fal ls - Typical ly 1-5 cubic yards. Blockage one lane.

2-03

p. lSlopes:

Natural X

CutFillLiquefactionSettlement

Field Data Sheet

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 12

By: CHPDate: 6/23/81

Highway/Road: pi ab 1 o South Elev.: Quad.: Port San Luis

T R: Sect.: Surface: AC Width:35'earing:NW/SESlope/Rd. Relationship:

Slope Bearing NW/SE Slope Height: To 1200'imensions: 5400'iscontinuous

Slope Inclination: 2:1 to k:1 Terrain: Smooth to very precipitous

Drainage: Natural Sheet Wash Cover: Grass — dense low brush

Erosion: Hinimal Uncon. Surf. Material: adobe

Thickness: 2-3'onsistency:Soils: Granular: Organic: Cohesive: X Strength Factor: Hod/low

Bedrock Type: Obispo fm - tuff, basalt diabase

Weathering: Hod

Consistency: Large bouldersBlockey to Slabby

Hardness/Cementation: v. hard 9 outcrop

Structure (Type/Attitudes): NW/SE trend

Bedrock Engr. Characteristics: v. hard intact but incoherent large boulders

Ground Water (Evidence/Depth): None

Unstable Conditions (Evidence) Happed landslide

Exist. Retaining Struct.: None

Site Est. Max. Accel.: .47 9 Est. Damage/Blockage: Coul d cover both lanes

Remedial Repairs: Loader/dozer to remove debris and grade over

Est. Time To Repair: Several hours est 12+

Remarks/Conclusions/Recommendations:

Happed existing landslide - appears more as talus debris slides - not deep seated.

Natural slope above slide is very steep eg ( > 14:1 - more like 1:1 to 4:1 in outcrop

area. This area wi 11 have minimum rock falls and rock slides/debris slides (surficial

materials). The road traverses along the toe of the slide, therefore move can be expected

to cover road - particularly large boulders.

Landslide deposits - rock frags (sed - si ltstone/shale) in a clayey silt matrox

12-B designator. No landslide Q toe'- slope is susceptible to rockfalls.

f~4

p. lSlopes:

NaturalCutFill x

LiquefactionSettlement

Field Data Sheet

Potential Unstable Conditions(Roads and Highways)

Site Ref. No.

By CMP

Date; 6/23/81

Highway/Road: D i ab I o South

R: Sect.:Elev.: Quad- - Port San Lui s

Surface: Width:Bearing: SloPe/Rd. RelationshiP: Road above

Slope Bearing yariable Slope Height: 40~-50~ Dimensions: 250~-300~

Slope Inclination: Ig:I Terrain- Smooth/Rough slopesDrainage: Cover: Grass low shrubs

Erosion: Uncon. Sur f . Material - cl ayey sandyMedium silt w/rock fragments to 3"-4"Thickness: Consistency: Dense

Soils: Granular: Organic: Cohesive: x Strength Factor:Bedrock Type: Si1tstoneWeathering:Consistency:

Mod - to very Hardness/Cementation- Med Hard

Structure (Type/Attitudes):

Bedrock Engr. Characteristics:Ground Water (Evidence/Depth): None

Unstable Conditions (Evidence) over steepened fill in excess of30'o

benching, tension cracks (turned in) slight settlementExist. Retaining Struct.:Site Est. Max. Accel,: 0.36 to 0.42g Est. Damage/Blockage: poss ible loss of

southbound lane or portion of both.Settlement debris slides slumps latteral spread

Remedial Repairs: Fill in or abandon 1 laneEst. Time To Repair - +1 dayRemarks/Conclusions/Recommendations:

- Typical road fills - performing okay, but are over 30'nd 14:1 slopes

" Most all of ¹13 fills have been patched, or repaired - Cracks are common onperimeter

In general, the road is very poorly built with regard to fill. Numerous tension cracks onany fill have been repaired; cracks run parallel to road usually on open faceside. May be much side cast or poor compaction.

2-55

p. 1

Slopes:NaturalCutFill loca t i ons

LiquefactionSettlement

Field Data Sheet

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 14

By - CMP

Date: 6/23/81

Highway/Road: Diablo South Elev.: Quad.: Port San Luis

R: Sect.: Surface: Width:Bearing: Slope/Rd. Relationship:

Slope Height: 30>

300 Terrain: v.Slope BearingSlope Inclination:Drainage: NA

Erosion: NA

Thickness: NA Consistency:

Ri p rap above road

Dimensions: 50't base

roughCover: coverUncon. Surf. Material: NA

Soils: Granular:Bedrock Type: NA

Weathering:Consistency:

X Organic: Cohesive: Strength Factor: NA

Hardness/Cementation:Structure (Type/Attitudes):

Bedrock Engr. Characteristics: NA

Ground Water (Evidence/Depth):

Unstable Conditions (Evidence) Loose boulders rip rap to 3'n diameter place on

cut slope - old landslide for back fillExist. Retaining Struct.:Site Est. Max. Accel.: 0.35 g Est. Damage/Blockage: 500 cubic yards

Remedial Repairs: Loader/dozer push over road

Est. Time To Repair: 4 hours

Remarks/Conclusions/Recommendations:Uncemented - loose rubble fills, rip rap - will surely all fail.

2-56

p. lSlopes:

NaturalCut x

LiquefactionSettlement

Field Data Sheet

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 15

By: CMP

Date: 6/23/81

Quad.: Port San Luise: 'idth:

Cover: Scattered brush and grass

Uncon. Surf. Material:

Highway/Road: PGE Rd South from Elev.:plant - See map

T: 31S R: 1lE Sect:: SurfacBearing: N IOW Slope/Rd. Relationship: Above road east facingSlope Bearing N10M Slope Height: 75~ est Dimensions: 200~

Slope Inclination: Ig:I Terrain:Drainage: Sheetwash/gul 1 eys

Erosion: Yes, fal 1 ing apartThickness: Consistency:

Bedrock Type:Weathering: Hardness/Cementation: moderate

Structure (Type/Attitudes): Moderate tovery fractured

veryblockyConsistency:

v. fractured

Bedrock Engr. Characteristics:Ground Water (Evidence/Depth): None

'

Soils: Granular: Organic: Cohesive: Strength Factor:Graywacke

Unstable Conditions (Evidence) Slope appears unstable, raveling and gul leying

Exist. Retaining Struct.: None

Site Est. Max. Accel.: 0.35 g Est. Damage/Blockage: one or more lanes

Remedial Repairs:Est. Time To Repair: 0-6 hours

Remarks/Conclusions/Recommendations:Potential rock slide/folds. lf wet - debris slides and possibly shallow slumps

2-57

p. 1 Field Data Sheet BY: CMPDate: 6/23/81

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 16

Slopes:Natural xCut xFill x

LiquefactionSettlement x Guard gate PGE to Pt. San Luis about one mile - the last 4 mile

is ok - See mark on mapQuad.:

Bedrock Engr. Characteristics: General ly very poor

Ground Water (Evidence/Depth): Non observed

Highway/Road: See above Elev.:T: R: Sect:: Surface: AC c di rt Width: 12~ (one

Bearing: -- Slope/Rd. Relationship: lane)

Slope Bearing Slope Height: Variable Dimensions:

Slope Inclination: 2:1 to p.. 1Terrain: Extremes

Drainage: poor Grass bush treesErosion: Excessive to minor Uncon. Surf. Material-Silty sandy clays

Thickness: 0 to 6-8'Consistency: Very soft to stiffSoils: Granular: Organic: Cohesive: x Strength Factor: low

Bedrock Type: Franciscan-arkose/graywacke sandstone si1 tstoneWeathering: v. to intense Hardness/Cementation- soft to med. hard

Consistency: Easily broken Structure (Type/Attitudes): Extensive randorrfracturingshearing jointy

Unstable Conditions (Evidence) Very thick slope wash cover local ly tension cracksalong road probably some landsl iding

Exist. Retaining Struct.:Site Est. Max. Accel.: 0 35 g 0 36 g

Est. Damage/Blockage: Below

Remedial Repairs: doubtfulEst. Time To Repair: many days

Remarks/Conclusions/Recommendations:

Numerous blockages can be anticipated from rock falls, rock slides, soil debris flowsand s 1 i des - S 1 umps poss i b1 e.

'n alternate route should be considered - especially the 4 wheel drive road on oceanside.Natural slopes irregular with occassional outcrops. Slopes 2:1 tb $ ;1 naturaland cut. Fill are very old - may failRoad is in poor repair

2-58

p. 1 Field Data Sheet By-.CNPDate: 6/23

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 1/

Slopes:NaturalCut xFill

LiquefactionSettlementHighway/Road: Avi la Rd 0 turnoff Elev.: Quad.: Port San Luis

for'GEE (near guard gate)T: 32S R: 11E Sect.: Surface: Width: 2 l,nesBearing: N10 E Slope/Rd. Relationship:Slope Bearing N10oE Slope Height: 40> Dimensions: 250

Slope Inclination: (:1 Terrain: I rregu 1 arDr'ainage: Sheet wash Cover: None

Erosion: Yes excessive Uncon. Surf. Material: Landsl ide debrisThickness: ent i re Consistency: loosecutSoils: Granular: x Organic: Cohesive: Strength Factor: low

Bedrock Type: Serpentinite (ultra basics)Weathering: v. weathered Hardness/Cementation: soft to med hard

Consistency: Structure (Type/Attitudes): v. fracturedrandom 1

- 2'locksBedrock Engr. Characteristics:Ground Water (Evidence/Depth):

Blocky loose

None observed

Unstable Conditions (Evidence) Slump 1000 yds about 50 yds west of this cutloose block

Exist. Retaining Struct.: None

Site Est. Max. Accel.: 0.34 g

Remedial Repair s: 1 oad er/catEst. Time To Repair: 2-4 hrsRemarks/Conclusions/Recommendations:Cover both lanes in case of failure

Est. Damage/Blockage: Rock fa 1 1 s andpossible rock slides.

2-59

p~ l Field Data Sheet By: CMPDate: 6/23/81

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 18

Thickness: Consistency:Soils: Granular: Organic: Cohesive: Strength Factor: low

Bedrock Type: Sandstone and Graywacke - Squire Fm (member)

Weathering: Hardness/Cementation:Consistency: Structure (Type/Attitudes): Mass i ve to

thinly bedded

Bedrock Engr. Characteristics: Blocky loose sand

Ground Water (Evidence/Depth): None observed

Slopes:NaturalCut '

FillLiquefactionSettlementHighway/Road: Avila Rd. 3 cuts Elev.: 20+ Quad.: port San Luis 8 Pismo Beach

T: 31S R: 11E Sect.: Sur face: AC Width:45'earing:

N85E Slope/Rd. Relationship: Adjacent to road above

Slope Bearing N85E Slope Height: to 100'imensions: 600'est, 500'enter,Slope Inclination: 1:'i to $ :'I Terrain: 1,300'ast Q toe cuts

Drainage: S 1 opewash Cover: Brush and grass

Erosion: Minor Uncon. Surf. Material: NA

Unstable Conditions (Evidence) Mapped landslide west of the most westerlyslide, oversteepened cuts very high

Exist. Retaining Struct.: None

Site Est. Max. Accel.: .33 g

Remedial Repairs: Loader

Est. Time To Repair: 1 day (+)Remarks/Conclusions/Recommendations:

2 lanes

45'ide AC

Slope constructed adjacent to highway

Central cut benched

Est. Damage/Blockage: Both lanes wi throck slides and rock falls and debris slides(mostly) soil/sand

2-60

p. lSlopes:

NaturalCut x

~

~Filliquefaction

Settlement

Field Data Sheet

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 20

By: CMPDate: 6/23

Highway/Road: Avila Elev.: 20 'uad.: Pismo Beach

T: 31S R: 12E Sect.: Surface: AC Width:35'earing-

NSW facingSlope/Rd. Relationship: Cut/natural above road

Slope BearingNN far'ing Slope Height: 600 '+ Dimensions: 3500 9 toe

Slope Inclination - 1 g: 1 Natura 1 Terrain: s teep14:1+1:1 cutDrainage: Sheetwash/ Swa les Cover: thick trees/brush

Erosion: None Uncon. Surf. Material: 3-6'lope wash

Thickness: 3-6'onsistency: siltySoils: Granular: x Organic: x Cohesive: x Strength Factor: Low/med.

Bedrock Type: Si 1 tstone/Shale Monterey Fm

Weathering: Mod to fresh Hardness/Cementation: Med. ha rd

Consistency: Tabular/pl aty Structure (Type/Attitudes): Bedding N9 45v. fractural

Bedrock Engr. Characteristics: Mod hi strength

Ground Water (Evidence/Depth):)

Unstable Conditions (Evidence) v. steep natural and oversteered natural s-lope

with possible bedding plain sliding, some talus

None observed - few needs

Exist. Retaining Struct.: None

Site Est. Max. Accel.: . 30 g Est. Damage/Blockage: Both 1 anes tota 1 1 yblocked w/debris (soil) slides 6 rock falls 6 rock slides in cut - particular no. facing and

possible slip plain sliding - mod sizeRemedial RePairs: Major gradingEst ~ Time To Repair- Require considerable time to clean up-several days - would expect

Femirks/Conclusions/Recommendations:Major area of blockage - obstruction of soil and rocks debris - both lanes. Alternate togo around this paved road - on a dirt road north of freeway.

2-6l

p. 1 Field Data Sheet By: CMP

Date; 6/23/81Potential Unstable Conditions

(Roads and Highways)Slopes:

NaturalCut x Site Ref. No. "

21FillLiquefactionSettlementHighway/Road: Av.i 1 a Rd. Elev.: Quad- - Pismo Beach

T: 31S R: 12E Sect:: Surface: AC-2 1 anes Width:Bearing: Ng80 Slope/Rd. Relationship- slope adjacent North Facing to road

Slope Bearing N80g Slope Height: 70 i Dimensions: 500 <y toe

Slope Inclination: 1/4:1 Terrain: v. steep

Drainage: Sheetwash Cover: trees

Erosion: Mod Uncon. Surf. Material- 3'ilt clayThickness: 3'onsistency:Soils: Granular: Organic: Cohesive: x Strength Factor:Bedrock Type: S i 1 ts tone Shale Monterey formation

Weathering: mod Hardness/Cementation: mod

Consistency: Block/slabby tabular Structure (Type/Attitudes) - bedding isout of slope - wel 1 bedded

Bedrock Engr. Characteristics: adverselyGround Water (Evidence/DePth) Hone observed

Unstable Conditions (Evidence) Many pop outs have occured and smal 1 beddingplane sl ides

Exist. Retaining Struct.: chain 1 ink fenceSite Est. Max. Accel.: .29 Est. Damage/Blockage: Rock fal 1 s rock

slides w/possible mod to small beddPng plain slides

Remedial Repairs: pozer/ loaderEst. Time To Repair- 8 hrs. to open both lanes, 4 hrs. for 1 laneRemarks/Conclusions/Recommendations:

Both lanes would be covered—Also - about 500'outh side following the 70'i cut1/0:] -, 15'i w/high natural slope = debris slides

2-62

p 1 Field Data Sheet By: CMP

Date: 6/23/81Potential Unstable Conditions

(Roads and Highways)Site Ref. No. 23

Uncon. Surf. Material: NAN. excessive w/ravelingThickness: NA Consistency:Soils: Granular: Organic: Cohesive: Strength Factor:Bedrock Type- Siltstone Miguelito FM and El Gragg member, SS above

Weathering: Mod Hardness/Cementation: Med. hard

Consistency: B 1 ocky Structure (Type/Attitudes) - bedd i ng

dipping into slope g 25-30 striking N 80 W., intenseley fractured thinly bedded

Bedrock Engr. Characteristics:Ground Water (Evidence/Depth):

Slopes:NaturalCut xFill

Liquefactz.onSettlement

gray/Road.Frontage Road(Serv ice Road)nextto 101 to Avi la Road (South) 20-200':

31S R: 12E Sect: Sur face: concrete Width -3Q'earing:

N10E Slope/Rd. Relationship- Above Rd s 30'ast of highway

Slope Bearing N10E Slope Height: 80~ Dimensions: F00~ q toe

SloPe Inclination: 1.1 Benched Terrain:Drainage: Sheet wash Cover: None

Unstable Conditions (Evidence) 1:1 over steepened bed rock

Exist. Retaining Struct.:Site Est. Max. Accel.: .29 g

Remedial RePairs: loaderEst. Time To Repair:Remarks/Conclusions/Recommendations:

Est. Damage/Blockage: Rock fa 1 1 s

minor blockage - one lane closed.

Doubtful if the sliding would close both lanes - consider 1 lane closure

Note: Borrow pit +500' W of cut - may be an ancient historic landslide - possibleunstable area - borrow might be available from here for backfill.

2-63

p. 1 Field Data Sheet By: CHPDate; 6/23/81

Potential Unstable Conditions(Roads and Highways)

Site Ref. No.,24

Width: 30'lanes

Hardness/Cementation: NA

Structure (Type/Attitudes): NAConsistency: NA

Slopes:NaturalCutFill

LiquefactionSettlement x

Highway/Road.. Avila No. Rd. Elev.: 120'uad. ~ Pismo BeacSan Luis Bay Drive

T R: Sect:: Surface: AC

Bearing: Slope/Rd. Relationship: both s i des-beneath road

Slope Bearing Slope Height: 35-40'imensions: 200'ong .

Slope Inclination: 14 1 Terrain:Drainage: beneath f i 1 1 Cover: grass brush

Erosion- Not excessive except in natural Uncon. Surf. Material: Siltstoneupstream frags /siltThickness: Consistency: Firm (fill) matrix

Soils: Granular: x Organic: Cohesive: x Strength Factor: low

Bedrock Type: NA

Weathering: NA

Bedrock Engr. Characteristics:Ground Water (Evidence/Depth):rainy season

Unstable Conditions (Evidence)

NA

Not observed (evidence) may be shallow during

over steepened fill slopes 1$ :1+35< -40'igh'I

Exist. Retaining Struct.: None

Site Est,. Max. Accel.: .28g Est. Damage/Blockage: settlement andpossible slumping on slope"-

Remedial Repairs: important borrow to fill in slumps and cracksEst. Time To Repair: 1 lane open in 4 hours.Remarks/Conclusions/Recommendations:No distress to highway noted (tension cracks) but it has beenresurfaced.

*Outside of both lanes would be lost if slumping occurs-particularly if it is saturated. Otherwise cracking can be anticipated parallel toroadway. Would est that passage could be made through center.

p. l Field Data Sheet By - CMPDate: 6/23

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 25

Slopes:Natural xCut xFill

LiquefactionPismo, Port San Luis

Highway/Road: See Cyn Elev.:40-]350> Quad.: (only 2 quads)

T R: Sect.: See map Surface: ACSGravel Width: 20-25 >

Bearing: variable Slope/Rd. Relationship-Cuts above roads 6 natural slope (4 mile

Slope Bearing variable Slope Height:0 4

D'Cmensxons:500-600'ae ral . See map section)30-40 cuts V long stretches

Slope Inclination: 2:1-lg:1 Terrain: Steep hillside irregularlocal 1:1Drainage: Sheet wash Cover: Heavy brush and trees

Erosion- Not excessiveYouthful Uncon. Sur f . Material: S i 1 ts/cl ays

Thickness:2- 6'onsistency: softocc.10'oils:Granular: ~Organic: x Cohesive:~Strength Factor: low

yp 'iguel i to Member pismo FM S il ts /shale 6 sandstoneWeathering: mod to very Hardness/Cementation: Mod/hard

Consistency: Structure (Type/Attitudes): Beddingvariable, mostly favorably dipping into slope

Bedrock engr. Characteristics: Mod . hard to softGround Water (Evidence/Depth) - Occ. Seeps wet spots issuing fkm bedrock thickgreen brush/trees soils stay moderately wetUnstable Conditions (Evidence)v.high over steepened slopes w/v. steep cuts along

toe adjacent to road, "creep" treesExist. Retaining Struct.:Site Est. Max. Accel.: .28 to .29 g

Est. Damage/Blockage: debris slidesand minor rock falls (cuts) - consider total blockageRemedial RePairs: dozer loaderEst. Time To RePair: several daysRemarks/Conclusions/Recommendations:

(See typical section next page). The 'road traverses along the west and south sides ofSee Canyon with North/Northeast/east facing slopes. Bedding is generally favorablewith local section daylighted. No mapped landslides. No obvious large slides (historic)Road cuts are 4 to 4".1 to 30-40.'igh exposing bedrock over slop~ wash Expect thatSlope wash - siltstone fragments in a clayey/sandy-silt matrix to 10'hick average

Damage anticipated - numerous debris slides a few 100'n length will cover entire roadlocally - wet condition will only enhance the problem. The natural slopes have beenundercut w/steep high slopes - even though bedding is favorable. Expect thatentire road will be impassable and will take many days for access. Possibly someliquefaction (settlement) in valley floor. Ground water expected to be shallow eg

5'centerof Sect.19, Davis (Cyn Crossing)

2-65

po 2Field Data Sheet

Site Ref. No. 25

Highway/Road: See Canyon

Field Sketch

~'-6OO'iIeII1 (PICA. SfcteIi

5LOt% 14ACH CoUAVIVfAMlcK

HhuCVVCvT6P:i 4. i:I Caookv~hts5 4a 3O'IIIOH

QuNa RHAR'fALLOV10+

f~p ao'im/saavzi/Ac

2-66

By: CWp

Date: 2/26/81Photo No.: B16

Field Data Sheetp. lSlopes: Potential Unstable Conditions

Natural X(above) (Roads and Highways)

~

~

Site Ref. No. 26Includes eight slide potential areasLiquefaction

Settlement X~fi11s

Highway/Road: See Cyn to Perfumo Cyn Elev:Variable Quad-: ~ San Luis ObispoGravel/AC to top Width One or two

T ~ ~ ect.: See map ur'narrow lanes

Bearing: See map Slope/Rd. Relationship: Road immediately adjacent to slopes

Slope Bearing Slope Height:30-40',60-70'Dimensions - Variable - See map

Slope Inclination: 4".1 to 1:1 Terrain: Steep hi 1 lyDiainage: Sheet wash Cover: Cleared to low grass/bush

Erosion: 1 oca 1 1 y mod. Uncon. Surf . Material: S i 1 ts/s lopewash

Thickness: 2'-6'onsistency- soft to firm clayey sandy siltSoils: Granular: X Organic: X Cohesive: X Strength Factor: .low

Bedrock Type: ~iguelito in See Cyn 6 Coon Creek. Rincon in Perfumo-Cyn all mostly. siltand shale and minor sandstone

Weathering: Hardness/Cementation: Hod hard

Consistency: Block to tabular-soft Structure (Type/Attitudes) -Edna Faul t cross i

Serpentinite in Perfumo Cyn. Bedding is variable usually NW/SE strike med dips~ NESSW. Hany structures v. fractured.

Bedrock Engr. Characteristics: At surface rock is loose blocky, raveling

Ground Water (Evidence/Depth): Occ. seeps wet spots in bedrock cuts

Unstable Conditions'Evidence) Oversteeped cuts, high adjacent to road

Exist. Retaining Struct.: None provided

Site Est. Max. Accel."..22 g Est. Damage/Blockage: Rock falls and rockslides-pop outs susceptable to complete blockagSeveral major blockages both lanes.

Remedial Repairs: Dozer loader

Est. Time To Repair: +One day to several days

Remarks/Conclusions/Recommendations:Both sides of road - narrow. No benching - loose. Landslide (mapped) - horseshoe bend-"ancient", slide debris exposed - doubtful of reactivation. Road traverses through entirehead scarp area - slide appears to be confined at toe. Not a hazard except in cuts - rockfalls/debris slides consolidated by coherent stands well in near vertical cut road cuts.

There are eight zones of potential sliding - all cuts somewhat similar - eg. v. steep, highwith bedrock exposed, susceptable to rock falls popouts, possible minor slumps. Also soildebris slides above where natural slopes are 2:1

Numerous small old fills across drainages - settlement outside lane is possible could be

repaired rapidly with dozer - Two hours estimated each.

2-67

pe l Field Data Sheet By: CNPDate: 6/24/81

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 27

Slopes:NaturalCutFill X

LiquefactionSettlementHighway/Road: Rd "o. «OCNPP Elev.: 100'uad.: Port San Luis

Fields Ranch RoadT: 31S R: 10E Sect.: Surface: AC Width: 14 lanes

Bearing- N15W Slope/Rd. Relationship:Slope Bearing N15W Slope Height: 30-40 Dimensions: 200' top

Slope Inclination: 1$ :1 Terrain: NA Fill both sides Rd.

Drainage: Under fi 1 1 Cover: grass

Erosion: minor gu1 1 ey ing Uncon. Surf. Material-Si 1 ty sand/sil tThickness: NA Consistency: Firm-soft Q surface w/bedrock frags.

Soils: Granular: x Organic: Cohesive: x Strength Factor: low

Bedrock Type: NA

Weathering: NA

Consistency: NA

Hardness/Cementation: NA

Structure (Type/Attitudes):

Bedrock Engr. Characteristics:Ground Water (Evidence/Depth):

NA

None observed

Unstable Conditions (Evidence) Very high "G" steep high slopes narrow roadway

Exist. Retaining Struct.: None

Site Est. Max. Accel.: 0.48g Est. Damage/Blockage: Antici pates s lumpingdebris slides plus possible settlement-both lanes

Remedial Repairs: Loader, dozer wi th import of f i 1 1

Est. Time To Repair: 2 - 6 hrs. depending on amount of damage sustained

Remarks/Conclusions/Recommendations: This is typical of the fills discussed undersite Reference no. 12.

- Compaction is unknown or when constructed.- Anticipate both lanes closed due to slumps (If EQ is preceeded by rainy period).

2-68

p. lSlopes:

Natural XCutFill

icluefactzonSettlement

Field Data Sheet

Potential Unstable Conditions(Roads and Highways)

Site Ref. No.28Two Slide Areas

By - CHPDate: 6/24/81

Highway/Road: No. from DCNPP-" Elev.: 200'uad.: port San LuisFied,d Ranch RoadT: 31S R: 10E >ec<.: Surface: Gravel/AC Wk.dth:1 1 ane

30'earing:NW/SESlope/Rd. Relationship Slope above road SW facingSlope Bearing NW/SE'lope Height: 300'+ Dimensions: 4500' toeSlope Inclination: 32 2:1+ Terrain:Nod steep, natural slopes, smooth

Drainage: Shee twas h Cover: 'rass slopes

Bedrock Engr,. Characteristics:Ground Water -(Evidence/Depth):

Unstable Conditions (Evidence)saturated condition

None observed

Hi "g",over steepened natural slopes especially if

Erosion: Not excess i ve Uncon. Surf . Material: Adobe s lopewashThickness: Consistency: firm, soft when wet unconsolidatedSoils: Granular: Organic: Cohesive: X Strength Factor:LowBedrock Type: Monterey Fm-S i 1 tstone/S hale diatomaceous

Weathering: Mod Hardness/Cementation: Nod/hardConsistency: Fragmented Structure (Type/Attitudes): D i ppi ng into

slope favorably, fractured (None exposed, coveredwi th slope wash)

OK

Exist. Retaining Struct.: None

Site Est. Max. Accel.: .49 g Est. Damage/Blockage: "Debris. slides"of slope wash materials due to oversteepened natural slopes cover lane.

Remedial RePairs: Dozen/loader - Push aside or bui ld over gradingEst. Time To Repair: 6-8 hrs.Remarks/Conclusions/Recommendations:

If saturated condition exist the problem will be greater 9 30-35 slope ratio could beconsiderable amount of regrading. No major cut 9 toe, side cast over ocean side ofroad. 2:1. Hinor debris slide could fail due to uncompacted nature -- anticipate 1/3of surface could fai 1 .

Happed landslide - subdued - ancient, reactivation doubtful, appears old and stable.

2-69

p. l Field Data Sheet By:Date: 6/24/

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 29

Slopes:Natural X

CutFillLiciuefactionSettlementHighway/Road: Field Ranch RD Elev. - 200'+ Quad.. Port San Lo~is and

Horrow Bay So,T: 31S R: 10 E Sect.: Sur face: Gravel Ldth:

20'earing:

N-S Slope/Rd. Relationship: S 1 ope above roadSlope Bearing N-S Slope Height: 200~ Dimensions: 600'+ at toeSlope Inclination: 32 Terrain. Smooth w/large boulders Bedrock expands

2/3 of way upDrainage: Sheetwash Cover: Grass brushErosion: Not excessive Uncon. Surf . Material: Slope wash

Thickness: 3-4'onsistency- Soft/Loose Silty/Sandy

Soils: Granular: X Organic: Cohesive:~Strength Factor: Low

Bedrock Type - Honterey shale/s i 1 ts toneWeathering: Hod to Very Hardness/Cementation: Sof t/Mod Hard

Consistency: Fragmented blocky Structure (Type/Attitudes):

Bedrock Engr. Characteristics: OK

Ground Water (Evidence/Depth): None observed

Unstable Conditions (Evidence) Over steepened natural slope, low strengthslopewash

Exist. Retaining Struct.:Site Est. Max. Accel.: .5] 9 Est. Damage/Blockage: "Rock fal 1 s"2'-4'n diameter. few debris slides or slumps.

Remedial Repairs: Dozer-loader - Push to side.Est. Time To Repair: 2 hrs.Remarks/Conclusions/Recommendations:

Landslide NW of F ield Ranch - Deep seated ancient no.reactivationSimilar to ¹28Fills in roadside up to 10'n this area.

2-70

Field Data Sheet By: CMPDa te: 6/24/81

Potential Unstable1Conditions(Roads and Highways)

Site Ref. No. 30

Slopes:NaturalCut xFill

iquefactionSettlementHighway/Road P ield Rch Rd Elev.: 13p 1

Opposite Pt. 8uchonT: 305 R: 10E Sect.. Surfac

Rel atacing Slope Height- 20'

lope inclination: Plus 1:1 T

Drainage: Sheetwash Cover:

Quad.: Morrow 8ay South

e: Paved Width:

30'ncon.

Surf. Material: NAErosion: Minor ravel ingThickness: NA Consistency: NA

Soils: Granular: Organic: Cohesive: Strength Factor:Bedrock Type: Monterey S 11tstoneWeatherin: Hardness Cemen a i n Hardness Cementation:g / t to /Consistency: Tabul ar Structure (Type/Attitudes): Adverse d i p

out ef slope

Bedrock Engr. Characteristics:Ground Water (Evidence/Depth):

Low due to adverse dipNone observed

nstable Conditions (Evidence) Over steepened slope, adverse dipping beds, 20'ut

Exist. Retaining Struct.: None

Site Est. Max. Accel.: .49 g Est. Damage/Blockage: Large pop-outsrock falls " Cover road, possibly both lanes

Remedial Repairs: Dozer/loader - Push out of wayEst. Time To Repair: 2 hoursRemarks/Conclusions/Recommendations:Fill at Toe of road (Coon Creek) 15'igh 35'ide road. Maybe a little settlement eachside of fill - Should not block road. Gate to Montana De Oro State Park.

s

2-71

p l Field Data Sheet By CMPDate: 6/24/8 I

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 31

Slopes:NaturalCutFill

LiquefactionSettlementHighway/Road: Montana De pro Rd Elev.: 30I Quad.: Morrow 8ay goutT: 30S R: 50S Sect.: Surface: gC Width ..25 < -30<.

Bearing: N45E Slope/Rd, Relationship: Slope NW facing aboye road.Slope Bearing N45E Slope Height: 25'imensions:

200'lopeInclination: I/4..l Terrain:Drainage: Cover:Erosion: Uncon. Surf. Material:Thickness: Consistency:Soils: Granular: Organic: Cohesive: , Strength Factor:Bedrock Type: SiltstoneWeathering: H

Consistency: Wel I bedded, tabular

ardness/Cementation: Mod hard to hardStructure (Type/Attitudes): Adversely d I ppingout of slope, well bedded.

Bedrock Engr. Characteristics: Low-mod strenth, shearGround Water (Evidence/Depth): None obsef yed

Unstable Conditions (Evidence)

Exist. Retaining Struct.:Est. Damage/Blockage: Rock Falls/pop outs-Few cubic yds. minor blockage if slope fallsin a slump.

Remedial Repairs: Dozer/loader, push asideEst. Time To Repair: 2 hrs.

Remarks/Conclusions/Recommendations:

Est. several hundred yards of material - If bedding plain slide, otherwise a few cubicyards of rocks (pop puts)- requiring minor cleanup.

2-72

p. 1 Field Data Sheet By: CMP

Date: 6/24/81Potential Unstable Conditions

(Roads and Highways)Site Ref. No.

Consistency: Poorly compactedSoils: Granular: X Organic: Cohesive: Strength Factor: Low

Bedrock Type: NA

Thickness: NA

Slopes:

~

~

NaturalCutFill X

LiquefactionSettlementHighway/Road: Montana De Oro '120' d 'orrow Bay NorthT: 30S R: 10E Sect.: 27, NE $ of SEP f e - AC Width: 20-25

'earing:e/SE Slope/Rd. Relationship: Underlying both sides of road

Slope Bearing Ng/SE Slope Height: 3Q 35I Dimensions: 70/Slope Inclination: Irregular surfaceDrainage: Culvert under Cover: Li tt le Grass Brush

Erosion: Excess i ve Uncon ~ Sur f . Material: Sandy/S i 1 ty

Weathering: NA

Consistency: NA

Hardness/Cementation:Structure (Type/Attitudes): NA

Bedrock Engr. Characteristics: . NA Loose sanddunes - "Sands"Ground Water (Evidence/Depth) - No evidence - Some flow thru'ulvert

Unstable Conditions (Evidence) Probably poorly compacted, steep high fill,probably old

Exist. Retaining Struct.:Site Est. Max. Accel.: .44 g Est. Damage/Blockage: Lose oceanward

side of road due to slumping (particularly if wet)Remedial Repairs- Loader (maybe import of fills) if entire road goesEst. Time To Repair: 2 hrs.Remarks/Conclusions/Recommendations:

Probably lose 1/2 of road (Downslope)Sandy material = Loose (Poor fill)Could build new road around grade

2-73

aaoidib2otential~,Unstable,-.-,Conditions( ayswffL(Roads„- ands Highways }

«;~ Si tedge f .o 1«lo.;gq33

p l '1N3 . gc q-g~~Lip y;,.ieldE~Data Sheet CHP «

f8~60,h: e.fsQ Date: 6/24/81Slopes:

NaturalCutFill

Liquefaction fKO«;:foie 8VpXZSettlement daemoXD+oR

Highway/Roke(.«c Q~GU(> 'levf- -.: .5'of 3 Quad„-'>, Nor row jBay,'South)gyrwdo j:H

T;-.l29S'.. dR":il«) E Sect.: 3]A:sos~ zg~> Suxlface:,:p,C ~«; -. go,,>p «Widtah: plane's

Bearing: N]0E; po;.„.Sgope/gdgn fRelat j.'onship.«:Fac.i:ngg'lesb~S'jde'(oQ Road g "gQ: nr.izsgGSlope Bearing,IfIOE: anode,Slopi 3Heightgg400t'.pisH Dimen'sions-g.„600 atiptoe>G eqoIBSlope Inclination:1:1 to,p.:,ga „p'px'palp-Seeepzlla5'ur'al above.ymoothidsoiXor(X eqo<B

Drainage: Sleety Ma«swig of~a i J -'xevo3 L i t tqlg)nu p q v fu3: e psalm s .Q

Ero'si«qn.'-.~e2 Notrexcess;ive. ixoB .goonU Uncon. Surf. Material>g +godThickness: NA Consistencyg»pA,,oo < f„ooq: yoqo~aq;:go~ AV« .-

a,.en>!oui"..'oils:

<Granular'.'I rM o.9rganic:: sv.Cohesive:: z~.;Strength Factor:„-zgBedrock Type: Dac 1 te - Volcanic Horrow Rock Comp) ex Aff „Qq+T goo+QQQ

Weathering: L i tt>l„e:ao.i„rggartdness/Cerflentation - Hard@to v. hardy g f QQQW

Consistency" (aB,l:ocky.ddt'««,eqvT) ozoyoir~Structure (Type/Attitudes):-«~v~.fractured:open

Bedrock Engr. CharacteyisticP„:,bn.a .„aoo~ A1;

Ground ««ater,„(Evidence@«Death).: apple;„Obaarved .. (cace««geo, ehzug e,ae hnco >,~Unstable Conditionsb,/Evidence) Speqpdput

bfo yfdsdoaq

Exist. Retaining Struct.: : .Dovx48 pnJ.airdeH .Ssix3Sigg~gsg-q Max«. Accel:.",sfggc'29;9@G .ga™> Est. Dapage/Blockage:. RockqFal„-lp,;wf thyone

lane closed; possibly a rockslide would close{Sew >1 'both'Ll>«nes".q) pniqmufa oP sub bsow >o obis

Remedial Repqipg:«o„Loade1-„„posh(ap~iffe debrl~s~mf ed«,,„} „absorb .«azisc",eR gs'papierEst. Time To Repair: 6 hrs. if major,and 2 hours for>«rock fal3isq.yfRemarks/Conclusions/Recommendations:

(eqofanwo0} boo» 'i~ <'«if soof «i fdsdoa'1

{ 1 f l3 ioo J} epoo..l " fi; i'ASS t«foal Qbn62

ebG'«q bnuoia bvoa «~l~n bi iud bfuoJ

2 74CE

p. lSlopes:

~

~

NaturalCut xFill

LiquefactionSettlement

Field Data Sheet

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 34

By: CMP

Date: 6/24/8]

Highway/Road: State 41 Elev.: 240'+ Quad-: Morrow Bay NorthT:,29S R:, 1 1 E Sect 9 SQ 0f SW$ 0f SW$ Surface: AC Width: 2 lanes, 40

Bearing: N7QE Slope/Rd; Relationship- South facing slope above 8 adjacent to roadSlope Bearing N70E Slope Height: 35~ Dimensions: 250 i 3QQ I

Slope Inclination: 1:1 Terrain: LowRolling'rainage:

Sheet Wash Cover: None

Erosion: Minor ravel ing Uncon. Surf. Material: NA

Thickness: NA Consistency: NA

Soils: Granular: X Organic: Cohesive: X Strength Factor:Bedrock Type: Fransciscan Rocks, Graywacke SS and ClaystoneWeathering: Mod Hardness/Cementation - Sof t/Mod Hard

Consistency: Soft Blockey Structure (Type/Attitudes): Sheared" Fract.

Bedrock Engr. Characteristics:Ground Water (Evidence/Depth): None observed

Unstable Conditions (Evidence) 1:1 cut blocky rocks

Exist. Retaining Struct. None

Site Est. Max. Accel.: 23 g Est. Damage/Blockage: Close one lane byrock slides " rock fal)s " possible slump

Remedial Repairs: Push debris aside or grade over with dozer and loaderEst. Time To Repair- 6 hours to clearRemarks/Conclusions/Recommendations:Not a serious blockage - probably one lane

2-75

p. l Field Data Sheet By: CMPDate: 6/24/81

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 35

Cover: New Cut7 None

Uncon. Surf. Material:Consistency:

Soils: Granular: x Organic: Cohesive: Strength Factor:Bedrock Type: Serpentinite

Thickness:

Slopes:NaturalCutFill

Liquefaction.SettlementHighway/Road: 101 Southbound Elev.: 200'+ Quad. - pi smo peach

31S R: 12E Sect.: 16 NE $ Surface: Width:Bearing: N 30 E Slope/Rd. RelationshiP- East Facing above highwaySlope Bearing N 30 E Slope Height: 60+ Dimensions:

500'lopeInclination: 14:1 'terrain:benches

Drainage: San Luis Obispo Creek

Erosion: Minor ravel ing

80>

Weathering:Consistency:

Hardness/Cementation:Structure (TYPe/Attitudes) . Sheared and very

fractured (random]

Bedrock Engr. Characteristics: Mod strong but shaking wi 1 1 dis'aggregateGround Water (Evidence/Depth):

Unstable Conditions (Evidence) high cut - loose materials

Exist. Retaining Struct.:Site Est. Max. Accel 26 g

Remedial Repairs: loaderEst. Time To Repair: 4 hrs.Remarks/Conclusions/Recommendations:

one southbound lane closed for 4 hours.

Est. Damage/Blockage: Rock fal ls, est. 200cubic yds-est. onelane closed.

2-76

Field Data Sheetp. l By: CMPDate: 4/24/9)

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 36

Width: 80 ~+

Uncon. Surf. Material:Thickness: Consistency:Soils: Granular: Organic: Cohesive: Strength Factor:

Squire member - sandstoneBedrock Type:Weathering:Consistency:

Hardness/Cementation:Structure {Type/Attitudes):

Slopes:NaturalCutFill

LiquefactionSettlementHighway/Road - 'l0l Southbound Elev.:60-70'uad. - Pismo Beach

T: 3I S R: l2E Sect.: Surface:Bearing: NS Slope/Rd. Relationship: East facing above roadSlope Bearing NS Slope Height:25-20 ~ Dimensions:600 I

Slope Inclination: I:I Terrain:Drainage: Sheet wash Cover:Erosion: Minor

Bedrock Engr. Characteristics:Ground Water (Evidence/Depth):

Massive to blockyNone

Unstable Conditions {Evidence)r

Oversteepened

Exist. Retaining Struct.:Site Est. Max. Accel.:.28g Est. Damage/Blockage: I b locked lane;

rockfal Is s possiblysmall slumps

Remedial Repairs:Est. Time To Repair: + 2 hoursRemarks/Conclusions/Recommendations:

I2'houlder and outside lanes blockedMinor failures - mostly rockfalls, could temporarily

Close one lane with rock falls

2-77

po lSlopes:

NaturalCutFill

LiquefactionSettlement

Field Data Sheet

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 37

By: CMP

Date: 6/24/81

Highway/Road: 101 Southbound Elev.: 120'uad.: pismo Beach

T: 32S R: 12E Sect.: Sur face: Concrete Width: 60

Bearing: N60W Slope/Rd. Relationship- Immed i ately adjacentSlope Bearing N60W Slope Height: g0 est Dimensions 70'Slope Inclination:Vert. rain 'I rregu 1 ar V. steep outcropDrainage: NA Cover: Bear Rock

Erosion: None (y. res i s tant) Uncon. Surf. Material:-+,Thickness: NA Consistency: NA

Soils: Granular: Organic: Cohesive: Strength Factor:Bedrock Type: Obispo Fm CRS grained crystal 1 ine tuffWeathering: Mod Q surface Hardness/Cementation: y. hqrd to hard

Consistency: Structure (Type/Attitudes): fractured "openrandom - jointed 2 '- 6' 8'pacing.

