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Sustainable Development in Bridge
En ineerin : Develo ment of MultiHazard Design Guidelines
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QuotationQuotation
Sustainability is a condition of existence
humans and other species to enjoy social well
being, a vibrant economy, and a healthyenvironment, and to experience fulfillment,
beauty and joy, without compromising the
a y o u ure genera ons o umans another species to enjoy the same.
,
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QuotationQuotation
Achieving sustainable development is perhaps
pressing goals we face. It requires on the part
of all of us commitment, action, partnershipsand, sometimes, sacrifices of our traditional life
pattern and personal interests.
Abraham Lincoln, 1864
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Sustainable Development in Bridge
ng neer ng: eve opmen o u -Hazard Desi n Guidelines
o e o s ruc ura eng neer ng
in sustainable development is
illustrated by an exampleexample of bridgeengineering research project.
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OutlineOutline.
2. Structural Desi n of Brid es in US
3. Development of Multi-Hazard LRFD
Progress Report
.
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IntroductionIntroduction
Sustainability An Emerging
A emerging field in science and engineering To achieve reasonable balance among
economic, environmental and societal
A significant component of sustainable
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Introduction (contd)
Sustainabilit and Structural En ineerin
Structural Engineering Emphases
Safety
Serviceability os Other
Environment/ecosystems quality Natural resources conservation Integrated consideration of present and future
Other
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Introduction (contd)
Sustainabilit and Structural En ineerin
Energy Consumption in USBuildings 40%
Industry 32%
Construction Waste:
ore an s concre e. Issues in Design Codes
Many over-conservative features
Some unsafe features
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Introduction (contd)Sustainability and Structural Engineering (contd)
ssues nvo v ng ruc ura es gnssues nvo v ng ruc ura es gn
Demand Ca acit
Demand involves all types of long term and short.
Capacity involves materials, analysis methods,failure modes, life cycle cost and sustainability
issues (e.g. reuse, retrofit and reuse, recycle,construction methods, energy, environmental
, .
Sustainable design requires holistic consideration.
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Introduction (contd)Sustainability and Structural Engineering (contd)
ssues nvo v ng ruc ura es gnssues nvo v ng ruc ura es gn
Demand Ca acit
How to set reasonable level of demand,
How to design a structure that fails at a load
Is no collapse a reasonable seismic
perspective?
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Structural Design of Bridges in US
Load and Resistance Factors Design (LRFD)approach calibrated for non-extreme loads
Individual desi n uidelines for variousextreme hazard loads under development
-hazard LRFD to achieve fully reliability-baseddesi n uidelines
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Structural Design of Bridges in US (contd)
Current LRFD specifications for basic bridges ruc ura componen s on wasinitially adopted by American Association of
(AASHTO) in 1994.
Fully calibrated for dead load and live load
only
Since then development of LRFD for otheraspec s o r ge sys ems ave een
initiated.
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Structural Design of Bridges in US (contd)
LRFD (contd)
Significance of AASHTO LRFDSignificance of AASHTO LRFD
ASD (LFD) and LRFD have virtually
based on load intensities.
i iwhere R = resistance = resistance factor
Qi = loads i = load factors
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Structural Design of Bridges in US (contd)
LRFD (contd)
Significance of AASHTO LRFD (contd)Significance of AASHTO LRFD (contd)
LRFD provides additional information on
decision making.
failure i iwhere
failure
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Structural Design of Bridges in US (contd)
LRFD (contd)
Probability Distribution o Load and ResistanceProbability Distribution o Load and Resistance
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Structural Design of Bridges in US (contd)
Limit state function Z = R Q
Failure occurs when Q > R
If Z is normal distribution,[ ]FP P Q R
Z
[ 0]P Z Z
Z
Probability of failure
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Structural Design of Bridges in US (contd)
Load and Resistance Factors Desi n LRFD contd
Design limit state = Z = R Q = 0
Probability distribution
of Resistance and loadwith respect to the
limit state
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Reliability Index and Corresponding ProbabilityReliability Index and Corresponding Probability
Structural Design of Bridges in US (contd)
LRFD (contd)
Prob. ofProb. ofexceedanceexceedance
RoundedRoundedreciprocalreciprocal
(approx. 1(approx. 1--inin--n)n)
. .