Bedrock Engr. Characteristics- Fractured - blocks - 2'-6'dia. - open faceGround Water (Evidence/Depth) - None

Unstable Conditions (Evidence) v. steep high - outcrop

Exist. Retaining Struct.:Site Est. Max. Accel.: 0.26 g Est. Damage/Blockage: Rock fal 1 s - large

boulders - possibly close both southbound lanes

Remedial Repairs: Dozer — push boulders asideEst. Time To Repair - Est ima ted 4 hours

Remarks/Conclusions/Recommendations:

Located in center meridian between North and South boundInside southbound

Possibly close bothsouthbound lanes-Northbound ok.

p. lSlopes:

NaturalCut xFill

LiquefactionSettlement

Field Data Sheet

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 38

CHP

6/24/81Photo No.: C-3

Highway/Road: Los Berros Elev.: 24O <+ Quad.: Oceano

T: 12N R: 13E Sect.: 35 Surface: AC Width:30'earing:

N65W Slope/Rd. Relationship: Immediately adjacent to southbound lane

Slope Bearing N65W Slope Height: 25< Dimensions:Slope Inclination: 1:1 Terrain: NA

Drainage: Sheetwash Cover: None

Erosion: Hinor ravel ing Uncon. Surf. Material:Thickness NA .Consistency:

I'oils:Granular: X Organic - Cohesive: Strength Factor: low/moderateBedrock Type: Happed as older sand dune deposits - sands 8 terrace w/fragments.siltstoneWeathering: Hod Hardness/Cementation: S 1 ight1y cementedConsistency: Friable Structure (Type/Attitudes) - Hass ive

Bedrock Engr. Characteristics: Low Cohes ionround Water (Evidence/Depth): None observed

Unstable Conditions (Evidence) Oversteepened low cementation

Exist. Retaining Struct.:Site Est. Max. Accel.: 22 g

Remedial Repairs: 1 oader

Est. Time To Repair: 2 hrs.Remarks/Conclusions/Recommendations:

Est. Damage/Blockage:1 1 ane closed

with rock falls

Considered minor " rock falls " soil fallsClosure of one lane for two hours.

2-79

po lSlopes:

NaturalCut XFill

LiquefactionSettlement

Field Data Sheet

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 39

By - CMPDate: 4/24/Sl

Width: 2 lanes "35'acingadjacent to eastbounc

Lane1,500'tretch

Cover - Trees/and bare

Highway/Road: Los Berros - Near Elev.: 100'+ Quad.: OceanoValley Road-Nipomo Hill areaT: 32S R: 13E Neet.: Surface:

Bearing: EW Slope/Rd. Relationship: D i s cont i nuous No.

Slope Bearing EW Slope Height: 35'imensionsSlope Inclination: k:1 Terrain:Drainage: Sheet wash

Erosion: Uncon. Surf . Material: TerraceThickness: Consistency:Soils: Granular: X Organic: Cohesive: Strength Factor:Bedrock Type: Franciscan graywacke (2) w/terraceWeathering: Mod Hardness/Cementation:Consistency: NA Structure (Type/Attitudes): v. fractured

Bedrock Engr. Characteristics: blockyGround Water (Evidence/Depth): None

Unstable Conditions (Evidence) Steep cuts b 1 ocky

Exist. Retaining Struct.:Site Est. Max. Accel.: 0.24 g

Remedial Repairs: Loader

~i'jy

Est. Damage/Blockage: Rock falls - slumps(small) s rock slides; One and possibly two lane's

Est. Time To Repair: Loader six to eight hours

Remarks/Conclusions/Recommendations:Eastbound large closure/possibly into west bound (but passable). Discontinuous section-Over 1,500'ection of road.

2-80

p. l Field Data Sheet By: CMP

Date: 6/24/81Potential Unstable Conditions

(Roads and Highways)Site Ref. No. 40

SandsThickness: 200+ Consistency: loose friabl e

Soils: Granular: x Organic: Cohesive: Strength Factor: Low cohes ion

Bedrock Type: Terrace/Older sand dune depositsWeathering: Mod Hardness/Cementation: SpftConsistency: Loose Structure (Type/Attitudes): Mass 1 ve flat

lyingBedrock Engr. Characteristics - Low strengthGround Water (Evidence/Depth): None evident

Slopes:NaturalCutFill

LiquefactionSettlementHighway/Road: Va 1 1 ey Road Elev.: 40 200> Quad. - Oceano

Narrow 2T: 12N R: 13 E Sect.: Surface: AC WidthB r ng: N15E Slope/Rd. Relationship Cuts adjacent to rd. west f ' loSlope Bearing N15E Slope Height ~ 20-25~ Dimensions:Slope Inclination:$ :1 tp 1:1 Terrain: River channel bluffDrainage: Sheet Mash Cover: Brush/grassErosion: Yes - moderate Uncon. Surf. Material:

Unstable Conditions (Evidence) Over steepened, low density, low strength, depositsexposed.

Exist. Retaining Struct.: lloneSite Est. Max. Accel.: 0.24 g Est. Damage/Blockage: Sp 1 1 fa 1 1 s rpckfalls, both lanes closed

Remedial Repairs- Dozer/Loader - side cast loose materialsEst. Time To Repair: + one dayPemarks/Conclusions/Recommendations:A 3000'ection cut/fill into a river bluff 160'igh with granular loose material.Both lanes closed for 1 day and possibly 1 lane open in six hours.

2-81

p. lSlopes:

NaturalCutFill X Ra I road

Settlement

Field Data Sheet

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 41overpass

By: CNPDate: 6/24/8)

Highway/Road: City of Oceano Elev.: 20'+ Quad-: Oceano

T: 12N R:13 E Sect.: Surface: AC

Bearing-N60W on Slope/Rd. Relationship: F j) ) bothSlope BearingN60W on Slope Height: 30l Dimensions:2"400'ection either

curve side of bridgeSlope Inclination: )$ :) Terrain- Irregu)arDrainage: Poor Cover: grass

Erosion: Yes — Excessive Uncon. Surf. Material: Sand f i )1

Width4 lanes - 60'

Hardness/Cementation:NA SoftStructure (Type/Attitudes): NA

Consistency: NA

Thickness: NA Consistency:Soils: Granular: X Organic: Cohesive: Strength Factor: Sandy mater ia)Bedrock Type: None

Weathering: NA

Bedrock Engr. Characteristics:ground Water (Evidence/Depth): possible shallow — liquefaction-settlement possible ~Unstable Conditions (Evidence) Loose fi)1 materia)s9 )g:) slopes

Exist. Retaining Struct.:Site Est. Max. Accel.: 0.26 g

Est. Damage/Blockage- Settlement and )ossof two outside lanes with debris slides, possiblslumps.

Remedial Repairs- Extensive grading w/inportEst. Time To Repair: 1 day plusRemarks/Conclusions/Recommendations:

If the bridge doesn't fail theloss of both outside lanes islikely w/slumps 8 debris slides.Liquefaction could also cause

settlement in this area.

Eko> ION

Flbb.

RR 7 ~~S

2-82

p 1 Field Data Sheet By: CMP

Date: 6/24/81Potential Unstable Conditions

(Roads and Highways)Site Ref. No. 42

2 laneWidt,h: 40 '-45

'lopes:NaturalCut XFill

LiquefactionSettlementHighwav/Road, Los Berros Rd. Elev: 400'uad. - OceanoSE of 161 (3 cut areas)T: 12N R: 35'g Sect.: 36 SEp Surface: AC

Bearing: N70M Slope/Rd. Relationship- Cuts both NE 6 SWfacing adj. to roadSlope Bearing N70W Slope Height - 25-35 Dimensions: 3-200'ect i ons

Slope inclination: 1:1 Terrain: low rol 1 ingDrainage: Sheet wash Cover'None g some grassErosion: ravel ing evident Uncon. Surf. Material:Thickness Consistency:Soils: Granular: X Organic: Cohesive:~strength Factor: low

Bedrock Type» Pasa Robles Formation - young terrace deposits FragmentsWeathering- Mod to verv Hardness/Cementation: Soft low cementation

ConsistencY: Loose friable . Structure (Type/Attitudes): f lat lying

Bedrock Engr. Characteristics: Low cohesionGround Water (Evidence/Depth):

Unstable Conditions (Evidence) Low strength (Northbound lane closure) oversteepened

Exist. Retaining Struct- - None

Site Est.. Max. Accel.: 0 '1 g Est.. Damage/Blockage: Slumping and soi 1

falls and debris slides-at least one

Remedial Repairs- Loader to clear - grade over or removeEst. Time To Repair - + 6 hrs. to cl ear both lanesRemarks/Conclusions/Recommendations:

'

Only partial closure - at least one lane

2-83

p. l Field Data Sheet By ~ CMP

Date: 6/24/81Slopes: Potential, Unstable Conditions

Natural (Roads and Highways}Cut X Site Ref. No. 43Fill

Liquefactzon 2 Cuts (both sides of highway).SettlementHighway/Road: 101 Northbound Elev.: 300 'uad.: Oceano

T: 12N R: 35W Sect.: 26 (Sma1 1 sect.) Surface: Width:40 'Northboun/Bearing: N45W .Slope/Rd. Relationship: Immed. adjacent to highway both sides

Slope Bearing N45W Slope Height:20+35'imensions: 300<

Slope Inclination: 1:1 Terrain: low rol 1 ingDrainage: Sheet wash Cover: None w/some grassErosion: M i nor Uncon. Surf. Material terrace d

Thickness: Consistency: Loose

Soils: Granular: x Organic: Cohesive: Strength Factor:Bedrock Type: Terrace - Pasa Robics Fm

Weathering: Mod Hardness/Cementation: low cementat ionConsistency: Loose fri able Structure (Type/Attitudes): Fl at 1 y 1 ng

Massive poorly bedded

Bedrock Engr. Characteristics: low strengthGround Water (Evidence/Depth): Hone observed

Unstable Conditions (Evidence) Low strength materials over steepened cut

Exist. Retaining Struct.: Hone

Site Est. Max. Accel.: .022 g. Est. Damage/Blockage: So 1 1 fa 1

and debris slides-partial closure of bothnorthbound lanes.gemedial Repairs: Loader to waste debris, short haul

Est. Time To Repair: 4-6 hrs.Remarks/Conclusions/Recommendations:

Not total closure - Parts of both lanes closed (Northbound only) - Not serious problem

2-84

p. l Field Data Sheet By: CMP

Date: 6/24/81Potential Unstable Conditions

(Roads and Highways)Site Ref. No. 44

Slopes:NaturalCut XFill

LiquefactionSettlement Old road (2 areas)

Highway/Road:- CORB I T Elev.: 280'uad ~ - Arroyo Grande

T: 31S R:13 E Sect.: '? Surface: AC, Width. 2 lanes

Bearing: N45W . Slope/Rd. Relationship: Immediate adjacent to road - both sid~s

Slope BearingN45W Slope Height: 20-30'imensions:2-200'lope

Inclination: p. I Terrain: low rol 1 ing

Drainage: Sheet wash Cover: None

Erosion: v. minimal Uncon. Surf. Material: NA

Thickness: NA Consistency:Soils: Granular: Organic: Cohesive:~Strength Factor:Bedrock Type: Sands tone S i 1 ts tone Diatomite Monterey Fm

Weathering: Mod. Hardness/Cementation: Mod ha rd to soft

Consistency: Structure (Type/Attitudes): Wel 1 beddedUnfavorable out of slope toward SW.

Bedrock Engr. Characteristics: I'ow mod strengthGround Water (Evidence/Depth): None observed

Unstable Conditions (Evidence) hi cuts steep inclination and possibly bedding daylighted

Exist. Retaining Struct.: None

Site Est. Max. Accel.: 0.21g Est. Damage/Blockage: Rock fa1 1 sand pop outs, both lanes temporarily blocked.

Remedial Repairs: Loader to grade s ing I e lane

Est. Time To Repair: 1 to 2 hrs.Remarks/Conclusions/Recommendations:

Enough rock would come down to block both lanes if severe - be easy to grade dirt roadaround or make several passes w/loader to clear.

2-85

p. l Field Data Sheet By: CMPDate: 4/26/81

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 45

Slopes:NaturalCutFill

LiciuefactionSettlementHighway/Road. State 227-Carpenter Elev.: Quad.: Arroyo Grande Quad

Cyn Rd-T: 31S R: 1313 Sect.. Surface: AC Width: 2 lanes

4nBearing: N45W Slope/Rd. Relationship: NE facing immediately adjacentSlope. Bearing N45g Slope Height: 20-25'imensions: 0iscontinuousSlope Inclination: k:1 to vert. Terrain: low rol 1 ing 3000'ectionDrainage: Sheet wash Cover:Erosion: Minor low Uncon. Surf . Material: NA

Thickness'. NA Consistency- Friable low cementationSoils: Granular: Organic: Cohesive: Strength Factor:Bedrock Type- Edna member - massive - Arkosic/Quartzose sandstone.Weathering: Mod Hardness/Cementation: Soft Mod hard

Consistency: Fr i able to med dense Structure (Type/Attitudes): Mass ive w/thick bedding and widely. spaced joints. Sheetingis taking place..

Bedrock Engr. Characteristics - low s t reng thGround Water (Evidence/Depth): None observed

Exist. Retaining Struct.: None

Site Est. Max. Accel.: 0.21g Est. Damage/Blockage- est $ of southbound lane closed from rock falls - largetablular slabs.bound lane c 1 osed from

Remedial Repairs- LoaderEst. Time To Repair:+ I day to open fui ly both lanesRemarks/Conclusions/Recommendations:Several discontinuous cuts - partial blockage of south bound lane. Northboundwill remain open.

Unstable Conditions (Evidence) High oversteepened slopes (al though cuts have per-formed fairly well 'according to Cal Trans.

2-86

p 1 Field Data Sheet By: CMP

Date: 6/24/81Slopes:

NaturalCut XFill

LiquefactionSettlement

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 46

3 cut areas - 1 with cuts on both sides {new fresh cuts)Highwav/Road- Price Cyn Rd. Elev.: 2q0i Quad.: Arroyo Grande

T: 31S R: 13E Sect.: Surface: AC Width: 2 lanes 40'Bearing: 13E Slope/Rd. Relationship: Cuts immediately adj to road

Slope Bearing N30E Slope Height: 30.~ ~40.~ Dimensions: 800'iscontinuousSlope Xnclination: 1:1 Terrain - low/mod. ro1 1 ingDrainage: Sheet wash Cover: None

Erosion- Minor ravel ling Uncon. Surf. Material: NA

Thickness: NA Consistency: NA

Soils: Granular: Organic: Cohesive: Strength Factor:Bedrock Type: Edna member/Pismo Fm si 1 tstone and sandstoneWeathering: fresh to med. Hardness/Cementation:

1

Consistency: f i rm med./blocky Structure (Type/Attitudes):„el 1 beddedfavorably oriented very fractured and jointed 1-2>

Bedrock Engr. Characteristics: 0K no problGround Water (Evidence/Depth): None observed

Unstable Conditions (Evidence) Steep high cuts over steepened rock that wi 1 1 ravel{blocky)

Exist. Retaining Struct.:Site Est. Max. Accel.: 0 19 g Est. Damage/Blockage: Rock fal ls blocking

k to $ of. each lane both directionsRemedial Repairs: Loader - a few passes to open 1 laneEst. Time To Repair: 8 hrs. if a lot of blockage.Remarks/Conclusions/Recommendations:

Oil seeps in cuts" Partial blockage = anticipated portion of southbound

and maybe northbound closed {partial) - should be central section of road notblocked or maybe a few passes to open

2-87

p. l Field Data Sheet By ~ CMPDate: 6/24/81

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 47

Dimensions:

1500'edrock

Engr. Characteristics:Ground Water (Evidence/Depth): None noted

Slopes:NaturalCut, XPill

LiquefactionSettlementHighway/Road: Price Cyn Rd. Elev.: Quad ~: Pismo Beach

T:32S R: 12E Sect.: Surface: AC Width:Bearing: NS Slope/Rd. Relationship:Slope Bearing NS Slope Height:50 90 <

Slope Inclination: 4:1 Terrain: Mod to steepDrainage: Cover:Erosion: Excessive locally Uncon. Surf. Material: NA

Thickness: NA Consistency: NA

Soils: Granular: Organic: 'Cohesive: Strength Factor:Bedrock Type: Monterey fm Claystone s Si 1 tstone/ShaleWeathering: v. to mod. Hardness/Cementation: Soft to mod

Consistency: ravel s/blocky slabby Structure (Type/Attitudes) - We 1 1 -Bedded, v.fractured and jointed, bedding favorably orientedsteep 50oE

low strength

Unstable Conditions (Evidence) Existing slide area v. steep cuts (overstee d)hi gh ta 1 us

Exist. Retaining Struct ~ - Chainiink fence 9 toe of slide area.Site Est. Max. Accel.: .024 g Est. Damage/Blockage - Rock s 1 ides, rockfalls, and slumps

Remedial Repairs:Est. Time To Repair: 2 days +

Remarks/Conclusions/Recommendations:Landslide 90':1 - 1000'ong major slump along bedding block glide several 1000' yds.Estimated two days to reopen one lane Northbound. This is considered a majorblockage area. Bedding and slope have about the same ratio.

p 1

Slopes:NaturalCut

LiquefactionSettlement

Field Data Sheet

Potential Unstable Conditions(Roads *and Highways)

Site Ref. No. 48

(underpass RR Xing)

By- CapDate: 6/25/81

Uncon. Surf. Material:Erosion - None/minorThickness: NA Consistency:Soils: Granular: Organic: Cohesive: Strength Factor:Bedrock Type: Franciscan Graywake

Weathering: Mod to fresh Hardness/Cementation'- Mell cemented to blocky hardConsistency: blocky Structure (Type/Attitudes): Very fractured

and jointed bedding

Highway'/Road: Johnson Rd in town Elev.: 25O>+ Quad.: San Luis Obispo

30S R'2E >e<< ~: SW$ of SE$ of SEJM/26 Surface - ACSan Luis Obispo Width:

4»nes-75'~aring:

N8OM Slope/Rd. Relationship: No. facing immediately adjacent so. side

Slope Bearing N8Og Slope Height: 3O ~ Dimensions: 2OO >

SloPe inclination: P to y.l Terrain:Drainage - Sheet wash Cover:

Bedrock Engr. Characteristics:Ground Water (Evidence/Depth): None observed

Unstable Conditions (Evidence) Oversteepened high slope

Exist. Retaining Struct.:Site Est. Max. Accel.: 0.21g Est. Damage/Blockage: Rock fa1 1 s close 1

lane (most southerly)

Remedial Repairs: loader to clear rock debrisEst. Time To Repair: 4 hoursRemarks/Conclusions/Recommendations:Close 1 of the 4 lanes (eastbound)

NOT total blockage

2-89

pe 1

Slopes:NaturalCutFill X

LiquefactionSettlement

Field Data Sheet

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 49

* Dam 6 Reservoir

By - CHPDate: 6/25/81

Hardness/Cementation: NA

Structure (Type/Attitudes): NAConsistency: NA

Highway/Road: Arroyo Grande Elev.: 320'uad.: Arroyo Grande

T: 32S R: 13E Sect.: Surface: NA Width-Bearing: Slope/Rd. Relationship - Road down stream of dam

600'lope

Bearing NA MM Height: Dam 30-35'imensions: 600'ide dam

Slope inclination: 2:1 s 3:1 Terrain: NodRes 2500'ong

Drainage: youthful downstream Cover: grass brush 6 treesErosion: None obvious to dam

Thickness: NA Consistency: NA

Soils: Granular: X Organic: Cohesive: X Strength Factor: low

Bedrock Type: NA

Weathering: NA

NA

Bedrock Engr. Characteristics:Ground Water (Evidence/Depth):

NA

Probably shal low under dam

IUnstable Conditions (Evidence) Possible 1 iquefaction, settlement seich - breachingof dam

Exist. Retaining Struct.:Site Est. Max. Accel.: 0.19 g. Est. Damage/Blockage: I f dam fails road

downstream will be impassable

Remedial Repairs: Regrade road - import fillEst. Time To Repair: 1 day +, maybe 2

Remarks/Conclusions/Recommendations:

Low g values in this area - but if dam ruptures - road would definitely be destroyed - 400'-500

section. Check with State Dam Safety for seismic study.*"Lopez water treatment facility"

2-90

p l Field Data Sheet By: CMPDate: 6/25/81

Potential Unstable Conditions(Roads and Highways)

Site Ref. No. 50

Drainage: Sheet wash

Erosion: Minor Uncon. Surf. Material:Thickness: NA Consistency: NA

Soils: Granular: Organic: Cohesive: Strength Factor:Bedrock Type: "Sandstone" Squi're 6 Edna member of Pismo Fm

Weathering: Mod Hardness/Cementation: 1 ow cemen ta t i on

Consistency: Blocky to massive s)abby Structure (Type/Attitudes) - beddingfriable indistinct, joints not prominent

Cover:

Bedrock Engr. Characteristics- Shaking wi'll cause slabs to fall and break up.Ground Water (Evidence/Depth): Hone observed

Slopes:NaturalCut 5 areas of cutsFill

LiciuefactionSettlementHighway/Road: Arroyo Grande Elev.: Quad. - Arroyo Grande

T: 32S R: 13E Sect.: Surface: Width - 2 1 anes 35Bearing: NESTS Slope/Rd. Relationsh>p -SE facing cuts N s ide of roadSlope Bearing NESTS Slope Height:30-.35 'imensions - 60, 2200'iscont inuousSlope Xnclination: $ :I Terrain:

Unstable Conditions (Evidence) Steep cuts $ :) s mod height

35'xist.

Retaining Struct.:Site Est. Max. Accel.: 0.21 g Est. Damage/Blockage:

1 lane, largepop outs, rock fa1 )s.

Remedial Repairs- Loader to clear debrisEst. Time To Repair: 2 hrs/cut = 10 hrs. to clearRemarks/Conclusions/Recommendations:

Not tota 1 blockage5 cut areas of slopes to 35'ith 4:) slopes, genera) ly massive sandstoneB)ockage of possibly up to 1 lane southbound

2-9l

Field Data Sheet By: CMP

Date: 6/25Photo No.: C-17, C-18

p. lPotential Unstable Conditions

(Roads and Highways)Site Ref. No. 51

Slopes:NaturalCut 2 cutsFill

LiquefactionSettlementHighway/Road: Elev.: 200'+ Quad-: Pismo Beach101 North and

South BoundT: 31/32S R: 12E Sect.: Surface: AC Width: 4 lanes+

Bearing: N20W Slope/Rd. Relationship-Cuts (EsW facing) both sides

Slope Bearing N20W Slope Height: Dimensions:

Slope Inclination: Terrain: Steep to mod. 'errain hillsDrainage: Sheet wash Cover: None

Erosion: X Uncon. Surf. Material: NA

Bedrock Engr. Characteristics: S 1 abby, b 1 ocky mass i ve

Ground Water (Evidence/Depth): No evi dence

Thickness: NA Consistency: NA

Soils: Granular: Organic: Cohesive: Strength Factor:Bedrock Type:,Miguel ito (Pismo Fm) Clayst,, Siltstone, Shale w/interbeded SS

Weathering: Li t tie to mod. Hardness/Cementation: soft to mod. hard

Consistency: Wel 1 thin to thick bedded Structure (Type/Attitudes) - Favorable beddingand blocky. V. fractured N45W 40-50N

Unstable Conditions (Evidence) Overs teepened high cuts

Exist. Retaining Struct.: None

Site Est. Max. Accel.: 0 ~ 28 g ~ Est. Damage/Blockage:

Remedial Repairs:Est. Time To Repair:Remarks/Conclusions/Recommendations:

"-NORTH BOUND %SOUTH BOUND

80'igh slope - very blocky 1:1 irregular,one bench at lower portion 14:1 and 40'igh,20'ide. Rock falls -, rock slides - twoNorthbound lanes and offramp to Avi la closed.Use center meridian, Estimate over one dayto grade over.

100'igh to 150'igh siltstone/sandstone1:1 to 4:1. Three benches - 600'ide atbase. Frontage Rd. between cut toe andfreeway. This would be blocked — doubt-ful if more than one southbound lane-rock slides and slumps (local out ofslope bedding) talus at toe of slopeestimated several days to clear. Lowerslope 30's 1$ :1

2-92

Field Data Sheet By: CMPDate: 6/25/81Photo No.:

p. lPotential Unstable Conditions

(Roads and Highways)Site Ref. No. 52

Bedrock Engr. Characteristics: blocky characterGround Water (Evidence/Depth): None observed

Unstable Conditions (Evidence) Oversteepened — high cut - blocky materials

Slopes:NaturalCut XFill

iquefactionSettlementHighway/Road: Northbound 101 on Elev. - 150-200'uad. Pi smo

ramp from AvilaT: 31S R.: 12E Sect.: Surface: AC Width. Four 1 anes

plus on/offBearing: N20W Slope/Rd. Relationship:Cut immediately adjacent to ramp

on rampSloPe B>aring N20W SloPe Height: 50-60'imensions: 400> long

Slope Inclination: 1:1 Terrain: Mod. terrain Hi 1 lsDrainage: Sheet wash Cover: None

Erosion: Minor ravel ing Uncon. Surf. Material: NA

Thickness: NA Consistency: NA

Soils: Granular: Organic: Cohesive: Strength Factor:Bedrock Type: Sandstone Pismo Fm

Weathering: Mod Hardness/Cementation: Sof t (fr i ab1 e) to Med. hard

Consistency: S 1 abby blocky/Mass i ve Structure (Type/Attitudes): BeddingN60-70 W 25-30 - North dip jointed/fractured - low

Exist. Retaining Struct.: None

Site Est. Max. Accel.: 0.28 g. Est. Damage/Blockage: Rock fa 1 1 s andpossible rocksl ides onto on-ramp only(Freeway OK)

Remedial Repairs: Loader to clearEst. Time To Repair: +one day if excessive otherwise few hours if rock fal lsRemarks/Conclusions/Recommendations:

On ramp Northbound from Avila highway would be closed with mostly rock fal ls - withpossible rock slides. Doubtful if it would extend on highway, few hours to one day +.

2-93

3.0 LIQUEFACTION

3. I OVERVIEW AND METHODOLOGY

Li uefaction - Overview

Under the proper soil and ground water conditions, ground failure by liquefaction

may occur during an earthquake. Liquefaction is defined as the transformation

of cohesionless water-saturated material, such as sand, from a solid state to a

fluid state. The cause of cyclic mobility or liquefaction in sands is the build-up

of excess hydrostatic pore pressure due to the application of cyclic shear

stresses. The shear stresses are generated in a soil deposit during ground

shaking. As a consequence of the applied cyclic stresses, the structure of the

undrained soil tends to become more compact. If the sand is loose, the pore

pressure increases rapidly to a value equal to the confining pressure, and the soil

layer may undergo large deformations and be in a state of extreme liquefaction.

If the sand is more compact, it will undergo limited deformation and partial

liquefaction. Any structure, fillor embankment located on a liquefying soil willundergo some deformation varying from minor settlement to complete sinking.

The goal of a liquefaction potential analysis is to differentiate between those

situations where liquefaction can cause damage and those situations where

liquefaction, per se, may not cause significant damage.

Three major factors are conducive to liquefaction: ground shaking, shallow

water table, and sandy material. Generally, low-lying areas mantled by young,

unconsolidated, well-sorted sand and/or silty sand (clay free) materials are the

most susceptible to liquefy. In addition, some minor topographic relief, such as

stream banks or gentle to steep slopes, is normally needed to cause liquefaction

ground failure. However, ground failure can occur on flat ground if the

liquefiable materials are unevenly loaded, such as in the case of road fills.

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Li uefaction - San Luis Obis o Area

Several of the evacuation routes travel through, areas susceptible to liquefactionin the event of a major earthquake. However, no known historic liquefaction has

occurred in the study area. The areas susceptible to liquefaction could

experience accelerations between 0.12 and 0.50 g for an event of magnitude 7.5

occurring on the Hosgri fault. According to Youd et al. (1978), the lower limitfor liquefaction to occur is an acceleration of about 0.2 g. This suggests thatalmost all locations within the study area have the potential to liquefy. The

resulting damage at each site will depend upon the specific soil and groundwater

conditions.

Those areas most capable of liquefaction damage to roads and highways are

located on valley floors, river channels, estuaries, and low-lying coastal areas.

These are areas that have been flooded historically or within the recent geologic

past. The most recent flooding may have deposited very young, loosely-packed

granular sediments. Generally, the continuous ground water table is shallow in

these areas, though it may fluctuate seasonally or over a period of time. Salt

water (intrusion) is reported to underlie the Morro Bay and other coastal sections

south of Pismo Beach (DWR, 1971 and 1972).h

The degree of damage to a road or highway caused by liquefaction is difficult toassess. Liquefaction may cause surface cracking, settlement, or lateral spread-

ing. During the process of high pore pressure generation,'ater is caused to flowupward to the ground surface where it emerges in the form of sand boils.Formation of cracks is associated with the initial emergence of water from theground. Such effects probably will not cause impairments to roads or highways.

With regard to roads and highways, liquefaction-induced settlement and slope

failure of artificial fills may be the most common and most dam'aging effects.The increase in pore water pressure in the fillor underlying materials can reduce

the shear strength of the materials causing failure by differential, lateral flow,settlement and/or slope failure. This may occur especially in the case of high

narrow fill slopes where there is a lack of lateral confinement. Lateral spreads

are defined as large masses of material that move laterally.on liquefied sand or

B-81-227 3-2

TERA CORPORATION

silt. This can cause sections of road to rotate or subside. This type of failure

usually occurs along high steep bluffs, though it has been known to occur in low

relief areas such as along flood plains and deltas (Youd, I 979).

Damage from liquefaction to roads and highways may be minor to severe.

Flexible pavement, such as asphalt, may be able to withstand minor differential

settlement, cracking, and lateral spreads without disruption of traffic flow.

Concrete roadways may crack, causing portions of the surface to heave or

separate several inches to several feet and rendering the road impassable. Road

embankment materials may slump or settle, partially removing one or more

lanes, or the total fillmay fail.

Remedial repairs may require only filling in cracked pavement or constructing

earthen ramps over areas that have been vertically displaced. Major lateral

displacements can probably be easily and quickly repaired by importing fillmaterials and regrading the displaced portion of the road. It is doubtful, though

possible, that a major settlement could cause flooding by surface or ground

water. Depending on the severity of the damage, it could be temporarily

repaired by importing fill and placing it in the flooded area to reestablish

continuity of the roadway.

Li uefaction Potential Assessment

Criteria developed by the U.S. Geological Survey (Youd et al., l 978) were used to

assess potential liquefaction areas in the San Fernando Valley, California. In

l979 the U.S. Geological Survey (Helley et al, l979) used techniques similar to,but more refined than, those used by Youd for the San Francisco Bay area. The

Seismic Safety Element for San Luis Obispo County (Envicom, 1974) has

delineated areas which have a potential to liquefy; however, their techniques for

classifying liquefied areas did not include the more recent techniques developed

by the U.S. Geological Survey. When boring logs and standard penetration tests

are available, more refined methods may be used to determine the liquefaction

potential, the most common one being the technique developed by Seed and ldriss

(l97 I) and Seed (1979).

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For this study, topographic soil and geologic maps, aerial photographs, and

ground water studies were used to delineate low-lying areas where youngersediments have been deposited and where ground water may be shallow (i.e., less

than l5 meters below the ground surface). A field reconnaissance was made toverify or characterize the relief, types of surficial sediments, and theirconsistency. No subsurface exploration was performed to determine the typesand consistencies of subsurface soils below a particular site. The subsurface

conditions were estimated using mapped and reported data and geologic projec-tion techniques. The criteria used in the study are similar to those used by theU.S. Geological Survey (Youd et al., l978, Helley et al., l979) and are presentedin Table 3- I.

In addition, boring logs at bridge locations were obtained from state and countytransportation departments to determine locally the subsurface conditions and

apply the procedure developed by Seed and Idriss (197I) and Seed (l979). Thiswas possible for about 50percent of the zones for which a potential forliquefaction exists.

This procedure is summarized below:

o Compute the maximum shear stress developed in the soil deposit

(Figure 3- I) during the earthquake:

'Yh~max = amax rd

9

where

v = unit weight of soil

h = depth of soil element

g = acceleration of gravity

amax = maximum ground surface acceleration

rd = stress reduction factor (Figure 3-2)

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o Compute the average equivalent shear stress for 20 significant cyclesfor an earthquake of magnitude 7.5:

b'av = 0.65 rmax

o Compute the effective stress in the soil element (Figure 3-2):

~'v = Vh- Vw {h hw~

where

V = unit weight of water

h = depth to water tablew

o Compute the cyclic stress ratio of average equivalent shear stress to

effective stress

~av~v

o Compute the modified penetration resistance:

Nl = (I - l.25 logl0 o'v~ N

where

o'v is in ton/ft2

N = measured penetration resistance in blow/foot.

o From Figure 3-3, determine the liquefaction potential for an earth-

quake of magnitude 7.5. A line is drawn for a magnitude 7.5

earthquake separating the diagram into two regions. Any combina-

tion of penetration resistance and cyclic stress ratio which lies in the

region above that line represents circumstances where liquefaction

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. has occurred in model tests and field cases. No liquefaction has been

observed for cases below that line. Also given at the top ofFigure 3-3 is a plot of potential shear strains which can accompany a

liquefaction event. This plot may help differentiate between a case

where ground failures are expected and a case where they are not.

Using the ground data provided by topographic and geologic maps and the sitespecific data at the bridges, the zones of potential liquefaction along thehighways and roads were localized and classified in term's of low or highsusceptibility. The low susceptibility areas include those underlain by young age(Holocene) alluvial materials that are estimated to contain appreciable amountsof sand and silt layers or lenses. Also, ground water is within 50 feet of theground surface. The high liquefaction susceptibility areas are included in thesame zones as the low susceptibility areas; however, these zones either lacklateral confinement, have gentle slopes, or are differentially loaded (artificialfills). In each case, accelerations are in excess of 0.2g. Maps and tablesdescribing these zones are presented in the Appendix.

Based on the assessment criteria, many areas along the evacuation routes havebeen categorized as potential liquefaction zones, capable of failing underexcessive seismic shaking. Since there is a reasonable amount of conservatismbuilt into the assessment criteria, not all areas considered will liquefy. Thenumber of actual liquefaction zones will decrease rapidly with distance from theepicenter, based principally on the attenuation of acceleration. Moreover, as

explained in the previous section, there is a difference between liquefaction, perse, and damage. In order to estimate the expected number of liquefaction zones

and the corresponding clearing times, the criteria presented in Table 3-2 weredeveloped for three damage levels. These criteria are based on topographic and

geologic conditions, soil profile characteristics (sand and silt layers, presence ofclay or gravel layers, depth to water level), level of earthquake shaking (PGA),liquefaction potential assessment using Seeds (l979) criterion, etc. Engineeringjudgment played an important role in this evaluation, especially in the areas

where subsurface conditions were not known. Each area of high liquefactionpotential was assigned a susceptibility level ranging from I to IV. Level I

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corresponds to a low potential for damage to roads and highways (i.e., very small

deformation with little or no impairment to the road). Level IV would corres-

pond to large deformation, settlement, slope failure and/or lateral spreading. In

this case the road would be impassable in some sections and a significant repair

time would be necessary. Levels II and III are intermediate between these two.

The susceptibility level was decreased by one unit for the adjacent low potential

zone. For a potential liquefaction area located in a given acceleration zone, the

expected footage of failure was obtained by multiplying the total potential

footage by the percentage corresponding to the selected damage level.

A summary of expected footage failure and clearing time is presented for each

road surveyed in Section 3.2. In this table the clearing times for the l2 main

roads considered (roads I- l2) are for the clearing of two lanes of traffic. For all

other roads it was considered necessary in an emergency situation to initiallyclear only one lane for traffic. This will be reflected in the clearing time in this

table.

Section 3.3 presents a summary of liquefaction potential for each liquefaction

site. This table divides each site into areas of low potential and high potential

liquefaction and sums the total expected length of failure for both potentials.

The number of lanes expected to be affected is also given.

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TABLE 3- I

LIQUEFACTION ASSESSMENT CRITERIA

Factors conducive and nonconducive to ground failure

Factor Conducive Not Conducive

Lateral Confinement Not confined along stream banks, near, Confined laterally, depressions such as a floodclifffaces. basin.

Slope

Loading

Sediment Grain Size

Sorting

Cementation

Consolidation(Compaction)Relative Density

Geologic Age

Water Saturation

Seismic Activity

Gentle to steep slopes, alluvial fans tohil I slopes

Nonuniform loading. Differential thick-ness of overlying materials.

Coarse silt and fine sand

Well sorted, clay free

Uncemented and loose

Unconsolidated, noncompacted, loose,low shear strength

Low relative density, less than 65%.

Generally Young Holocene

Saturated, water depth less than 50 ft(ism)2

'cceleration of over 0.2g, M =8 w/energy source less than 60 miles(l00 km) threshold & w/ IO+

significant'oading

cycles (6.5 M) or 30+ significantloading cycles (8.0 M)

Horizontal to gentle slope, flat alluvial surfaces,flat floors of flood basins.

Uniform loading, uniform thickness of overlyingmaterial.

Clay, coarse sand and gravel

Poorly sorted, over 3% clay

Cemented and hard

Semiconsolidated to consolidated. Moderately tohighly compacted. High shear strength.

High relative density, over 90%.

Pleistocene and older

Partly saturated to dry, water depth over 50 ft(is m).

Acceleration of less than 0.2g, M =8 w/energysource over 60 miles (l00km) threshold & w/lessthan IO significant loading cycles (6.5 M) or w/lessthan 30 significant loading cycles (8.0 M)

Bg (gl0Z

I Because liquefaction is a phenomena that takes placeb'eneath the ground surface, most of the information inthis table was abstracted from various maps or reportsand/or estimated by projecting information.

B-8 I-227

2 Water Depths - Liquefaction Potential:0-9 m (0-30 ft) - high to very high potential

9- l5 m (30 to 50 ft) - low potentialover 15 m (over 50 ft) - nil

TABLE 3-2

EXPECTED LIQUEFACTIONASSESSMENT CRITERIA

PercentageDeformation

0- 5

5-l5

l5-30

30

Percentage ofLiquefaction

Damage Level

I 2 3

0 5 IO

IO 20 30

30 40 50

50 75 IOO

Suscep-tibility

I Low

II Moderate

III High

IV Very High

3-9

TERA CORPORATION

h hw

SOIL ELEMENT

FIGURE 3- I

DETERMINATIONOF MAXIMUMSHEAR STRESS AND EFFECTIVE STRESS

3-10

TERA CORPORATION

LIQUEFACTION POTENTIAL

~(Trivia)

(<moi)r0 Ol 02 03 04 05 06 07 08 09 l0

lO

20 elvesverope v

30

40e~I

Ic 50a4O

Renege for difterentsoil profiles

70

80

90

IOO

F IGURE 3-2

LIQUEFACTION POTENTIAL

3-11TERA CORPORATION

50o<

.c540

g-308

v) 8

ob20Crn o

10

E

00

Estrmoted fieldbehovror

10 20 30 40

~Observed rn tests by De Albo et ol

50

cO

06

OOk

rn'O

E

0.5

DKlAID

VlEJ

Ll

O

O.l

00

c 040

Q eo

a CrI/l

Cf~oo —0.3c~b

O

g 02b) c~ l$p o.

6.5

65

60

&2

?8

~ 7.&O &2s.so

7.5

82

10 20 30 40Modified Penetrotion Resistance, Nr —blows/ft.-

50

FIGURE 3-3LIQUEFACTIONPOTENTIAL

VS. MAGNITUDE

B-8I-227 3-12

TERA CORPORATION

3.2 SUMMARYOF LIQUEFACTIONPOTENTIALBY ROAD

3-13TERA CORPORATION

SUMMARY OF L I QUEFACT I ON POTENT I AL

By Roads

Sheet 1 of 3

RoadNumber Road Name

LiquefactionSites Included

Total AffectedLength -(ft.)Damage Level

Total RepairTime (hours)

Damage Level

Route 101 " North 64 100 200 1.2 3 2

4a

4b

Route 101 - Central

Route 101 - South

Route 1- North

(SLO to Main St. 6 Morro Bay)

Route 1- North

(Main St. to Route 41)

~ 33-34-35-36-63-62

31-32

46-47-48-49-5065-66-67-68-69-70

52-71

2310

1900

350

1670

4920 7520

2600 3290

1860 3300

3000 4330

3.1/1.9

32.

1.6

10.5/6.5

20. 1/13 ~ 7

13.8 36

3.4

6.6 11.4

Route 1- South 3-4-5-17-18 1850 4335 6810 2.8 11.6 26

Route 41 72 to 80 350 1110 1810 2.9 13.8 31.9

7s8 Orcutt and Lopez Roads 6-7-61 380 750

Route 227 (Edna to SLO) 11-21-22-81 140 1155 2170 ~ 3 4.1

10 Price Canyon Road 12-13-19-20 280. 520 2.5 7.5

+To mber = NorthboundBop.tom number = Southbound

\

'-SUMMARY OF LIQUEFACTION POTENTIAL

By Roads

Sheet 2 of

RoadNumber Road Name

LiquefactionSites Included

Total AffectedLength (ft.)Damage Level

Total RepairTime (hours)

Damage Level

San Luis Bay Road 30 270 440 610 .5 1.7 3.2

12 Av i I a Road (101 to Av i I a Beach) 26-27-28-29 1620 2240 2890 2.4 6.5 12.2

15 Higuera Street 24-59-60-82 370 1445 2480 ~ 3 2.4 6.1

16 Madonna Road 58 210 420 5 1.5

17 Foothi I I Boulevard 56-57 0 290 560

19 Tank Farm Road 23 470 1160 1850 ~ 3 1.3 2.5

20 South Bay Boulevard 43-44-51 900 1340 1780 3.4 6.6

21 Hain Street and Country Club Drive 45 2400 3200 4000 1.5 2.6

22 Halcyon Road sect. of 3I 30 95 160 ~ 3 .8

23 Valley Road 30 230 430 .8'.8

SUHHARY OF LIQUEFACTION POTENTIAL

By RoadsI Sheet 3 of 3

Road—Number Road Name

LiquefactionSites Included

Total AffectedLength (ft.)Damage Level

Total RepairTime (hours)

Damage Level

24 Los Berros Road 120 24o 36o .6

25Av i I a Road(West of Avila Beach) 25-38 6oo 8oo 1000 1.3 2.4 4.6

26 See Canyon and Prefumo Roads 37 20 6o 90 .8 1.8

27 Los Osos Valley Road 40-41-42-53-54-55 110 1580 3100 .6 4.6 10.7

28 Corbit Canyon Road 8-9 170 320

29 Route 227 (Edna to Lopez Drive) 10-14-16 o 18o 370 1.3 3.8

30 Oak Park and Noyes Roads 15 20 4o .3 .8

3.3 SUMMARYOF LIQUEFACTIONPOTENTIALBY SITE

3-17

TERA CORPORATION

LIQUEFACTION POTENTIAL

By Site Number+ Sheet I of 12

LiquefactionSite

Number +

(Est. PGA)

Length(Ft)

Low Potential

Percentage "-:>

LiquefactionEx ected

Expected+»:>LengthAffected(f t)

Length(Ft)

~ High Potential

Percentage:>:>LiquefactionEx ected

Expected++*LengthAffected (ft)

TotalExpected .