0.5 0.3085375 3
1 0.1586553 6. .
2 0.0227501 50
2.5 0.0062097 200
. ,
3.5 0.0002326 5,000
4 3.167E-05 30,000
. . - ,
5 2.867E-07 3,500,000
5.5 1.899E-08 50,000,000
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Structural Design of Bridges in US (contd)
Load and Resistance Factors Design (LRFD) (contd)
Reference:Kulicki, J. M. (2005). Past, Present and
Future of Load and Resistance Factor
Design, Journal of the TRB.
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Structural Design of Bridges in US (contd)
Current Practice of Bridge Design AgainstExtreme Hazard Loads
Various current research efforts are devoted tobridge component performance and design forindividual extreme hazard load effects (e.g.earth uake tidal waves vessel collision etc.
Very limited efforts to consider the combinations ofextreme hazard load effects, either on thecomponen s or e r ge as a sys em o
components.
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Structural Design of Bridges in US (contd)
Current Practice of Bridge Design (contd)
Status in AASHTO LRFD
Dead Load Calibrated
Live Load Calibrated
Earthquake Included (Guidespec), but not completely calibrated
Scour Not in LRFD framework
EarthquakeScour
WindIntegrated in AASHTO LRFD strength limit state,
not completely calibrated
FireNew giudance information available from NCHRP
study
Storm SurgeWind
Vessel Collision Structurally consistent with LRFD, but not calibratedconsistently
Vehicular
CollisionRough estimate based on limited dataVessel collision Vehicular collision
Storm Surge New Guidespec provide design procedures
Debris Flow Provisions on debris raft (part of WA)
FireJohn Huseby, CaltransLandslide/debris flow
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,
All- Hazard LRFD
Many bridge failures due to various extreme hazardevents in recent years
-
MCEER in 2008, funded by FHWA
To establish uidin rinci les for the develo ment
of multi-hazard LRFD with emphasis given todesign limit states for collapse failures due to
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(Demand emphasis)
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Development of Multi-Hazard LRFD (contd)
gn can a enge o eve op nggn can a enge o eve op ng
MHMH--LRFDLRFD
Demand
CapacityTo establish
reliable, sim le, all-
To design structures
with redictable
hazard design limitstatus considering
behavior for highlyunpredictable hazard
non-extreme and
extreme loads.
load effects.
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Development of Multi-Hazard LRFD (contd)
MCEER Research Project
Develop design principles and framework for
MH-LRFD desi n limit states
Establish selected design limit statee uations as exam les
Work closely with AASHTO T5, FHWA andex erienced desi n rofessionals
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Development of Multi-Hazard LRFD (contd)
Some Project Challenges
Extreme hazard events are mostl randomprocesses.
Methodology to relate and combine theprobability distribution functions of bridge
failures due to two or more extreme load
e ec s Very limited data on bridge failures due to
ex reme even s or purpose o ca ra on
Outcome must be simple to use.
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Some Pro ect Challen es contd
Development of Multi-Hazard LRFD (contd)
Two (or more) extreme load
pfailure = P ( R iQi)
Exam leExam le: Consider
D (dead load), T (truck load) and E (earthquake load)
f D, T, E
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Development of Multi-Hazard LRFD (contd)
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Development of Multi-Hazard LRFD (contd)
Some Project Challenges (contd)
DL: Normal distribution.
Nominal super-structural mass is 600 ton.(not used in this example)
: r angu ar s r u on.
Max truck mass = 30 ton.Min truck mass = 1.0 ton.
Max number of trucks passing through thebridge in 10 seconds is 8.