AffectedLength (Ft)

No.of

Lanes

1

(.24)

2

(.24)

3

(.24)

4

(. 26)

5

(. 28)

6

(.20)

7

(.21)

3,400

7,000

4,400

7,500

3,600

600

10

10

10

10

10

10

I 0

340

50

700

220

440

380

180

360

30

60

1,200

300

600

1,100

5,800

500

1,200

10

20

30

10

20

30

10

20

30

10

20

10

20

0

10

10

120

240

360

60

90

60

120

180

110

220

30

580

1,160

I 40

50

60

120

120

240

360

230

430

60

470

880

110

440

580

i,540

240

210

410

90

180.

"- R~ to U.S.G.S. HapsC~sponding to Damage Levels I, 2, and 3.

:>:»> Values rounded

Al;

LIQUEFACTION ENTIAL

By Site Number» Sheet 2 of 12

LiquefactionSite

Number *(Est. PGA)

8

(.20)

Length(Ft)

1,600

Low Potential

Percentage »»LiquefactionEx ected

10

Expected«»»LengthAffected(f t)

80

160

Length(Ft)

700

High Potential

Percentage»*LiquefactionEx ected

10

Expected»»»LengthAffected (ft)

40

Tota 1

ExpectedAffected

Length (Ft)

120

2 0

No.of

Lanes

(.20)

10

(.20)

500

1,900

10

30

00

1 0

400

300

10

10

20

40

20

30

50

90

120

220

(.20)

12

(.20)

13

(.20)

5,300

2,400

260

120

240

1,400

1,700

500

10

10

70

140

90

170

30

330

670

210

410

30

50

(.18) 600

10 60

300

10

20

30

50

90'-

Refer to U.S.G.S. Haps"-:" Corresponding to Damage Levels I, 2, and 3.

»»» Values rounded

LIQUEFACT10N POTENTIAL

By Site Number» Sheet 3 of

LiquefactionSi te

Number »

(Est. PGA)

15

(.23)

16

(.22)

17

(.26)

18

(. 26)

19

(. 24)

20

(.24)

21

(.18)

Length(Ft)

2,800

4,300

400

Low Potential

Percentage »»

LiquefactionEx ected

0

10

10

10

20

30

10

30

10

10

Expected»»»LengthAffected(ft)

280

560

840

430

1,290

40

Length(Ft)

400

600

700

700

400

400

300

High Potential

Percentage»»LiquefactionEx ected

10

10

40

50

30

50

10

10

10

Expected*»*LengthAffected (ft)

20

40

30

60

210

280

350

210

350

20

40

20

40

20 ~"

TotalExpectedAffected

Length (Ft)

20

40

30

60

490

840

1,190

640

i,640

20

40

20

40

40

No.of

Lanes

Re r to U.S.G.S. Haps»* C sponding to Damage Levels 1, 2, and 3.

**» Va ues rounded

LIQUEFACTION ENTIAL

By Site Number+ Sheet 4 of 12

LiquefactionSite

Number *(Est. PGA)

22

(. 18)

23

( 22)

24

(.25)

25

(. 33)

26

(.31)

27

(.3o)

28

(.29)

Length(F't)

4,4oo

4,4oo

500

200

700

Low Potential

Percentage ++

LiquefactionEx ected

10

10

20

20

30

Expected+"-:"LengthAffected(f t)

20

44o

220

44

0.

20

4o

6o

140

210

Length(Ft)

1,400

4,700

3,700

6oo

3,700

500

4oo

High Potential

Percentage+:>LiquefactionEx ected

10

20

30

10

20

10

20

30

4o

30

4o

30

4o

50

4o

50

Expected+**LengthAffected (ft)

140

28o

42o

47o

940

41o

370

4o

I,IIO180

24o

00

I,llo1,48o

85o

150

200

250

120

160

200

TotalExpectedAffected

Length (Ft)

140

00

86o

47o

1,160

1,850370

770

1,160

180

24o

300

I, I 10

1,48o

1,850

170

24o

310

190

300

410

No.of

Lanes

* Refer to U.S.G.S. Maps~~ Corresponding to Damage Levels I, 2, and 3.

*:>* Values rounded

LIQUEFACTION POTENTIAL

By Site Number* Sheet 5 of 12

Liquefact i onSite

Number +

(Est. PGA)

29

(.29)

30

(.29)

31

(.25)

32

(. 28)

33

(.28)

34

(.27)

35

(.26)

Length(Ft)

300

1,200

8oo

Low Potential

Percentage >"-

LiquefactionEx ected

10

20

30

10

20

10

Exp ec ted:>*2"LengthAffected(ft)

30

6o

120

120

24o

36o

4o

8o

Length(Ft)

4oo

500

5,000

,8oo

1,000

6,200

7,100

High Potential

Pe rcen tage"-"-LiquefactionEx ected

30

4o

50

30

4o

50

40

'

75

100

30

40

50

10

20

30

10

20

30

Expected*-~LengthAffected (ft)

120

160

200

150

200

250

1,500

2,000

2,500

4oo

6oo

790

400

500

62o

I 24o

1,86o

710

420

2,130

TotalExpected.Affected

Length (Ft)

150

220

320

270

44o

61o

1,500

2,000

2,500

4oo

600

790

4oo

500

620

1,24o

. 1,860

710

1,46o

2,210

No.of

Lanes

~ R~ to U. S. G. S. HapsC~sponding to Damage Levels I, 2, and 3.

~:>+ Values rounded

LIQUEFACTION ENTIAL

By Site Number* Sheet 6 of 12

LiquefactionSite

Number »

(Est. PGA)

36

(. 24)

37

(.29)

38

(.34)

39

(.35)

4o

(.31)

41

(.29)

42

(.27)

Length(Ft)

4,ooo

300

1,700

4,100

4,5oo

Low Potential

Percentage *»LiquefactionEx ected

10

10

10

20

30

10

20

30

10

10

10

Expected»»»LengthAffected ft)

0

200

4oo

20

90

170

200

410

0

2 0

45o

Length(Ft)

2,400

200

1,4oo

. Soo

4oo

500

200

High Potential

Percentage»*LiquefactionEx ected

10

20

30

10

20

50

30

4o

50

10

20

30

10

20

20

30

Expected»»*LengthAffected (ft)

24o

48o

720

20

4o

6o

700

24o

320

4oo

4o

So

120

100

150

20

40

6o

TotalExpectedAffected

Length (Ft)

24o

680

1,12020

6o

700

24o

320

4oo

4o

170

290

00

66o

2 0

510

No.of

Lanes

Refer to U.S.G.S. Maps»» Corresponding to Damage Levels I, 2, and 3.

Values rounded

L I QUEFACT I ON POTENT I AL

By Site Number* Sheet 7 of

l.iquefactionSite

Number »

(Est. PGA)

43

(.3o)

44

(.3o)

45

(. 3o)

46

(.3o)

47

(.3o)

48

(.31)

(.27)

Length(Ft)

1,4oo

2,200

1,400

500

Low Potential

Percentage »«LiquefactionEx ected

10

10

10

0

10

Expected«*«LengthAffected(ft)

70

140

0

1 lo

220

140

0

50

Length(Ft)

2,000

Soo

S,ooo

500

4oo

1,600

700

High Potential

Percentage"-«LiquefactionEx ected

30

4o

50

4o

50

4o

50

10

20

30

10

20

30

10

20

0

20

Expected««*LengthAffected (ft)

6oo

Soo

1,000

24o

20

4oo

2 40o

200

4,ooo

50

100

150

4o

8o

120

i6o

20

48o

140 ~

210

TotalExpectedAffected

Length (Ft)

6oo

Soo

1,000

24o

20

4oo

2 4oo

200

4 ooo

50

170

290

4o

190

34o

i6o

62o

I 0

26o

No.of

Lanes

Ref~ to U.S.G.S. Haps»» Co~ponding to Damage Levels 1, 2, and 3.

*»» Values rounded

LIQUEFACTION ENTIAL

By Site Number+ Sheet 8 of

Liquefact i onSite

Number *(Est. PGA)

50

(.28)

51

(.29)

52

(.30)

53

(.25)

54

(.25)

55

(.24)

56

(.24)

Length(Ft)

1,500

2,000

3,700

6,300

1

5,600

2,900

Low Potential

Percentage *~LiquefactionEx ected

10

10

10

10

10

0

10

'10

Expec ted~~":" .

LengthAffected(ft)

80

150

100

200

190

320

630

280

560

2 0

Length(Ft)

300

600

1,600

300

300

200

300

High Potential

Percentage»>'<LiquefactionEx ected

10

20

30

10

20

30

10

20

30

10

-5

10

Expected:"++LengthAffected (ft)

30

60

90

60

120

180

160

20

480

20

20

10

20

TotalExpectedAffected

Length (Ft)

30

140

240

220

80

i60

20

480

210

400

340

660

2 0

580

No.of

Lanes

* Refer to U.S.G.S. Haps** Corresponding to Damage Levels I, 2, and 3.

~~* Values rounded

LIQUEFACTION POTENTIAL

By Site Number» Sheet 9 of 12

LiquefactionSite

Number *(Est. PGA)

57

(.23)

58

(. 23)

59

(.23)

6o

( ~ 23)

61

(.21)

62

(.23)

63

(.22)

Length(Ft)

I,ooo

3,600

3,100

1,500

1,200

4,300

Soo

Low Potential

Percentage »»LiquefactionEx ected.

10

10

10

lo

10

10

10

Expected**:".LengthAffected(ft)

50

100

180

36o

16o

310

8o

150

60

120

220

43o

4o

So

Length(Ft)

1,4oo

6oo

6oo

500

4oo

4,ooo

4oo

High Potential

Percentage»»LiquefactionEx ected

10

10

10

10

10

10

20

30

10

20

30

Expected*»*LengthAffected (ft)

70

14o

6o

6o

30

50

20

40

4oo

8oo

1,200

4o

So

120

Tota 1

ExpectedAffected

Length (Ft)

0

120

24o

210

42o

190

370

110

200

&o

— 160

4oo

1 020

1,63o

4o

120

200

No.of

Lanes

Ref~ to U. S. G.S. Haps»* Co~ponding to Damage Levels I, 2, and 3.

***Values rounded

LIQUEFACTION ENTIAL

By Site Number* Sheet 10 of

Liquef act i onSite

Number *(Est. PGA)

64

( 2l)

65

( 22)

66

( 22)

67

( 23)

68

(.23)

69

(.24)

70

(.24)

Length(Ft)

Soo

2,400

1,000

1,700

Soo

1,500

900

Low Potential

Percentage »*LiquefactionEx ected

10

10

10

10

IO

10

10

Expected»»»LengthAffected(ft)

0

4o

8o

120

24o

100

90

170

4o

8o

So

150

90

Length(Ft)

18200

1,400

Soo

4,ooo

300

300

4oo

High Potential

Percentage»*LiquefactionEx ected

lo

10

10

~ 0

10

10

10

10

Expected*»»LengthAffected (ft)

60

120

140

40

So

200

4oo

20

30

20

4o

TotalExpectedAffected

Length (Ft)

200

l 0

So

18o

290

570

110

100

180

1

0'o.

ofLanes

Refer to U.S.G.S. HapsCorresponding to Damage Levels I, 2, and 3.Values rounded

,LIQUEFACTION POTENTIAL

By Site Number* Sheet 11 of 12

Liquef act i onSite

Number *(Est. PGA)

71

(-3o)

72

(.29)

73

(-27)

74

(.28)

75

(.27)

76

(.27)

77

(.26)

Length(Ft)

10,000

6oo

1,8oo

1,000

Soo

700

1, IOO

Low Potential

IO

10

10

10

10

10

Percentage »»LiquefactionEx ected

10

20

30

0

'xpected»»»LengthAffected(ft)

'I,000

2 000

3,000

6o

90

180

50

100

4o

8o

4o

70

6o

110

Length(Ft)

1, 700

300

1,000

300

300

4oo

300

High Potential

Percentage*«LiquefactionEx ected

30

4o

50

20

30

10

20

30

10

20

30

10

20

30

10

20

30

Expected"-*»LengthAffected (ft)

510

68o

85o

200

300

30

6o

90

6o

90

4o

So

120

30

6o

90

TotalExpectedAffected

Length (Ft)

1,510

2,68o

3,850

2 0

48o

30

110

190

100 ~

170

4o

120

190

30 ~

120

200

No.of

Lanes

R~ to U.S.G.S. Haps»* C~spondlng to Damage Levels

»*» Values rounded1,2, and 3.

LIQUEFACTION ENTIAL

By Site Number« Sheet 12 of 12

LiquefactionSite

Number *(Est. PGA)

78

(.25)

79

(.25)

8o

(.24)

81

(.21),

82

(.21)

Length(Ft)

300

8oo

700

5,700

7,500

Low Potential

Percentage **LiquefactionEx ected

10

10

10

10

10

Expected*««LengthAffected(ft)

20

30

40

So

40

70

285

570

375

Length(Ft)

200

4oo

300

High Potential

Percentage«*LiquefactionEx ected

10

20

30

20

30

10

20

30

Expected«««LengthAffected (ft)

20

4o

6o

4o

So

120

30

6o

90

Tota I

ExpectedAffected

Length (Ft)

20

6o

90

4o

120

200

30

100

16o

285

570

375

750

No.of

Lanes

* Refer to U.S.G.S. Haps«* Corresponding to Damage Levels I, 2, and 3.

*«* Values rounded

h

~

~ l

4 Q

~ ~' ~ ~ '

,yO

APPENDIX

BRIDGES AND EVACUATION

TABLEOF CONTENTS

Section Pacae

I.O GUIDELINES FOR EVALUATINGTHE PROBABLE SEISMIC DAMAGE'O

HIGHWAYBRIDGES IN THE SAN LUIS OBISPO AREA......... I-I

I. I

I.2l.3I.4l.5

Introduction 0 ~ ~ ~ ~ ~ ~ ~ ~

Bearings ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Piers and Columns ...Abutments ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Foundations ~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ t ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

I-II-21-3l-4I-5

2.0 TESTING OF BRIDGE EVALUATIONGUIDELINES ............... 2- I

3.0 SEISMIC EVALUATIONOF BRIDGE COLUMNS .................. 3-I

3 .I Introduction ...............................3.2 Development of Column Vulnerability Factor ..

3-I3-2

4.0 SUMMARYDATAOF BRIDGES SURVEYED ................. ~ ~ ~ . 4-I

4.I4.24.34.4

4.5

Bridge Performance Summary Sheets .........P tIctul'es ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ e ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Bridge Seismic Data Forms..................Summary of Evaluation of Bridges for which NoW

olere Available ............................Behavior of Bridges During Past Earthquakes ..

~ ~ ~ ~ ~ ~ ~ ~ I ~ ~ ~ ~

Plans

4-24-I 34-32

4-l9I4-I94

5.0 EVACUATIONNETWORK....................... ~ - ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 5-I

5. I Evacuation Network...............5.2 Formulae for Traffic Flow Quantities5.3 Access to Evacuation Routes .......5.4 'outing of Vehicles ...............5.5 Pictures - Communications Elements

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0

I-0 GUIDELINES FOR EVALUATINGTHEPROBABLE SEISMIC DAMAGETO HIGHWAYBRIDGES

IN THE SAN LUIS OBISPO AREA

I. I INTRODUCTION

For the purpose of this study, bridge damage will be classified into one of the

following three categories:

Category I: Little or no damage resulting in no delays to traffic.

Category 2: Moderate damage that can be repaired within four hours

provided sufficient labor and materials are available.

Category 3: Major damage that will necessitate closure of the bridge formore than four hours.

Bridges shall be classified according to their effect on the evacuation routeunder consideration. Therefore, for a route passing under the bridge, totalcollapse would be necessary to delay traffic.

Potential damage categories will be assigned to each of the following four bridgecomponents which are subject to damage during an earthquake.

r

I. Bearings

2. Columns and Piers

3., Abutments

4.. Foundations

Possible interactions between the failure of these components should be con-sidered. The failure of any one component will be assessed with respect to itseffect on the performance of the entire structure.

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Seismic vulnerability of the bridge structures will be evaluated according to

these guidelines, which are based on observations of damage in past earthquakes

and engineering judgment with respect to the performance of critical bridge

components in future earthquakes. The following paragraphs describe methods

for evaluating the seismic vulnerability of each of the four components listed

above.

l.2 BEARINGS

Bearings shall be considered to include longitudinal and transverse restrainers as

well as vertical load carrying components. Bearings shall be evaluated withrespect to their ability to continue to support the vertical load when subjected tothe forces and displacements generated by an earthquake. The step-by-stepprocedure detailed below should be followed in evaluating the seismic vulner-ability of bridge bearings.

Screen non-vulnerable bridges (these should be classified in

damage category I).

A. No bearings - continuous structure with end diaphragm

abutments

B. Continuous multi-span or single-span structures withskew $20o not supported on rocker bearings

C. Continuous multi-span or single-span structure withskew )20o not supported on rocker bearings and having a

length-to-width ratio greater than I.5.

Note: Structures qualifying in B and C must have an allowable transversemovement greater than (A/.4)N where A is the maximum expectedground acceleration (in g) and N is the required support lengthdefined in the Applied Technology Council's "Guidelines for theSeismic Design of Highway Bridges" (Report ATC-6, I 98 I) anddiscussed below.

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2. Calculate in inches the ATC-6 required support length

N = l2+.03L+.I2H

where

N = Required support length in inches

L = Length of bridge deck to adjacent joint or end of bridge in

feet

H = (Abutments) The average height (in feet) of columns

supporting the bridge deck to the next expansion joint.(H = 0 for single span bridges)

(Piers) The height of the pier (in feet)

(Midspan Joint) The average height (in feet) of adjacent

two columns.

3. Measure the allowable transverse movement at the support. Allow-able movement will be the limit at which all girders of a multigirderbridge will lose support. The displacement required to move one

girder off the edge of the seat will be considered allowable for a 2 or

3 girder bridge.

4. Assume keeper plates and anchor bolts will fail in shear at a peak

ground acceleration of .20 g. If skew is greater than 40 then rockerbearings will probably topple. The upper bound transverse movement,

which may be assumed equal to (A/.4)N, must be compared to theallowable transverse movement measured in Step 3.

If bearings topple, the minimum distance to the edge. of the bearingseat from any corner of the bearing must exceed. the bearing heightto prevent total collapse.

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For pedestal seats, the transverse distance from the edge of the

bearing to the edge of the seat must exceed the sum of the height

and the width of the bearing. In addition, the longitudinal distance

from the face of the bearing to the edge of the seat must exceed

D= putana +W h

cos a

where

W = the width of the bearing

h = the height of the bearing

a = skew angle

5. Nominally reinforced concrete shear keys are assumed to fail in shear

at a peak ground acceleration'f .30 g. Check transverse motion

after failure as in Step 4.

6. Rocker bearings in nonskewed structures are assumed to topple at

.30g. Assume span collapse will not occur if structure otherwise

qualifies under IB and IC above or if support length exceeds (A/.4)N.

7. Loss of support at abutments or midspan joints has a slight chance of

occurring in bridges with one or more midspan joints if (A/.4)N

exceeds the support length. If the structure has non-skewed

(skew $20 ) joints and the support length is greater than twice the

sum of the nominal joint openings plus ten inches times the peak

ground acceleration in "g's" times the number of joints in the bridge

deck, then no loss of support is assumed.

8. Classify failures as follows:

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A. Little or no vertical movement (Category I)

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B. Vertical movement equal to bearing height (Category 2). Ifstructural collapse will not result from support loss at an inspanbearing, then shoring may be possible and Category 2 damagemay be assumed.

C. Loss of girder support resulting in collapse (Category 3).

Note: If structure crosses an evacuation route, only Category 3 needs to beconsidered.

I.3 PIERS AND COLUMNS

Columns shall be evaluated for failure due to shear and pull-out of longitudinalreinforcement. Column vulnerability to shear failure will be determined based

on an empirical relationship observed during the San Fernando earthquake (see

Section 3.2). The following steps will be followed in evaluating the vulnerabilityof bridge columns.

I. Relate the possible categories of damage to the expected ground

accelerations.

A. A (.20g (Category I)

B..20g QA(.30g (Category I or 2)

C. A $ .30g (Category I, 2 or 3)

2. Eliminate piers from consideration (H/W 2.5) for ground accelera-

tions below .40 g.

3. When bearing keeper plates transfer load to columns, damage Cate-

gory I may be assumed.

4. Calculate the empirical factor for column vulnerability to shear

failure.

LCVF =~p

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where

Column length in feet (Soffit to top of footing)

Percent main reinforcing steel

Framing factor

2 (Multi-column bents fixed at top and bottom)

I (Multi-column bents pinned at top or bottom)

l.5 (Single column bent fixed top and bottom — boxgirder)

l.25 (Single column bent fixed top and bottom - openweb girders)

Maximum transverse column dimension (feet)

5. Determine the range of damage potential for the stiffest column in

the structure.

For A)'.30g

CVF Damage Category

0-.65.50 - l. I5

) l.00

For .20g gA 4.30g

CVF Damage Category

0-.65).So

Overlap of values has been designed to provide a defined area where

engineering judgment should be applied to determine the proper

damage category for a structure.

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6. If CVF falls in a range of overlap, judgment shouid be used to

determine the appropriate damage category.

Select higher damage category for one or more of the following:

A. Skew )40 degrees

B. Seat-type abutment

C. Length to width ratio of deck exceeds 4

D. Abutments in fill

E. Unequal foundation conditions at abutments

Select lower damage category for one or more of the following:

A. Right Structure (Skew C20o)

B. Length to width ratio of deck is less than 4

C. Diaphragm abutment

D. Only one of many bents is critical

7. Check for longitudinal reinforcement pull-out. Assume damageCategory 3 if the following criteria are met:

A. Main steel spliced at base of column

B. Single column bent with flexible superstructure

C. A ).30g

8. For structure over evacuation route, only longitudinal steel pull-out

will result in damage Category 3. All others will be damage Cate-

gory I. Shear collapse is not probable unless the CVF (.5 and A ).5.

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l.4 ABUTMENTS

Abutment damage in past earthquakes is primarily related to displacements

resulting from seismic earth pressures or high lateral inertia forces transferred

from the superstructure. Settlement of abutment fill is fairly common and can

result in bridge access problems. The following steps should be followed in

evaluating potential abutment damage.

I. If A C.20 g the damage category will be I.

2. If the structure is an overcrossing, assume damage Category I.

3. The upper limit for fill settlement in well-engineered fills will be

assumed to be IO percent of the fill height for accelerations greater

than .30 g. For accelerations between .20 and .30 g, the maximum

settlement can be assumed 5 percent. If the fill is well-retained by

wingwalls extending below original ground or if roadway exceeds 2

lanes in width, these values may be multiplied by one-half. If the

structure does not cross water, multiply results by a separate factorequal to one-half.

4. Massive abutments in excess of IO feet high and relying on gravity

for stability shall be assumed to result in Category 2 damage during

an earthquake with ground acceleration greater than .20 g.

5. Free-standing seat abutments in excess of I4 feet high shall be

assumed to result in Category 2 damage when A) .30 g.

6. Diaphragm abutments without continuous wingwalls and founded in

fillshall be assumed to suffer Category 2 damage when A) .30 g.

7. Free-standing abutments with skews greater than 40 shall suffer

Category 2 damage at A) .30 g.

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I.5 FOUNDATION

Foundation failures resulting from liquefaction have been the most common typeof bridge failure in past earthquakes. Liquefaction occurs when loose cohesion-

less material consolidates during an earthquake resulting in the buildup of porewater pressure. This causes a temporary loss of soil shear strength due toreduced granular contact pressures. The resulting foundation failures can be

dramatic.

In the case of bridges, this usually occurs at stream crossings where the soil is

loose and ground water is present. The classic mode of failure involves themovement of abutment embankments toward the center of the stream. This can

occur at acceleration coefficients as low as;l5 g provided the duration of theground motion is long enough. This can result in serious settlements at theabutments and the buckling or dislodging of the superstructure from its supports.Continuous superstructures have historically performed better than discontinuoussuperstructures under these circumstances.

The following steps shall be followed when evaluating the upper bound of damage

resulting from foundation failure:

I. Establish the extent of potential liquefaction (very severe, severe,

moderate, or small), following the procedures outlined in the sectionon liquefaction.

2. For a site with very severe liquefaction potential, all bridges shall be

assigned to damage Category 3, except for single span bridges withskew less than 20o or rigid box culverts with floors which may be

classified as damage Category 2.

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3. For a site with severe liquefaction potential, all bridges shall be

assumed in damage Category 3, except that damage Category 2 may

be assumed for single span bridges with skew less than 40o, rigid box

culverts with floors, and continuous multi-span bridges with skew less

than 20o provided one of the following is true:

A. Reinforced concrete columns continuous with the superstruc-ture have a CVF greater than !.5 and a height in excess of 25feet.

B. Steel columns are constructed of mild steel and are in excess of25 feet high.

C. Columns are discontinuous with the superstructure, and shiftingof the superstructure will not result in instability.

4. For sites with moderate liquefaction potential, damage Category 2

will be assumed, except for bridges which have been classified in

damage Category 2 for bearing failure, in which case damage

Category 3 shal I be assigned.

5. Damage Category I shall be assumed for the foundations if the

liquefaction potential is small.

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2.0 TESTING OF BRIDGE EVALUATIONGUIDELINES

The guidelines for evaluating the probable seismic damage to highway bridgeswere applied to several bridges which have experienced various levels of failureduring past earthquakes. As can be seen from the following paragraphs, theguidelines generally yield reliable results.

The damage levels indicated by the evaluation guidelines were in very closeconformance with the observed bridge damage in the Imperial Valley, Californiaearthquake of October I 5, I 979. The following bridges were investigated:

I. Bridge across New River (Br. 58-05 R/L)

Predicted Dama e:

Damage Category I

Minor abutment fillsettlements (2")Shifting at abutment (9.4")

~AI ~

Damage Category 2Moderate abutment fillsettlements (6")Shifting at abutment (7.5") - Minor column spalling

Reconciliation:

Movement at abutment indicated moderate liquefaction mayhave occurred. Peak ground accelerations may have beenhigher during aftershocks. These factors could account for thehigher damage category.

2. Bridge across Alamo River (Br. 58-292)

Predicted Dama e:

Damage Category I

Bearing keeper bars fail, but bearings remain standingMinor abutment fillsettlements (4")

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Damage Category I

Bearing keeper bars failed but bearings remain standingNo fillsettlement reported

Reconciliation:

Longer duration of shaking would have probably producedgreater set t lements.

3. Rte 8/I I I Separation (Br. 58-256 R/L)

Predicted Dama e:

Damage Category I

Minor abutment fillsettlements (4")

~A»Damage Category I

Minor abutment fillsettlements (I /2")

Reconciliation:

Longer duration of shaking would have probably producedgreater settlements.

4. Alamo River Bridge (Br. 58- I 36)

Predicted Dama e:

Damage Category I or 2Slight to moderate column damageMinor fillsettlement (36")

Damage Category I

Slight column spoilingMinor fillsettlement (amount not reported)

Reconciliation:

Column steel was estimated which probably yielded lowerCVFs.

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5. Meloland Road O.C. (Br. 58-2 I 5)

Predicted Dama e:

Damage Category 2Moderate fillsettlements (6")

Damage Category I

Minor fillsettlements (amount not reported)

Reconciliation:

Longer duration of shaking would have probably producedgreater settlements.

6. Bridge across Alamo River (Br. 58-07)

Predicted Dama e:

Damage Category I

Failure of keeper plates at bearingsTransverse shifting of superstructureMinor abutment fillsettlements (26")

~AID

Damage Category I

Failure of keeper plates at bearingsSlight transverse shifting of superstructureFill settlements not reported

Reconciliation:

Transverse shifting limited by keeper bars and short duration ofshaking. Duration also responsible for low abutment fillsettle-ments.

The guidelines were also applied to the Fields Landing Overhead (Br. 4-I2I) thatfailed during the Trinidad-Eureka Earthquake of November 8, l980. For an

estimated peak ground acceleration of . I 2g the required support length is

calculated to be slightly over 6 inches. Since only 6 inches was provided, the

collapse of the structure was accurately predicted. Since many of the spans did

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not collapse, the required support length must have been very close to the actual

movement.

The guidelines also predicted Category 2 damage due to fill settlement at the

Greenville Rd. Undercrossing during the Greenville, California earthquake ofD

January 24, l980. A settlement of 0.6 feet was predicted, and settlements

between 0.0 and I.O feet actually occurred.

An earthquake of very short duration occurred near Coyote Lake, California on

August 6, I 979. Bridge damage was investigated for several bridges.

I. Pajaro River Bridge (Br. 43-0 I)

Predicted Dama e:

Damage Category I

Minor fillsettlements (3")Shifting at abutments (IO")

~A* I D

Damage Category I

Shifting at abutments (5")No settlements reported at abutmentsMinor column spal ling

Reconciliation:

Short duration of motion caused small fillsettlements.

As was the case in the other bridges investigated for this earthquake, Category I

damage was predicted.

The investigation and analysis of the Feburary 9, l97I San Fernando Earthquake

is discussed in Section 3.2 under the development of the column vulnerabilityfactor.

The bridge seismic data forms for most of the bridges investigated are included

in Section 4.5 of this appendix.

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3-0 SEISMIC EVALUATIONOF BRIDGE COLUMNS

3. I INTRODUCTION

It is desirable to have a simple method for predicting the behavior of bridge

columns during an earthquake. It has been reasonably well established by

experience and research that transverse reinforcement in the zones of yielding

plays an important role in the successful performance of reinforced concrete

columns. Transverse reinforcement serves to confine the main longitudinal

reinforcement and the concrete within t6e core of the column, thus preventingthe buckling of the main reinforcement and the severe loss of shear strength in

the concrete. Transverse reinforcement is also effective as shear reinforcementand increases the shear capacity of the column.

Modern bridge design standards such as the AASHTO specifications and theATC-6 Guidelines require minimum transveise confinement reinforcement and

sufficient shear reinforcement to resist forces developed by the formation ofplastic hinges. Careful attention is also given to the reinforcement details toinsure that transverse reinforcement remains effective during the cyclic loadingcharacteristic of large earthquakes.

Unfortunately, prior to l97l the transverse reinforcement placed in most bridgecolumns was totally inadequate by today's standards. For example, a typicalCalifornia Department of Transportation detail consisted of hoops of 6-inch bars

spaced at l2 inches on center. Hoops usually were lap spliced and often therewere no cross ties to support rectangular hoops at intermediate points. Thecolumn damage suffered during the San Fernando Earthquake demonstrated theinadequacy of this detail. Most bridges in service today have column transversereinforcement details that are just as inadequate for seismic loading.

Therefore, in evaluating the seismic vulnerability of existing structure, a fastand effective way of screening the most critical of these columns is needed.

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3.2 DEVELOPMENT OF COLUMN VULNERABILITYFACTOR

Although most bridge columns within the area of heavy damage in the San

Fernando earthquake had inadequate transverse reinforcement details, there was

a vast difference in the way they performed during the earthquake as noted by

Fung, et al . Of the heavily damaged columns it appeared that shear was theI

primary mode of failure whether it was due to inadequacy of the initial shear

capacity, or the degradation of shear capacity resulting from confinement

fai lure.

Since shear has been observed as the critical column failure mode it is proposed

that a simple parameter be developed which would reflect the ratio of relativeshear capacity to relative expected shear force during an earthquake. This

parameter should be derived from data that can be obtained easily and rapidly

from a set of "as-built" bridge plans. The significance of this parameter as an

indicator of column vulnerability should be evaluated by comparing it to column

damage observed in past earthquakes. If critical values of the parameter can be

identified, then the parameter could be used as an indicator of column

vulnerability for identification of critical bridge columns.

Consider a bridge column which is rectangular in cross-section. The shear

capacity has classically been considered a function of the cross-sectional area ofthe column and the amount of shear reinforcement crossing a plane of potential

diagonal tension failure. For columns with constant transverse reinforcement

details, the relative shear capacity is approximately linearly related to the

cross-sectional area of the column. Therefore,

VR ——k lbh

where VR = The relative shear capacity of the column

klh

An arbitrary constant

The depth of the column in the direction of shear

The thickness of the column.

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The maximum expected shear force resulting from an earthquake in which

flexural yielding takes place is given by

MT™BVc=

L

where VcMT,M

The maximum shear force resulting from the earthquake

The ultimate bending moments at the top and the bottomof the column respectively

L = The effective length of the column.

The sum of the ultimate moments at the top and the bottom of the column willdepend on the column dimensions, the amount of longitudinal reinforcing steel,and the ultimate stresses in the material. For simplicity assume that the column

cross-section is constant over its length and therefore the top andbottom'oments

are equal. The ultimate moment of a conventional beam without axial

load is roughly given by

u ss P ss

where A = The area of the tension reinforcements

f = The ultimate steel stresss

d = The distance from the tension reinforcement to the extremefiber in compression

h = The total depth of the concrete section

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a and k2 Constants associated with the size of the concrete compression

block and, in the case of k2, the relative dimensions of theconcrete cover.

For a column the main steel is usually uniformly distributed about the perimeterof the column cross-section. Therefore, the area of the tension reinforcement is

approximately equal to a constant proportion of the total main reinforcement.

A = k3pbh

where p = The ratio of longitudinal reinforcement area to gross

concrete area

k3 — An arbitrary constant

Most bridge columns will have axial loads approximately equal to IO percent ofthe ultimate axial load. If the ultimate moment at this axial load is assumed tobe a constant proportion to the ultimate moment at zero axial load, and the steelstress, f, and constants k2 and k3 are assumed approximately constant for mosttypical columns, the ultimate moment at the top and bottom of the column is

given by:

MT MB —kgpbh2

where k< — an arbitrary constant.

In many columns, the ultimate moment can only be produced at one end. Toaccount for this it would be useful to consider a framing factor, F. This framingfactor would be multiplied by the ultimate moment to give an approximation of

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the sum of the moments at the top and the bottom of the column. Therefore,the maximum earthquake shear force would be given by:

FMT k4 F pbh

where F = 2.0 For multi-column bents - both ends fixed

F = I.O . For multi-column bent' one end fixed

F = I.O For single column bents - one end fixed

F = l.5 For single column bents - both ends fixed - torsionallyrigid superstructure

F = I.25 For single column bents — both ends fixed - torsionallyflexible superstructure

Therefore, a parameter which reflects the relative likelihood of a shear failure,and thus the column vulnerability, may be given by the ratio of relative shearcapacity to the expected maximum earthquake shear force. Therefore, thecolumn vulnerability factor CVF, is given by

V~ klbh klCVF = —= 2

VC k4FPbh k4 FPh

L

by setting I = I, the column vulnerability factor becomes:k

k4

CVF =—LF~d

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To test the validity of this factor as an indicator of potential column damage itwas compared with the column damage observed in the San Fernando earthquake

of l97I. In doing this, column damage was classified as follows:

0 = no damage observed

I = minor damage (spalling) - does not weaken structure

2 = moderate damage which weakens structure but not to the extentthat normal light traffic should be restricted

3 = major damage necessitating closure to traffic but no structurecollapse - damage may be irreparable

4 = total damage —column disintegration and structure collapse.

Using these damage classifications and data from the field investigation ofbridges in the San Fernando Earthquake, several bridges were considered in an

attempt to evaluate the column vulnerability factor concept. The following is a

tabulation of results for the bridges studied:

I. Rte 5 (Truck Lane)/405 Separation (Br. No. 53-I 548)

L =20'=5'

= 3.9%

F = 2.0

CVF = 20/2(3.9)(5.0)

Damage Classification.5I

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2. San Fernando Road Overhead O.H. (Br. No. 53- I 990R)

L=32'=

7'

= 4.2%

F = l.5CVF = 32/I.5 (4.2) (7)

Damage Classification

= .73

= 3.0-3.5

3. Northbound Truck Route Undercrossing (Br.. No. 53- I 99 I R)

L =20'1

p = 3.5%

F = I 0

CVF = 20/2(3.5)(4.0)

Damage Classification

= !.43

= 2.0.- 2.5

4.. Foothill Blvd. U.C. (Br. No. 53-20I 6R)

L = l9d= 4'

= 4.2%

F = 2.0

CVF = I9/2 (4.2) (4)

Damage Classification

= .57= 3.0 -3.5

5. Foothill Blvd. U.C. (Br. No. 53-20 I 6L)

L =22'=4'= 2.9%

F =2.0CVF = 22/2(2.9)(4)

Damage Classification

= .95

= 2.0

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L =40'=

4'

= 3.0%

F = 2.0

CVF = 40/2(4)(3)

Damage Classification

I.67I.O

7. West Sylmar O.H. (Br. No. 53- I 984R/L)

L = 30'

=4'= 4.4%

F = I.0 or 2.0

CVF = 30/F(4.4)(4.0)

Damage Classification

= .85

= 1.0

8. Bledsoe St. O.C. (Br. No. 53-1926)

L=24'=

5'

= 2.2%

F = 2.0

CVF = 24/2.0(2.2)(5)

Damage Classification

= I.09

= I.5-20

A plot of the damage classification versus the proposed column vulnerability

factor is'shown in Figure I. It is evident from this graph that there is a useful

correlation between the proposed CVF and the damage classification.

I

Some observations should be made about the proposed column vulnerability

factor. First, it is noted that columns with higher longitudinal reinforcement

ratios are considered more vulnerable than similar columns with low

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Z0I-U4.

lA

UJlD

+.35 - I. I 5

L

.85 - 1.65

Q l.35 - 2.I5

l0.5 I.O I.5 2.0 2.5

COLUMN VULNERABILITYFACTOR

FIGURE I

COLUMN DAMAGEIN

SHORT TO MEDIUMPERIODBRIDGES DURING THESAN FERNANDO EQ.

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reinforcement ratios. This will probably only be the case for columns withapproximately equal ductility demands. For columns designed for similar forcelevels in regions where seismic loading governs the column design, this is

probably approximately true. Secondly, it should be noted that all the bridgesinvestigated were in the short to medium period range. It is expected that thelonger the period of the structure the less important the CVF as an indicator ofindividual column damage since both the maximum and cumulative ductilitydemands will be less. In general, the primary mode of column failure in long

period structures would tend to be flexural.

A flexural failure can be critical if the supports are single column bents.Another critical failure can result from the pullout of main longitudinal re-inforcement as was the case in the Route 2IO/5 Separation and O.H. during theSan Fernando Earthquake. This structure had CVFs that average approximatelyI.89 which are well above the range corresponding to serious column damage due

to shear failure in the short to medium period structures.

Certain factors besides the CVF appear to affect the performance of short tomedium period bridge structures although CVF seems to be the most important.For example, a highly skewed structure will tend to respond in a torsional modewhich introduces additional torsional shear stresses in the columns which mayaccelerate a column shear failure. This could have been the case in bridges 3

and 4 above. The flexibility of the foundation can be important since it canreduce the effective fixity at the footing. This may have been important in

bridge 5 mentioned above with a CVF which would seem to indicate moredamage than actually occurred. Variation in the foundation flexibility at theabutments may also be important. This was probably important in bridges I and

3, where one abutment was in filland the other in cut. This may have caused thedamage to be more severe than it ordinarily would have been. A transverselyrigid and continuous superstructure on continuous diaphragm abutments willcarry excess load and tend to mitigate the seriousness of column failures.Although no examples were studied, it is assumed that architectural flares willincrease the sum of the moments and thus result in a greater maximumearthquake shear force.

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Obviously, the intensity and duration of the earthquake ground motion will effectthe performance of the column. The greater resulting maximum and cumulative

ductility demands will cause a more rapid degradation of column strength. The

estimated peak acceleration of each of the bridges studied above was near .40g

or greater. A lower peak acceleration but longer duration of ground motion.could have similar effects.

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TERA CORPORATION

4.0 DETAILEDDATAON BRIDGES SURVEYED

This section contains summary and detailed information concerning the investi-

gation and analysis of bridges and bridge response presented in this report.

Section 4.l is a brief summary description of the bridges surveyed in the study

area. They are described by route in a general south to north direction. Section

4.2 consists of pictures of those bridges presented in the same order. There are

some bridges pictured in this section but not described in the previous table. Allof these are not expected to sustain significant damage (Category I).

Section 4.3 presents detailed data sheets of the bridges, ordered as in Sec-

tion 4. I. Section 4.4 summarizes our evaluation of bridges for which no plans are

available. Section 4.5 contains detailed data sheets for the study of bridgeresponse in past earthquakes.

B-8 I-227 4- I

TERA CORPORATION

4. I BRIDGE PERFORMANCE SUMMARYSHEETS

4-2

BRIDGE PERFORMANCE SUMMARY

State Route 101 (South to North)

Sheet I « IO

Bridge No. Description .PGA

(9) Structure

Damage

SoilEffect

on TrafficType

of Repair

RepairTime(Mrs.)

FullCapacity

(vph)Bypass Description

49-173R Bridge StreetUndercrossing

.22 Possible collapse of No soil failurespans 1&3; probable anticipatedtoppling of bearings

Traffic over struc-ture delayed orstopped; trafficunder unaffected

Ramping atbearings;possibletotal loss

1/72 . 3790 NB:*Frontage RoadSB: Hot needed (no

structure)

49-174 Valley RoadOvercrossing

.22 No damage affecting No soil failure Nonetraffic under bridge anticipated that

will affect trafficunder structures

Nonerequired

3790 NB&SB: Adjacent streets

49-175L/R Bridges AcrossArroyo GrandeCreek

.22 No damage antici-pated

Minor fill settle-ments 5"i

Traffic may have toslow to 15-20 mph

Ramping tobutmentay speed

traffic

0/1 3790 NB&SB: Traffic way

49-176 Grand AvenueOvercrossing

.23 Ho damage antici-pated; trafficunder bridgeunaffected

Moderate 1 iquefac- Nonetion will notaffect traffic underthe structure

onerequired

3580 NB&SB: Interchange ramps

49-154 Brisco RoadUndercrossing

.24 o damage antici-pated

Minor fill settle-ment 2"a; possibleliquefaction

None onerequired

3580 NB: Interchange rampsSB: Frontage Road

, 49-155 Oak Park RoadOvercrossing

.25 No damage antici-pated; trafficunder bridgeunaffected

Moderate liquefac- Honetion should notaffect trafficunder the structure

Nonerequired

3580 NB&SB: Interchange ramps

49-156 Pismo OaksOvercrossing

.24 Sheared keeperplates; trafficunder bridgeunaffected

Moderate 1 iquefac- Honetion should notaffect trafficunder the structure

oneequired

3580 NB&SB: Interchange ramps

49-16L/R

49-15L/R/C

Pismo Overhead

Pismo CreekBridge (VillaCr. )

.25

.25

Ho structuraldamage anticipated

Possible columndamage resultingfrom liquefaction

Moderate groundmovements due toliquefaction

Moderate to severeground movementsdue to liquefaction

Traffic delayed

Traffic delayed; ifliquefaction issevere only leftbri'dge may bereopened

Ramping toabutments

Ramping toabutment;possiblebentshoring

0/2

1/4

3580

3580

NB&SB: Adjacent streets

NB: Parallel streetsSB: Frontage Road

49-130 Hinds AvenueOvercrossing

.26 No damage antici-pated; trafficunder bridgeunaffected

Moderate liquefac- Honetion will notaffect trafficunder the structure

onerequired

3880 NB&SB: Frontage Road

* NB = NorthboundSB = Southbound

BRIDGE PERFORHANCE SNHARY

State Route 101 (South to North) - Cont'd

2 of 10

Bridge Ho. Description PGA

(9) Structure

Damage

SoilEffect

on TrafficType

of Repair

Repair FullTime Capacity(Hrs.) (vph)

Bypass Description

40-139 Pismo StreetPedestrian U.C.

.27 No damageanticipated

Ho soil failureanticpated

None Honerequired

3880

49-183R/L Wadsworth Ave.Undercrossing

.27 No damageanticipated

Hinor fill settle-ments 3"x

Traffic may have to Noneslow to 25-30 mph required

3880 NB&SB: Frontage Roadand streets

49-184R

49-184L

49-189R/L

North PismoSeparation

North PismoSeparation

Shell BeachUndercrossing

.27

27

.28

No damageanticipated

No damageanticipated

No damageanticipated

No soil failureanticipated

Hinor to moderateabutment fillsettlements 7"s

Possible moderateliquefaction

None

Traffic delayed

Probably none;possible delays

Nonerequired

Ramping toabutment

Probablyone re-uired;ossibleamping

(1 hrs)

0/1

0/1

3880 NB: Interchange ramps

3880 SB: Frontage Road

3880 NB&SB: Interchange ramps

49-191R/L Avila RoadUndercrossing

.28 No structural dam-age except at col-umns due to lique-faction

Severe liquefaction Closed to trafficwith large groundmovements

tructureovid behored;xtra fillehindbutment

8/48 3880 NB&SB: Interchange ramps

49-14L San Luis ObispoCreek Bridge

.28 Loss of support atspans 2&13; par tialcollapse

Severe liquefaction Closed to trafficwith large groundmovement

otal loss's likely

72 3880 SB: Parallel roads

49-14R San Luis ObispoCreek Bridge

.28 Possible supportloss due to perm-anent ground

ovement

Severe liquefaction Closed to trafficwith large groundmovement

ossiblebutmentamping andenthoring

8/72 3880 NB: Parallel roads

49-192 North Avila Road .27 No damage antici-pated; trafficunder bridgeunaffected

Hoderate liquefac- Nonetion will notaffect traffic underthe structure

oneequired

3880 NB&SB: Interchange ramps

49-115R/L Santa FeUndercrossing

.26 No damageanticipated

Ho soil failureanticipated

None oneequired

3880 NB: Frontage RoadSB: Blocked

BRIDGE PERFORMANCE SUHHARY

State Route 101 (South to North) - Cont'dSheet 3 of IO

Bridge No. Description PGA

(9) StructureDamage

SoilEffect

on TrafficType

of Repair

RepairTime(Hrs.)

FullCapacity

(vph)Bypass Description

49-185

49-190

Los Osos RoadOvercrossing

Madonna RoadOvercrossing

.23 Ho damageanticipated

.22 Ho damageanticipated

Moderate liquefac-tion will not affecttraffic understructure

Noderate liquefac-tion will not affecttraffic understructure

Hone

Hone

Nonerequired

'lonerequired

3880

3780

NB: Parallel RoadSB: Interchange Ramps

NB: Interchange RampsSB: Blocked

49-08 L/R Harsh StreetSeparation

.22 No damageanticipated

Ninor fill settle-ment 3"a

Traffic may have to oneslow to 25-30 mph equired

3780 NB: Interchange RampsSB: Blocked

49-146 Stenner CreekCulvert

.21 No damageanticipated

Possible moderateliquefaction - notraffic delay

None Nonerequired

3780 NB&SB: City Streets

49-39 L/R

49-144I

Chorro StreetUndercrossing

Rte. 1/101Separation

.21 No damageanticipated

.21 No damageanticipated

Minor fill settle-ment 2"s

Minor fill settle-ments 2"s

None

Hone

Nonerequired

Nonerequired

3780 NB&SB: City Streets

3780 NB&SB: City Streets

49-79 California Blvd. .21 No damageOvercrossing . anticipated

Ho soil failureanticipated

Hone onerequired

3780 NB&SB: City Streets

49-147 California Blvd.Underpass

.21 No damage antici-pated that willaffect traffic

Ho soil failureanticipated

Hone oneequired

3780 NB&SB: City Streets

49-84 R/L Grand AvenueUndercrossing

.20 Loss of supportat Span 4 - PartialCollapse

Ho soil failureanticipated

Closed to traffic dd newtemporarypan-aileyridge

8/48 3780 NB&SB: City Streets

49-94 Buena Vista Ave.Overcrossing

.20 No damageanticipated

No soil failureanticipated

Hone oneequired

3550 NB&SB: City Streets

49-60 Cuesta GradeOvercrossing

.18 Loss of support atexpansion joints-Possible partialcollapse

No soil failureanticipated

Traffic Delayed - horing ofPossibly closed to idspantraffic expansion

'oints

4/8 3550 NB&SB: None

BRIDGE PERFORNNCE SINlQRY

State Route 101 (South to North) - Cont'd

Sheet 4 of >0

Bridge No. Description PGA

(g) Structure

Damage

SoilEffect

on TrafficType

of Repair

RepairTime(Hrs.)

FullCapacity

(vph)Bypass Description

49-07 Santa HargaritaCreek Bridge

.18 No damageanticipated

No soil failureanticipated

None Nonerequired

3550 NBSSB: None

49-158 Route 58/101Separation

.17 Not probable atthese force levels;collapse at higherlevels

No soil failureanticipated

Probably none, but Probablycould close road to onetraffic for higherforce levels

3780 NB: Frontage Road, ramps

BRIDGE PERFORMANCE SUMMARY

Route I (South to North)Sheet 5 of 10

Bridge No. Description 'GA(9) Structure

Damage

SoilEffect

on TrafficType

of Repair

Repair FullTime Capacity(Hrs.) (vph)

Bypass Descriptim

49-22

49-19

Bridge AcrossLos Berros Cr.

Arroyo GrandeCreek Bridge

.24

.23

No damageanticipated

No damageanticipated

Minorfill settle-ments - II"Minor fill settle-ments - 2k"

None

Traffic may have toslow to 25-30 mph

Nonerequired

Nonerequired

1490

1490

NB&SB: Halcyon Rd,Wailer Rd

NB&SB: Detour - Halcyon RdFair Oaks Ave,Valley Rd

49-12 Oceano Overhead .26 Rocker bearings may Minor fill settle-topple ments - 4I"

Traffic delayed orslowed to 15 mph

Ramping atabutments

1/2 1490 NB&SB: Railroad Rd,Beach St

49-10 Bridge AcrossVilla Creek

.26 No damageanticipated

Minor fill settle-ments - 4";possible severeliquefaction

Traffic delayed orpossibly stopped

Ramping atabutments;ossibleenthoring

1/8 1600 NB&SB: Cypress St

49-123

49-63I'V

Stenner CreekBridge

Chorro CreekOverhead

.21

.23

No damageanticipated

Minor bearing dam-age; deck damage dueto pounding; minorsuperstructuredamage

Minor fill settle-ments - 14"

Moderate fillsettlements - 9">;possible severeliquefaction

None

Traffic delayed orpossibly stopped

oneequired

Ramping atbutments;

or possibletotal loss

2/72 3800 NB: 4-mile alternate routeStart Calif. Men'Colony, end near CampSLO.

SB: 7-mile, route startnear Camp SLO, endin SLO

3800 NB&SB: City Streets

49-177 Baywood Park RdUndercrossing

.27 No damageahticipated

Minor fill settle-ments - 2I"

Traffic may have toslow to 25-30 mph

Lonerequired

3940 NB&jSB: Interchange ramps

49-108 South Horro BayOvercrossing

.29 No damageanticipated

Minor fill settle-ments - 3"

Traffic may have toslow to 25-30 mph

oneequired

3940 NB&SB: Frontage Rd

49-109

49-181

49-182 R/L

North Horro BayUndercrossing

Horro CreekBridges

Route 1/41Separation

.32

.32

.32

No damageanticipated

No damage antici-pated except atcolumns due toliquefaction

Minor abutmentfailure

Hoderate fillsettlements - 6"

Moderate fillsettlements - 8";possible severeliquefaction

Moderate fillsettlements - 6"

Traffic delayed

Traffic delayed

Traffic delayed

amping atbutments

amping atbutments;ossibleent

shoring

amping atbutments

0/1

1/8

1/2

3940

3940

3940

NB: Wrong lane or SB rampsSB: Ramps

NB&SB:,Frontage Rd

NB&SB: Interchange ramps

, 49-68 R Bridge AcrossToro Creek

.32 No damageanticipated

Hoderate fillsettlements - 12">

Traffic delayed amping atbutments

1/2 3940 To CA 46 west ofAtascadero (8.2 mi)

BR1DGE PERFORMANCE SUMMARY

Route 1 (South to North) - Cont'dSheet 6 of 10

Bridge No. Description PGA

(g) Structure

Damage

SoilEffect

on TrafficType

of Repair

Repair FullTime Capacity(Hrs.) (vph)

Bypass Description

49-68 L Bridge AcrossToro Creek

.32 No damageanticipated

Moderate fillsettlements - 12"+

Traffic del ayed amping atbutments

1/2 3940 NBLSB: Use CypressMountain Dr aroundWhale Rock Reservoir

BR1DGE PERFORMANCE SW'CRY

Route 227 (South to North)

Sheet 7 of 10

Bridy.'o. Description 'GA(9) Structure

Damage

SoilEffect

on TrafficType

of Repair

Repair FullTime Capacity(Mrs.) (vph)

Bypass Description

49-77

49-201

49-112

49-103

49-204

I

49-220

49-116

Corbit CreekCanyon

Branch StreetPedestrianOvercrossing

East Fork PismoCreek Bridge

East Corral dePiedra Creek Br.

West Corral dePiedra Creek Br.

North EdnaOverhead

East Fork SanLuis OpispoCreek Bridge

.22 No damageanticipated

.21 No damage antici-pated that wouldaffect traffic

.21 No damageanticipated

.21 No damageanticipated

.21 No damageanticipated

.21 No damageanticipated

.21 Ho damageanticipated

No soil failureanticipated

No soil failureanticipated thatwill affect trafficunder the structure

Minor fill settle-ment 2"+

No soil failuresanticipated

Minor fill settle-ment lk"+

Minor fill settle-ment - 4"

Minor fill settle-ment - 3"

None

None

None

Hone

Hone

Traffic may have toslow to 20-25 mph

Traffic may have toslow to 25-30 mph

Nonerequired

Nonerequired

onerequired

onerequired

oneequired

Nonerequired

Nonerequired

1260

1260

1490

1490

NB: Left on Mason St thenright 9 LePoint Stto 227 (.5 mi)

SB: Right Ia LePoint St,left 8 Mason St to227 (.5 mi)

NBSSB: Use Crown Stparallel to 227(on the north side)(.3 mi)

None

Hone

None

None

None

49-117

49-58

Acacia CreekCulvert

Bridge AcrossSan Luis ObispoCreek

.21 No damageanticipated

.21 Possible bearingfailures resultingin vertical offset

Settlements will notresult in roadwaydiscontinuities

Low liquefactionpotential

Hone

Traffic delayed

oneequired

amping atbutments

1490

1490

None

NB(WB): Higuera to MadonnaSB(EB): Madonna exit on

101 to Higuerato 227

BRIDGE PERFORMANCE SUMMARY

Route 41

Sheet 8 of 10

Description PGA

(9) Structure

Damage

SoilEffect

on TrafficType

of Repair

Repair FullTime Capacity(Hrs.) (vph)

Bypass Description

49-49

49-50

49-51

Bridge AcrossAtascadero Creek

Bridge AcrossAtascadero Creek

Bridge AcrossAtascadero Creek

Route 101/41Separation

.18 No damage antici- No soil failurepated because of low anticipatedforce levels

No damage antici- No soil failure. 18 pated because of low anticipated

force levels

. 18 No damage antici- No soil failurepated because of low anticipatedforce levels

.17 No damage antici- Low to moderatepated because of low liquefactionforce levels

Hone

None

Hone

Possible trafficdelay

Nonerequired

Nonerequired

Nonerequired

amping tobutments

0/2

1310

1310

1310

1310

Use parallel dirt road

Use parallel dirt road

None

Frontage Rd or 9th St

BRIDGE PERFORMANCE SUMMARY

County Roads

Sheet 9 of 10

Bridge No. Description PGA

(9) Structure SoilEffect

on TrafficType

of Repair

RepairTime(Hrs.)

FullCapacity

(vph)Bypass Descri ption

49C-151

49C-150

49C-327

Avila Cut-off Rd

SLO Creek Bridge

Avila Cut-off Rd

See Canyon CreekBridge

Harford Dr. Bridg8 Avila Beach

.31

.31

.33

No damageanticipated

Hinor abutmenttilting

Superstructureshifted at bearings;collapse possible

Moderate fillsettlement 7"+

Traffic delayed

Minor fi'll settle- Traffic delayedment 5"+;severe liquefaction

Moderate fill Possibly closed tosettlements; trafficsevere liquefaction

Ramping toabutment

Ramping to 1/4abutment

Supplemen- 4/72tary bents;span re-placement

None

Dirt road and light dutyroad

13027-81 Los Osos-Horro BayRd.-Bridge at .LosOsos Creek

.30 Possible loss ofsuppor t andcollapse

Moderate fillsettlements

Possibly closed totraffic

Ramping atbutments;ossible

span re-lacement

1/72 None

49C-238

49C-197

Los Osos Valley RdLos Osos Creek

Ontario Rd Bridge,San Luis ObispoCreek

.31

.29

No damage antici-pated except due toliquefaction

Collapse of approachspans; shear failurein columns

Minor fill settle- Traffic delayedments 6">;severe liquefaction

Moderate fill Closed to trafficsettlement 6">;severe liquefaction

amping tohutment

upplemen-ary bents;pan re-lacement

1/4

72

None

None

49C-11714008-81

Orcutt Rd. Culvert-Bridge 1

.19 No damageanticipated

Minor fill settle-ment 2"+

None None 1260 *NB; Left on Tiffany RanchRd, north on CorbitCanyon Rd to 227 NB,right 9 Biddle(total 5 mi)

SB: Right 9 Biddle, southon 227, left La CorbitCanyon Rd, left La

Tiffany Ranch Rd,(5 mi)

49C-11614008-82

49C-11514008-B3

Orcutt Rd. Culver-Bridge 2

Orcutt Rd. Culver-Bridge 3

.20

.20

No damageanticipated

No damageanticipated

Hinor fill settle-ment 2">

None

Minor fill settle- Nonement 2"+

None

one

1260

1260

Same as 49C-11714008-Bl

Same as 49C-11714008-Bl

Alternate route

BRIDGE PERFORMANCE SUMMARY

County Roads - Cont'd

Sheet 10 of 10

Bridge No.

49C-11414008-84

49C-11314008-85

13008-81

Description PGA

(9) Structure

Orcutt Rd. Culvert .21 No damage-Bridge 5 anticipated

Orcutt Rd. Culvert .22 No damage-Bridge BIA anticipated

Orcutt Rd. Culvert .20 No damage-Bridge 4 anticipated

Soil

Minor fill settle-ment 2"+

Minor fill settle-ment; severeliquefaction

Minor fill settle-ment 2"-+

Effecton Traffic

Traffic delayed

None

Typeof Repair

Ramping toabutments

None

RepairTime(Hrs. )

I/4

Capacity(vph)

1260

1260

Bypass Description

*NB: No direct bypass; useLopez Dr & Pozo NB oruse NB 227 & CorbitCanyon Rd

SB: Right turn La TiffanyRanch Rd, & SB onCorbit Canyon Rd

Same as 49C-11414008-B4

*NB: Left turn on Biddle,then NB on 227, rightturn La Orcutt (5 mi)or continue NB

SB: from Johnson Av rightturn La Orcutt, SB on227, left turn La

Biddle (5 mi) orcontinue SB

13008-S2

49C-229C2085-82

49C-227C2085-83

49C-226C2085-84

49C-223C2085-85

49C-329 Price Canyon Rd.Overhead

.21 No damageanticipated

Orcutt Rd. Culvert .22 No damage-Bridge S2 anticipated

Prefumo Canyon Rd..27 No damageCulvert - BR2 anticipated

Prefumo Canyon Rd. .26 No damageCulvert - BR3 anticipated

Prefumo Canyon Rd. .26 No damageCulvert - BR4 anticipated

Prefumo Canyon Rd. .25 No damageCulvert - BR5 anticipated

Hinor fill settle-ment 2">

Minor fillsettlement

Minor fillsettlement

Minor fillsettlement

Minor fillsettlement

Moderate fillsettlement - 7"+;moderateliquefaction

None

None

None

None

None

Traffic delayed

None

None

None

None

None

Ramping toabutment

I/2

1260 Same as 13008-81

None

None

None

None

NB&SB: Old Price CanyonRd

49C-330 Price Canyon Rd.Corral de PiedraCreek

.21 No damageanticipated

Severe liquefaction Closed to traffic Bentshoring;span re-lacement

8/72 NB&SB: Old Price CanyonRd

49C-352 Valley Road atLos Berros Creek

.23 No damageanticipated

Moderateliquefaction

Traffic delayed amping tobutment

I/2 None

4.2 PICTURES OF BRIDGES SURVEYED

4-13

h

~f1 ..g~~„,0

"~~XEEP,~ Iwt.)(~S:-'RICH1,

W

J

WOI ~ ~

,1

" ~.C-=-'Z

BRIDGE ST UC49-l73

fT

+l

J

yrR

h

. P.htt-'W ~i" FC1PR

VALLEYRD OC49-174

j>

WO l'lW, ~

Pgyf h

.ge.h,

1PtW"

W

y'„"C l i

'rt "; 4th'.g r

l'PR

'Wl

'L= 9tt'Ih

R

~WAR»

ARRYO GRANDE BP49- ! 75

W

W) tt"'I,

ARRYO GRANDE C49-l75

GRAND AVE SEP49-I 76

BRISCO RD UC49-I54

~

'IIIIIIIIIIIIII

OAK PARK RD OC',49-I 55 4

4,, 4.

PISMO OAKS OC49-l56

Q

P)SMO OH49-I 6

PISMO CRK49-I 5

lb'i.

p( j(i /

pter

~K 5I

PISMO CRK49-l5

HINDS AVE OC49-I 30

aJQ

PISMO ST PUC49-I 39

« I

4 fif

WADSWORTH AVE U49-I83

NORTH PISMO S49- I 84

REFER TO PAGE 5

~ «

SHELL BEACH UC49- I 89

AVILARD UC49-I 9 I

SLO CRK49-l4

N AVILARD OC49-I92

SANTA FE UC49-II5

'V

LOS OSOS RD OC49- I 85

MADDONNARD OC49-I90

t DRL

1

ct ~ ~V

MARSH ST SEP49-08

I

IL=1

CHORRO ST UC49-39

RTE I I 0 I SEP49-l44

CALIF BLVD. OC49-79

CALIF BLVD. UP49-I47

GRAND AVE UC49-84

BUENA VISTA AO49-94

SLO CRK49-52

gl F

r

CUESTA OVER H49-60

RTE 58 IOI SEP49- I 58

LOS BERROS CRK49-22

Q

ARROYO GRANDE C49- I 9

OCEANO OH9A2

VILLACRK49- IO

X

C

VS

NORTH PISMO S

49- I 84

STENNER CRK49- I 23

I l,l

~ jt

CHORRO CRK OH49-63

fit

'N BRNRDO EQ U49- I 88

IF

*

<l

SAN BERNARDO C49-66 BAYWOOD PK RU

49-l77

QI-.

S MORRO BAY OC49-I08

N MORRO BAY UC,49-l 0 9

MORRO CRK49- I 8 I

MORRO CRK49-I8I

RTE I 4 I SEP49-I82

TORO CRK49-68

GRAND AyE SPP49-I76

REFER TO PAGE I

Yj

gp3

CORBIT C'N CHK49-77

~~Mal% I%x~w

CROWN HILLPOC49-20 I~

C

CORISIT CANY CRK49- I IO

E CORRAL PIEDRA49-l03

W CORRAL PIEDRA49-204

~i-F

N EDNA OH49-220

z

E FKSLO CRK49-I I 6

ACACIACRK49-I l7

KP

~YiARSH SLO CRK49-58

~) q~

ATASCAOERO CRK49-49

j'*

Ac. c. ~ "j

'I

I, g

r-t,

,w'el

4" 4. o~

jATASCADERO CRK

49-50

'I

4

J

r W "- ~

i.;r-

- ~~v~-C

ATASCADERO CRK49-5 I

F

AIPP -,9'll

z ., -Wgl. s

)iF „

AVILASLO CRK49C- I 5 I

HARTFORD DR BR49C-327

.s„' rr'

J'.i~ - ~

C 44e LOS OSOS V RD

49C-238

pg

I

V

'r <s gt

a

-~y-~ '*9> ~~ > " y I 'L(

49C-I 97

~ ~cA~ „.~gaN ~'

«g'~i%<j Hw.l»

PREFUMO CANY RD49C-226

PREFUMO CANY RD49C-223

a )g

~ >~~a

h,

C

9

PRICE CANY RD OH49C-329 '—

PRICE CANY RD/ 49C-330

7

r,

rI

4n A-

~>Mi%

iblh "

VALLEYRD49C-352

'

TRAFFIC WAY49C-3 I 8

4.3 BRIDGE SEISMIC DATAFORMS

4-32

TERA CORPORATION

BRIDGE SEISMIC DATA FORM

General:

Name- Brid e Street Undercrossin 49-173R

Location: Rte 101 PM 12.5

Alignmen t: Stra ightLength:

219'kewed 67'urved

Width:34'ear

Built: 1959

Seismically Retrofitted: Yea X No No Plans

Site:Classification: Regular X Irregular

Peak Acceleration:

Liquefaction Potential:.22

Su erstructure:Material and Type: Welded Steel Plate Girder w/ Com osite PCC Deck

Number of Spans: 3

Continuous: Yes No X

Bear inces:

Type - Steel rocker bearin s

Condition: Functioning X Not Functioning

Restraint (Trans): Steel Kee er Bars

Restraint (Longit): A arentl none - not visible from hoto raphs

Bearing Height:

Support Length: 1' 3"

4-33

Columns & Piers:

Material and Type: R C Multi-Column bent

Transverse Cross-Section Dimension: 3' 0"

Longitudinal Cross-Section Dimension:

Height Range:15'onfinementDetails: II4 9 12"

Steel .9X

Foundation Type: Pile footin s

Abutments:

Type: R C Seat

Height:10'oundationType: Pile footin s

Wingwalls: Continuous X Discontinuous Length15'va

lua tion:Earthquake Resistance Mechanism: Inertia forces a'e

transferred to su orts throu h rocker bearin s - Deck i s

discontinuous and cannot distribute force.

Probable Failure Mode (s): Bearin failure resul tin in 6"

vertical deck settlement - Possible loss of su ort at abutments-

Minor abutment fill settlement.

Classif ication of Damage: Dama e cate or 2 or 3 (u er

lanes Dama e Cate or 1 (lower lanes)

4-34

BRIDGE SEISMIC DATA FORM

General:

Name: 49 — 174 Val le Road Overcrossin

Location: Rte 101 PM 12.80

Alignment: StraightLength:

126'idth:

65'ear

Built: 1959

Skewed 20 Curved

Site:

Seismically Retrofitted: Yes No X

Classif ication: Regular X Irregular

Peak Acceleration: .22

Liquefaction Potential:

Su erstructure:Material and Type: Prestressed continuous lab

Number of Spans: 2

Continuous: Yes X No

Bearinces:

Type: Asbestos sheet ackin at abutmen s.

Condition: Functioning X Not Functioning

Restraint (Trans): Curtain wall

Restraint (Longit) - None

Bearing Height:

Support Length:

0

1I 9ll

4-35

Columns 6 Piers:

Material and Type: R/C 4-column piers, w/ bent ca s

Transverse Cross-Section Dimension: 4' 0"

Longitudinal Cross-Section Dimension: 3' 0"

Height Range:

Confinement Details: b4 9 12"

(Steel 1.0X)

Foundation Type: Footings on piles (conc.)

Abutmen ts:Type: Bearin wall, cantilever retaining wall s

Height:153; feet

Foundation Type: Footin on iles (conc. )

Wingwalls: Continuous Discontinuous X Length47'va

lua tion:Earthquake Resistance Mechanism: Abutment carries load

transmitted from deck b bearin friction - Bent carries load

in shear and bendin .

Probable Failure Mode(s): No failure anticipated that could

effect traffic under structure.

Classif ication of Damage: Dama e cate or 1.

4-36

BRIDGE SEISMIC DATA FORM

General:

Name: Brid es across Arro o Grande Creek 49-175 L/R)

Location: Route 101 PN 13.02

Alignment: Straight X Skewed

Length: 172

Width: L-38'-39'o 54

Year Built: 1959

Curved

Site:

Seismically Retrof itted: Yes No X

Classif ication: Regular L Irregular R

Peak Acceleration: .22

Liquefaction Potential:

Su erstructure:Material and Type: R T - beam

Number of Spans:

Continuous: Yes No

B~earinces:

Type: None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Functioning

4-37

Columns 6 Piers:

Material and Type Reinforced concrete pile bents

Transverse Cross-Section Dimension: 16" g pile extension

Longitudinal Cross-Section Dimension:

Height Range: 11 - 23

Confinement Details:

Foundation Type: .piles

Abutments:

Type: R/C 'di aphr agm

Height: .

3'oundationType: pi 1 es

Wingwalls: Continuous X Discontinuous Length "1

Evaluation:

Earthquake Resistance Mechanism: Pile bents abutments

resist lateral forces in shear - continuous deck distributes load.

Probable Failure Mode (s): Slight abutment fill settlement

possible minor spalling of pile extensions.

Classif ication of Damage: Damage category 2

4-38

BRIDGE SEISMIC DATA FORM

General:

Name: Grand Avenue 0. C.

Location: Route 101, PM 13.17

Alignmen t: S tra ightLength:

170'idth:

67'kewed 47 Curved

Site:

Year, Built: 1959

Seismically Retrofitted: Yes No X

Classification: Regular X Irregular

Peak Acceleration: .23

Liquefaction Potential: I - IISu erstructure:

Material and Type: R C Box irder

Number of Spans: 2

Continuous: Yes X No

~Baarin a:

Type: Asbestos sheet k

Condition: Functioning~ Not Functioning

Restraint (Trans):

Restraint (Longit):

Bearing Height:

Support Length:

2'-39

Columns S Piers:

Material and Type: R/C 6 -column bent w ca

Transverse Cross-Section Dimension: 4

Longitudinal Cross-Section Dimension: 3

Height Range:17'onfinementDetails: 84 9 12"

(Steel 1%)

Foundation Type: Footings on 'i1 es (Concr . )

Abutmen ts:

Type: Cantil ever retainin wal 1

Height:

Foundation Type: Footing on piles (Conc.)

Wingwalls: Continuous Discontinuous " Length 40

Evaluation:

Earthquake Resistance Mechanism: Shear by friction at

abutment, shear and bending at b«<>

Probable Failure Mode(s): Settlement of 3" + at fill

,Classif ication of Damage: Category 1

4-40

BRIDGE SEISMIC DATA FORM

General:

Name: Brisco Road undercrossin

Location: Route 101 PM 13.8

Alignment: Straight X Skewed

Length:45'idth:

106'ear

Built: 1956

Curved

Site:

Seismically Retrofitted: Yes No X

Classif ication: Regular X Irregular

Peak Acceleration: a24

Liquefaction Potential: I - IISu erstructure:

Material and Type:

Number of Spans: 1

Continuous: Yes~ No

Bearinces:

Type:

Condition: Functioning

Restraint (Trans):

Restraint (Longit):

Bearing Height:

Support Length:

R C slab

Not Functioning

4-41

Columns 6 Piers:NoneMaterial and Type:

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range:

Confinement Details:

Foundation Type:

Abutments:

Type: Bearin wall retainin wall s

Height:16'oundation Type: Stri footin

Wingwa lls:

Evaluation:

Continuous Discontinuous X Length 30

Earthquake Resistance Mechanism: Concrete ri id frames

lateral load transmitted throu h frames

Probable Failure Mode (s): Minor fill settlement

Classif ication of Damage: Oama e Cate ory 1

4-42

BRIDGE SEISMIC DATA FORM

General:

Name: 49 — 155 Oak Park Road 0.L.

Location: Route 101 PM 14.6

Alignmen t: S tra ight X Skewed Curved

Length:

Width:

Year Built: 56

Seismically Retrofitted: Yes No X

Classif ication: Regular X IrregularSite:

Peak Acceleration: .25

Liquefaction Potential:

Su erstructure:Material and Type: ontinuous R slab

Number of Spans: 2

Continuous: Yes~ No

Bearinces:

Type:

Condition: Functioning~ Not FunctioningGirders at edges act

Restraint (Trans): Curtain wall + as shear ke s See hotos

Restraint (Longit):

Bearing Height:

rt L

4-43

Columns & Piers:

Material and Type: R/C 2 — Col. bent, framing at footing

Transverse Cross-Section Dimension: 5

Longitudinal Cross-Section Dimension:

Height Range:

Confinement Details: 5/8" 9 18"

Foundation Type:, Piles (Conc.)

Abutments:

Type. Cantilever retaining wall

Height:

Foundation Type: Footing on Pi les (Conc. )

Wingwalls: Continuous " Discontinuous Length

Evaluation:

Earthquake Resistance Mechanism: Force carried in shear

in all pier walls - in bending and shear in the bent - deck is

discontinuous at interior pier walls.

Probable Failure Mode(s): No failure is anticipated that

could affect traffic under structures. (Settlement of fillexpected to be 6". )

Classif ication of Damage: Damage Category 1

4-44

BRIDGE SEISMIC DATA FORM

General:

Name: 49 - 156, Pismo Oaks O.C.

Location: Route 101, PM 15.58

Alignment: Straight X Skewed

Length:178'idth:

33'ear

Built: 1956

Seismically Retrof itted: Yes No

Classif ication: Regular " IrregularSite:

Peak Acceleration: .24 g

Liquefaction Potential: IISu erstructure:

Material and Type: R/C Box girder

Number of Spans:

Continuous: Yes No

Bearinces:

Type: Steel rocker bearings at Abts

Condition: Functioning " Not Functioning

Restraint (Trans): Keeper plates & curtain wall

Restraint (Longit): None

Bearing Height:

Support Length: 2' 0"

4-45

Columns & Piers:

Material and Type: R/C 2-Col. w/cap & framing at footing

Transverse Cross-Section Dimension: 1"

Longitudinal Cross-Section Dimension:

Height Range:17'onfinementDetails:

Foundation Type: Stri footin

Abutments:

Type- Closed end Abt w two abt walls

Height: N: 20':16'oundationType: Stri footin

Wingwalls: Continuous X Discontinuous Length

Evaluation:

Earthquake Resistance Mechanism: Pier walls carr lateral

in shear - Bents in shear and bendin — deck is discontinuous

b grin s - therefore load will be transferred to bent

Probable Failure Mode(s): Kee er lates will robabl

h ar at rocker bearin s - will not affect traffic under

ucture.

Classif ication of Damage: Dama e Cate or 1. Li uefactionshould not affect traffic under the structure.

4-46

BRIDGE SE ISMIC DATA FORM

General:Identical to L. except

Name: 49 - 16 L R Pismo Overhead, R - S4EW, width = 2. col bents.

Location: Rte. 101 P.M. 16.2

Alignment: Straight Skewed 20 Curved

Length:283'idth:

28'ite:

Year Built: 56

Seismically Retrof itted: Yes

Classif ication: Regular

Peak Acce lera tion: . 25

No X

Irregular X (Column Hei ghts)

Lique faction Potential: I I

Su erstructure:Material and Type:

Number of Spans: 7

Continuous: Yes

Bearinces:

R C Slab

No X Exp. joints at Bent 5

Type:(Other bents restrained by)dowels N20 dowels bent

Condition: Functioning X Not Functioning

Restraint (Trans):

Restraint (Longit):

Bearing Height:

N ne

Support Length: 1' 0"

4-47

Columns 6 Piers:

Material and Type.-R C 2 Column Bents

. Transverse Cross-Section Dimension: 4'-6"

Longitudinal Cross-Section Dimension:

Height Range: 20'37''-6"

Confinement Details: g4 9 12"

Foundation Type: Pi 1 es 10 BP 42

Abutments:

Type Dia hra m

Height:6'oundation Type: P 1 s 10 BP 42

Wingwalls: Continuous X Discontinuous Length~1

Evaluation:

Earthquake Resistance Mechanism: Except for joint at bent

5, structure is continuous and will distribute loads to bents

and abutments.

Probable Failure Mode(s): Abutment full settlement and

possible support movement due to liquefaction.

Classification of Damage:

liquefaction potential (II).Damage category 2 due to

4-48

BRIDGE SEISMIC DATA FORM

General:Pi smo

Name: 49 — 15 L/R/C, C (Villa) Creek Brid e

Location: Route 101, PM 16.4

Alignment: StraightLength:

138'idth:

22'ear

Built: 1960

Skewed 25 Curved Sl ightly

Seismically Retrofitted: Yes No X

Site:Classif ication: Regular X Irregular

Peak Acceleration: . 25

~Y- YY

Su erstructure:Material and Type: R C T-Beam

Number of Spans: 3

Continuous: Yes X No

Bearinces:

Type: None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):

Bearing Height:

Support Length:

Not Functioning

4-49

15 L.R.C. C

Columns 6 Piers:

Material and Type: R C 2-Col. Bent.

Q I QllTransverse Cross-Section Dimension:0 I @IILongitudinal Cross-Section Dimension: 3

/Height Range:, '6'5

9 12"Conf inement Details:,At Bents:Rebars continue into dia hra ms

Foundation Type: Concr. iles

Abutments:

Type: Dia hra m

Height:5'oundationType: Concr. i 1 es

Wingwalls: Continuous X Discontinuous Lengthl2'-6"

Evaluation:

Earthquake Resistance Mechanism: Continuous superstructure will

distribute loads to the supports - abutments will carry loads in

shear — bents in shear and bending.

Probable Failure Mode (s): Settlement of abutment fills.Possible critical damage of columns due to liquefaction.

Classification of Damage: Damage Category 2. Possibly damage

Category 3 if liquefaction is severe.

4-50

BRIDGE SEISMIC DATA FORM

General:Pismo

Name: 49 - 15 L/R/C; L (Villa) Creek Bridge

Location: Route 101, PM 16.4

Alignment: Straight Skewed ig Curved0

Length: 264

Width:37'ear

Built: 1960

Seismically Retrof itted: yes

Classif ication: Regular Zrregular X ( Column Heights)

Site:Peak Acceleration: 259

Liquefaction Potential: II - IIISu erstructure:

Material and Type: R/C T-beam

Number of Spans: 4

Continuous: Yes X No

Bearinces:

Type: None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):

Bearing Height:

Support Length:

Not Functioning

4-51

15 L/R/C L

Columns & Piers:

Material and Type: R/C 2 - Col Bent

Transverse Cross-Section Dimension: P 3

Longitudinal Cross-Section Dimension:

Height Range:16'0'onfinementDetails:

At bents: Column Reinf. continues into the diaphragms

Foundation Type: Footing on piles (Concr.)

Abutments:

Type: Diaphragm on piles

Height:6'oundationType: Pi 1 es (Conr. )

Wingwalls: Continuous X Discontinuous Length >~

Evaluation:

Earthquake Resistance Mechanism: Continuous superstructure

will distribute loads to the supports - abutments will carry load

in shear - bents in shear and bending

Probable Failure Mode(s): Settlement of abutment fills.Possible damage of columns due to liquefaction.

Classif ication of Damage: Damage category 2

4-52

BRIDGE SEISMIC DATA FORM

General:Pismo

Name: 49 - 15 L R C. R Villa Creek Brid e

Loca tion: Route 101 PM 16. 4

Alignment: Straight Skewed 15 Curved

Length:311'idth:

37'ear

Built: 1960

Seismically Retrofitted: Yes No X

Site:Classif ication: Regular Irregular X (Column Heights)

Peak Acceleration: a 25

Liquefaction Potential: >I - IIISu erstructure:

Material and Type: R/C T-Beam

Number of Spans: 4

Continuous: Yes X No

Bearinces:

Type: None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Func tion ing

4-53

15 L/R/C

Columns & Piers:

Material and Type: R/C 2 - Col. Bent

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range: 16'40'onf

inement Details:At Bents:Column reinf. continues into diapragms.

Foundation Type: Concr. piles

Abutments:

Type: Diaphragm on piles

Height:6'oundationType: Concr. piles

Wingwalls: Continuous X Discontinuous Length 15

Evaluation:

Earthquake Resistance Mechanism: Cont inuous superstructure

will distribute loads to the supports - abutments will carry loads

in shear - bents in shear and bending.

Probable Failure Mode (s): Settlement of abutment fills.Possible critical damage of columns due to liquefaction.

.Classification of Damage: Damage Category 2. Possibly damage

Category 3 if liquefaction is severe.

4-54

BRIDGE SEISMIC DATA FORM

General:

Name: Hinds Avenue O.C., 49 - 130

Location: Route 101, PH 16.6

Alignment:Straight'ength:

206

'idth:

45'ear

Built: 1960

Skewed Curved

Seismically Retrof itted: Yes No X

Site:Classification: Regular " Irregular

Peak Acceleration:

Liquefaction Potential:Su erstructure:

.26 g.

I — II

Material and Type:

Number of Spans:

R/C T-beam

Continuous: Yes X No

Bearinces:

Type- None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):

Bearing Height:

Support Length:

Not Functioning

4-55

130

Columns 6 Piers:

Material and Type: R C 3 - Col.Bent

Transverse Cross-Section Dimension: 3' 6"

Longitudinal Cross-Section Dimension:

Height Range:17'4'onfinement.Details: 85 9 12"

At Bents:Rebars continue to the dia hra ms

Foundation Type: S read footin

Abutments:

Type- Dia hra m on iles

Height:2'oundationType: Piles Concr. South-end'tri footin North-End

Wingwalls: Continuous X Discontinuous Length12'valuation:

Earthquake Resistance Mechanism: Abutments take lateral

load in shear - Bents take load in shear and bending - Deck is

continuous and distributes load.

Probable Failure Mode(s): No significant failures anticipated

Classif ication of Damage: Damage Category 1

4-56

BRIDGE SEISMIC DATA FORM

General:

Name: Pismo Street Pedestrian U.C. 49 - 139

Location: Route 101, PM 16.8

Alignment: Straight X Skewed

Length:10'idth:

210'ear

Built: 1960

Seismically Retrof itted: Yes

Curved

No "

Site:Classif ication: Regular " Irregular

Peak Acceleration: 27 9 ~

Liquefaction Potential:Su erstructure:

Material and Type: Concrete Culvert

Number of Spans: 1

Continuous: Yes X No

Bearinces:

Type: None

Condition: Functioning Not Functioning

Restraint (Trans):

Restraint (Longit):

Bearing Height:

Support Length:

4-57

Columns & Piers:

Material and Type: 8" retaining walls, R/C

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range:

Conf inement Details:

Foundation Type: Concr. sl ab

Abutments: None

Type:

Height:

Foundation Type:

Wingwalls: Continuous Discontinuous Length

Evaluation:

Earthquake Resistance Mechanism: Ri id R C Box

Probable Failure Mode(s): No failure antici ated

Classif ication of Damage: Dama e Cate or 1

4-S8

BRIDGE SEISMIC DATA FORM

General:

Name: Wadsworth Ave. U.C. 49 — 183 R/L, R&L Equal

Location: Route 101 PM 16.9

Alignment: Straight X

Length:121'idth:

37'ear

Built: 1960

Skewed Curved

Site:

Seismically Retrofitted: Yes No X

Classif ication: Regular X Irregular

Peak Acceleration: .27

Liquefaction Potential: I

Su erstructure:Material and Type: R C T-beam

Number of Spans: 3

Continuous: Yes X No

Bearinces:

Type: None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):

Bearing Height:

Support Length:

Not Functioning

4-59

Columns 6 Piers:

Material and Type: R/C 2 Col Bent

Transverse Cross-Section Dimension: P3

Longitudinal Cross-Section Dimension:

Height Range:

Confinement Details:At BentsRebars continue into diaphragms

Foundation Type: Spread footing

Abutments:

Type: Diaphragm on piles

Height:

Foundation Type: Pi 1 es (Concr. )

Wingwalls: Continuous " Discontinuous Length 11

Evaluation:

Earthquake Resistance Mechanism: Abutments resist

load in shears - bents in shear 8 bending - deck is continuous

and can distribute forces

Probable Failure Mode(s): Minor approach fill settlements

Classification of Damage: Damage Category 1

4-60

BRIDGE SEISMIC DATA FORM

General:(R&L Equal except, SKEW)

Name: North Pismo Separation, 49 - 184 R/L

Location: Rte 101, PM 17.7

Alignment: StraightLength:

123'idth:

37'

leftSkewed1S Curved13 t'ight

Year Built: 1960

Seismically Retrof itted: Yes

Classification: Regular X

Site:Peak Acceleration: .27 g.

No X

Irregular

Liquefaction Potential: I - IISu erstructure:

Material and Type: R C T-beam

Number of Spans: 3

Continuous: Yes X No

Bearinces: None

Type:

Condition: Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

,Support Length:

Not Functioning

4-61 '

184 R/L

Columns & Piers:

Ma ter ia 1 and Type: R C 2 - Col Bent

Transverse Cross-Section Dimension: g3'

6'ongitudinalCross-Section Dimension:

Height Range:20'onfinementDetails: b5 9 12"

At BentsRebars continue into the dia hra ms

Foundation Type: Footin on i 1 es Concr.

Abutments:

Type:

Height:

End dia hra m

2'oundationType: Pi 1 es

Wingwalls: Continuous X Discontinuous Length13'valuation:

Earthquake Resistance Mechanism: Abutments carr load

hear — bents in shear and bendin - continuous deck distributes

rces to su orts

Probable Failure Mode (s): Minor to moderate approach fillsettlement at southbound brid e -'No settlement at northbound

brid e.

Classif ication of Damage: Southbound brid e - Dama e category

2. Northbound brid e - Dama e cate or 1

4-62

BRIDGE SEISMIC DATA FORM

General:

Name: Shell Beach U.C., 49 - 189 R/L. RSL equal

Location: Route 101, PM 19.8

Alignment: Straight I Skewed Cursed

Length:118'idth:

37

'earBuilt: 1964

Seismically Retrof itted:, Yes No I

Site:Classif ication: Regular I Irregular

Peak Acceleration: ~ 28 9 ~

Liquefaction Potential: I - IISu erstructure:

Material and Type: R/C T-beam

Number of Spans: 3

Continuous: Yes X No

Bearinces:

Type:

Condition: Functioning

Restraint (Trans):

Restraint (Longit):

Bearing Height:

Support Length:

Not Functioning

4-63

189 R/L

Columns 6 Piers:

Material and Type.-R C Pier Wall + Curtain Walls

Transverse Cross-Sec tion Dimension: 37

'ongitudinalCross-Section Dimension: 1I 3ll

Height Range:18'onfinementDetails: Horiz 84 9 4' 0" At Bents: Reinforcm.