EL: Vertical component = lognamal
distribution in 75 year period.
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Development of Multi-Hazard LRFD (contd)
Some Project Challenges (contd)
Example of TL and EL Combinations
Definitions:
=
EDT = Event time interval (seconds)
= v TSY = Total service life of bridge in years
Earth Direct = Max. possible EL in TSY
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Development of Multi-Hazard LRFD (contd)
Example of TL and EL Combinations (contd)
4
6x 10
- Probability Mass Curve of Dead Load
ss
0
2PM
. .
x 104Intensity (KN)
1Cumulative Probability Mass Curve of Dead Load
0.5
CPMass
0 0.5 1 1.5 2
x 104
0
Intensity (KN)
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-3
Development of Multi-Hazard LRFD (contd)
Example of TL and EL Combinations (contd)
6
8
ass
0 50 100 150 200 250 3000
2P
Intensity (KN)
1Cumulative Probability Mass Curve of Each Passing Truck
0.5
CPMa
s
0 50 100 150 200 250 3000
Intensity (KN)
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-3 Truck Load Prob. Mass Curve for Varied Num. of Truck
Development of Multi-Hazard LRFD (contd)
Example of TL and EL Combinations (contd)
7
8
1 Truck Passing2 Truck Passing
3 Truck Passing
5
6
Mass
4 ruc ass ng
5 Truck Passing
6 Truck Passing
7 Truck Passing
3
4
Probability
1
2
0 500 1000 1500 2000 25000
Intensity (KN)
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Development of Multi-Hazard LRFD (contd)
Example of TL and EL Combinations (contd)
0.01om ne ro a y ass or ruc oa n
ityMass
0 500 1000 1500 2000 25000
.
Probabil
Intensity (KN)
1Cumulativ Combined Probability Mass for Truck Load in TSY
bilityMass
0.5
lativeProba
0 500 1000 1500 2000 25000
Intensity (KN)Cumu
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Development of Multi-Hazard LRFD (contd)
Example of TL and EL Combinations (contd)
1x 10
- ro a y ass or ar qua e oa n
ityMas
s
OriginalRe-Estimated
0 0.5 1 1.5 20
.
Probabil
x 104Intensity (KN)
1Cumulativ Probability Mass for Earthquake Load in TSY
bilityMass
Original
0.5
lativePro
be- s ma e
0 0.5 1 1.5 2
x 104Intensity (KN)C
um
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Development of Multi-Hazard LRFD (contd)
Example of TL and EL Combinations (contd)
0.9
1Cumulative Probability Mass in TSY
0.6
0.7
0.8
bilityMass
0.4
0.5
ulativProb
0.1
0.2
.
C
u
A--Truck onlyB--Earthquake only
C--Truck & Earthquake
D--Truck & Earth.-Direct
0 500 1000 1500 2000 2500 30000
Intensity (KN)
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Progress Report
Development of Multi-Hazard LRFD (contd)
A major challenge in establishing multi-hazard LRFD equations is to provide a
simple process for the bridge designers.
One important task is to identify significantdesign limit status for a region vulnerable to
multiple hazard threat to that region.
A workshop was carried out for this purpose.
Worksho Steerin Committee: Harry Capers,John Kulicki, Thomas Murphy (Chair), George Lee
(coordinator), W. Philip Yen
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Progress Report (contd)
Development of Multi-Hazard LRFD (contd)
Questionnaire to all AASHTO bridge
bridges and special bridges)
AASHTO bridge engineers, FHWA officials,
bridge design experts and academic
researchers to consider the survey results. Formulate regional design limit states in the
US (work in progress).