Vertic k'4 9 18"continues snto ecdia hra ms.

Foundation Type:

Abutments:

Piles

Type: End Dia hra m

Height:8-10'oundation

Type: Piles

Wingwalls: Continuous X Discontinuous Length10'valuation:

Earthquake Resistance Mechanism: Abutments and bents carr

transverse loads in shear - Deck is continuous acts as strut between

a roach fills.

Probable Failure Mode (s): Minor a roach 'fill settlements.

Classification of Damage: Dama e Category 1- Possibly

Damage Category 2 if liquefaction is moderate.

4-G4

BRIDGE SEISMIC DATA FORM

General:

Name: Avila Road U.C., 49-191 R/L R&L Equal except length

Location: Route 101, PM 21.1

0Alignment: Straight I SkewedSS Curved

Length: 150'eft; 168'ightWidth:

40'ear

Built: 1964

Seismically Retrofitted: Yes Ro IClassification: Regular I Irregular

Site:

Peak Acceleration: 2B g ~

Liquefaction Potential: III - IV

Su erstructure:Material and Type: R/C Box - girder

Number of Spans: 3

Continuous: Yes X No

Bearinces:

Type: None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Functioning

4-65

191 R/L

Columns E Piers:

Material and Type: R/C 3 -Col. Bent

Transverse Cross-Section Dimension: 3 I 6II

Longitudinal Cross-Section Dimension: 2' 6"

Height Range: 18'

19'onfinementDetails: ¹4 9 12"At BentsRebars continue into the deck dia hra ms

Foundation Type: Piles steel 10 BP 57

Abutments:

Type:

Height:

End dia hra m

9I

Foundation Type: Pil es 10 BP 57 Steel, Pilot

Wingwalls: Continuous X Discontinuous Length18'valuation:

Earthquake Resistance Mechanism: Abutments resist load

in shear - bents in bendin ; shear - continuous deck distributes

1 oad.

Probable Failure Mode(s): Abutment fill settlement along

with eneral settlement of the brid e site. Because bridge is on

iles into ori inal round it will robabl not settle resulting

in discontinuit at abutment. Li uefaction otentia1 hi h.

Classification of Damage: Dama e CategorY 3 due to 11 uefact1on.

4-66

General:

BRIDGE SEISMIC DATA FORMSame as the old section ofR, except no cable restr ainersinstalled yet.

Name: San Luis Obis o Cr. Bridge, 49 - 14, L/R, L

Location: Route 101 (PM 21.5)0Alignatent: Straight Skewed 45 Curved

Length:570'idth:

31'ear

Built: 1948

Seismically Retrof itted: Yes No X

Site:Classification: Regular X Irregular

Peak Acceleration: ~ 28 g.

Liquefaction Potential: III - IV

Su erstructure:Material and Type: R C "T" beam

Number of Spans: 14

Continuous: Yes

Bearinces:

No X 2 suspended spans

Type: Steel rocker - steel sliding bearing

Condition: Functioning X Not Functioning

Restraint (Trans): Keeper bars

Restraint (Longit): Keeper bars

Bearing Height:

Support. Length:

2 II

5 I I

4-67

Columns & Piers:

Material and Type: R C Multi-column bents with intermediate ier walls

Transverse Cross-Section Dimension:2.2'ongitudinalCross-Section Dimension: -

1.6'eight

Range:16'onfinementDetails: 1 2" 9 12" o.c.

Foundation Type: Pile footin s

Abutments:

Type: End bent

Height:

Foundation

Wingwalls:

Type:

Continuous Discontinuous Length,

Evaluation:

Earthquake Resistance Mechanism: Transverse 1 pads transferred

the bents at m d - Bearin kee er bars at ex .

ints and at the hin es rovide transverse restraint for small

earth uake loads.

probable Failure Mode (s): Loss of su ort at exp. joints

or hin es most robabl at s ans 2 or . Also high liquefaction

potential.

Classif ication of Damage: Dama e Cate or 3.

4-68

Please see plans

BRIDGE SEISMIC DATA FORM

General:R widened 1978

Name: San Luis Obispo cr. bridge, 49 - 14 L/R,

Location: Route 101, PN 21.5

Alignment: Straight Skewed46 Curved0

Length:570'idth:

S:48, N:41

Year Built: 1941, widened 1978

Seismically Retrofitted: Yes à No

Classification: Regular I IrregularSite:

Peak Acceleration: .28 g.

Liquefaction Potential: III - IV

Su erstructure:Material and Type: R C T-beam

R with widening (1978)

Number of Spans: 14

Continuous: Yes No X

Bearinces:.

Type: Ex . pints and hin e pints 5 cs. alto ether within s ans)No bearings

Condition: Functioning X Not FunctioningShear keys (2>" high, 1'-6" wide) + cable restrainer~a, pcs. in a

Restraint (Trans): section Northbound retrofi tted

Restraint (Longit):

Bearing Height:

Support Length: 5" at expansion joints)

4-69

Columns 6 Piers:

Material and Type: R/C Pier Wall for the widening ('78)R/C 4 - Column bent for o sec ionTransverse Cross-Section Dimension:.See plans 2' 2"

Longitudinal Cross-Section Dimension.-- -- 2 - 9widen: 1'-3" pier wa

Height Range:

Confinement Details: 3~" 0 9 12" Oldk'5 9 3'n the pier wall.

9 4'oriz.Foundation Type: Pi 1 es cr'eosoted D.F. iles bents 1215

Untreated D.F. piles, bents 2 to 14 incl.Abutments:

Widening: Steel pilesType: End dia hra ms on ile Steel

Height:

Foundation Type: Piles Steel for widenin

Wingwalls: Continuous X Discontinuous Length16'valuation:

For old

Earthquake Resistance Mechanism: Abutment and bents resist

seismic forces in shear and bending - Discontinuous deck will not

distribute load as effectively as a continuous deck.

Probable Failure Mode (s): Moderate abutment fillsettlement, High liquefaction potential

Classification of Damage: Damage Category 3 due to liquefaction.

4-70

BRIDGE SEISMIC DATA FORM

General:

Name: North Avila Road O.C., 49-192

Location: Rte. 101, P.M. 22.30

0Alignment: Straight Skewed ~S Curved

Length:230'idth:

37'ear

Built: 1964

Site:

Seismically Retrofitted: Yes No

Classification: Regular irregular

Peak Acceleration: 27 g

Liquefaction Potential:Su erstructure:

Mid Spans:Material and Type: End Spans:

Precast PrestressedPrecast Reinforced

Number of Spans:The prestressed girders are continuous at bents.

Continuous: Yes X No See Plans: Typical sect. 6 girder layout.

Bearinces:

Type: At Bents the deck "rests" on the bents.

Condition: Functioning Not Functioning

Restraint (Trans): Shear Keys 4/Bent at bents

Restraint (Longit):Shear Keys 4/Bent at bents

Bearing Height:

5'0" X 6" X 2" - Height ofShear Key.

5'0" X 6" X 2"—e<g o ear Key.

Support Length: See Plans: Bent details, Typical section 8 girder layout.

4-71

Columns & Piers:

Material and Type: R/C 1 Col . P i er

Transverse Cross-Section Dimension: 8'-0"

Longitudinal Cross-Section Dimension: 3'-0"

Height Range: 20'..25'onfinementDetails: ¹4 W 8 12"

Foundation Type: Goner. Pi les

Abutments:

Type: Dia hra m

Height:9'oundationType: Goner. Piles

Wingwalls: Continuous Discontinuous X Length

Evaluation:I

Earthquake Resistance Mechanism: inertia forces carried b

shear at abutments - Shear 8 bendin at bents.

Probable Failure Mode(s): None, except liquefaction causing

moderate settlements.

Classification of Damage: Settlement potential up to 9" in the

fills at the ends. Overcrossin structure so assume dama e Cate ory l.

4-72

BRIDGE SEISMIC DATA FORM

General:

Name: Santa Fe U.C. 49-115 R/L: R 6 L Equal Except Length

Location: Rte. 101, P.M. 24.4

Alignment: S tra ightLength: 143' ~ 161',Width:

40'ear

Built: 1963

0Skewed 4> Curved

Site:

Seismically Retrofitted: Yes No X

Classif ication: Regular X Irregular

Peak Acceleration: .26 9

Liquefaction Potential:Su erstructure:

Material and Type: R/C Box

Number of Spans: 3

Continuous: Yes X No

Bearinces:

Type: None

Condition: Functioning

Restraint (Trans):

Restraint. (Longit):

Bearing Height:

'Support Length:

Not Functioning

4-73

Columns 6 Piers:

Material and Type: R/C 3-Co i . Bent

Transverse Cross-Section Dimension: 3'-6"

Longitudinal Cross-Section Dimension: 2'-6"

Height Range: 16'..17'onfinementDetails: ¹4 IW 9 12"

At Bent: Coiumn reinforcement continues to the dia hra ms of th'e deck.

Foundation Type: S read foot i n

Abu tmen ts:Type: End diaphragm

Height:9'oundation Type: No foundation (End diaphragm rest'ing in the round)

Wingwalls: Continuous X Discontinuous Length12'valuation:

Earthquake Resistance Mechanism: Shear at abutments + Shear 8

Bending at bents.

Probable Failure Mode (s): None

Classif ication of Damage: Category 1

4-74

BRIDGE SEISMIC DATA FORM

General:

Name: s s Road Overcrossin 49 - 185

Location: Route 1Ol p.M. 25. 9

Alignment: Straight Skewed 43 Curved

Length:

Width:

Site:

Seismically Retrof itted: Yes

Classification: Regular

No X

Irregular X

Peak Acceleration: .23

Liquefaction Potential:Su erstructure:

Material and Type: R/C Box Girder

Number of Spans: 4

Continuous: Yes X No

Bearinces:

Type: Rocker bearings at Abut.

Condition: Functioning X Not Functioning

Restraint (Trans): Deck - bent fixed joint. Keeperbar. Wing Walls

Restraint (Longit): "--—---"——

Bearing Height: 6" at abut.

Support Length: 2't abut.

4-75

Columns 6 Piers:

Material and Type: Circular X-Sect. 2-col bents

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range:2o'-24'onfinement

Details: 811 Tot. 37/extended spiral 4 turns

into footing. Also 4 turns into cap; 33;" between turns/2'X2'Xl-5/8"ey a ase

Foundation Type: Bent 4 on R C Piles Others stri

Abutments:

Type - R C Seat Abut w edestel s

Height: Smal 1

Foundation Type: P.C.C. iles. some battered 1:4

Wingwalls: Continuous Discontinuous X Length17'valuation:

Earthquake Resistance Mechanism: Abutments carr shear

ed f om bearin s which will slide 9 PGA of .20 +

il carr for ce in shear bendin . Continuous deck will'b te 1 ad to su orts.

Probable Failure Mode (s): Possible bearin failure at

en - i 1 not effect traffic under structure.

Classif ication of Damage: Dama e Cate or 1.

4-76

BRIDGE SEISMIC DATA FORM

General:

Name: Hadonna Road Overcross ing (49-190)

Location: P.H. 27.50

Alignment: Straight Skeweda 500 Wcurved

Length:266'idth:

64'ear

Built: 1963

Seismically Retrofitted: Yes No

Classification: Regular X IrregularSite:

Peak Acceleration: .22 g

Liquefaction Potential:Su erstructure:

Precast prestressed I-beams and s1ab spans 2 8 3.Material and Type: R/C - Cast in place T-beams spans 1 6 4.

Number of Spans: 4

Continuous: Yes No X

Bearinces:

Type: 4" Exp. Jt. Filler S 4" Brg. Pad

Condition: Functioning X Not FunctioningRestraint (Trans): ¹8 dowel s .5 per bay X 2'-6"; None on the next span.

Restraint (Longit): ¹8 dowels .5 per bay X 2'-6"; None on the next span.

Bearing Height:

'Support Length: 1'-6" 9 bents

4-77

Columns 6 Piers:

Material and Type: R/C 4-Col . Bents

Transverse Cross-Section Dimension:

4'ongitudinalCross-Section Dimension:

Height Range:~18'onf

inement Details: ¹4 ~ 9 12 / ¹11 L Tot. 22 at baseII

Foundation Type: Concrete Piles

Abutments:

Type: R/C diaphragms

Height:9'oundation Type: Concrete piles - Some battered '(1:3)

Wingwalls: Continuous X Discontinuous Length 21

'valuation:

Earthquake Resistance Mechanism: Abutments carr load in shear.

Bents 2 8 4 carr transverse load from s ans 2 L 3. Bent 3 has dowel s

to carry transverse and ion itudinal load.

Probable Failure Mode(s): Dama e affecting traffic under the

structure is unlikely except for the case of liquefaction where

collapse of a span could result from excessive displacement.

Classif ication of Damage: Damage Category 2.

4-78

BRIDGE SEISMIC DATA FORM

General:

Name- Marsh Street Se .

Location: P.M. 28.07

49 - 08 LSR similar

Alignment: StraightLength:

3'kewedSmal1 Curved

Width-:28'8'50'ari es)

Year Built: '53

Seismically Retrof itted:Classif ication: Regular

Site:

Yes No X

Irregular X

Peak Acceleration: . 22

Liquefaction Potential:Su erstructure:

Material and Type: R C slab

Number of Spans: 3

Continuous: Yes~ No

Bearinces:

Type:

None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):

Bearing Height:

Support Length:

Not Functioning

4-79

Columns & Piers:

Material and Type: R C 3 - Col. bent

Transverse Cross-Section Dimension:

4'ongitudinalCross-Section Dimension:

RRR2Confinement Details: 1

3-1 1/4 dowel s Tot. 62-1 1 4 dowe s Tot. 10

3-1 4 tot. 6 2-1 1 4 tot. 10 at to .

Foundation Type: Stri found R/C

Abutments:

Type- R C dia hra m

Height: 6' 0"

Foundation Type: Concrete iles

Wingwalls: Continuous X Discontinuous Length14'valuation:

Earthquake Resistance Mechanism: Shear to abutments and

shear and bendin to columns - Continuous deck distributes load to

su orts.

Probable Failure Mode (s): Hinor abutment fill settlement

is ossible

Classif ication of Damage: Dama e Cate ory 1 ~

4-80

BRIDGE SEISMIC DATA FORM

General:

Name: Stenner Creek Cul vert 49-146

Location:

Alignment: StraightLength:

230'idth: 25't.20'ear

Built: '77

0Skewed H curved

Seismically Retrof itted: Yes

Classif ication: Regular

No

IrregularSite:

Peak Acceleration: .21 .

Liquefaction Potential: I - IISuperstructure: None

Material and Type:

Number of Spans:

Continuous: Yes

Bearinces: None

Type:

Condition: Functioning

Restraint (Trans):

Not Functioning

Restraint (Longit):Bearing Height:

Support Length:

Columns & Piers: None

Material and Type:

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range:

Conf inement Details:

Foundation Type:

Abutments:

Type:

Height:

Foundation Type:.

Wingwa 1ls:

Evaluation:

Continuous Discontinuous

Length25,'arthquake

Resistance Mechanism: Excessive seismic

earth ressures will be resisted b arch action of culvert.

Probable Failure Mode (s): Fill settlement may occur, but no

discontiuities should a ear in the roadway.

Classification of Damage: Dama e Cate ory 1

4-82

BRIDGE SEISMIC DATA FORM

General:

Name: Chorro Street Under Crossin 49 - 39 L & R simil

Loca tion: RM 28. 81

Alignment: Straight

Length:136'idth:

R 33'-40'/ L38'

45'kewed35 Curved

Year Built: '53

Site:

Seismically Retrofitted: Yes No X

Classif ication: Regular X Irregular

Peak Acceleration: .21

Liquefaction Potential:

Su erstructure:Material and Type: R C Sl ab n

Number of Spans: 3

Continuous: Yes X No

Bearinces:

Type:

None

Condition: Functioning Not Functioning

Restraint (Trans):

Restraint (Longit):

Bearing Height:

Support Length:

4-83

Columns & Piers:

Material and Type: R/C 3 - Col. Bents

Transverse Cross-Section Dimension:5'ongitudinalCross-Section Dimension:

3'eight

Range:

Confinement Details: ~i 9 12/2 - 13-L dowels to3 - l>4 tot. 62 - 13; totl 10 at top - Inner Col. dowels more extensive

18'- 13;L dowels tot 6 at base

t 10 for outer cols.

Foundation Type:

Abutments:

Type: Diaphragm R/C

Height:6'oundationType: Concrete pi 1 es

Wingwalls: Continuous X Discontinuous Length14'valuation:

Earthquake Resistance Mechanism: Abutments in shear and

bents in shear and bending - Deck is continuous and will distri-bute force to supports.

Probable Failure Mode (s): Minor abutment fill settlement.

Classif ication of Damage: Damage category 1

4-84

BRIDGE SEISMIC DATA FORM

General:

Name: Rte 1/101 Se .

Location: Rte. 101, Ptl 29.07

Alignment: StraightLength:

129'idth:

52'49- 144)

Skewed7 Curved0

Site:

Year Built: 53

Seismically Retrof itted: Yes No X

Classif ication: Regular X Irregular

Peak Acceleration: .21 g

Liquefaction Potential: 1

Su erstructure:Material and Type:

Number of Spans: 2

Continuous: Yes X No

R C Box Girder

Bearinces: None

Type:

Condition: Functioning

Restraint (Trans):

Restraint (Longit):

Bearing Height-

Support Length:

Not Functioning

4-85

Columns a Piers:

Material and Type: R/C 4 - Col. Bents

Transverse Cross-Section Dimension: 4

Longitudinal Cross-Section Dimension: 3

Height Range:18'onf

inement Details: >~ 9 12/4-13; dowel s Tot. 8 at base4- 1>4 0 02 - 13„- Tot. 8 each at soffit-col. Joint 2-1k dowels Tot. 8

Foundation Type: Strip found. on R/C piles

Abutments:

~ Type: Struted - R/C

Height:22'oundation Type: Concrete piles; some battered (1:3)

Wingwalls: Continuous X Discontinuous Length~4

Evaluation:

Earthquake Resistance Mechanism: Shear in abutment

(nominal shear key) and Shear ; bending is columns

Continuous decks distributes forces

Probable Failure Mode (s): Minor, abutment fill settlement.

Classif ication of Damage: Damage category 1 for both Route 1

and 101

4-86

BRIDGE SEISMIC DATA FORM

General:

Name: California Blvd. Over Crossin

Location: Rte 101; P.M. 29.4

Alignment: Straight Skewed Curved

Length:2'idth:

53l

2'ear Built: 1954 d 2

Site:

Seismically Retrof itted: Yes No

Classif ication: Regular~ Irregular

Peak Acceleration: .21

Liquefaction Potential:Su erstructure:

Material and Type: R C Box irder

Number of Spans: 2

Continuous: Yes I No

Bearinces:

Type o

None

Condition: Functioning Not Functioning

Restraint (Trans):

Restraint (Longit):

Bearing Height:

Support Length:

4-87

16 R/L R

Columns 6 Piers:

Material and Type: R/C 2 Col. Bent

Transverse Cross-Section Dimension: 4 - 6"4

Longitudinal Cross-Sec tion D imen sion: 2 ' 6"

Height Range: 20'37'onf

inement Details: t4 9 12"

Foundation Type: Piles, 10 BP 42

Abutments:

Type: Diaphragm

Height: 6I

Foundation Type: Piles, 10 BP 42

Wingwalls: Continuous X Discontinuous Length I2

Evaluation:

Earthquake Resistance Mechanism: Except for joint at

bent 5, structure is continuous and wi11 distribute loads to

bents and abutments.

Probable Failure Mode(s): Abutment fill settlement and

possible minor support movements due to liquefaction

Classif ication of Damage: Damage category 2 due to

liquefaction Potential (II).

4-88

BRIDGE SEISMIC DATA FORM

General:California Blvd. U.P.

Name: Ida Street Underpass 49 - 147

Location: Route 101 P.M. 29.4

Alignment: StraightLength:

136'idth:

48'kewed 7 Curved0

Year Built: 1953

Seismically Retrofitted: Yes No X

Classification: Regular x Irregular.Site:

Peak Acceleration: .21

Liquefaction Potential: I

Su erstructure:Material and Type:

Number of Spans:

Continuous: Yes

Steel late irder

No x

Bearinces:

Type: Rocker t e ex ansion bearin s at abut hin es at bents.

Condition: Functioning X Not Functioning

Restraint (Trans): Bolts connectin bearin s to kee er late wingwalls.II

Restraint (Longit):Bearing Height:

15'upportLength:

4'-89

Columns & Piers:

Material and Type: R C 2-Col. bents

Transverse Cross-Section Dimension:6'ongitudinalCross-Section Dimension:6'eight

Range:]8'onfinementDetails: k4 9 12 ea Col 13- dowels X 7' 6"

32 base

Foundation Type: Stri found. Joined to ether

Abutments:

Type- Pedestal s restin on foundation — ht. 18'ike columns

Height:8'oundation Type: 'tri

Wingwalls: Continuous Discontinuous X Length47'valuation:

Earthquake Resistance Mechanism: Bearin s transfer force

n c 1 mns which resist lateral forces in shear and

P ex erience has shown railroad tracks andbal~lst

n ntinuit .

Probable Failure Mode(s): Bearin s could fail in shear

in s are unlikel to to le at this force level.

1 e is even less likel

Classif ication of Damage: Dama e Cate or 1.

4-90

BRIDGE SEISMIC DATA FORM

General:

Name: Grand Avenue Undercrossin 49 - 84 R L - b'oth summerere; similar

Location: Route 101 P.M. 29. 8

Alignment: Straight X Skewed

Length:185'urved

Width:28'ear

Built: 1953 1 en th ext. 1959)

Seismically Retrof itted: Yes No X

Classif ication: Regular X IrregularSite:

Peak Acceleration: .20

L'iquefaction Potential:

Su erstructure:Material and Type: R C Box irder

Number of Spans:

Continuous: Yes

Bearinces:

Type: e b t.

X Expansion joints between bent4 and abut 5.

Condition: Functioning x Not Functioning

Restraint (Trans): Steel kee er bar win walls

Restraint (Longit) '- None

Bearing Height:

Support Length: 'I/Ab . d 1 2" 9'"

4-91

2

Columns 6 Piers:

Material and Type: 2 column bents; R/C

Transverse Cross-Section Dimension: 3

Longitudinal Cross-Section Dimension:

Height Range:17'onf

inement Details:at base of each Col. 1

g4 9 12 each column/4 - 13; dowels" Tot. 8

owe s ot. 10

Foundation Type: stri foundJ

Abutments:

Type! Seat ty e w/ pedestels

Height:1-2'oundation

Type: Piles on Abut 2/strip on Abut'2

Wingwalls: Continuous Discontinuous X Length

Evaluation:

Earthquake Resistance Mechanism: Because of nonexistence

of lateral restraint on east span, a minimum resistance is offered

to an lateral force on this section of the bridge. The exp. Jt.

must be tied or otherwise retrofitted for any improvement.

Probable Failure Mode(s): The span between bent 4 and Abut

5 will fall off; su ort length at me expansion joint is too small.

Classif ication of Damage: Category 3.

4-92

BRIDGE SEISMIC DATA FORM

General:

Name: Buena Vista Avenue Overcrossin 49 - 94

Location: Route 101 P.M. 29. 99

Alignment: StraightLength:

140'idth:

28'kewed 20 Curved0

Year Built: 1953

Site:

Seismically Retrof itted: Yes No X

Classif ication: Regular X Irregular

Peak Acceleration:

Liquefaction Potential:

Su erstructure:

.20 g.

Material and Type: R C Box irder

Number of Spans: 2

Continuous: Yes X No

Bearinces:

Type: Rocker t e at Abut

Condition: Functioning X Not Functioning

Restraint (Trans):Bent-deck Joint 13- Tot 18 no dowel s Win wall s keeper bar.

Restraint (Longit):

Bearing Height:

Support Length:

] Oll

1IBII

4-93

Columns & Piers:

Material and Type: One 2-column R/C. beret

Transverse Cross-Section Dimension: 6'

Longitudinal Cross-Section Dimension:3'eight

Range:17'onfinementDetails: 1>4 Tot 18 at base/ b4 912

for each column confinement

Foundation Type: Stri foundation

Abutments:

Type: Seat t e w/ edestels

Height:15'oundationType: stri

Wingwalls: Continuous Discontinuous X Length 56'ingwal 1 joined

Evaluation ~Northeast wingwall curve outwards R = 3 'allsto Abut. bearing

Earthquake Resistance Mechanism: The su ort len th is

lar e enou h to accomodate transverse movements. The ex ected

PGA of .2 . will not cause to in of bearin s. Columns will

resist in shear and are stable.

Probable Failure Mode (s): None

Classif ication of Damage: Category 1.

4-94

BRIDGE SEISMIC DATA FORM

General:

Name:

Location: p.M. 35.58 Route 101

Alignment: Straight Skewed 22 Curved at North end0

Length:467'idth:

30'ear

Built: 1938 Modified '60

Seismically Retrof itted: Yes No X

Classif ication: Regular X IrregularSite:

Peak Acceleration: .18

Liquefaction Potential:

Su erstructure:Material and Type: R C T-Cross Section Girders - Cross Section varies

parabolic in elevation)Number of Spans: 10

Continuous: Yes No X

Bearinces:

Type: Roller bearings at abutments, hinges 5 exp. Jt. 9 midspan

Condition: Functioning X

1 S 1 1 9 S

Not Functioning

Restraint (Trans): Shear ke s at rollers

Restraint (Longit): None

Bearing Height: 16" 9 abut.

Support Length:

Columns & Piers:

Material and Type: R/C 3-column bents: mid ht. beco umns at bents

Transverse Cross-Section Dimension: .

2'ongitudinalCross-Section Dimension:3'eight

Range: Abt

25'onfinementDetails: Total 12-1 1/8" bars each C 1 3-"

1 1/8" i:I X6'-0 dowels Join each Col. to stri found.

s 9 18" ctr

Foundation Type: Stri foundation

Abutments:

Type:

Height:

Seat type w/pedestels

3 I 9II+

Foundation Type: strip

Ningwalls: Continuous X Discontinuous Length~5<

Evaluation:

Earthcpxake Resistance Mechanism: Shear in abutment

shear and bending in the columns. Transfer of force throu h the

deck relies on friction. Short su ort len ths exist at interibearing.

Probable Failure Mode (s): Loss of su ort at interiorhinges due to longitudinal movement {can be shored . Sus ended

end spans wi11 possibly co11apse.

Classification of Damage: Cate or 2 Probable with special

commitment to repair. Category 3 Possible.under unfavorabie conditions.

4-96

BRIDGE SEISMIC DATA FORM

General:

Name:

Location: Route 101 - P.N. 36.6

- 07

Alignment: Stra ightLength:

Width:

Year Built: 1929

Skewed 26 Curved0

Seismically Retrof itted: Yes No 'X

Site:Classification: Regular X Irregular

Peak Acceleration: .18

Liquefaction Potential:

Su erstructure:Material and Type:

Number of Spans:

R C "T" beam

Continuous: Yes~ No

Bear inces:

Type-

None

Condition: Functioning Not Functioning

Restraint (Trans):

Restraint (Longit):

Bearing Height:

Support Length:

4-97

Columns 6 Piers:

Material and Type: None

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range:

Conf inement Details:

Foundation Type:

Abutments:

Type: Dia hra

Height:15'oundationType: S read footin

Wingwalls: Continuous X Discontinuous Length

Evaluation:

Earthquake Resistance Mechanism: Ri id frame sin le

s an structure

Probable Failure Mode (s): No failure anticipated

Classif ication of Damage: Dama e Cate ory 1

, 4-98

BRIDGE SEISMIC DATA FORM

General:

Name- Route 8/101 Se aration

Location: Rte. 101 P.H. 37.86

49-158

Alignment: Straight Skewed 49 Curved Super elevation 2'6"

Length:305'idth:

28'ear

Built: 1956

Site:

Seismically Retrofitted: yes No

Classif ication: Regular~ Irregular

Peak Acceleration: .17 g

Liquefaction Potential:Su erstructure:

Material and Type: Steel Plate Girder; welded / R/C Slab

Number of Spans: 4

Continuous: Yes No~Bearinces:

Type F i xed bear i ngs at abutmen ts / Expans i on Jo i nts at Ben ts ( Rockers)

Condition: Functioning X Not Functioning

Restraint (Trans): Fixed bearin s at abutments and bents. Wingwal 1s 9 abut.

Restraint (Longit): Fixed bearin s at abutments and bents. Wingwal ls 0 abut.

Bearing Height: 5"

Support Length: 18"

Columns & Piers:

Material and Type: R C 2-column bents with R C ben c s

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension: 5'0"

Height Range: ~22'onfinementDetails: 4 Cff3 11 12 / 1$ t dowals at base

Foundation Type: Strip 14 dowels extend from found. to col.

Abutments:

Type: Seat type with pedestals

Height: 10.

5'oundationType: S t r i p foundation

Wingwalls: Continuous Discontinuous X Length ~15

Evaluation:

Earthquake Resistance Mechanism: Al 1 load transferred to supports

through steel rocker bearings. Discontinuous deck. Failure at

bearings at low acceleration will require dependence on friction to

prevent col l apse.

Probable Failure Mode (s) . Loss of suPPort at one or more of

bearings possible but not probable at low force levels. Probable

total collapse at slightly higher force levels due to discontinuity

and short support length.

Classif ication of Damage: Dama e Cate or 1— Dama e Cate ory 3

at hi her PGA's.

4-100

BRIDGE SEISMIC DATA FORM

General:

Name: Br. Across Los Berros Cr. 49-22

Location: Rte. 1, P.M. 10.35

Alignment: StraightLength: 90

'idth:28'd. way.

Year Built: 1952

Skewed 40 Curved 54 Supere1 .0

Seismically Retrof itted: Yes No X

Site:Classif ication: Regular " Irregular

Peak Acceleration: 0.24 9

Liquefaction Potential:Su erstructure:

Material and Type: R/C Slab

Number of Spans: 3

Continuous: Yes X No

Bearinces:

Type: None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Functioning

4-101

Columns & Piers:

Material and Type: R/C Pi le Ext. 8-Pile-Ext. Bents

Transverse Cross-Section Dimension: ~1'iam.Longitudinal Cross-Sec tion Dimen sion: ~1 ' i am.

Height Range: ~7'onf

inement Details: (stand.) ¹5 wi re 9 6" i tch.

Foundation Type: R/C i 1 es.

Abutmen ts:Type: Diaphragm

Height:6'oundat ion Type: R/C p i l es.

Wingwalls: Continuous X Discontinuous Length 9'6"

Evaluation:

Earthquake Resistance Mechanism: Pile extensions behaving

in a ductile manner in shear. Continuous slab su erstructure

distributes load.

Probable Failure Mode (s): None

Classif ication of Damage: Category 1

4-102

BRIDGE SEISMIC DATA FORM

General:

Name: Arroyo Grande Creek Bridge (49-19)

Location: Rte. 1, P.M. 10.94

Alignment: Straight Skewed 30 CurveS

Length:123'idth:

32'ear

Built: 1952

Seismically Retrofitted: Yes No X

Classif ication: Regular X IrregularSite:

Peak Acceleration: 23 g

Liquefaction Potential:Su erstructure:

Material and Type: Concrete Slab (Continuous)

Number of Spans: 3

Continuous: Yes X No

Be a r in ce s:

Type:None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support. Length:

Not Functioning

4-103

Columns 6 Piers:7-Pile Bents - R/C Pile Ext. = Col.

Transverse Cross-Section Dimension:Pile Ext. ~1'iam.Longitudinal Cross-Section Dimension:

Confinement Details: (Standard P5 9 6" Pitch.

Foundation Type:

Abutmen ts:Type: R/C dia hra m

'eight:.~

3'oundationType: Concrete P i 1 es (45 ton)

Wingwalls:

Evaluation:

Continuous X Discontinuous Length 10''

Earthquake Resistance Mechanism: Shear in abutments and shear

and bendin in i le bents - Force distributed to su orts b

continuous su erstructure.

Probable Failure Mode (s): Sli ht settlement at abutment fills(less than 3").

Classif ication of Damage: Category l.

4-104

BRIDGE SEISMIC DATA FORM

General:

Name: Oceano Overhead 49-12

Location: Rte. 1, P.M. 212.60

Alignment: S tra ightLength:

260'idth:

32'ear

Built: 1964

Skewed Sg curved at West fnd

Seismically Retrofitted: Yes No

Classification: Regular " IrregularSite:

Peak Acceleration: .26 9

Liquefaction Potential:Su erstructure:

Material and Type:

Number of Spans: 3

Continuous: Yes

R/Concrete Box Girder

No

~Bearin s:

Type: Steel Rocker Bearings

Condition: Functioning X Not Functioning

Restraint (Trans): Steel KeePer Pl ates

Restraint (Longit):Bearing Height:

Support Length:

4-105

Columns & Piers:

Material and Type: R C

1'ransverseCross-Section Dimension:g ILongitudinal Cross-Section Dimension:

Height Range: ~

26'onfinementDetails: g4 CI'2" 4- 11 ~ dowels a b

Rebar continues from column to deck ca . 11 Tnt. 12

Foundation Type: Concrete Piles.

Abutments:

Type: Seat t e with edestals.

Height: 1

Foundation Type: Concrete Pi les Class I Some bat ered 1:

Wingwalls: Continuous Discontinuous X Length ]6> - 21>

Evaluation:

Earthquake Resistance Mechanism- Bearin s ran

abutments act as fuses u on failure - Bents carr inertia for e in

shear & bendin - Skewed continuous deck distributes load to su orting

members.

Probable Failure Mode (s): Probable to lin of rocker bearings-

Hoderate settlement of a roach fills . 8 ft. - Li uefaction

could cause severe abutment dama e due to hi h skew and abutment fills.

Classif ication of Damage: Dama e Cate or 2.

4-106

BRIDGE SEISMIC DATA FORM

General:

Name: Bridge Across Villa Creek

Location: Rte. 1 P.M. 15.27

Alignment: Straight " Skewed

Length:116'idth:

26'ear

Built: 1947

49-10

Curved

Seismically Retrof itted: Yes No X

Site:Classification: Regular irregular

Peak Acceleration: 0 26 9

Liquefaction Potential: I i

Su erstructure:Material and Type: Continuous R/Concrete Slab

Number of Spans: 5

Continuous: Yes X No (Construction Joint)

~Bearin s:

Type-None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Functioning

4-107

Col-umns 6 Piers:

Material and Type: R/Concrete Pile Ext. -Pi le Bents.

Transverse Cross-Section Dimension: 1 '6"

Longitudinal Cz'oss-Section Dimension: 1'6"

Height, Range: 4' 8' average pile penetration: 26'40'onf

inement Details: No. 5 0 6" i tch / dowel s ca

Foundation Type: R/Concrete P i 1 e Ext. -Pile Bents.

Abutments:

Type: S 1 ab R/C

Height: Sma 1 1

Foundation Type: R/C Pi les

Wingwalls: Continuous Discontinuous Length 'one.Evaluation:

Earthquake Resistance Mechanism: 5- i le Ext. Bents and a

cont inuous superstructure.

Probable Failure Mode (s): None; Fi ll settlement 4"

Moderate to high liquefaction potential.

Classification of Damage: Cate ory 2 or possibl Cate ory 3.

4-108

BRIDGE SEISMIC DATA FORM

General:

Name: Stenner Creek Bridge (Widening)

Location: Rte. 1 P. M. 17. 05

49-123

Alignment: StraightLength:

50'kewed 41 Curved

Width:64'ear

Built: 1899 - Widened 1968

Seismically Retrof itted: Yes

Classification: Regular

Site:

No X

Irregular

4

Peak Acceleration: 0.21 g

Liquefaction Potential:Su erstructure:

Material and Type: R/C Slab; T-beams / part Masonry Arch.

Number of Spans:

Continuous: Yes X No

Bearinces:None

Type-

Condition: Func t ion ing

Restraint (Trans):

Restraint (Longit):

Bearing Height:

Support Length:

Not Functioning

4-109

Columns & Piers:

Material and Type:None

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range:

Confinement Details:

Foundation Type:

Abutments:

Type: Diaphragm Type - side walls

Height:

Foundation Type: S«i p

Wingwalls: Continuous X Discontinuous Length

Eva lua tion:Earthquake Resistance Mechanism: Abutments and a continuous

deck/supe rs t rue ture.

Probable Failure Mode(s): None

Classif ication of Damage: Category 1

4-110

BRIDGE SEISMIC DATA FORM

General:

Name: Chorro Creek Overhead 49-63

Location: Rte. 1 P.H. 21.14

Alignment: StraightLength:

395'idth:

54

Skewed 48 Curved

Year Built: 1942

Seismically Retrofitted: Yes No X

Classif ication: Regular X IrregularSite:

Peak Acceleration:

Liquefaction Potential:

~ 23 g

I I - I I I (assumed)

Su erstructure:Material and Type: Steel Plate Girder - R/C Slab deck

Number of Spans: 4

Continuous: Yes No X Exp. Jts.

Bearinces:

Type: Steel Roller at bent caps / Fixed to column for translation.

Condition: Functioning X Not Functioning

Restraint (Trans): Keeper plates

Restraint (Longit):Bearing Height: 3"

Support Length:

Hanger bars at intermediate expansion jt. - nothing aabutments.

at abutment

4-111

Columns & Piers:

Material and Type: I-section Steel C 1. n e 5-Col. Bents(one pier cracked)

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range:32'm&ineateatDetails: N.A.

Foundation Type: Pile Footin s

Abutments:

Type

Height:

None

Foundation Type:

Wingwalls: Continuous Discontinuous Length

Evaluation:

Earthquake Resistance Mechanism: Fixed bearin s transfer load to

the abutments or bents. Bents a ear ver flexible but deck is unable

to transfer load to abutments because of discontinuit of ex ansion

oint - Abilit of structure to withstand dis lacement is critical.Probable Failure Mode(s): The most robable failure mode results from

excessive displacements caused b fill settlement or li uefaction.

Possible minor dama e at or near.mid span bearin s - Possible abutment

bearing failure resul tin in 3" settlement. High liquefaction potential.

Classification of Damage: Cate or 2 or Cate or 3 if lar e

round movements due to li uefaction occur. Also hi her force levels

ma cause bearin failures and colla se.

4-112

BRIDGE SEISMIC DATA FORM

General:

Name: Ba wood Park Road U.C. (49-177)

Location: Rte. 1 P.M. 27.88

Alignment: Straight X Skewed

Length:44'idth:

64'urved

Site:

Year Built: 1959

Seismically Retrof itted: Yes No X

Classif ication: Regular X Irregular

Peak Acceleration: 0.27 g

Liquefaction Potential:Su erstructure:

Material and Type: R/C Slab - Forms a Portal Frame with Abutment Faces.

Number of Spans:

Continuous: Yes X No

Bearinces:

Type:None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):

Bearing Height:

Support Length:

Not Functioning

4-113

Columns & Piers:

Material and Type:None

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range:

Confinement Details:

Foundation Type:

Abu tmen ts:Type: Col. part of Portal Frame / Win -walls (Cantilever Retain. Wal ls)

Height: . 10'G.L. to Foundation)

Foundation Type: S t r i p

Wingwalls: Continuous X Discontinuous Length25'valuation:

Earthciuake Resistance Mechanism: Abutments and a continuous deck

forming a portal frame.

Probable Failure Mode (s) . None; Fill Settlement ~ 5"

Classif ication of Damage:

4-114

BRIDGE SEISMIC DATA FORM

General:

Name: South Morro Bay Overcrossing

Location: Rte. 1 P.M. 28.82

(49-1O8)

Alignment: StraightLength:

233'idth:

32'ear

Built: 1962

Skewed Curved

Site:

Seismically Retrofitted: Yes No

Classif ication: Regular X Irregular

Peak Acceleration: 0.29 g

Liquefaction Potential:Su erstructure:

Material and Type: R/C T-beam

Number of Spans: 4

Continuous: Yes X No

~Bearin s:

Type: Rocker Type Exp. Bearings Q Abutments

Condition: Functioning X Not Functioning

Restraint (Trans): Keeper Plate, Wingwa1 1 s

Restraint (Longit): None

Bearing Height.: 3't Abutment

Support Length:

2.5'-115

Columns & Piers:

Material and Type: R/C 1 Wall - Piers

Transverse Cross-Section Dimension:12'ongitudinalCross-Section Dimension: ~ 1'6"

Height Range:18'onfinementDetails: P4 WW4 0 18 for Pier Wal 1 / P9 L and

ke 12" X 12' 1"5/8" ke Ia base / Pier Cap widens to deck width.

Foundation Type: Stri . found.

Abu tmen ts:Type'. Seat t e wi th edes tais

Height: ~6'oundation Type: S t r i p found.

Wingwalls: Continuous Discontinuous X Length14'valuation:

Earthquake Resistance Mechanism: Possible keeper plate failure

at abutment bearings. Shear at piers. Support lengths are expected

to accommodate transl. and long. movements.

Probable Failure Mode (s): Structural damage not expected, Fi 1 l

settlement 3" (Overcorssing: OK)

Classif ication of Damage: Category 1

4-116

BRIDGE SEISMIC DATA FORM

General:

Name: North Morro Bay Undercrossing

Location: Ate P.M. 29. 62

(49-109)

Alignment: Straight Skewed 3> Curved0

Leng th: 61

'idth:

74'ear

Built: 1962

Seismically Retrofitted: Yes No X

Classification: Regular ~ IrregularSite:

Peak Acceleration: O 32 g

Liquefaction Potential:Su erstructure:

Material and Type: R/C Box Girder

Number of Spans:

Continuous: Yes " No Exp. Jts. 9 Abutment

Bearinces:

Type: Expansion Jts. 9 Abutment

Condition: Functioning X Not Functioning

Restraint (Trans): Shear keys 9 Abut. 2'ey 9 15'enters.

Restraint (Longit): Abutment wingwa11s.

Bearing Height:

Support Length:

4-117

Columns & Piers:

Material and Type:None

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range:

Confinement Details:

Foundation Type:

Abutments:

Type: Abut. Walls and Wingwalls

Height: ~25'oundation Type.. Strip found.

Wingwalls: Continuous X Discontinuous Length —35

Evaluation:

Earthquake Resistance Mechanism: Shear keys Q abutments may

fail in shear.

Probable Failure Mode ~s1. Possible shear key failure 9 abutments;

Excessive settlement ~ 6".

Classification of - Damage Category 1 due to settlement only.

4-118

BRIDGE SEISMIC DATA FORYi

General:

Name: Morro Creek Bridges 49-181 with Left 6 Right outer hwy. structure

Location: Rte. 1 P.M. 30.10

Alignment: Straight X Skewed Curved

Length:80'idth:

Site:

Year Built: 1962

Seismically Retrofitted: Yes

Classification: Regular

Peak Acceleration: 0.32 9

No X

Irregular

Liquefaction Potential:Su erstructure:

Material and Type: R/C Slab

Number of Spans: 4

Continuous: Yes X No

Bearinces:NoneType:

Condition: Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Functioning

4-119

Columns & Piers:

Material and Type: R/C Piles Extendin from Pier Walls R/C

Transverse Cross-Section Dimension: ~1'4" diam.

Longitudinal Cross-Section Dimension: 1'4" diam.

Height Range: 4'

12'onfinementDetails: No. 5 9 6" pitch

Foundation Type:I

Abutments:

Concrete Piles

Type D i aphragm

Height:

Foundation Type: Concrete Pi les

Wingwa 1ls: Continuous Discontinuous " Length

Eva lua t ion:

Earthquake Resistance Mechanism: Pile Ext. expected to behave

in a ductile mode to accommodate movement of deck. Also shear in bents.

Probable Failure Mode (s): Non-structural dama e. Fi11 settlement

~8" ex ected. Ram structures ma ex erience minor column dama e-Hi h li uefaction otential.

Classification of Damage: Cate or 2 or Category 3 if liquefaction

exce tionall severe.

4-120

BRIDGE SEISMIC DATA FORM

General:

Name: Route 1/41 Separation

Location: R«. 1 P.~ 3o 1o

49-182 R 6 1 Similar

Alignment: Straight ~ Skewed Cursed

Length:69'idth:

74 t

Year Built:Seismically Retrofitted: Yes No

Classit ic'ation: Regular x IrregularSite:

Peak Acceleration: 0. 2

Liquefaction Potential:Su erstructure:

Material and Type- R C Box Girder

Number of Spans: 1

Continuous: Ye X No

Bearinces:

Type: Ex . Jt.

Condition: Functioning X Not Functioning

Re stra int (Tran s ): dowe 1 s

Restraint (Longit):dowe 1 sut.

Bearing Height: "3k"

Support Length:

¹5 g 18" X 2'6" long. Abut. Wingwalls shear keysong p ace 9 15'ent.

¹5 Q 18" X 2'6" long.ingwa s.

4-121

Columns & Piers:

Material and Type:None

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range:

Confinement Details:

Foundation Type:

Abutments:

Type; Di aPhragm

Height.-22'.L. to face of strip footing.

Foundation Type: Strip found.

Wingwalls: Continuous X Discontinuous Length"20'valuation:

Earthquake Resistance Mechanism: Shear keYs 9 abut. resisting

transverse motion and possibly failing in shear.

Probable Failure Mode (s): Shear ke s fai 1 in . Set leme

6". Possible abutment tiltin . Moderate li uefaction otential.

Classif ication of Damage: Cate or 2

4-122

BRIDGE SEISMIC DATA FORM

General:

Name: Bridge Across Toro Creek 49-68 R

Location: Rre. 1 P.H. 32.61

0Alignment: Straight Shewed 20 Car<ed

Length:

Width:

Year Built:Seismically Retrofitted: Yes No X

Classif ication: Regular X - IrregularSite:

Peak Acceleration: 0. 2

Liquefaction Potential:Su erstructure:

Material and Type: R/C Slab

Number of Spans: 5

Continuous: Yes X No

Bearinces:

Type:None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Functioning

4-123

Columns & Piers:

Material and Type: -Pile-Ext. en 'b n

Transverse Cross-Section D'imension: ~1'"Longitudinal Cross-Section Dimension: ~1'"Height. Range: 5' 12' rom G. L. to Cap.

Confinement Details: ¹5 wire I 6" itch.

Dowels at pile cap.

Foundation Type: R. Concrete Piles.

Abutments:

Type: Diaphragm (assumed same as 49-68 L)

Height: 3'assumed same as 49-68 L)

Foundation Type: R/C P i l es

Wingwalls: Continuous X Discontinuous Length10'5'valuation:

Earth~age Resistance Mechanism: Shear in pile ext. Pil~s behaving

in a ductile mode.

Probable Failure Mode (s): None exPected. 1 'ettlement of f i 1 l.

Classif ication of Damage:

4-124

check new setl. criteria

BRIDGE SEISMIC DATA FORM

General:

Name: Bridge Across Toro Creek

Location: Rte. P.H. 32.61

49-68 L

Alignment: Straight Skewed"Ie Curved

Length:117'idth:

37'ear

Built: 1962

Seismically Retrofitted: Yes Ro .

Classification: Regular " IrregularSite:

Peak Acceleration:

Liquefaction Potential:Su erstructure:

Material and Type: R R C Sl ab

Number of Spans: 4

Continuous: Yes X No

Bearinces:

Type:None

Condition: Functioning

Restraint (Trans):

Not Functioning

Restraint (Longit):

Bearing Height:

Support Length:

4-125

Columns & Piers:

Material and Type: -Pi le-Ext. Bents. R C Pi le Ext. no bent caps)

Transverse Cross-Section Dimension: diam. 1'2"

Longitudinal Cross-Section Dimension: diam. 1'2"

Height Range: 60'otal lt./penetration-40'onfinementDetails: '¹5 0 6" pitch

Foundation Type: Concrete Piles

Abutments:

Type: D i aphragm Type

Height: 3

Foundation Type: Concrete Pi les

Wingwalls: Continuous X Discontinuous Length

Evaluation:

Earthquake Resistance Mechanism:

a ductile mode to al)ow movement of deck.

Piles in shear, behaving in

Probable Failure Mode (s): None ex ected. Fill settlement over 1'.

Classif ication of Damage: Cate or 2

4-126

BRIDGE SEISMIC DATA FORM

Only One plan (For repair in 1979) available

General:

Name: Corb| t Canyon Creek,

Location: Route 227, PM 0.50

49 - 77

Alignmen t: S tra ight " Skewed

Length:13'idth:

75'ear

Built: 1899, Repair 1980

Seismically Retrof itted: Yes

Curved

No X

Site:Classif ication: Regular X Irregular

Peak Acceleration: .22

Liquefaction Potential: ~ (»sum«)

Su erstructure:Material and Type: Concrete Arc. Cul vert

Number of Spans:

Continuous: Yes No

Bea~inces:

Type:

Condition: Functioning

Restraint (Trans):

Restraint, (Longit):

Not Functioning

Bearing Height:

Support Length:

4-127

Columns & Piers:None

Material and Type:

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range:

Confinement Details:

Foundation Type:.

Abutments:None

Type-

Height:

Foundation Type:

Wingwa l1 s: Continuous Discontinuous Length

Evaluation:

Earthquake Resistance Mechanism:

4

Probable Failure Mode (s):

Classif ication of Damage: Cate or 1

4-126

BRIDGE SEISMIC DATA FORM

General:

Name: Branch Street Pedestrian O.C. 49 - 201

Location: Rte 227, PM 0.86

Alignmentl Straight X Skewed Curved

Length:144'idth:

9'ear

Built: 1963

Seismically Retrofitted: Yes No X

Col HeightsClassification: Regular Irregular " ~ " f"d "PP "

Site:Peak Acceleration: .21

Liquefaction Potential:Su erstructure:

Material and Type: oncrete irder corcrete slab no abutmentin the "right" end

Number of Spans: 3

Continuous: Yes~ No

~Bearin s: Seat type abutment. in the",left" end. Pier 1: Fixed bearingPier 2: Roller bearing

Type-

Condition: Functioning~ Not Functioning

Restraint (Trans):

Restraint (Longit):r Plates

Bearing Height: 4 4ll

Support Length:

4-129

Columns & Piers:

Material and Type: R C Piers

Transverse Cross-Section Dimension:

8'ongitudinalCross-Section Dimension: 14"

Height Range: 13'3'gConf inement Details: ¹3 9 12" in iers

Foundation Type: S read footin1

Abutments: None

Type:

Height:

Foundation Type:

Wingwalls: Continuous Discontinuous Length

Evaluation:

Earthquake Resistance Mechanism: Transversel the lateral

force is transmitted to the iers throu h the bearin s. Lon itudiall the

stabilit of the main s an de ends on the tie to the fixed bearin s. Hi h

PGA or deformation could result in instabilit .

Probable Failure Mode(s): Failure of kee er bars and shifting

of superstructure on su orts. Because of low PGA bearin s will robabl

not to le.

Classif ication of Damage: Dama e cate or 1

4-130

BRIDGE SEISMIC DATA FORM

General:

Name: East Fork Pismo Creek Bridge, 49 - 112

Location: Rte 227 PN 5.3

Alignment: Straight Skewed 45 Curved0

Length:78'idth:

32'ear

Built: 1966

Site:

Seismically Retrof itted: Yes No X

Classification: Regular X Irregular

Peak Acceleration: .21

Liquefaction Potential: I

Su erstructure:Material and Type: Concrete slab

Number of Spans: 3

Continuous: Yes X No

Bearinces: None

Type:

Condition: Funct,ioning

Restraint (Trans):

Restraint (Longit):

Not Functioning

Bearing Height:

Support Length:

4-131

Columns & Piers:

Material and Type: R C Piles Pile. columns

Transverse Cross-Section Dimension: 1' 3"

Longitudinal Cross-Section Dimension: 1' 3"

Height Range:16'onfinementDetails: 85 9 6" itch standard

Foundation Type: R/C i les

Abutments:

Type: Dia hra m

Height:

Foundation Type: R/C iles

Wingwalls: Continuous X Discontinuous Length13'valuation:

Earthquake Resistance Mechanism: Shear at abutments

shear and bendin at bents.

Probable Failure Mode(s): Minor settlement at the fill.

Classif ication of Damage: Cate ory l.

4-132

BRIDGE SEISMIC DATA FORM

General:

Name: East Corral De Piedra Creek Bridge, 49 - 103

Location: Rte. 227, PM 7.1

Alignment: StraightLength:

42'idth:

56'

Skewed l7 Curved

Year Built: 1978

Seismically Retrofitted: Yes No

Classification: Regular " IrregularSite:

Peak Acceleration: .21 g.

Liquefaction Potential:Su erstructure:

Material and Type:

Number of Spans:

R/C slab

Continuous: Yes X No

~Baarin s:

Type. NONE

Condition: * Functioning

Restraint (Trans):

Restraint (Longit):

Bearing Height:

Support Length:

Not Functioning

4-133

Columns a Piers:

Material and Type: Pier wall Whole width of BR

Transverse Cross-Section Dimension:56'ongitudinalCross-Section Dimension: 1 '-0" thi ckness

Height Range:~12'onf

inement Details: Not iven on lans. Vertical

rebars k5 9 18" in the ier walls continue into the R C slab

Foundation Type: Concr. iles

Abutments:

Type: Dia hra m

Height:

Foundation Type: Conc. iles

Wingwalls: Continuous X Discontinuous Length13'valuation:

Earthquake Resistance Mechanism: Shear at abutments shear

and bendin 4 the bent.

Probable Failure Mode (s): No damage.

Classification of Damage: .Categor .l.

4-134

BRIDGE SEISMIC DATA FORM

General:

Name: West Corral de Piedra Creek Bridge 49 - 204

Location: Rte 227 PH 7 3

Alignment: StraightLength:

.73'idth:

45

0Skewed 15 Curved

Year Built: 1971

Seismically Retrofitted: Yes No

Classif ication: Regular X IrregularSite:

Peak Acceleration: .21 g.

Liquefaction Potential:Su erstructure:

Material and Type:

Number of Spans: 1

R C box irder

Continuous: Yes X No

Bearinces:

Type:

NONE

Condition: Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Functioning

4-135

Columns & Piers:

Material and Type: No bents

Tran sverse Cross-Sec tion Dimension:

Longitudinal Cross-Section Dimension:

Height Range:

Confinement Details:

Foundation Type:

Abutments:

Type:

Height:

Dia hra m

7I

Foundation Type: Steel iles

Wingwalls: Continuous X Discontinuous Length18'valuation:

Earthquake Resistance Mechanism: Shear in the abutments.

Probable Failure Mode(s): Minor settlement at fill

Classification of Damage: Cate or 1

4-136

BRIDGE SEISMIC DATA FORM

General:

Name: North Edna overhead, 49 - 220

Location: Rte 227, PM 8.7

Alignment: StraightLength:

231'idth:

40'

Skewed 60 Curved

Year Built: 1978

Seismically Retrofitted: Yes

Classification: Regular "

Site:

No X

Irregular

Peak Acceleration: .21 g.

Liquefaction Potential:Su erstructure:

Material and Type:

Number of Spans:

R/C Box Girder

Continuous: Yes X No

~Bearin s:

Type: Neo rene stri at the foot of abutment end diaphragms

Condition: Functioning X Not Functioning

Restraint (Trans): Shear keys (See 'abutment details')

Restraint (Longit):

Bearing Height: 0

Support Length:

4-137

I

Columns & Piers:

Material and Type: R/C 2 column bent

Transverse Cross-Section Dimension: 84 - 0

Longitudinal Cross-Section Dimension:

Height Range:

Confinement Details: "4 9 3~At BentsColumn rebars continue into the dia hra m of the deck

Founda tion Type: Steel i 1 es

Abutments:

Type: End dia hra m restin on a concrete stri w neo rene bearing

Height:

Foundation Type: S read footin

Wingwalls: Continuous Discontinuous X Length~18'valuation:

Earthquake Resistance Mechanism: Shear at abutments b

friction at neo rene str| and b shear ke s. Shear and

bendin at bents.

Probable Failure Mode (s): Minor settlement in the fill.

Classif ication of Damage: Cate or 1

4-138

BRIDGE SEISMIC DATA FORM

General:

Name: East Fork San Luis Obispo Creek Bridge, 49 - 116

Location: Rte 227 PN 1O 9

Alignment: Straight X Skewed

Length: 45

Width:

9O'urvedYear Built: 1978

Seismically Retrof itted: Yes No "

Site:Classif ication: Regular " Irregular

Peak Acceleration: .21 g.

Liquefaction Potential:

Su erstructure:Material and Type:

Number of Spans:

R/C Box girder

Continuous: Yes X No

Bearinces:

Type:

None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):

Bearing Height:

Support Length:

Not Functioning

4-139

Columns & Piers: No bents

Material and Type:

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range:

Confinement Details:

Foundation Type:

Abutments:

Type:

Height:

Dia hra m

Hi h

Foundation Type: Steel i 1 es

Wingwalls: Continuous X Discontinuous Length30'valuation:

Earthquake Resistance Mechanism: Rigid frame structures

Probable Failure Mode(s): Minor abutment fill settlement.

Classif ication of Damage: Damage category 1

4-140

BRIDGE SEISMIC DATA FORM

General:

Name: Acacia Creek Culvert

Location: Route 227, PM 11. 7

49 - 117

0Alignment: Straight Skewed 4S Curved

Length:39'idth:

145'ear

Built: 1968

Seismically Retrofitted: Yes No Y

Classification: Regular X XrregularSite:

Peak Acceleration: .21 g

Liquefaction Potential:Su erstructure:

Material and Type:

Number of Spans: 1

Concrete box culvert

Continuous: Yes~ No

Bearinces:lNone

Type-

Condition: Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Functioning

4-141

Columns & Piers: No bents

Material and Type:

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range:

Confinement Details:

Foundation Type:

Abutments:

Type: Culvert wall and win wall

Height:14'oundationType: S read footin s under win walls

Wingwalls: Continuous Discontinuous X Length 29

'valuation:

Earthquake Resistance Mechanism: Ri id concrete box

culvert - Resists loads as a ri id frame.

Probable Failure Mode(s): Minor abutment fill settlements

which robabl will not result in roadwa discontinuit .

0

Classif ication of Damage: Dama e Cate or 1

4-142

BRIDGE SEISMIC DATA FORM

General:

Name: Bridge across San Luis Obispo Creek, 49 - 58

Location: Rte. 227, PM 13.8

Alignment: S tra ightLength:

136'idth:

74'

Skewed 52 Curved

Site:

Year Built: 1948

Seismically Retrof itted: Yes No X

Classif ication: Regular " Irregular

Peak Acceleration: .21 g.

Liquefaction Potential: I I I (assumed)

Su erstructure:Material and Type: Steel stringer girders, R/C Slab

Number of Spans: 3

Continuous: Yes X No

~Bearin s:

Type: Steel rocker bearin s at abutments and bents

Condition: Functioning X Not Functioning

Restraint (Trans): keeper plates

Restraint (Longit): none

Bearing Height:

Support Length:

6 II

20"

4-143

Columns 6 Piers:

Material and Type: R/C ier wall

Transverse Cross-Section Dimension:50'ongitudinalCross-Section Dimension: 2' 4"

Height Range:16'onfinementDetails: 3-" 9 6' 0" Horizontal and vertical

in the walls.

Foundation Type: Steel iles

Abutments:

Type: Seat t e

Height: ~ 15'ariesFoundation Type: Steel iles 10 BP 42

Wingwalls: Continuous Discontinuous X Length20'valuation:

Earthquake Resistance Mechanism: Continuous steel late

irder su erstructures - Rocker bearin s transmit loads to wide

iers and abutments.

Probable Failure Mode (s): Bearin kee er bars ma fail.Because of lar e skew bearin s could to le.

Classif ication of Damage: Dama e cate ory 2

4-144

BRIDGE SEISMIC DATA FORM1 eGeneral:

Name: Bridge Across Atascadero Creek

Location: Rte. 41, P.M. 13.1

49-49

Alignment: Straight 0Skewed 4O Curved

Length:

Width: 117'4'ear

Built: 1937

. Seismically Retrof itted: Yes No X

Classif ication: Regular X IrregularSite:

Peak Acceleration: ~ 18 9

Iiquefaction Potential:Su erstructure:

Material and Type: T imbe r S t ringer

Number of Spans:

Continuous: Yes No X

Bearinces:

Type: Exp. Joints at Abutments, 1 Exp. Joint Midspan at middle of bridge.

Condition: Functioning X Not Fun'ctioning

Restraint (Trans): Drift pins in stringers

Restraint (Longit): Dri ft pins in stringers

Bearing Height:

Support Length: ~14"

4-145

Columns & Piers:Next Abutments: Concrete bents + 6 wood columns + cross

Material and Type: + lumns.

Transverse Cross-Section Dimension: 2»

Longitudinal- Cross-Section Dimension: ]2»

Height Range:28'onfinementDetails:

Foundation Type: Pedestal Foot in sNext to Abutments: Spread Footings

Abutments:

Type: Seat Abutment L-section

Height:

Foundation Type: S read Foot in

Wingwalls: Continuous Discontinuous X Length ~] p ~

Evaluation:

Earthquake Resistance Mechanism: Timber structure is tied together

with drift ins - Lateral loads are carried throu h these ins to the

su orts'he structure is hi hl discontinuous.

Probable Failure Mode(s): Because of low PGA serious failure is

not antici ated. Hinor failure of drift ins and shiftin of stringer

ma occur. It is conceivable that ed e strin er ma become unseated,

but this should not im air traffic. Hi h force levels could be critical.Classification of Damage: Dama e Cate or 1 unless 1 i uefaction is

robable in which case structure colla se is likel

4-146

BRIDGE SEISMIC DATA FORM

General:

Name: Brid e across Atascadero Creek, 49 - 50

Location: Rte. 41, PM 13.2 .

Alignment: Straight Skewed 40 Cursed

Length:98'idth:

24'ite:

Year Built: 1937

Seismically Retrof itted: Yes No X

Classification: Regular I Irregular

Peak Acceleration: .18

Liquefaction Potential:Su erstructure:

Material and Type:

Number of Spans:

Continuous: Yes

Timber Strin er

No X

Bearinces:

Type: Like 49 - 49

Condition: Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Functioning

4-147

Columns & Piers: Like 49 - 49

Material and Type:

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range:

Confinement Details:

Foundation Type:

Abutments: like 49 - 49

Type:

Height:

Foundation Type:

Wingwalls: Continuous Discontinuous Length

Evaluation:

Earthquake Resistance Mechanism:

Same as 49 — 49

Probable Failure Mode (s):Same as 49 - 49

Classif ication of Damage:

4-148

BRIDGE SEISMIC DATA FORM

General:

Name: Bridge across Atascadero Creek 49 - 51

Location: Rte 41, PH 13.3

Alignment: Straight Skewed 40 Curved

Length:98'idth:

24

Site:

Year Built: 1937

Seismically Retrofitted: Yes -No

Classif ication: Regular I Irregular

Peak Acceleration: .18

Liquefaction Potential:Su erstructure: Like 49 - 49

Material and Type:

Number of Spans:

Continuous: Yes No

Bearinces:

Type:

Like 49 - 49

Condition: Functioning

Restraint (Trans):

Restraint (Longit):

Bearing Height:

Support Length:

Not Functioning

4-149

Columns & Piers: Like 49 - 49

Material and Type:

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range:

Confinement Details:

Foundation Type:,

Abutments: Like 49 - 49

Type-

Height:

Foundation Type:

Wingwalls: Continuous Discontinuous Length

Evaluation:

Earthquake Resistance Mechanism:

Probable Failure Mode (s): Same as 9-

Classif ication of Damage: Same

4-150

BRIDGE SEISMXC DATA FORM

General:101-41

Name: Route 2-125 Separation, 49 - 150 R/L RSL Equal

Location: Rte 41, PM 16. 0

Alignment: StraightLength:

139'idth:

28'ear

Built: 1956

Skewed 21 Curved

Site:

Seismically Retrofitted: Yes No X

Classification: Regular I Irregular

Peak Acceleration: .17g.

Liquefaction Potential: I - I I

Su erstructure:Material and Type: Steel girder, welded, conc. slab

Number of Spans: 1

Continuous: Yes X No

Bear incesl

Type: Rocker bearin s at one abutment, fixed bearing in the other

Condition: Functioning X Not Functioning

Restraint (Trans): Kee er late and curtain wall

Restraint (Longit): None

Bearing Height:

Support Length: ~ 1'"511

4-151

2

Columns 6 Piers: None

Material and Type:

Transverse Cross-Section. Dimension:

Longitudinal Cross-Section Dimension:

Height Range:

Confinement Details:

Foundation Type:

Abutments:

Type: Seat t e bearin wall and win walls

Height:~15'oundation

Type: Steel iles 10 BP'42

Wingwalls:

Evaluation:

Continuous Discontinuous X Length

Earthquake Resistance Mechanism: Sin le s an steel

plate irdes su erstructure su orted on rocker bearin s

Probable Failure Mode(s): Because of low PGA no dama e is

antici ated. Hi her force levels could result in Cate or 2 dama e.

Classification of Damage: Cate ory 1 or 2

4-152

BRIDGE SEISMIC DATA FORM

General:

San Luis Obispo Creek Bridge'n Avila Cut-off Road 49C-151

Location:

Alignment: Straight " Skewed Curved

Length:

Width:

Year Built:Seismically Retrofitted: Yes No X

Site:Classification: Regular irregular X (tel «i gals)

Peak Acceleration: s31 g

Liquefaction Potential:Su erstructure:

Material and Type:

Number of Spans: 5

R/C T-Beam

Continuous: Yes X No

Bearinces:

TYpe: None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Functioning

4-153

BRIDGE SEISMIC DATA FORM

General:

Name: Brid e Across See Canyon Creek

Location:

49C-150

0Alignment: Straight Skewed 5 Curved

Length:32'idth:

28'ear

Built:Seismically Retrof itted: Yes No X

Site:Classif ication: Regular X Irregular

Peak Acceleration:

Liquefaction Potential:Su erstructure:

Material and Type: R/C Sla6

Number of Spans:

Continuous: Yes " No

Bearinces:

Type None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Functioning

4-154

Columns & Piers:

Material and Type: P C ~ C. 5 Column Bents

Transverse Cross-Section Dimension: 1'"Longitudinal Cross-Section Dimension: 1'"

12'ent 2

Height Range: 27'ent 4

Confinement Details: ¹5 6 6"

Foundation Type: Steel Piles on R/C Footing at Bent 2oncrete i es, ot er ents.

Abu tmen ts:Type. Di aPhragm

Height:

Foundation Type Steel Pi les north end, R/Concrete Pi les, south end

Wingwalls: Continuous " Discontinuous Length

Evaluation:

Earthquake Resistance Mechanism: Continuous R/C slabs distribute

loads to pile bents which resist in shear and bending and

abutments which resist in shear.

Probable Failure Mode (s): Moderate Abutment Fil 1 Settlements.

Classif ication of Damage: Dama e Cate or 2.

4-155

Columns & Piers:

Material and Type:

Transverse Cross-Section Dimension: L+ XLongitudinal Cross-Section Dimension:

Height Range:12'onfinementDetails: t4 9 12"

Foundation Type: Stri Footin

Abu tmen ts:Type: None; Ends of deck rest on the round.

Height:

Foundation Type:

Wingwalls: Continuous Discontinuous Length

Evaluation:

Earthquake

force

Resistance Mechanism: Abutments and bent resist

in shear and bending. Continuous deck distributes load

wel 1.

Probable Failure Mode (s): Abutment tilting " Moderate fil,l

settlement - High 1 iquefact ion potential".

Classif ication of Damage: Damage Category 2.

4-156

BRIDGE SEISMIC DATA FORM

General:

Name: Harford Drive Bridge (SLO 49C-327)

Location Ha rford D r i ve 0 Av i 1 a Beach

Alignment: StraightLength: 480

Skewed Curved

Width:38'ear

Built:Seismically Retrofitted: Yes No X

Site:Classification: Regular X Irregular

Peak Acceleration:

Liquefaction Potential:Su erstructure:

Material and Type: P/C P/S Concrete "I" Girders

Number of Spans: 8

Continuous: Yes No X

Bearinces:

Type: Elastomeric Pads

Expansion Jts. 9 Some Piers

Condition: Functioning X Not Functioning

Restraint (Trans): Concrete Shear Keys

Restraint (Longit): None 9 Expansion Joints

Bearing Height:

Support Length: i '-2" 9 Exp. Jt.2'-2" 9 Abut.

4-157

Columns & Piers:

Material and Type: R Pie

F'ransverseCross-Section Dimension: 20'in.Longitudinal Cross-Section Dimension: 1.

Height Range: 30' 15'IConfinement Details: ¹4 0 18 verticall with ¹4 ties 0u

Foundation Type: Spread s Pile Footing

Abutmen ts:Type: Seat type with end of bridge deck retaining fill.Height: 10'ax.

Foundation Type: Spread 0 A-1; Pi les 9 A-9

Wingwalls: Continuous X Discontinuous Length10'valuation:

Earthquake Resistance Mechanism: Abutments and 'Piers resist

lateral forces in shear and bending. Nominal shear keys

transfer loads to piers. Discontinuous deck prevents distribution

of all load to the support.

Probable Failure Mode (s):~~Shiftin of su ers r r -C 1

Classification of Damage: Dama e Cate or 3 due to li uefaction

and ossible loss of su ort.

4-158

BRIDGE SEISMIC DATA 'FORM has LOTB

South Bay Boulevard

Name: Los Osos — Morro Bay Road

Location:

13027 - B1

Alignment: Straight ~ Skewed Curved

Length: 189

Width:37'ear

Built: 1966

Seismically Retrofitted: Yes No

Classification: Regular IrregularSite:

Peak Acceleration: .30 g

Liquefaction Potential:Su erstructure:

Material and Type: Prestressed Concr. - I-Beams R/C Slab

Number of Spans:

Continuous: Yes No X

Bearinces:

Type- Ex . Joints at Bents 2 6 Hin es at Abutments

Condition: Functioning X Not Functioning

Restraint (Trans): None, Bents / Wingwal 1 s, Abutm.

Restraint (Longit): None, Bents / Shear Keys, Abutm.

Bearing Height: ~ 0"

Support Length: ~ 12" at3't

bents

abutments

4-159

Columns & Piers:

Material and Type: R/C Pile Extensions /Bent

Transverse Cross-Section Dimension: 18"

Longitudinal Cross-Section Dimension: 18"

Height Range: ~~

28'onfinementDetails:

Foundation Type:

Abutments:

Type- Seat"type with Shear Keys

Height:

Foundation Type:

Wingwalls: Continuous

Evaluation:

Discontinuous " Length ~15

Earthquake Resistance Mechanism: Concrete shear keys and

sliding bearings transfer load to abutments and pile bents-

Discontinuous deck does not distribute load well.

Probable Failure Mode (s): p sib e e u

robable li uefac ion. Pr bable abutment fill settlement.

Classif ication of Damage: Dama e Cate or 3.

4-160

BRIDGE SEISMIC DATA FORM

General:

Name:

Location:

49C-238-Los Osos Valley Road 2088 BR-1 (13028 - B1)

Alignment: Straight X Skewed Curved

Length: 30'52')Nidth: 30'fter widening

Year . Built: 1921, widened 1958

Seismically Retrof itted: Yes No

Classif ication: Regular " IrregularSite:

Peak Acceleration:

Liquefaction Potential:Su erstructure:

Material and Type: R/C T-Girder

Number of Spans:

Continuous: res X No

Bearinces:

Type:None

Condition:, Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Functioning

4-161

Columns & Piers:

Material and Type:

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range:

Confinement Details:

Foundation Type:

Abutments:

Type- Closed

Height:

Foundation Type:

Wingwalls: Continuous " Discontinuous Length

Evaluation:

Earthquake Re'sistance Mechanism: Single sPan bridge with

diaphragm abutments.

Probable Failure Mode (s): Min r fi 1 lee - i

li uefaction otential.

Classif ication of Damage: Dama e Cate or 2.

4-162

BRIDGE SEISMIC DATA FORM

General:

Name: Ontario Road Brid e 49C-197

Location: County Road 9 San Luis Obispo Creek

Alignment: Straight X Skewed Curved

Length:686'idth:

20'ear

Built: 1915

Seismically Retrofitted: yes Ro X

Site:Classification: Regular irregular ,X

Peak Acceleration: .29 g

Liquefaction Potential:Su erstructure:

Material and Type R/C T-Beam Approaches " P rat t Truss Ha in Span

Number of Spans 1 7 approach spans -1 ma i n span

continuous: ye Ro x S Joints S tenss

Bearinces:

Type: Steel sliding plates at approach spans,.- Roller nest Q truss

Cond it ion: Functioning Not Functionin 2 - Columns at ExP. jts.cracked

Restraint (Trans) - Steel an le kee er lates

Restraint (Longit): None

4-163

Columns & Piers:

Material and Type: R/C 2 column bents

Transverse Cross-Section Dimension: O' 6 truss - 36" (approaches)

Longitudinal Cross-Section Dimension: 15" (approaches)

Height Range: 6' estimate from photo's

Conf inement Details: Apparently none

Foundation Type:

Abutments:

TyPe: Dia hra m

Height: 1' est.+

Foundation Type: S read Footin

Wingwa 1 1 s: Continuous X Discontinuous Length~Evaluation:

Earthquake Resistance Mechanism: Abutme

lateral loads in shear and bendin - Su erstructure is

discontinuous and transfers load oorl

Probable Failure Mode (s): Loss of sup ort in a roach s ans.

Shear failure in concrete approach columns. Hoderate

abutment fill settlement. High liquefaction potential.

Classif ication of Damage: Damage Category 3.

4-164

BRiDGE SEISMIC DATA FORM

General:

Name: Orcutt Road Culvert - Br. 1 (14008 - Bl)

Location: Orcutt Road 9 Canada Verde Creek

Alignment: Straight X Skewed Curved

Length: 14

'idth:

Year Built:

Site:

Seismically Retrofitted: Yes No X

Classification: Regular X Zrregular

Peak Acceleration: 9 g

Liquefaction Potential:Su erstructure:

Material and Type: R/C Box Culvert

Number of Spans:

Continuous: Yes No

Bearinces:

Type- None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):

Not Functioning

Bearing Height:

Support Length:

4-165

Columns & Piers:

Material and Type: None

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range:

Confinement Details:

Foundation Type:

Abutments:

Type: Continuous Frame with R/C Slab

Height:+

Foundation Type:

Wingwalls: Continuous Discontinuous 'ength

Evaluation:

Earthquake Resistance Mechanism: Rigid R/C Box Culvert

Probable Failure Mode ( s ): None an t i c i pated.

Classification of Damage: Dama e Cate or 1.

4-166

BRIDGE SEISMIC DATA FORM

General:

Name: Orcutt Road Culvert - Br. 2 (14008 - B2)

Location: Orcutt Road near Tiffany Ranch Road

Alignment: Straight < Skewed Curved

Length: 16. 5

'idth:19.5'ear

Built,:

Site:

Seismically Retrofitted: Yes No

Classif ication: Regular~ Irregular

Peak Acceleration:Liquefaction Potential:

Su erstructure:Material and Type: R/C Slab

Number of Spans:

Continuous: Yes No

Bearinces:

Type: None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Functioning

4-167

Columns & Piers:

Material and Type: None

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range:

Confinement Details:

Foundation Type:

Abutments:

Type:

Height: 8'-Continuous Frame with R/C Slab

Foundation Type:

Wingwa 1 1 s: Continuous Discontinuous Length

Evaluation:

Earthquake Resistance ~Mechanism: Rigid R/C Box Culvert

Probable Failure Mode (s): None anticipated

Classification of Damage: Damage Category 1.

4-168

BRIDGE SEISMIC DATA FORM

General:

Name: Orcutt Road Culvert - Br. 3 (14008 - B3)

Location: Ti ffany Ranch Road

Alignment: Straight X Skewed Curved

Length:14.4'idth:

22.0'ear

Built:Seismically Retrofitted: Yes No

Classification: Regular " IrregularSite:

Peak Acceleration: .20 g

Liquefaction potential: I (assumed)

Su erstructure:Material and Type:

Number of Spans:

R/C Box Culvert

Continuous: Ye, No

Bear inces:

Type: None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):

Bearing Height:

Support Length:

Not Functioning

4-169

Columns & Piers:

Material and Type:None

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range:

Confinement Details:

Foundation Type:

Abutments:

Type:

Height: 8»

Foundation Type:

Wingwalls: Continuous1

Discontinuous Length

'valuation:

Earthquake Resistance Mechanism: Rigid R/C Box Culvert

Probable Failure Mode (s): Hone anticipated.

Classif ication of Damage: Dama e Cate or 1.

4-170

BRIDGE SEISMIC DATA FORM

General:

Name: Orcutt Road Culvert - Br. 4 (14008 - B4)

Location: Piedra Villa Creek

Alignment: Straight X Skewed Curved

Length:18'idth:

32'ear

Built:Seismically Retrofitted: Yes No

Classification: Regular IrregularSite:

Peak Acceleration:Liquefaction Potential:

Su erstructure:Material and Type Double R/C Box Culvert

Number of Spans:

Continuous: Yes No

Bearinces:

Type: None

Condition: Funct,ioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Functioning

4-171

Columns & Piers:

Material and Type: None

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range:

Conf inement Details:

Foundation Type:

Abutments:

Type Cont inuous Frame wi th R/C Sl ab

Height:

Foundation Type: Continuous Floor

Wingwa 11 s: Continuous X Discontinuous Length 9

Evaluation:

Earthquake Resistance Mechanism: R/C Box 'u1 ver t

probable Failure Mode (s) '- None ant i c i

Pated.'lassif

ication of Damage: Dama e Cate or 1.

4-172

BRIDGE SEISMIC DATA FORM

General:

Name: Orcutt Road Bridge - Br. 5 (14008 - B5)

Location: Corral de Piedra Creek

Alignment: Straight Skewed Curved

Length: 32

'idth:24~

Year Built: 1949

Seismically Retrofitted: Yes No

Classification: Regular X IrregularSite:

Peak Acceleration:

Liquefaction Potential:Su erstructure:

Material and Type:

Number of Spans: 1

R/C Ri id Frame

Continuous: Yes X No

Bearinces:

Type: None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Functioning

4-173

Columns & Piers:

Material and Type: None

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range: .

Confinement Details:

Foundation Type:

Abutments:

Type. Continuous Frame with R/C Slab

Height: 14'+

Foundation Type:

Wingwalls: Continuous Discontinuous Length

Eva lua tion:Earthquake Res is tance Mechanism: Rigid R/C Frame

Probable Failure Mode (s): None antici ated - Hi h l i uefaction

otential.

Classif ication of Damage: Dama e Category 2 due to 1 i uefaction.

4-174

BRIDGE SEISMIC DATA FORM

General:

Name: Orcutt Road Culvert (13008 - Bl)

Location: North of Biddle Road

Alignment: Straight < Skewed Curved

Length:

Width:

Year Built:Seismically Retrof itted: Yes No

Site:

Classif ication: Regular~ Irregular

Peak Acceleration:Liquefaction Potential:

~ 22 9

I assumed

Su erstructure:Material and Type: R C Slab

Number of Spans: 1

Continuous: Yes X No

Bearinces:

Type- Friction - direct contact with abutment wal 1

Condition: Functioning 2 Not FunctioningRestra int (Tran s): Fr i c t i on

Restraint (Longit): Fr i c t i on

Bearing Height:

Support Length: 2'est ~ )

4-175

Columns 6 Piers:

Material and Type:

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height, Range:

Confinement Details:

Foundation Type:

Abutments:

Type: Free standing R/C retaining wall

Height:

Foundation Type:

Ningwalls: Continuous~ Discontinuous

Eva lua tion:

Length

Earthquake Resistance Mechanism: Inertia forces in slab are

transferred to abutments by friction.

Probable Failure Mode (s): None anticiPated.

Classification of Damage: Damage Category 1.

4-176

BRIDGE SEISMIC DATA FORM

General:

Name: Orcutt Road Culvert - Br. S-2 (13008 - S2)

Loca tion: Per ry C reek

Alignment: Straight X Skewed

Length:8.5'urved

Site:

Width:20'ear

Built:Seismically Retrof itted: Yes No X

Classif ication: Regular~ Irregular

Peak Acceleration:

Liquefaction Potential:Su erstructure:

Material and Type: Timber stringers with plank deck.

Number of Spans:

Continuous: Yes

Bearinces:

TyPe- - F i i n a sumed

No X

Condition: Functioning 7 Not Functioning

, Restraint (Trans): Fr ict ion

Restraint (Longit) - Fr i ct i on

Bearing Height:

Support Length: 2'est,)

4-177

Columns & Piers:

Material and Type:

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range:

Conf inement Details:

Foundation Type:

Abutments:

Type. Rubb I e Seat Type

Height:7'oundation Type:

Wingwalls: Continuous Discontinuous Length

Evaluation:

Earthquake Resistance Mechanism:,Inertia forces are

transferred to abutments by friction.

Probable Failure Mode (s): None anticiPated ~

Classif ication of Damage: Dama e Cate or 1.

4-178

BRIDGE SEISMIC DATA FORM

General:

Name: Prefumo Canyon Road (C2085 Br. No, 3)

Location: Rte. 2085

49C-227

0Alignment: Straight Skewed Curved

Length: 48

Width: 34

Year Built:Seismically Retrofitted: Yes No X

Site:Classification: Regular X Irregular

Peak Acceleration: .26

Liquefaction Potential: I (assumed)

Su erstructure:Material and Type: R/C Slab

Number of Spans: 1

Continuous: Yes X No

Bearinces:

Type: 'Hin es'Shear Keys) at Abutments

Condition: Functioning

Restraint (Trans): Shear Key

Restraint (Longit,): Shear Key

Bearing Height:

Support, Length: 18"

Not Functioning

4-179

Columns & Piers:

Material and Type:None

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range:

Confinement Details:

Foundation Type:

Abutments:

Type Bearing Wal 1 (on Pi les)

Height. ~ 16

'oundationType: Steel Pi les

LengthDiscontinuousWingwalls: ContinuousNo Wingwall~

Evaluation:

Earthquake Resistance Mechanism:

strutted abutments.

Single span R/C Slab wi'th

Probable Failure Mode(s): None antici ated.

Classif ication of Damage: Dama e Cate or 1.

4-180

BRIDGE SEISMIC DATA FORM

General:

Name: Prefumo Canyon Road (2085-BR4)

Location:

49C-226

Alignment: StraightLength: 32

'idth:24

0Skewed 15 Curved

Site:

Year Built: (P lans 1969)

Seismically Retrofitted: Yes No X

Cia ssif ication: Regular~ Irregular

Peak Acceleration: .26

Su erstructure:Material and Type: R C Box Cu1vert

Number of Spans: 2

Continuous: Yes X No

Bearinces:None

Type

-'ondition: Functioning

Restraint (Trans):

Restraint (Longit):

Bearing Height:

Support Length:

Not Functioning

4-181

Columns & Piers:

Material and Type:

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension".

Height Range:

Confinement Details:

Foundation Type:

Abutments:

Type:

Height:

Foundation Type:

Wingwa 11 s: Con tinuou s Discontinuous Length

Evaluation:

Earthquake Resistance Mechanism:

ncre e 1

Probable Failure Mode (s): None antici ated.

Classif ication of Damage: Dama e Cate or 1.

4-182

BRIDGE SEISMIC DATA FORM

General:

Name: Pret'umo Can on Road (2085 - BR5)

Location:

49C-223

Site:

Alignment: Straight Skewed 50 Curved0

Length:63'idth:

36'ear

Built: (P lans 1969)

Seismically Retrofitted: Yes No X

Classif ication: Regular X Irregular

Peak Acceleration: 25 g

Liquefaction Potential:

Su erstructure:

Material and Type: R/C Box Culvert

Number of Spans:

Continuous: Yes " No

Bearinces:

None

Condition: Funct,ioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Functioning

4-1S3

Columns & Piers:

Material and Type:.

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range:

Confinement Details:

Foundation Type:

Abutments:

Type:

Height:

Foundation Type:

Wingwalls: Continuous Discontinuous Length

Eva lua tion:Earthquake Resistance Mechanism: Ri id box culvert with

concrete floor.

Probab le Fa ilure Mode ( s ): None ant i c i pated.

Classif ication of Damage: Damage Category l.

4-184

BRIDGE SEISMIC DATA FORM

General:

Name: Price Canyon Road Overhead, 49C-329

Location:0Alignment: Straight Skewed IS Curved

Length:134'idth:

33'ite:

Year Built:. 1963

Seismically Retrofitted: Yes Ro

Classification: Regular~ Irregular

Peak Acceleration: 21

Liquefaction Potential: II (assumed)

Su erstructure:Material and Type:

Number of Spans:

Continuous: Yes

Prestressed concrete girders, R/C slab

No X

Bearinces:

Type: Ex ansion 'oints with shear ke s at abutments and piers

Condition: Functioning X Not FunctioningRestraint (Trans): Shear Keys

Restraint (Longit): None

Bearing Height: (Height of shear keys ~~3")

Support Length: 16" at piers; ~20" at abutments

4-185

Columns & Piers:

Material and Type: Pier Walls

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

25'eightRange:

I 3I I

Conf inement Details:

Foundation Type: Conc. Piles

Abutmen ts:Type: Seat Type

Height:15'oundation Type: On R/C Piles

Wingwalls: Continuous Discontinuous X Length ~ 28'ther end19'ther end

Evaluation:

Earthquake Resistance Mechanism: S 1 i ding bear ings and concrete

shear keys transfer load to abutments and piers which will carry

load in shear. Discontinuous deck does not distribute load well.

Probable Failure Mode (s): None anticiPated at this force level,

except abutment fill settlement.

Classif ication of Damage:

4-186

BRIDGE SEISMIC DATA FORM

General:

Name: Price Canyon Road / Corral de Piedra Creek 49C-330 A2001-B3

Location:0Alignment: Straight Skewed >g Curved

Length:

Width:

Year Built:Seismically Retrofitted: Yes No X

Classification: Regular X IrregularSite:

Peak Acceleration: .21

Su erstructure:Material and Type: Prestressed Conc. Girders / R/C Slab

Number of Spans:

Continuous: Yes No X

Bearinces:

Type: Ex . Joints with Shear Keys at Abutments and Bents

Condition: Functioning X Not Functioning

Restraint (Trans): Shear Keys

Restraint (Longit): None

Bearing Height: (Height of shear keys = 3")

Support Length: ~22" at abutments; ~18" at bents

4-187

Columns & Piers:

material and Type: '/C Pile Bents, 7 Piles/Bent

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range: ~~

24'onfinementDetails:

Foundation Type: P i 1 es

Abutments:

Type Seat type

Height:9'oundation Type: Concrete Piles

Wingwalls: Continuous Discontinuous X Length

Evaluation:

Earthquake Resistance mechanism: Concrete shear keys and sl iding

bearings transfer load to abutments and pile bents.

Discontinuous deck does not distribute load well.

Probable Failure gode (s): High 1 iquefaction potential.

Classification of Damage: Dama e Cate or due to li uefaction.

4-188

BRIDGE SEISMIC DATA FORM

General:

Name: Val le Road at Los Berros Creek A1140-B1 49C-352

Location: 'On County Road 28 (South of the city of Arroyo Grande)

Alignment: Straight X

Length: 93

'idth:

3O'kewed Curved

Year Built: 1962 (Plan approved 1959)

Site:

Seismically Retrofitted: Yes No

Classification: Regular~ Irregular

Peak Acceleration:

Liquefaction Potential:Su erstructure:

Material and Type:

Continuous: Yes~ No

~Bearin s:

TYpe: None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Functioning

4-189

Columns 6, Piers:

Material and Type: R C Pile - C

Transverse Cross-Section Dimension: 1i-4»

Longitudinal Cross-Section Dimension: 1'-4»

Height Range:14'onf

inement Details:

Foundation Type: P i i es

Abutmen ts:Type, Di aphragm

Height:

Foundation Type: Footing on pi les (R/C)

Wingwalls:

Evaluation:

Continuous X Discontinuous Length

10'arthquake

Resistance Mechanism: Diaphragm abutment carries

- load in shear - Pile bents in shear and bending

Continuous R/C slab deck distributes load.

Probable Failure Mode (s): No failure is anticipated.

Classif ication of Damage: Dama e cate or 2 due to 1 i uefaction.P

4-190

4.4 SUMMARYOF EVALUATIONOF BRIDGES

FOR WHICH NO PLANS WERE AVAILABLE

4-191

TERA CORPORATION

SUMMARy OF EVALUATION OF

BRIDGES FOR WHICH NO PLANS WERE AVAILABLE

(Best First Estimate of Capacit )

State Route 101

Br. 49-52 - Damage category 1- Concrete arch culvert with earth fill.

Br. 49-57 - Damage category 1- Same as Br. 49-52.

State Route 1

Br. 49-66 - Damage category 1 - R/C box culvert with earth fill.Br. 49-188 - Damage category 1

- R/C rigid box with earth fill.

State Route 227

Br. 49-110 - Damage category 1- R/C "T" beam -- Single span with

diaphram abutments.

Corbit Can on Road

Br. 49C-155 - Damage category 1 or 2 - Two span timber stringer bridgewith timber deck supported on rock abutments. Some fillsettlement might occur.

Orcutt Road (Johnson Avenue)

Br. 49C-367 - Damage category 1- Railroad underpass - Rails will provide

sufficient continuity to prevent collapse.

Los Osos Valley Road

Br. 49C-83 - Damage category 1- CMP arch culvert.

Mill Street

(C-19) 0 SPRR tracks — Damage category 1— Precast concrete deck panels

have sufficient support lengths to prevent collapse.Minor abutment fill settlements may occur.

4-192

po 2

Montere Road

Br. 49C-299 — Damage category 1- Railroad underpass - Rails will

provide sufficient continuity to prevent collapse.

Orcutt Road

Br. 49C-366 — Damage category 1- R/C rigid frame culvert.

North Plant Road (Pecho Valley Road)

(C-22) 0 Islay Creek - Damage category 1 or 2 - Structure could shifttransversely at abutments (no restraint) ormoderate settlement (5"+) could occur.

South Ba Boulevard

(C-23) - Pedestrian U.C. - Damage category 1- R/C box culvert.

Br. 49C"241 - Damage category 1 or 2 " Appears to be single span timberstringer bridge. Abutment fill settlements may occur.

Br. 49C-242 - Damage category 2 or 3 - Multispan simply supported timberstringer bridge supported on timber bents with 12 X 12caps. Possible loss of support at bearings or collapsedue to liquefaction.

Traffic Way

Br. 49C-318 - Damage category 2 or 3 - Multispan simply supported R/C"T" beam bridge supported on R/C pile bents., Possibleloss of support at bearings, or moderate fill settlement.

4-1 o3

4.5 BEHAVIOR OF BRIDGES DURING PAST EARTHQUAKES

BRIDGE SEISMIC DATAFORMS

4-194

TERA CORPORATION

General:

BRIDGE SEISMIC DATA FORM

Imperial Va11ey Earthquake Oct.15, 1979

Name: Bridge across New River, 58-05 R/L

Location: Rte. 86 P.M. 21.57

0Alignment: Straight Skewed Ig Curved

Length:

R/L Equal

Width: 301

Year Built:Seismically Retrofitted: Yes No

Site:Classification: Regular Irregular I (Col. Heights)

Peak Acceleration: 0.21

Liquefaction Potential:Su erstructure:

aftershocks ma have been higher)

Material and Type:

Number of Spans: 8

R/C S lab

Continuous: Yes X No

Bearinces:

Type: Slidin Bearin s at Abutments

Condition: Functioning X Not Functioning

Restraint (Trans): Hone

Restraint (Longit): None

Bearing Height:

Support Length: "

2.5'-195

Columns & Piers:

Material and Type: R/C 6-Pile Bents

Transverse Cross-Section Dimension: -1.5'4

Longitudinal Cross-Section Dimension: -1.5'4

Height Range:

Confinement Details: ¹5 y 6" itch

Foundation Type: Pi les

Abutments:

Type Seat TyPe

Height: - 4

Foundation Type: Concr. Pi les, Fi l l

6,5'ingwa

1 1 s: Continuous Discontinuous " Length =g

Evaluation:

Earthquak e

Shear

Resistance Mechanism: Shear at abutments,

8 bending at bents.

Probable Failure Mode (s): Minor fill settlement ='2" can be

expected.

Classif ication of Damage: Ca«gory

4-196

BRIDGE SEISMIC DATA FORM

Imperial Valley Earthquake Oct. 15, 1979

General:

Name: Bridge across Alamo River

Location: Rte. 115 P.M. 10.1

58-292

N

Alignment: Straight 0Skewed S Curved

Length:

Width:

Year Built:

205'0'958

Seismically Retrofitted: Yes No

Site:Classification: Regular " Irregular

Peak Acceleration:Liquefaction Potential:

Su erstructure:Material and Type: R/C T-Girders

Number of Spans: 3

Continuous: Yes X No

~Bearin s:

Type:— Rocker Bar Br s. at Abutments

Condition: Functioning X Not Functioning

Restraint (Trans): Keeper P lates

Restraint (Longit): None

Bearing Height:

Support Length:

6I I

- 20"

4-197

Columns 6 Piers:

Material and Type:

Transverse Cross-Section Dimension: -1. 5'

Longitudinal Cross-Section Dimension: -1.5'4

Height Range: ."12'onf

inement Details: Standard 85 9 6" itch

Founda tion Type: Pi les

Abutments:

Type Sea t TyPe

Height:

Foundation Type: Concrete Piles, Fill ~

12'ingwalls:'Continuous Discontinuous " Length

Evaluation:

Earthquake Resistance Mechanism: Continuous "T" beam on Pile

bents. Rocker bearings at seat abutment.

Probable Failure Mode (s): KeePer bars fail - Bearings do not toPPle.

Minor abutment f i 1 1 settlement.

Classi fication of Damage: a g eg ry

4-198 =

BRIDGE SEISMIC DATA FORM

Imperial Valley Earthquake Oct. 15, 1979

General:

Name Alamo River Bridge 58-136

close to Imperial faultand epicenter-M - 6.4

Location: Rte. 98 P.M. 39,92

Alignment: Straight < Skewed Curved

Length:

Width:

Year Built:

196'0'977

Seisinically Retrofitted: Yes No

Classif ication: Regular IrregularSite:

Peak Acceleration: .44

Liquefaction Potential:Su erstructure:

Material and Type: R C Slab

Continuous: Yes X No

Bearinces:None

Type-

Condition: Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Functioning

4-199

Columns & Piers:

Material and Type: 5-Pile-Ext. Bents (P. P. C. Piles)

Transverse Cross-Section Dimension:

Longitudinal Cross-Section D imen sion:

Height Range: 8' 22'. L. to Cap.

Conf inement Details: ¹4 - Ca ¹4 1

1l 3II

Foundation Type: Prestressed Precast Conc. Piles

Abutmen ts:

Type. Di aphragm

Height: 6'4"

Foundation Type Conc. P i 1 es (Precast Pres t ressed)

Wingwells: Continuous " Discontinuous Length 12'

18'valuation:

Earthquake Resistance Mechanism: Cont inuous s lab wi th

continuous pile bents.

Probable Failure Mode (s): S 1 ight to moderate column dama e.

Slight abutment settlement.

Classif ication of Damage: Damage Category 1 or 2.

4-200

General:

BRIDGE SEISMIC DATA FORM

Imperial Valley Earthquake Oct. 15, 1979

Name Meloland Road Overcrossing

Location: Rte. 8 e.M. 43.6

(58-215)near the Imperial faultMag.. 6.4no amage

Alignment: Straight ~ Skewed Curved

Length: 208

'idth:40

Year Built: 1971

Site:

Seismically Retrof itted: Yes No

Classit ication: Regular Irregular

(1979)

Peak Acceleration: .29 g

Liquefaction Potential:Su erstructure:

Material and Type: R/C Box Girder

Number of Spans: 2

Continuous: Yes X No

Bearinces:

Type: None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Functioning

4-201

Columns 6 Piers:

Material and Type:

Transverse Cross-Section Dimension:

. Longitudinal Cross-Section Dimension:

20'eightRange:

5'0" dia.

5'0" dia.

Conf inement Details: ¹5 S iral 0 5" itch/Extended turns into ca .

Foundation Type: R/C P i 1 es

Abutmen ts:

Type: Diaphragm

Height: - 0< +

Foundation Type: R Pil

gingwa] ].s: Continuous X Discontinuous Densth~ g'valuation:

Earthquake Resistance Mechanism: Con in

Sin le column bents and dia hra m abutments.

Probable Failure Mode (s): Moderate f i 1 1 settlements (6")

Classif ication of Damage: Damage Category 2

4-202

General:

BRIDGE SEISMIC DATA FORM

Imperial Valley Earthquake Oct. 15, 1979

Name: Bridge across Alamo River, 58-07

Location: Rte. 115 P.H. 10.31

Alignment: Straight " Skewed Curved

Length:252'idth:

Year Built: 1955

Seismically Retrof itted: Yes No

Site:Classification: Regular Irregular I (Col. Lengths)

Peak Acceleration:Liquefaction Potential:

Su erstructure:

0.26

Material and Type:

Number of Spans: 6

R/C T-Beam

Continuous: Yes X No

Bearinces:

Type: Rocker Bearin s at Abutments

Condition: Functioning X Not Functioning

Restraint (Trans): Keeper Plates

Restraint (Longit):Bearing Height:

Support Length:

None

4-203

Columns 6 Piers:

Material and Type: P. C. C. 6-Pile"Col. Bents

Transverse Cross-Section Dimension: -1.5'4

Longitudinal Cross-Section Dimension: -1.5'4

Height Range: 6'..24'onf

inement Details: 85 wire 9 6" itch

Foundation Type:

Abutments:

Type: Seat TyPe

Height:

Foundation Type: Piles (Con«.), Fi1 1

7.5'ingwells:Continuous Discontinuous X Length

Evaluation:

Earthquake Resistance Mechanism: Continuous superstiucture

transfers load to pile bents. Keeper plates transfer

load to abutments.

Probable Failure Mode (s): Keeper plates at bearin s failTransverse shifting of superstructure " Hinor abutment fillsettlement.

Classif ication of Damage: »»9e Cate9ory

4-204

General:

BRIDGE SEISMIC DATA FORM

Imperial Valley Earthquake Oct. 15, 1979

Name: Bridge Across Pajaro River

Location: Rte. 180 P. H. 0. 0

43" 01

Alignment:

Length:

Width:

0 IStraight Skewed 12 Curved R = 5000

Site:

Year Built: 1 1

Seismically Retrofitted: Yes No X (1979)

Classification: Regular Irregular

Peak Acceleration: 0.22

Liquefaction Potential:Superstructure:

Material and, Type:

Number of Spans: 6

R/C Siab

Continuous: Yes X No

Bearinces:

TYpe: Asbestos Sheet Packings

Condition: Functioning X Not Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

4-205

Columns & Piers:

Material and Type:

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range: 10' 18'bove G.L.

Conf inement Details: Stand. ¹5 Wire Q 6" pitch

-1.5 0

1.5 8

Foundation Type: P. C. C. P i les

Abutments:Small Seat Type

Height:4.5'oundation

Type: R/C Pi les (Some battered

Wingwa 1 1 s:

Evaluation:

Continuous Discontinuous X Length~

Earthquake Resistance Mechanism: Continuous deck distributing

1 a terai forces to the pi le-ext. uni formly. P i 1 e-ext. behaving

in ductile mode to accommodate movement.

Probable Failure Mode (s): Non-structural. Fi 1 1 settlement of

~3" expected.

Classif ication of Damage: Cate or 1

4-206

General:

BRIDGE SEISMIC DATA FORM

Eureka Earthquake Nov. 8, 1980

Name: Finch Creek Road undercrossin, 4-113 R/L

Location: Route 101, PM 63.1

Alignment: Straight Skewed SS'urvedLength:

129'idth:

37'

8 L Equal

Year Built: 1958

Seismically Retrofitted: Yes No XX

Classification: Regular "" IrregularSite:

Peak Acceleration:Liquefaction Potential:

Su erstructure:Material and Type: R C T - beam irder

Number of Spans: 3

Continuous: Yes XX No

Bearinces:

Type: None =

Condition: Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Functioning

4-207

Columns & Piers:

Material and Type: R C 3 col bent

Transverse Cross-Sec'tion Dimension: 3' 6"

Longitudinal Cross-Section Dimension: 2' 6"

Height Range:=22'onfinementDetails: k4 9 12"

steel .8Ã

Foundation Type: R/C piles

Abutments:

Type: Diaphragm

Height:6'oundation Type: R/C piles, fill

26'ingwalls:

Evaluate.on:

Continuous XX Discontinuous Length

12'arthquake

distributes

and shear.

Resistance Mechanism: Continu'ous deck

lateral forces to bents. Bents resist in bending

Probable Failure Mode (s):

Classification of Damage: Category 1

4-208

General:

BRIDGE SEISMIC DATA FORM

Eureka Earthquake Nov. 8, 1980

Name: Fourth Street 0.L. 4 - 49

Location: Route 101, PM 85.8 (Route 255/101 separation)

Alignment: StraightLength:

328'idth:

58'kewed 19 Curved

Site:

Year Built: 1965

Seismically Retrofitted: Yes No YY

Classif ication: Regular XX Irregular

Peak Acceleration: 0 11 g

Liquefaction Potential:Su erstructure:

Material and Type: R/C box girder

-Number of Spans: 4

Continuous: Yes "" No

Bear in ces:

Type: None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Functioning

4-209

Columns & Piers:

Material and Type: R C 3-col bents

Transverse Cross-Section Dimension: 4' 0"

Longitudinal Cross-Section Dimension: 3'-0"

Height, Range:=20'onfinementDetails: b'4 9 12"

(steel 1.2X)

Foundation Type: footin on R/C piles

Abutments:

Type: di aphragm

Height:ll'oundation Type: R/C piles, fill

19'ingwalls:Continuous Discontinuous "" Length 18

Evaluation:

Earthquake Resistance Mechanism: Continuous deck

1 distributes lateral forces. to bents.

Probable Failure Mode (s): none

Classif ication of Damage: Category 1

4-210

General:

BRIDGE SEISMIC DATA FORM

Eureka Earthquake Nov. S, 1980

Name: Salmon Avenue U.C., 4 - 67 R/L

Location: Route 101, PM 72.90Alignment: Straight Skewed 15 Curved

Length:120'idth:

37'ear

Built: 1963

R & L Equal

Seismically Retrof itted: Yes No XX

Site:

Classif ication: Regular XX Irregular

Peak Acceleration:- 0 11 g

Liquefaction Potential:Su erstructure:

Material and Type: R/C T-beam girder

Number of Spans:

Continuous: Yes "" No

Bearinces:

Type: None

Condition: Functioning

Restraint (Trans):

Not Functioning

Restraint (Longit):Bearing Height:

Support Length:

4-211

Columns & Piers:

Material and Type: R 2-col. bent

Transverse Cross-Section Dimension: 3'-6"

Longitudinal Cross-Section Dimension: 2"-6"

Height Range: = 17

'onfinementDetails: k'4 9 12"

(steel 1.4%)

Foundation Type: R/C iles

Abutments:

Type: di aphragm

Height:8'oundation Type: R/C piles, fill

22'ingwalls:

Evaluation:

IContinuous "" Discontinuous Length 16

Earthquake Resistance Mechanism: Continuous deck

s lateral loads to bents.

Probable Failure Mode (s): None

Classification of Damage: Category 1

4-212

General:

BRIDGE SEISMIC DATA FORM

Eureka Earthquake Nov. 8, 1980

Name: Sin le Road U.C. 4 - 110 R/L

Location: Route 101 PM 64.3

Alignment: Straight Skewed=30 Curved

Length:145'idth:

37'

& L Equal

Year Built: 1957

Seismically Retrof itted: Yes Ro XX

Site:Classification: Regular "X Irregular

Peak Acceleration: 0.11

Liquefaction Potential:Su erstructure:

Material and Type: R C T-beam irders

Number of Spans: 2

Continuous: Yes XX No

~Bearin s:

Type: ne

Condition: Functioning Not Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

4-213

Columns & Piers:

Material and Type: R - l

Transverse Cross-Section Dimension: 3'-6"

Longitudinal Cross-Section Dimension: 2'-6"

Height Range:18'onfinementDetails: 0'4 8 12"

(steel .8%)

Foundation Type: R/C footing on piles

Abutments:

Type: di aphragm

Height:~18'oundation

Type: Piles, fill25'ingwa

1 1 s: Continuous "" Discontinuous Length 12

Evaluation:

Earthquake

in bendin

Resistance Mechanism: Column bents resisting

and shear.

Probable Failure Mode (s): None

Classif ication of Damage: Category 1

4-214

General:

BRIDGE SEISMIC DATA FORM

Greenville Earthquakes Jan., 1980

Name: Las P' id e

Location- Route 580 P.M. 11.72

Alignment: Straight Skewed small Curved

Length:131'idth:

152'ear

.Built: 1972

Site:

Seismically Retrofitted: Yes No

Classification: Regular Q Irregular

Peak Acceleration: 0.16 g

Liquefaction Potential:Su erstructure:

Material and Type: R/C Girder

Number of Spans:

Continuous: Yes XX No

Bearinces:

Type: None

Condition: Functioning

Restraint (Trans):

Restraint. (Longit):

Not Functioning

Bearing Height:

Suppor't Length:

4-215

Columns & Piers:

Material and Type: n e

Transverse Cross-Section Dimension: 3'0"

Longitudinal Cross-Section Dimension: 2'6"

Height Range:19'ondinementDetails: 85 '5 9 6't base and cap and 8 12"

elsewhere.

Foundation Type: Steel Piles 10 BP 42

Abutments:

Type: Diaphragm Type

Height:

Foundation Type: Steel Piles 10 BP 42

il IWingwalls: Continuous "" Discontinuous Length 14

Evaluation:

Earthquake Resistance Mechanism: Bents in shear and bending.

Continuous deck distributes lateral forces to bents.

Probable Failure Mode (s):

Classification of Damage:

4-2l6

General:

BRIDGE SEISMIC DATA FORM

Greenville Earthwuakes Jan., 1980

Name: Greenvi 1 1 e Road U.C.

Location: Route 580, PM 8.2

33-26 R/L Similar R 8 L

Alignment: Straight Skewed 20 Curved

Length: R: 185':299'idth:

R: 66':78'ear

Built: 1969

Seismically Retrof itted: Yes So XX

Site:Classification: Regular " Irregular XX 'Ccl. Hei9hts)

Peak Acceleration: 0 17 9

Liquefaction Potential:Su erstructure:

Material and Type: R C Box Girder

Number of Spans: 3

Continuous: Yes XX No

~Bearin s:

Type: None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

'Support Length:

Not Functioning

4-217

Columns & Piers:

Material and Type: R C 3-column Bents

Transverse Cross-Section Dimension: 4'-0"

Longitudinal Cross-Section Dimension: 3'-0"

Height Range: 18'...26'onfinementDetails: II4 8 12"

(2.2X steel)

Foundation Type: Concrete Piles

Abutments:

Type: Diaphragm

Heighto™10'oundation

Type: Concrete Pi les

Wingwalls: Continuous Discontinuous XX Length 1B

Evaluation:

Earthquake Resistance Mechanism: Bents in shear and bending.

Continuous deck distributes lateral forces to bents.

Probable Failure Mode (s):

Classif ication of 'Damage:

4-218

BRIDGE SEISMIC DATA FORM

Greenville Earthquakes Jan., 1980

eGeneral:

Name: h Fl nn Over Crossin

Location: Route 580 PM

Alignment: Straight Skewed 21 Curved

Length:373'idth:,

34'ear

Built: 1969

Seismically Retrof itted: Yes

Classification: Regular

No XX

IrregularXX (curved in the S.E. end)

Site:

Peak Acceleration: 0.16 g

Liquefaction Potential:Su erstructure:

Material and Type: R C Box Girder

Number of Spans: 4

Continuous: Yes

Bearinces:

No XX

Type: Expansion 'pints at abutments and hin e in the third s an.

Condition: Functioning XX Not FunctioningRestraint (Trans): None

Res tra int (Longit): None

Bearing Height: (hieght of "bearing wa11" = 4'-2" at abutments)

(very roughly)

4-219

Columns & Piers:

Material and Type: sin le column bents

Transverse Cross-Section Dimension: 7'-0" bottom... 10'-0" top

Longitudinal Cross-Section Dimension: 3'-0"

Height Range:-22'onfinementDetails: 85 9 12"

Foundation Type: spread footing

Abutments:

Type: Diaphragm (diaphragm not continuous)

Height:-9'oundation Type: spread footing

Wingwalls: Continuous lx Discontinuous Length ~

Evaluation:

Earthquake Resistance Mechanism: Noncontinuous deck will

transfer more lateral forces to bent 4 relative to bent 2 and 3.

Columns should resist in bending and shear.

Probable Failure Mode(s): Loss of support, at exp. jt. possible

for a sli htl hi her PGA. Bent 4 will be critical in this case and

in an case. S licing at base of columns could initiate collapse

due to loss of bonding after spaling of concrete.

Classif ication of Damage: CategorY 1

4-220

General:

BRIDGE SEISMIC DATA FORM

Greenville Earthquakes Jan., 1980.

Name: Vasco Road Over Crossing

Location: Route 580 PM 9.67

Alignment: Straight Skewed 13 Curved

Length:326'idth:

73'ear

Built: 1970

Site:

Seismically Retrof itted: Yes No XX

Classification: Regular XX Irregular

Peak Acceleration: 0 169

Liquefaction Potential:Su erstructure:

Material and Type: Prestressed "I" irder R C slab

Number of Spans: 4

Continuous: Yes XX No

Bearinces:

Type: 1 t mriCondition: Functioning~I Not Functioning

Restraint (Trans): None

Restraint (Longit) - None

Bearing Height: 0

Support Length:

2'-221

Columns & Piers:

Material and Type- 3-c ]umn bent

Transverse Cross-Section Dimension: 8'-0"

Longitudinal Cross-Section Dimension: 2'-0"

Height Range:-25'onfinementDetails: ¹4 9 12"

(1.4% steel )

Foundation Type: s read footin

Abutments:

Type: Dia hra m

Height:6'oundationType: Concrete piles

Wingwalls: Continuous XX Discontinuous Length ~4

Evaluation:

Earthquake Resistance Mechanism: A continuous deck

niforml the transverse forces to the bent. Bents

resist in shear and in bendin .

Probable Failure Mode (s): None

Classif ication of Damage: Category 1

4-222

General:

BRIDGE SEISMIC DATA FORM

Coyote Lake Earthquake Aug. 6, 1979

Name: Carnadero Creek Brid e 37-156 Dist. 4

Location: Route 180, PM 1.0

Alignment: StraightLength:

163'idth:

28'ear

Built: 1956

Skewed 25 Curved0

Site:

Seismically Retrof itted: Yes

Classification: Regular

Nu XX

IrregularXX

Peak Acceleration: 0.20 g

Liquefaction Potential:Su erstructure:

Material and Type: R/C s1ab

Number of Spans: 4

Continuous: Yes XX No

~Bearin a:

Type: None

Condition: Functioning

Restraint (Trans):

Restraint.(Longit):Bearing Height:

Support Length:

Not Functioning

4-223

Columns & Piers:

Material and Type: '~ -v bents

Transverse Cross-Section Dimension:33'ongitudinalCross-Section Dimension:

1'eightRange: 16'

22'onfinementDetails: 3- 9 18"

Foundation Type: R/C i 1 es

Abutments:

Type: Dia hra m abutments

Height:2>'oundation Type: R/C pi 1 es

Wingwalls: Continuous Discontinuous Length 11

Evaluation:

Earthquake Resistance Mechanism: pier walls in shear is the

main resistance mechanism.

Probable Failure Mode (s): None - maximum expected

setl. = 3".

Classif ication of Damage: Category 1

4-224

General:

BRIDGE SEISMIC DATA FORM

Coyote Lake Earthquake Aug: 6, 1979

Name: Tennant Ave. 0.C.~ ~

Location: Route 101 PM 15. 07

37-333

Alignment: Straight II Skewed Curved

Length:245'idth:

40'ear

Built: 1972

Seismically Retrof itted: Yes Ro XX

Classification: Regular II IrregularSite:

Peak Acceleration: 0.23

Liquefaction Potential:Su erstructure:

Material and Type: Prestressed concrete box irder

Number of Spans: 2

Continuous: Yes XX No

~Bearin s:

Type: None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Functioning

4-225

Columns & Piers:

Material and Type:

Transverse Cross-Section Dimension: r ies base:10.5'ongitudinalCross-Section Dimension: varies. base:

3.5'eight

Range:22': 22.5'ap:

7.5'onf

inement Details: g5 9 6 for ca and base

9 12 elsewhere

Foundation Type: stri footin

Abutments:

Type: Dia hra m

Height: varies=12'oundation

Type: strip footing

Wingwalls: Continuous XX Discontinuous Length~Evaluate.on:

Earthquake Resistance Mechanism: Pier resistin in shear and

bendin to ether with dia hra m abutment mostl in shear.

Probable Failure Mode (s): Relatively well confined concrete

in pier reduces chances of longitudinal rebar pull-out.

Classif ication of Damage: Categol y 1

4-226

General:

BRIDGE SEISMIC DATA FORM

Coyote Lake Earthquake Aug. 6, 1979

Name: Anzar Road U.

Location: Route 101 PM 4.25

43-33 R Similar

Alignment: Straight Skewed 20 Curved

Length: L: 124':126'idth:

L: 54':42'ear

Built: 1972 -'oth

Site:

Seismically Retrofitted: Yes No XX

Classification: Regular XX Irregular

Peak Acceleration: 0.11

Liquefaction Potential:Su erstructure:

Material and Type: box irder - restressed

Number of Spans: 1

Continuous: Yes XX No

Bearinces:

Type: Elastomeric br . ads

Condition: Functioning XX Not FunctioningRestraint (Trans): wingwal 1 s

Restraint (Longit): None

Bearing Height:

Support Length:

4-227

Columns & Piers:

Material and Type: N

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension:

Height Range:

Confinement Details:

Foundation Type:

Abutments:

Type: Seat t e

Height:9'oundation Type: R/C piles (some battered)

Wingwalls: Continuous Discontinuous XX Length=15'valuation:

Earthquake Resistance Mechanism: Continuous sin le span box

irder on dia hra abutments.

Probable Failure Mode (s): None anticipated.

Classification of Damage: Damage Category 1

4-228

BRIDGE SEISMIC DATA FORM

General:

Coyote Lake Earthquake Aug. 6, 1979

Name: Pa aro River rid e 43-13

Location: Route 129 PM .01

Alignment: Straight Skewed 23 Curved

Length: 306

'idth:

26'ear'Built:

1949

Seismically Retrofitted: Yes No XX

Site:Classification: Regular XX Irregular

Peak Acceleration: 0.12 g

Liquefaction Potential:Su erstructure:

Material and Type: steel late girder R de

Number of Spans: 3

Continuous: Yes XX No

Bea~inces:

Type: Rocker t e 9 abutments 8 bents ex . 'ts. some re aired after1954 e.g. )Condition: Functioning XX Not Functioning

Restraint (Trans): kee er 1 ates/anchor bol ts

Restraint (Longit): None

Bearing Height: 11"

Support Length: 4'10" 9 abutments / =1'~ long 9 bent caps / ~

exp. jts. = 1'3; (estimated)

4-229

Columns a Piers:

Material and Type- - ier l

Transverse Cross-Section Dimension:4'ongitudinalCross-Section Dimension: varies 2'9" - 4'6" cap to base

Height Range:30'onfinementDetails: 3-"0 ties ~~ 9 18" ctrs each face.

3/4" 4 dowels J at 16" ctrs, 6'-0" l . 9 base

Foundation Type: R/C i 1 es

Abutments:

Type: seat t e with edestals

Height: =10'oundationType: R C iles-some battered

Wingwalls:

Evaluate.on:

Continuous XX Discontinuous Length 10'9"

Earthquake Resistance Mechanism: At the estimated PGA level

the rocker bearin s at abutments and at bents rovide t.ansverse

restraint (the bearin s are not supposed to fail). Piers resist

in shear.

Probable Failure Mode(s): None (spans 1 & 3 vulnerable)

Classif ication of Damage: Cate9oU 1

4-230

BRIDGE SEISMIC DATA FORM

Coyote Lake Earthquake Aug. 6, 1979

General:

Name: Sar ent Brid e O.H.

Location: Route 101 PM 0.8

Alignment: Straight Skewed 65 Curved

Length:

672'7-06LWidth:

39'ear

Built: 1970

Seismically Retrofitted: Yes No II (1979)

Classification: Regular Irregular YY

Site:

Peak Acceleration: 16 g

Liquefaction Potential:Su erstructure:

I

Material and Type: R C box irder rest. concrete I- irder for span 4)

Number of Spans: 7

Continuous: Yes No XX

Bearinces:

Type: Exp. Jts. / hin es at outer columns

Condition: Functioning XX Not Functioning

Restraint (Trans): none for exp. jts. / dowels for hin es

Restraint (Longit): none for exp. jts. / dowel s for hinges

Bearing Height: 0

Support Length: = 2 5

g-231

Columns & Piers:

Material and Type: R C 3-column bents - hin ed at base'ome also at caps

Transverse Cross-Section Dimension:4'ongitudinalCross-Section Dimension:

3'eight

Range: 20'

30'onfinementDetails: P4 D 9 12"; dowels 9 cap and base

Foundation Type: R/C pile footings

Abutments:

Type: Di aphragm

Height: 10'2"

Foundation Type: R/C i 1 es

,„. Wingwalls: Continuous XX Discontinuous Length 45

Eva lua t3.on:

Earthquake Resistance Mechanism: For the given earthquake of

= , 6 the most critical section S an 4 which is sim 1

su orted resists lateral movement b friction. The columns will

resist in shear and bendin .

Probable Failure Mode (s): None (More significant ground motion

could cause cim ly supported Span 4 to drop off. The skewed and

curved deck increases this possibility.)

Classif ication of Damage: Category 1

4-232

General:

BRIDGE SEISMIC DATA FORM

Coyote Lake Earthquake Aug. 6, 1979

Name: Route 156 101 Se .

Location: Route 101 PM 0.01

Alignment: Straight Skewed 35 Curved

Length:326'idth:

28'ite:

Year Built: 1958

Seismically Retrof itted: Yes No~XX 1979)

Classification: Regular Irregular XX

Peak Acceleration: 0 11g

Liquefaction Potential:Su erstructure:

Material and Type: steel late irder wel ded

Number of Spans:

Continuous: Yes

Bearinces:

No XX exp. jt. in deck

Type: Rocker brn s. at bents and abutments

Condition: Functioning XX Not Functioning

Restraint (Trans): kee er lates

Restraint (Longit): None

Bearing Height: =4"' abutments; standard 9 bents

Support Length: 2' abutments; 15" 9 bents

4-233

Columns & Piers:

Material and Type: R C 2-column bents shear ke inned at base)

Transverse Cross-Section Dimension:

4'ongitudinalCross-Section Dimension:3'eight

Range: 17'

22'onfinementDetails: 0'4 5 9 12"

Foundation Type: stri footin

Abutments:

Type: seat type with pedestal s

Height: =9.5'oundation

Type: strip footing

Wingwalls: Continuous Discontinuous "" Length 16

Evaluation:

Earthquake Resistance Mechanism: For the ex ected PGA,

keeper lates should offer the main resistance to lateral forces.

Probable Failure Mode (s): None

Classification of Damage: Category 1

4-234

BRIDGE SEISMIC DATA FORM

San Fernando Earthquake Feb. 9, 1981

General:

Name: Bledsoe Street overcrossing

Location: Route 210, PM 2.8

Alignment: Straight D Skewed

Length:209'idth:

64'ear

Built: 1969

Seismically Retrofitted: Yes

Curved

Bo XX

Site:Classification: Regular >> Irregular

Peak Acceleration: .50

Liquefaction Potential:Su erstructure:

Material and Type: CIP R/C box irder

Number of Spans: 2

Continuous: Yes XX No

Bearinces:

Type: None

Condition: Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Functioning

4-235

Columns & Piers:

Material and Type: R C 2-column bent

Transverse Cross-Section Dimension: 5'ith flare

Longitudinal Cross-Section Dimension:3'eight

Range:24'onfinementDetails: 85 hoops 9 12" oc; lap splice; P= 2.2

Foundation Type: spread

Abutments:

Type: Diaphragm

Height:14'oundation Type: spread footing

Wingwalls: Continuous "" Discontinuous Length 1" +

Evaluation:

Earthquake Resistance Mechanism: Continuous superstructur e

transfers load to bents and abutments.

Probable Failure Mode (s): Column tilted and spalled at

su erstructure soffit.

Classif ication of Damage: Damage Category 2

4-236

General:

. BRIDGE SEISMIC DATA FORM

San Fernando Earthquake Feb. 9, 1971

Name: West S lman O.H.

Location: Route 5, PM 44. 6

(Br. No. 53-1984 R)

Alignment: Straight Skewed XX curved XX

Length:551'idth:

92'ear

Built: 1969

Seismically Retrofitted: Yes XX

Classif ication: Regular "" IrregularSite:

Peak Acceleration: .439

Liquefaction Potential:Su erstructure:

Material and Type: CIP R/C box girder

Number of Spans:

~ Continuous: Yes

Bear in ca s:

XX 2 In span Joints

Type: Elastomeric bearing pads

Condition: Functioning "" Not Functioning

Restraint (Trans): Concrete shear key

Restraint (Longit) ~ Equalizer bol ts (1>" 4 ) (hinges only)

Bearing Height:

Support Length- 18"+ (hinges) 24"+ (abutments)

4-237

Columns 8 Piers:

Material and Type: R/C mutli-column bents - pinned at base except bent 4

Transverse Cross-Section Dimension:

Longitudinal Cross-Section Dimension: 4

Height, Range: 30 - 35'bent 4 = 30')

Confinement Details: P4 hoops 9 12"; simple lap splice

Foundation Type:. iles and s read

Abutments:

Type -. Seat Cantel ever backwa1 1 )

Height:15.5'oundation

Type: spread

Wingwalls: Continuous XX Discontinuous Length 25

Evaluation:

Earthquake Resistance Mechanism: Shear and bending in

columns - small transfer of force between sections because of

expansion joint - abutment forces will be only slightly increased

due to column yielding.

Probable Failure Mode (s) .- Rotational di spl acements causing

cracked abutments and wingwalls. Hinges spalled at overhang,

Classif ication of Damage: Damage Category 1

4-238

General:

BRIDGE SEISMIC DATA FORM

San Fernando Earthquake Feb. 9, 1971

Name: Route 5 Truck Lane 405 Se aration

Location: Route 5 PM 41.55

53-1548

Alignment: Straight Skewed 50 + Curved

Length:'55'idth:

36'ear

Built: 1970

Site:

Seismically Retrofitted: Yes Ro XX

Classification: Regular XX Xrregular

Peak Acceleration: ~ 649

Liquefaction Potential:Su erstructure:

Material and Type: CIP Prestressed concrete box girder

Number of Spans:

Continuous: Yes XX No

Bearinces:

Type: Slidin — asbestos sheet ackin

Condition: Functioning XX Not Functioning

Restraint. (Trans): shear key

Restraint. (Longit): earth fill at abutment diaphragm

Bearing Height: 0

Support Length: 18"

4-239

Columns 6 Piers:

Material and Type: Reinforced concrete 2-column bent

Transverse Cross-Section Dimension:5'ongitudinalCross-Section Dimension:

4'eight

Range: 20'2

Conf inement Details: ¹4 hoo s 9 12" oc - la s 1 ices; no

information on main steel splices

Foundation Type: spread footing - in Cut

Abutments:

Type: Di aphragm

Height:14'oundation Type: spread footing - East in Cut - West in Fill

Wingwalls: Continuous Discontinuous Length

Evaluation:

Earthquake Resistance Mechanism: Transversely columns

will resist seismic forces to yield then deck will carry excess

forces to abutments. Longitudinally abutment fills will take

force when columns fail. Skew will cause rotational mode.

Probable Failure Mode (s>: Total column failures resulting in

collapse of the superstructure.

Classif ication of Damage: Damage Category 3

4-240

BRIDGE SEISMIC DATA FORM

San Fernando Earthquake Feb. 9, 1971

General:

Name: sAn 1 tLocation: Foothil 1 Blvd. PN 44. 2

1 d. Br.

Alignment: Straight Skewed XX Curved

Length:155'idth:

40'ear

Built: 1969

Site:

Seismically Retrof itted: Yes No XX

Classification: Regular XX Irregular

Peak Acceleration: .469

Liquefaction Potential:Su erstructure:

Material and Type: CIP R/C box irder

Number of Spans: 3

Continuous: Yes XX No

~Bearin s:

Type: None

Condition: Functioning,. Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Func tion ing

4-241

Columns a Piers:

Material and Type: R 2- olumn bent

Transverse Cross-Section Dimension: 4'caledLongitudinal Cross-Section Dimension: 4'caledHeight Range: 40'eal ed)

Confinement Details:,Assume 84 9 12" oc; sim le las splice;

~= 3.0

Foundation Type: ile footings

Abutments:

Type: Diaphragm

Height: 13'+

Foundation Type: spread footing

Wingwa 1 1 s: Continuous Discontinuous Length 35

Evaluation:

Earthquake Resistance Mechanism: Columns in bending and

r abutment or column ield.

Probable Failure Mode(s): Abutment damage - moderate

abutm nt fill settlement ( = 1')

Classif ication of Damage: Damage Category 2

4-242

General:

BRIDGE SEISMIC DATA FORM

San Fernando Earthquake Feb. 9, 1971

Name: Northbound Truck Route 'nder ssin 53-1991R

Location: Route 5 PM 43.9

Alignment: Straight Skewed 60 + Curved

Length:224'idth:

51'ear

Built: 1969

Site:

Seismically Retrofitted: yes No IIClassification: Regular XX Irregular

Peak Acceleration: .489

Liquefaction Potential:Su erstructure:

Material and Type: Reinforced concrete box irder

Number of Spans: 3

Continuous: yes II'oBearinces:

Type: ne

Condition: Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height:

Support Length:

Not Functioning

4-243

Columns & Piers:

Material and Type: Reinforced concrete 4-column bent

Transverse Cross-Section Dimension:4'ongitudinalCross-Section Dimension:

4'eight

Range:24'onfinementDetails: P4 spiral 9 12" pitch

Foundation Type: spread footings

Abutments:

Type: Diaphragm

Height:

Foundation Type: spread footings - Cut 9 West - Fill 9 East

Wingwalls: Continuous Discontinuous ~X Length

Evaluate.on:

Earthquake Resistance Mechanism: Continuous deck distributes

load to abutments and bents.

Probable Failure Mode(s): Approach fill settlement - moderate

column and abutment damage.

"Classification of Damage: Moderate - reparable by contract-

light traffic okay with ramping (Damage Category 2)

4-244

BRIDGE SEISMIC DATA FORM

San Fernando Earthquake Feb. 9, 1971

General:

Name: San Fernando Road O.H.

Location: Route 5 PN 43.8

Alignment: Straight XX Skewed Curved

Length:244'idth:

34'ear

Built: 1969

53-1990 R

Seismically Retrofitted: Yes No XX

Site:Classif ication: Regular XX Irregular

Peak Acceleration: .48

Liquefaction Potential:

Su erstructure:Material and Type: CIP Prestressed concrete box irder

Number of Spans: 2

Continuous: Yes XX No

Bearinces:

Type: None

Condition: Functioning Not Functioning

Restraint (Trans):

Restraint (Longit):

Bearing Height:

Support Length:

4-245

Columns & Piers:

Material and Type- Reinforced concrete sin le column bent

Transverse Cross-Section Dimension:7'ongitudinalCross-Section Dimension:

3'eight

Range:30'onfinementDetails: ¹4 hoo s 9 12"

Foundation Type: pi 1 es

Abutments:

Type Diaphragm

Height:

Foundation Type: piles in approach fi1 1

Wingwalls: Continuous "" Discontinuous

Evaluation:

Length 20

Earthquake Resistance Mechanism: Continuous concrete

su erstructure distributes load to abutments and bents.

Probable Failure Mode(s): Column failed due to lack of

confinement - A roach fills settled. The abutments apparently

rovided ver little help in preventing column failure.

Classif ication of Damage: Damage Category 3

4-246

General:

BRIDGE SEISMIC DATA FORM

San Fernando Earthquake Feb. 9, 1971

Name: Route 210 5 ra Overhead

Location: Route 5 PN 43. 99

Alignment: StraightLength:

771'idth:

32'kewed Curved XX

Year Built: 1969

Site:

Seismically Retrof itted: Yes No XX

Classif ication: Regular XX Irregular

Peak Acceleration: .48

Liquefaction Potential:Su erstructure:

Material and Type: Reinforced concrete box irder

Number of Spans: 7

Continuous: Yes

Bearinces:

Type:

No XX 1 mid-span joint

Condition: Functioning~ Not Functioning

Restraint (Trans):

Restraint (Longit):Bearing Height: 2"

(hinge)

4-247

Columns & Piers:/

Material and Type: Reinforced concrete single column bents

Transverse Cross-Section Dimension: 6

Longitudinal Cross-Section Dimension: 4

Height Range:

Confinement Details: P4 hoo s 9 12" oc - lap s lice;6' lice of main reinforcement at foundation

Foundatiori Type: CIDH pile - 6 ' - pile footings

Abutments:

Type-

Height:

Seat

13'oundationType: piles - South; spread footing - North

Wingwalls:

Evaluation:

Continuous XX Discontinuous Length

Earthquake Resistance Mechanism: Cantilever bending of

sin le column bents. Poor distribution of load from super-

structure.

Probable Failure Mode(s): Columns failed at base - pulled

abutments off seat - spans collapsed

'lassif ication of Damage- Damage Category 3

4-248

e

5.0 EVACUATIONNETWORK

5-1TERA CORPORATION

TABLE I

EVACUATION NETWORK

Route NodeNo. No. Node

OutsideStudy Area

Possible (2)

Average Capaci tyHighway (Vehicles/

Tyye Speed Hr.)

DirectionalAdjustedCapacity(Vehicles/Hr.)

.OptimumSpeed

'(Miles/Hr.)

OptimumDensity(Vehicles/Hr.)

34 Study AreaBoundary =Yerba Buena 3

33 San JacintoSt.

65

65

1920 (2)

388o

1730

3940

29

32

60

123

32 Route 41

30 Morro BayBlvd.

65

65

388o

388o

3940

3940

32 123

32 . 123

29 South BayBlvd.

27 Camp SLOEntrance

26 Calif. Men'Colony

25 HighlandDrive 4

23 Route 101 2

65

65

65

65

55

388o

364o

364o

364o

364o

3940

384o

3800

3800

3800

32

32

32

32

17

123 ~120

119

119

224

(Merger of Route 1 with U.S. 101 between SLO 8 Pismo Beach summarized under Route 101)

22 Route 101

20 Route 227,Grand Ave. 5

19 Halcyon Rd. 5

OutsideStudy Area

4o

50

50

1780 (2)

166o (2)

166o (2)

1600

1490

1490

17

25

60

60

5-2

TABLE I

EVACUATION NETWORK (cont'd)

Route NodeNo.

No.'01

17

Node

Outs ideStudy Area

Route 58,Santa Marg.

65 3560

Possible (2)

Average CapacityHighway (Vehicles/

~Tpe ~Seed Nr. )

DirectionalAdjustedCapacity(Vehicles/Hr.)

3780

.OptimumSpeed

-(Miles/Hr.)

32

OptimumDensity(Vehicles/Hr.)

118

16 Monterey St.65

70

3220

3560

3550

3780

32

32 11814 Santa Rosa

Street70 3560 3780 32 118

12 Marsh St.

11 Madonna Rd.70

70

3560

3760

3780

3880

32

32

118

12110 Los Osos

Valley Rd.

SouthHiguera St.

San LuisBay Rd.

70

70

70

3760

3760

3760

3880

3880

3880

32

32

32

121

121

121

7 Avila Rd.

6 Shell Beach

5 Route 1

702 (2)

702

70

3760

3760

3760

3880

3880

3880

32

32

32

121

121

121

4 PriceCanyon Rd. 2

3 Oak Park Blvd. 2 (2)

2 Route 227 2

1 OutsideStudy Area

70

70

70

3160

3160

3680

3580

3580

3840

32

32

32

112

112

120

5-3

TABLE I

EVACUATION NETWORK (cont'd)

Route NodeNo. No. Node

Possible (2)

Average CapacityHighway (Vehicles/

~Tpe Speed Hr.)

DirectionalAdj ustedCapacity(Vehicles/Hr.)

OptimumSpeed(Hiles/Hr.)

OptimumDensity(Vehicles/Hr.)

41 40 Route 1,Morro Bay

Outs ideStudy Area

55 146O (2) 1310 27 49

227 39 Harsh St.,SLO

38 Orcutt Rd.,SLO

37 Price Canyon 1

4 PC Route 101,Pismo Beach

50

50

'0

166O (2)

166O (2)

166O (2)

1490

1490

1490

17

25

25

88

60

60 ~

Orcutt 36 Johnson Ave.,SLO

35 Route 227 E

Huasna Rd.,AG 1

(2) Route 101,.Arroyo Grande 2

45

14OO (2)

1400 (2)

126O

1260

23

17

55

74

Type of1.2.

3 ~

4.5.

Node key:Dummy node (no access)Freeway interchange; assume one ramp at each interchange; if aparenthetic two, (2), appears after the key number calculate accessfrom two ramps.Expressway at-grade intt„rsection with cross-over.Expressway intersection with signals.Multiple surface streets.

Parenthetic two, (2), after .the possible capacity indicates a two-laneroad or street with capacity expressed for both directions.

5-4

TABLE I

EVACUATION NETWORK (cont'd)

DEFIN'ITIONS

Average Highway Speed - a safe driving speed when there is little or no

traffic. It is indicative of the roadway geometries.

Possible Capacity - the maximum number of vehicles that the roadway can carryin an hour, under typical traffic mix (2-directional volume for 2-lane roads

and streets; 1-directional volume for freeways and expressways).

Directional Adjusted Capacity - the assumed maximum 1-directional trafficvolume under evacuation conditions. This volume assumes that the proportionof heavy trucks will be approximately one-half of the normal peak-hour truckproportion; and that 2-lane, 2-way roads and streets can carry 90 percentof the 2-directional possible capacity in the predominant evacuationdirection (i.e., that return traffic will be either absent or very light).

Optimum Speed (sopt) the operating speed of the traffic stream at peakcapacity (derived From Highway Capacity Manual), in miles per hour.

Optimum Density ( popt) the density of cars on the roadway moving in theevacuation directio~i at peak capacity (also derived from Highway CapacityManual), in cars per mile (note that the Popt number includes both lanesor routes where there a'e two lanes moving in one direction).

5 5

TABLE II

FORMULAE FOR TRAFFIC FLOW OUANTITIES

Basic Traffic Flow

s (2 - —), for 0 ~—~1.7p p

optopt P opt

for —3 1.7p

'opt

where s = speed in m.p.h.;

s = speed at maximum capacity;optP = density in cars per mile of highway moving in one direction;

p = density of cars when highway is operating at maximumopt capacity.

2. maximum capacity, c = p „ sopt opt

3. traffic volume, v = p s.

Intersection Access Rates

Type 1 nodes: no access.

Type 2 nodes:

At freeway interchanges the maximum entering ramp traffic volume,

.5(l - —~ —) pl

1.7 P optopt'pt

vehicles per hour (if s

for —= 0 to I ~ 7P

optis expressed in miles per hour).

Type 3 nodes:

At expressway at-grade crossovers, maximum entering traffic rate,

e=.3(l - —') p s

I

1.7 P opt optopt

TABLE I I (cont'd)

Type 4 nodes:

At expressway signalized intersections, maximum entering traffic rate,

e = .25(l - ——) P s , for one-side access, and1

1.7 p opt opt'pt

e=.5(l - —~ —) p s1 P

1.7 p optopt'pt

for access from two sides.

Type 5 nodes:

For roads and streets with multiple surface street connections, maximumentering volume,

e=.6(l - —~'

)1

1 7 opt

opt'hese

equations describe some conditions that are outside the scope ofthe Highway Capacity Manual (HCM) and take account of conditions that wi'llprobably prevail during any evacuation. For example, left turn movements ontoexpressways and surface streets are ass'umed to be free of interference fromoncoming traffic. Also, on freeways, weaving movements and similar frictionwith exiting traffic should be absent.

5-7

TABLE IIIACCESS TO EVACUATION ROUTES

Emergency Planning Zones andDirection of Evacuat'ion " Probable Access to Evacuation Routes

I. North Horro Bay"

a. North on 1

b. South on 1

c. East on 41

San Jacinto St. and Yerba Buena St. intersectionsYerba Buena St., San Jacinto St. intersections,Atascadero Rd. interchangeRte. 1 and Frontage Rd., Ironwood Ave.:intersection

II. South Morro Bay

a. North on 1

b. South on 1

c. East on 41

Hain St. and Horro Bay Blvd. interchangesMorro Bay Blvd. interchange plus 10''ach toHain and South Bay interchangesvia Rte. 1 to Atascadero Rd. interchange

III. Los Osos

a. North on ~ 1-

b. South on 101

c. North on 101

South Bay Blvd. interchangeLos Osos Valley Rd. interchangeLos Osos Valley Rd. to Madonna Rd. and Madonna Rd.interchange

IV. Montana De Oro same as Los Osos study area

V. Camp San Luis Obispo none required (thru camp entrance onto Rte. 1)

VI. Cali fornia Hen's Colony none required (thru colony entrance onto Rte. 1)

V I I . Foothi 11-0 'onnera. North on 1

b. North or South on 101

multiple surface intersectionsvia Rte. 1 to Chorro and Santa Rosa St. tointerchanges in SLO

VIII. Laguna Lake

a. North on 101

b. South on 101

c. North on 1

Madonna Rd. and Los Osos Rd. interchanges

Los Osos Rd. interchange

via 101 N. and South Bay Blvd.

5-8

TABLE III (cont'd)

Emergency Planning Zones andDirection of Evacuation Probable Access to Evacuation Routes

IX. San Luis Bay San Luis Bay Rd. interchange with Rte. 101

X. Avila Beach

a. North on 101

b. South on 101

San Luis Bay Rd. and Avila Beach interchanges

Avila Beach and Shell Beach interchanges

X I . Ca I Pol y

a. North on Rte. 1

b. North on Rte. 101

c. South on Rte. 101

Surface intersectionsMonterey St. and California Blvd. Northboundentrance ramps

Lemon St., Taft St., and Grand Ave. Southboundentrance ramps

XII. Central San Luis Obispo

a. North on Rte. 1

b. North on Rte. 101

c. South on Rte. 101

d. South on 227 or Orcutt

Surface intersections (Santa Rosa and 101)

Harsh St., Broad St., Osos St., Toro St.,California Blvd., and Monterey St. ent'rance ramps

Grand Ave., Taft St., Lemon St., Broad St.,Harsh St., and Madonna Rd. entrance ramps

Surface intersections (227, Broad and Orcutt)

XIII. South Higuera

a. North on 1

b. North on 101

c. South on 101

d. South on 227

via Harsh St. to Santa Rosa St.Madonna Rd. and Marsh St. No. Bd. entrance ramps

Hlguera St. interchange

via Tank Farm Rd.

XIV. Edna

a. North or 1

b. North on 101

c. South on 227 and Orcuttd. South on 101

same as So. Higuera study area

same as Central SLO study area

surface intersectionsvia 227 and Orcutt routes

XV. Squire Canyon

a. North on 101

b. South on 101

San Luis Bay and Avila Beach interchanges

same as North

5-9

TABLE III (cont'd)

Emergency Planning Zones andDirection of Evacuation Probable Access to Evacuation Routes

XVI. Pismo Beach

a. North on 101

b. South on 101

c. North on 227 (altern.)d. South on 1

four diamond type Northbound entrance ramps

four diamond type Southbound entrance ramps

via Price Canyon Rd.

via Shel 1 Beach Frontage Rd. and surfaceintersections

XVII. North Arroyo Grande

a. South on 101

b. North on 101

c. South on 1

d. North on Orcutt

two diamond type, one left lane Southboundentrance ramps

two diamond type entrance ramps

via surface streets and roads

via Lopez Drive

XVIII. South Arroyo Grande

a. South on 101

b. South on 1

c. North on 101

d. North on 227 (altern.)

four diamond type Southbound entrance ramps

surface intersectionsfour diamond type Northbound entrance ramps

via Price Canyon Rd.

5-10

5.4 ROUTING OF VEHICLES

5-11TERA CORPORATION

TOTAL EVACUATION - NO DAMAGE

~ Distribution and Direction of Evacuating Traffic

NodeRoute Number Node Name

Route 1 33 North Morro Bay

32 Route 41

30 Morro Bay Blvd.

29. South Bay Blvd.

27 Camp SLO Entrance

Number of Vehicles

2650

3200

6100

50

Direction

North

North

North

North

North

26 Calif. Men's Colony 200 North

25 Highland Drive

23 SLO Intersection Route 101

2075

1750

North

North

(Merger of Route 1 with Route 101 between SLO and Pismo Beach summarized under Route 101)

22 . Pismo Beach Inters. Route 101

20 Route 227 (Grand Ave.)

19 Halcyon Rd.

1000

2050

2375

South

Sout

South

Route 101 17 Route 58 North

16 Monterey St.

14 Santa Rosa St.

12 Marsh St.

ll Madonna Rd.

10 Los Osos Valley Rd.

Higuera St.

San Luis Bay Rd.

7 'vila Rd.

6 Shell Beach

Price Canyon Rd.

3 Oak Park Rd.

2 Route 227

5-12

1750, Cal Poly-3525

4000, Cal Poly-3525

1375

1750

1500

325

)000

600

1250

4050

4425

North

Nor th

North

North

South

South

South

South

South

South

Sout

South

Route

Route 41

NodeNumber Node Name

Number of cars routedonto Rt. 41 from Rt. 1

4325 North

Number of Vehicles Direction

Route 227 39 Marsh St., SLO

38 Orcutt Rd., SLO

37 Inters. of 227 5 Price Canyon Rd.

1000

500

South

South

South

(Evacuation Route follows Price Canyon Rd. at this point)

4 PC Inters. of Price Canyon Rd. 8 Rt. 101 South

Orcutt Rd. 36 Johnson Ave., SLO 875 South

(Evacuation Route .follows Orcutt Rd. to Lopez Dr. to Huasna Rd.)

Los BerrosRd.

35 Inters. of Huasna Rd. 5 Rt. 227

42 Valley Rd. 2250

South-.

South

5-13

NORTHERN EVACUATION — NO DAMAGE

Distribution and Direction of Evacuating Traffic'ode

Route Number Node Name Number- of Vehicles Direction

Route 1 33 North Morro Bay

32 Route 41

2650 North

North

30

29N

29S

27

Morro Bay Blvd.South Bay Blvd.South Bay Blvd.

Camp SLO Entrance

Calif. Men's Colony

3200

3475

2625

0

0

North

North

South

South

South

25 Highland Drive

23 SLO Intersection Route 101

(Merger of Route 1 with Route 101 between SLO and

South

South

Pismo Beach summarized under Route 101)

22 . Pismo Beach Inters. Route 101

20 Route 227 (Grand Ave.)

19 Halcyon Rd.

Route 101 17 Route 58

16 Monterey St.

14 Santa Rosa St.

12 Marsh St.

11 Madonna Rd.

10 Los Osos Valley Rd.

Higuera St.

8 San Luis Bay Rd.

Avila Rd.

Shell Beach

4 Price Canyon Rd.

3 Oak Park Rd.

2 Route 227

0

0

0

South

South

South

North

North

North

North

North

South

South

South

South

South

South

South

South

5-14

RouteNode

Number Node Name Number of Vehicles Direction

Route 41

Route 227

Number of cars routedonto Rt. 41 from Rt. 1

39 Marsh St., SLO

38 Orcutt Rd., SLO

37 Inters. of 227 8 Price Canyon Rd.

2300 North

South

South

South

(Evacuation Route follows Price Canyon Rd. at this point)

4 PC Inters. of Price Canyon Rd. 5 Rt. 101

Orcutt Rd. 36 Johnson Ave., SLO

(Evacuation Route follows Orcutt Rd. to Lopez Dr. to Huasna Rd.)

South

South

Los Ber rosRd.

35 Inters. of Huasna Rd. 5 Rt. 227

42 Valley Rd.

South

South

5-15

SOUTHERN EVACUATION - NO DAMAGE

Distribution and Direction of Evacuating Traffic

Node,Route Number Node Name Number of Vehicles Direction

Route 1 '3 North Morro Bay

32 Route 41

30 Morro Bay Blvd.

29, South Bay Blvd.

27 Camp SLO Entrance

26 Calif. Men's Colony

25 Highland Drive

23 SLO Intersection Route 101

North

North

North

North

North

North

North

North

(Merger of Route 1 with Route 101 between SLO and Pismo Beach summarized under Route 101)

22 Pismo Beach Inters. Route 101

20 Route 227 (Grand Ave.)

19 Halcyon Rd.

Route 101 17 Route 5S

16 Monterey St.

14 'Santa Rosa St.

12 Marsh St.

11 Madonna Rd.

10 Los Osos Valley Rd.

9 Higuera. St.

8 San Luis Bay Rd.

7 Avila Rd.

6 Shell Beach

4 Price Canyon Rd.

3 Pak Park Rd.

2 Route 227

5-16

1500

1500

'0

1000

325

1075

4925

3000

4750

South

South

South

North

North

North

North

No'rth

North

North

North

North

North

North

.South

South

RouteNode

Number Node Name Number of Vehicles Direction

Route 41

Route 227

Number of cars routedonto Rt. 41 from Rt. 1

39 'arsh St., SLO

38 Orcutt Rd., SLO

37 Inters. of 227 5 Price Canyon Rd.

0 North

South

South

South

(Evacuation Route follows Price Canyon Rd. at

4 PC Inters. of Price Canyon Rd. 5 Rt. 101

Orcutt Rd. 36 Johnson Ave., SLO

this point)

South

South

(Evacuation Route follows Orcutt Rd. to Lopez Dr. to Huasna Rd.)

Los BerrosRd.

35 Inters. of Huasna Rd. & Rt. 227

42 Valley Rd. 1250

South

South

5-17

EASTERN EVACUATION - NO DAMAGE

~ Distribution and Direction of Evacuating Traffic

NodeRoute Number Node Name Number of Vehicles Direction

Route 1 33 North Morro Bay

32 Route 41

30 Morro Bay Blvd.

29. South Bay Blvd.

27 Camp SLO Entrance

26 Calif. Men's Colony

25 Highland Drive

23 SLO Intersection Route 101

50

200

3075, Cal Poly-2050

2375

North

North

North

Nor th

North

North

North

North

(Merger of Route 1 with Route 101 between SLO and Pismo Beach summarized under Route 101)

22

20

Pismo Beach Inters. Route 101

Route 227 (Grand Ave.)

5-18

19 Hal cyon Rd.

Route 101 17 Route 58

16 Monterey St.

14 Santa Rosa St.

12 Marsh St.

11 Madonna Rd.

10 Los Osos Valley Rd.

9 Higuera St.

San Luis Bay Rd.

Avila Rd.

Shell Beach

4 Price Canyon Rd.

3 Oak Park Rd.

2 Route 227

0, Cal Poly - 5000

1500

1350

2425

1500

0

0

South

South

South

North

North

South

South

South

South

South

South

South

South

South

South

South

Route

Route 41

NodeNumber Node Name

Number of cars routedonto Rt. 41 from Rt. 1

Number of Vehicles Direction

2325

Route 227 39 Marsh St., SLO

38 Orcutt Rd., SLO

37 Inters. of 227 8 Price Canyon Rd.

1250

1175

South

South

South

(Evacuation Route follows Price Canyon Rd. at this point)

4 PC Inters. of Price Canyon Rd. & Rt. 101 South

Orcutt Rd. 36 Johnson Ave., SLO 1925 South

Los BerrosRd.

(Evacuation Route follows Orcutt Rd. to Lopez Dr. to Huasna Rd.)

35 Inters. of Huasna Rd. 5 Rt. 227

42 Valley Rd.

South

South

TOTAL EVACUATION - LIGHT DAMAGE

Distribution and Direction of Evacuatin'g Traffic

NodeRoute Number Node Name Number .of 'Vehicles Direction

Route 1 33 North Morro Bay

32 Route 41

30 Morro Bay Blvd.

29 South Bay Blvd.

27 Camp SLO Entrance

26 Calif. Men's Colony

25 Highland Drive

2650

3200

6100

50

200

2825

North

North

North

North

North

North

North

- 23

(Merger of Route

SLO Intersection Route 101

1 with Route 101 between SLO and

750 North

Pismo Beach summarized under Route 101)'2

Pismo Beach Inters. Route 101

20 Route 227 (Grand Ave.)

19 Halcyon Rd.

Route 101 17 Route 58

16 Monterey St.

14 Santa Rosa St.

12 Marsh St.

ll Madonna Rd.

10 Los Osos Valley Rd.

Higuera St.

8 San Luis Bay Rd.

1250

2800

2250

1250, Cal Poly-3525

2625, Cal Poly-3525

750

3)75

750

South

South

South

North

North

North

North

North

North

North

North

6

'3

'vi la Rd.

Shell Beach

Price Canyon Rd.

Oak Park Rd.

1325

600

750

3550

South

South

South

South

2 Route 227 4425 South

Routefllh%Ã Route 41

Route 227

NodeNumber Node Name

Number of cars routedonto Rt. 41 from Rt. 1

39 Marsh St., SLO

38 Orcutt Rd., SLO

37 Inters. of 227 8 Price Canyon Rd.

1875

500

Nor th

South

South

South

Number of Vehicles Direction

(Evacuation Route follows Price Canyon Rd. at this point)

4 PC Inters. of Price Canyon Rd. 5 Rt. 101 South

Orcutt Rd. 36 Johnson Ave., SLO 2075 South

(Evacuation Route follows Orcutt Rd. to Lopez Dr. to Huasna Rd.)

Los BerrosRd.

35 Inters. of Huasna 'Rd. 8 Rt. 227

42 Valley Rd. 2375

South

South

5-21

NORTHERN EVACUATION - LIGHT DAMAGE

Distribution and Direction of Evacuating Traffic

NodeRoute Number Node Name Number of Vehicles Direction

Route 1 33 North Morro Bay

32 Route 41

2650 North

North

30

29N

29S

27

Morro Bay Blvd.South Bay Blvd.South Bay Blvd.

Camp SLO Entrance

3200

3475

2625

0

North

North- South

South

26 Calif. Men's Colony South

25

23

(Merger of Route 1

Highland Drive-

SLO Intersection Route 101 0

South

South

with Route 101 between SLO and Pismo Beach summarized under Route 101)

22

20

Pismo Beach Inters. Route 101t

Route 227 (Grand Ave.)

19 Halcyon Rd.

Route 101 17 Route 58

16 Monterey St.

14 Santa Rosa St.

12 Marsh St.

11 Madonna Rd.

10 Los Osos Valley Rd.

, 9 Higuera St.

8 San Luis Bay Rd.

7 Avila Rd.

6 Shell Beach

Price Canyon Rd.

3 Oak Park Rd.

2 Route 227

South

'outh

South

North

North

North

North

North

South

South

South

South

South

South

South

South

5-22

Route

Route 41

NodeNumber Node Name

Number of cars routedonto Rt. 41 from Rt. 1

Number of Vehicles Direction

North

Route 227 39 Marsh St., SLO

38 Orcutt Rd., SLO

37 Inters. of 227 8 Price Canyon Rd.

(Evacuation Route follows Price Canyon Rd. at this point)

4 PC Inters. of Price Canyon Rd. 8 Rt. 101

South

South

South

South

Orcutt Rd. 36 Johnson Ave., SLO

(Evacuation Route follows Orcutt Rd. to Lopez Dr. to Huasna Rd.)

South

Los BerrosRd.

35 Inters. of Huasna Rd. 5 Rt. 227

42 Valley Rd.

South

South

5-23

SOUTHERN EVACUATION - LIGHT DAMAGE

Distr'ibution and Direction of Evacuating Traffic

NodeRoute Number Node Name Number of Vehicles Direction

Route 1 33 North Morro Bay

32 Route 41

30 Morro Bay Blvd.

29 South Bay Blvd.

27 Camp SLO Entrance

26 Calif. Men's Colony

25 Highland Drive

23 SLO Intersection Route 101 aO

North

North

North

North

North

North

North

North

(Merger of Route 1 with Route 101 between SLO and Pismo Beach summarized under Route 101)

Route 101

- 19

17

Halcyon Rd.

Route 58

16 Monterey St.

14 Santa Rosa St.

12 Marsh St.

11 Madonna Rd.

10 Los Osos Valley Rd.

Higuera St.

San'Luis Bay Rd.

Avila Rd.

She'l Beach

Price Canyon Rd.

3 Oak Park Rd..

2 Route 227

22 'ismo Beach Inters. Route 101

20 Route 227 (Grand Ave.) 1625

1500

0

1325

925

1750

4750

3200

South

South

South

North

North

North

North

North

North

North

North

South

South

South

South

South

5-24

Route

Route 41

NodeNumber Node Name

Number of cars routedonto Rt. 41 from Rt. 1

Number of Vehicles Direction

North

Route 227 39 Marsh St., SLO

38 Orcutt Rd., SLO

37 Inters. of 227 8 Price Canyon Rd.

(Evacuation Route follows Price Canyon Rd. at this point)

North

North

North

4 PC Inters. of Price Canyon Rd. 8 Rt: 101

Orcutt Rd. 36 Johnson Ave., SLO

1250 North

North

(Evacuation Route follows Orcutt Rd. to Lopez Dr. to kuasna Rd.)

Los BerrosRd.

35 Inters. of kuasna Rd. & Rt. 227

42 Valley Rd.

1625

1375

North

South

5-25

EASTERN EVACUATION - LIGHT DAMAGE

Distribution and Direction of Evacuating Traffic

NodeRoute Number Node Name Number of Vehicles Direction

Route 1 33 North Morro Bay

32 Route 41

30 Morro Bay Blvd.

29 South Bay Blvd.

27 Camp SLO Entrance

26 Calif. Men's Colony

25 Highland Drive

23 SLO Intersection Route 101

50

200

4250, Cal, Poly-2050

1000

North

North

North

North

North

North

North

North

(Merger of Route 1 with Route 101 between SLO and Pismo Beach summarized under Route 101)

22 Pismo Beach Inters. Route 101

20 Route 227 (Grand Ave.)

South

South

19

Route 101 17

Halcyon Rd.

Route 58

0. South

North

16 Monterey St.

14 Santa Rosa St.

12 Marsh St.

ll Madonna Rd.

10 Los Osos Valley Rd.

Higuera St.

8 San Luis Bay Rd.

7 'vila Rd.

6 Shell Beach

Price Canyon Rd.

3 Pak Park Rd.

2 Route 227

500, Cal Poly -5000

1000

750

1000

750

0

North

North

North

North

North

North

South

South

South

South

South

South

5-26

Route

Route 41

NodeNumber Node Name

Number of cars routedonto Rt . 41 from Rt . 1

Number of Vehicles Direction

North

Route 227 39 Marsh St., SLO

38 Orcutt Rd., SLO

37 Inters. of 227 8 Price Canyon Rd.

2900

1425

South

South

South

(Evacuation Route follows Price Canyon Rd. at 'this point)

4 PC Inters. of Price Canyon Rd. 8 Rt. 101 0 South

Orcutt Rd. 36 Johnson Ave., SLO 3000 South

Los Ber rosRd.

(Evacuation Route follows Orcutt Rd. to Lopez Dr. to Huasna Rd.)

35 Inters. of Huasna Rd. 5- Rt. 227

42 Valley Rd.

South

South

5-27

TOTAL EVACUATION - MODERATE DAMAGE

Distribution and Direction of Evacuating Traffic

NodeRoute Number Node Name Number of'Vehicles Direction

Route 1 33 North Morro Bay 2650 North

32

30

Route 41

Morro Bay Bl vd. 3200 North

0 North

29

26

South Bay Blvd.

Camp SLO Entrance

Calif. Men's Colony

6100

50

200

North

North

North

20

19

Route 101 17

16

Pismo Beach Inters. Route 101

Route 227 (Grand Ave.)

Halcyon Rd.

Route 58

Monterey St.

25 Highland Drive

23 SLO Intersection Route 101

(Merger of Route 1 with Route 101 between SLO and

3075, Cal Poly - 3900 North

North

Route 101)

South

South

South

North

North

2750

Pismo Beach summarized under

1250

3550

2750

0

O,,Cal Poly - 3150

14

12

10

Santa Rosa St.

Marsh St.

Madonna Rd.

Los Osos Valley Rd.

Higuera St.

San Luis Bay Rd.

Avila Rd.

1325

North

North

North

North

North

North

South

6 Shell Beach

Price Canyon Rd.

3 Oak Park Rd.

2 Route 227

600

750

3050

3675

South

South

South

South

5-28

Route

Route 41

NodeNumber Node Name

Number of cars routedonto Rt. 41 from Rt. 1

Number of Vehicles Direction

North

Route 227 39 Marsh St , SLO

38 Orcutt Rd., SLO

37 Inters. of 227 5 Price Canyon Rd.

4875

1500

South

South

South

(Evacuation Route follows Price Canyon Rd. at this point)

Orcutt Rd.

Los BerrosRd.

4 PC Inters. of Price Canyon Rd. 5 Rt. 101k

36 Johnson Ave., SLO

(Evacuation Route follows- Orcutt Rd. to Lopez

35 Inters. of Huasna Rd. 8 Rt. 227

42 Valley Rd.

4375

Dr. to Huasna Rd.)

2375

South

South

South

South

5-29

NORTHERN EVACUATION — MODERATE DAMAGE

Distribution and Direction of Evacuating Traffic

NodeRoute Number Node Name Number of Vehicles Direction

Route 1 33 North Morro Bay 2650 North

32

30

29N

29S

27

26

Route 41

Morro Bay Blvd.South Bay, Blvd.

South Bay Blvd.Camp SLO

Entrance'alif.

Men's Colony

3200

5000

1100

North

North

North

South

South

South

25 Highland Drive

23 SLO Intersection Route 101

South

South

{Merger of Route 1 with Route 101 between SLO and Pismo Beach summarized under Route 101)

22

20

Pismo Beach Inters. Route 101

Route 227 (Grand Ave.)

South

South

19 Halcyon Rd.

Route 101 17 Route 58

16 Monterey St.

14 Santa Rosa St.

12 Marsh St.

ll Madonna Rd.

10 Los Osos ValleyRd.'iguera

St.

8 San Luis Bay Rd.

'vila Rd.I

Shell Beach

4 Price Canyon Rd.

3 Pak Park Rd.

2 Route 227

0

South

North

North

North

North

North

South

South

South

South

South

South

South

South

5-30

Route

Route 41

NodeNumber Node Name

Number of cars routedonto Rt. 41 from Rt. 1

Number of Vehicles Direction

North

Route 227 39 Marsh St., SLO

38 Orcutt Rd., SLO

37 Inters. of 227 8 Price Canyon Rd.

(Evacuation Route follows Price Canyon Rd. at this point)

4 PC Inters. of Price Canyon Rd. 8 Rt. 101

South'outh

South

South

Orcutt Rd. 36 Johnson Ave., SLO

(Evacuation Route follows Orcutt Rd. to Lopez Dr. to Huasna Rd.)

South

Los BerrosRd.

35 Inters. of Huasna Rd. 8 Rt. 227

42 Valley Rd.

South

South

5-31

SOUTHERN EVACUATION — MODERATE DAMAGE

Distribution and Direction of Evacuating Traffic

NodeRoute Number Node Name Number of Vehicles Direction

Route 1 33 North Morro Bay

32 Route 41

30 Morro Bay Blvd.

29 South Bay Blvd.

27 Camp SLO Entrance

26 Calif. Men's Colony

25 Highland Drive

23 SLO Intersection Route 101

0

0 ~

0

North

North

North

Nor th

North

North

North

North

22 Pismo Beach Inters. Route 101

(Merger of Route 1 with Route 101 between SLO and Pismo Beach summarized under Route 101)

South

20 Route 227 (Grand Ave.)

19 Halcyon Rd.

Route 101 17 Route 58

16 Monterey St.

14 Santa Rosa St.

12 Marsh St.

ll Madonna Rd.

10 Los Osos Valley Rd.

Higuera St.

8 San Luis Bay Rd.

'vila Rd.

Shell Beach

Price Canyon Rd.

3 Oak Park Rd.

2 Route 227

1625

1750

1325

925

2500

4750

4950

Sout

South

North

North

North

North

North

North

North

North

North

North

South

Sout

South

5-32

Route

Route 41

Route 227

NodeNumber Node Name

Number of cars routedonto Rt. 41 from Rt. 1

39 Marsh St., SLO

38 Orcutt Rd., SLO

37 Inters. of 227 8 Price Canyon Rd.

Number of Vehicles Direction

0 North

North

North

North

(Evacuation Route follows Price Canyon Rd. at this point)

4 PC Inters. of Price Canyon Rd. 8 Rt. 101

Orcutt Rd. 36 Johnson Ave., SLO

0 North

North

(Evacuation Route follows Orcutt Rd. to Lopez Dr. to Huasna Rd.)

Los BerrosRd.

35 Inters. of Huasna Rd. 8 Rt. 227

42 Valley Rd. 1500

North

South

5-33

EASTERN EVACUATION — MODERATE DAMAGE

Distribution and Direction of Evacuating Traffic

NodeRoute Number Node Name

I

Number of Vehicles 'irection

29

27

South Bay Blvd.C

Camp SLO Entrance

Route 1 33 North Morro Bay

32 Route 41

30 . Morro Bay Blvd.

50 North

0 North

0 North

0 North

0 North

26 Cal if. Men ' Col ony 200 North

25 Highland Drive 5500, Cal Poly - 2750 North

23 SLO Intersection Route 101 1375 North

(Merger of Route 1 with Route 101 between SLO and Pismo Beach summarized under Route 101)

22 Pismo Beach Inters. Route 101

20 Route 227 (Grand Ave. )

19 Halcyon Rd.

South

South

South

Route 101 17 Route 58 0 North

16 Monterey St.

Santa Rosa St.

12 Marsh St.

ll Madonna Rd.

10 Los Osos Valley Rd.

Higuera St.

, 8 San Luis Bay Rd.

'vila Rd.

Shell Beach

Price Canyon Rd.

3 Oak Park Rd.

2 Route 227

0, Cal Poly - 4300

0

Nor th

North

North

North

North

North

South

South

South

South

South

South

5-34

Route

Route 41

NodeNumber Node Name

Number of cars routedonto Rt. 41 from Rt. 1

Number of Vehicles Direction

0 North

Route 227 39 Marsh St., SLO

38 Orcutt Rd., SLO

37 Inters. of 227 5 Price Canyon Rd.

4400

1425

South

South

South

(Evacuation Route follows Price Canyon Rd. at this point)

4 PC Inters. of Price Canyon Rd. & Rt. 101 South

Orcutt Rd. 36 Johnson Ave., SLO 3875 South

Los BerrosRd.

(Evacuation Route follows Orcutt Rd. to Lopez Dr. to Huasna Rd.)

35 Inters. of Huasna Rd. 5 Rt. 227

42 Valley Rd.

South

South

5-35

TOTAL EVACUATION - HEAVY DAMAGE

Distribution and Direction of Evacuating Traffic

NodeRoute Number Node Name Number of Vehicles Direction

Route 1 . 33

32

North Morro Bay

Route 41

2650 North

North

30 Morro Bay Blvd.

29 South Bay Blvd.

3200

6100

Nor th

North

27 Camp SLO Entrance 50 North

26 Calif. Men's Colony 200 .North

25 Highland Drive 3075, Cal Poly — 4550 North

23 SLO Intersection Route 101 3750 North

(Merger of Route 1 with Route 101 between SLO and Pismo Beach summarized under Route 101)

22 Pismo Beach Inters. Route 101

20 Route 227 (Grand Ave.)

19 Halcyon Rd.

Route 101 17 Route 58

16 Monterey St.

14 Santa Rosa St.

12 Marsh St.

ll Madonna Rd.

10 Los Osos Valley Rd.

Higuera St.

8 San Luis Bay Rd.

Avila Rd.r

Shell Beach

Price Canyon Rd.

3 Oak Park Rd.

2 Route 227

1250

3250

4000

0

0, Cal Poly - 2500

~ 0

1325

600

750

1800

3050

South

South

South

North

North

NorthNorth

onto Rt.

North

North

North

North

South

South

South

South

South

5-36

Route

Route 41

NodeNumber Node Name

Number of cars routedonto Rt. 41 from Rt. 1

Number of Vehicles Direction

North

Route 227 39 Marsh St., SLO

38 Orcutt Rd., SLO

37 Inters. of 227 8 Price Canyon Rd.

6550. Cal Poly- 0

2000

South

South

South

(Evacuation Route follows Price Canyon Rd. at this point)

4 PC Inters. of Price Canyon Rd. 8 Rt. 101 South

Orcutt Rd. 36 Johnson Ave., SLO

(Evacuation Route follows Orcutt Rd. to Lopezr

35 Inters. of Huasna Rd. 8 Rt. 227

1200

Dr. to Huasna Rd.)

South

South

Los BerrosRd.

42 Valley Rd; 3300 South

5-37

NORTHERN EVACUATION - HEAVY DAMAGE

Distribution and Direction of Evacuating Traffic

NodeRoute Number Node Name Number of Vehicles Direction

Route 1 33 North Morro Bay

32 Route 41

2650 North

North

30

29N

29S

27

26

25

Morro Bay Blvd.South Bay Blvd.

South Bay Blvd.

Camp SLO Entrance

Calif. Men's Colony

Highland Drive

3200

6100

North

North

South

South

South

South

23 SLO Intersection Route 101

(Merger of. Route 1 with Route 101 between SLO and

22 Pismo Beach Inters. Route 101

0

Pismo Beach summarized under

0.

South

Route 101)

South

Route 101

20 Route 227 (Grand Ave.)

19 Halcyon Rd.

17 Route 58

16 Monterey St.

14 Santa Rosa St.

12 Marsh St.

ll Madonna Rd.

10 Los Osos Valley Rd.

Higuera St.

San Luis Bay Rd.

Avi1 a Rd.

Shell Beach

Price Canyon Rd.me

Oak Park Rd.

2 Route 227

0

South

South

North

North

North

North

North

South

South

South

South

South

South

South

South

5-38

Route

Route 41

NodeNumber Node Name

Number of cars routedonto Rt. 41 from Rt. 1

Number of Vehicles Direction

North

Route 227 39 Marsh St., SLO

38 Orcutt Rd., SLO

37 Inters. of 227 & Price Canyon Rd.

(Evacuation Route follows Price Canyon Rd. at this point)

4 PC Inters. of Price Canyon Rd. 5 Rt. 101

South

South

South

South

Orcutt Rd. 36 Johnson Ave., SLO

(Evacuation Route follows Orcutt Rd. to Lopez Dr. to Huasna Rd.)

South

Los BerrosRd.

35 Inters. of Huasna Rd. 8 Rt. 227

42 Valley Rd.

South

South

5-39

SOUTHERN EVACUATION - HEAVY DAMAGE

Distribution and Direction of Evacuating Traffic

NodeRoute Number Node Name Number of Vehicles Direction

Route 1 33 North Morro Bay

32 Route 41

30 Morro Bay Blvd.

29 South Bay Blvd.

27 Camp SLO Entrance

26 Calif. Men's Colony

25 Highland Drive

23 SLO Intersection Route 101

North

Nor th

North

North

North

North

North

North

(Merger of Route 1 with Route 101 between SLO and Pismo Beach summarized under Route 101)-

Route 101

22 Pismo Beach Inters. Route 101

20 Route 227 (Grand Ave. )

19 Halcyon Rd.

17 Route 58

16 Monterey St.

14 Santa Rosa St.

12 Marsh St.

ll Madonna Rd.

10 Los Osos Valley Rd.

Higuera St.

8 San Luis Bay Rd.

Avi1 a Rd.

Shell Beach

Price Canyon Rd.

3 Oak Park Rd.

2 Route 227

5-40

625

2250

1325

925

3000

4000

3875

South

South

South

North

North

NorthNorth

onto Rt. 1

North

North

North

North

South

South

South

South

South

Route

Route 41

NodeNumber Node Name

Number of cars routedonto Rt. 41 from Rt. 1

Number of Vehicles Direction

North

Route 227 39 Marsh St., SLO

38 Orcutt Rd., SLO

37 Inters. of 227 5 Price Canyon Rd.

(Evacuation Route follows Price Canyon Rd. at this point)

North

North

North

4 PC Inters. of Price Canyon Rd. 5 Rt. 101

Orcutt Rd. 36 Johnson Ave., SLO

1825 North

North

(Evacuation Route follows Orcutt Rd. to Lopez Dr. to Huasna Rd.)

Los BerrosRd.

35 Inters. of Huasna Rd. 8 Rt. 227

42 Valley Rd. 1500

Nor th

South

5-41

EASTERN EVACUATION - HEAVY DAMAGE

Distribution and Direction of Evacuating Traffic

NodeRoute Number Node Name Number. of Vehicles Direction

Route 1 33 North Morro Bay

32 Route 41

30 Morro Bay Blvd.

29 South Bay Blvd.

North

Nor th

North

North

27

26

. Camp SLO Entrance

Calif. Men's Colony

50

200

North

Nor th

25 Highland Drive

23 SLO Intersection Route 101 2500 North

5500, Cal Poly - 4375 North

(Merger of Route 1 with Route 101 between SLO and Pismo Beach summarized under Route 101)

22 Pismo Beach Inters. Route 101

20 Route 227 (Grand Ave.)

19 Halcyon Rd.

Route 101 17 Route 58

16 Monterey St.

14 Santa Rosa St.

12 Marsh St.

11 Madonna Rd.

10 Los Osos Valley Rd.

Higuera St.

8 San Luis Bay Rd.

7 Avila Rd.

6 Shell Beach

Price Canyon Rd.

Oak Park Rd.

2 Route 227

0

0, Cal Poly - 2675

0

South

South

South

North

North

North

North

North

North

North

South

South

South

South

South

South

5-42

Route

Route 41

NodeNumber Node Name

Number of cars routedonto Rt. 41 from Rt. 1

Number of Vehicles Direction

0 North

Route 227 39 Marsh St., SLO

38 Orcutt Rd., SLO

37 Inters. of 227 5 Price Canyon Rd.

6650

1925

South

South

South

(Evacuation Route follows Price Canyon Rd. at this point)

4 PC Inters. of Price Canyon Rd. 5 Rt. 101

Orcutt Rd. 36 Johnson Ave., SLO

(Evacuation Route follows Orcutt Rd. to Lopez Dr. to Huasna Rd.)

South

South

Los BerrosRd.

35 Inters. of Huasna Rd. 5 Rt. 227

42 Valley Rd.

South

South

5-43

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