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Development of Multi-Hazard LRFD (contd)
Progress Report (contd)
Sample Survey Results andSample Survey Results andPreliminary MessagesPreliminary Messages
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Development of Multi-Hazard LRFD (contd)
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Development of Multi-Hazard LRFD (contd)
e ar se ar s yp ca r gesyp ca r ges
1No,0,
0%
2
Maybe,
2,6%
Scour VesselCollision Earthquake 3Always,2,6%
StormSurge
1No,9,
28%
3
Always,
10,31%
1No,7,
22%
2
3
Always,
16,50%
1No,
13,41%
2
Maybe,3
Always,
30,94%
2
Maybe,
13,41%
3Fire
30, 94% means: 30tates (94% ofespondent) gave this
Maybe,
9,28%
17,53%
Wind Debris Flow
2
Maybe,
10,31%
Always,
0,0%
. 1No,1,3%
2
Maybe,
10,31%
1No,5,
15%
3
Always,
5,16%
1No,
22,69%
3
Always,
21,66% 2
Maybe,
22,69%
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Development of Multi-Hazard LRFD (contd)
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Development of Multi-Hazard LRFD (contd)
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Combination of Scour and Debris FlowCombination of Scour and Debris Flow
Development of Multi-Hazard LRFD (contd)
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Potential Regional SimplificationPotential Regional Simplification
Development of Multi-Hazard LRFD (contd)
To make it practical in design using thelar e set of limit states a rocedure tochoose dominant limit states by region maybe developed.
I II III
I: High seismicity, non-hurricanecoastal wind
II: Lon -term hi h seismicit
Low temperature-related
issues
II
V
Inland windIII: Inland wind
IV: Hurricane zoneregionSpecialregion
V: Long-term high seismicity,
hurricane zone
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Potential Hazards in Each RegionPotential Hazards in Each Region
Development of Multi-Hazard LRFD (contd)
Region I:
Earthquake, non-extreme wind, scour, fire, and vehicular collision.Vessel collision is possible in some area.
Earthquake (long-term), non-extreme wind, scour, fire, andvehicular collision.
Region III:- , , , ,
collision. Northern central plain: debris flow (ice)
Region IV:Extreme wind (hurricane), scour, fire, and vehicular collision, and
.
Region V:Earthquake (long-term), extreme wind, scour, fire, and vehicularcollision, and vessel collision.
Special Region (NY, NJ, NH, DE, CA, ):Earthquake, non-extreme wind, scour, fire, vehicular collision,vessel collision, and blast.
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Preliminary MessagesPreliminary Messages
Development of Multi-Hazard LRFD (contd)
Geographical features and natural hazards
are substantiated.
Importance of cascading events for whichour knowledge for design is extremely
.
Unique features for NE and CA corridors with
consequence)
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formulated for several regions.
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Next Step:Next Step:
Development of Multi-Hazard LRFD (contd)
Continue to address the major challengesor t e eve opment o - .
Continue to refine the regional designconcept and to establish a selected sets
of design limit state equations.
Workshop involving AASHTO, FHWA anddesign professionals to establish the
sets of design limit state equations.
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Development of Multiple Hazards Design GuidelinesDevelopment of Multiple Hazards Design Guidelines
To establish the LRFD guidelines for all-azar res ent, susta na e r ges s
complex and intellectually challenging.
equ res susta ne eve opment ymultidisciplinary team research efforts.
equ res sus a ne e uca on e or odevelop new generation engineers and - .
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Development of Multiple Hazards Design GuidelinesDevelopment of Multiple Hazards Design Guidelines
Summary contdSummary contd
This lecture is only intended to provide
bridge engineering under early stage of
development to the students, as anexample of sustainable development in
bridge engineering.
The description of developing regionaldesign limit states of combined hazards
s researc curren y n progress. e
final outcome may be different.
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Development of Multiple Hazards Design GuidelinesDevelopment of Multiple Hazards Design Guidelines
AcknowledgementAcknowledgement
Federal Highway Administration (funding)
Pro ect Research Team Or anizationsAurora & Associates, FHWA,
University at Buffalo, UC Irvine
UB Research Team
. . , . . . ,
scholars and graduate students
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.
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Review Quest ions
1. Why should bridge design include all hazards in order to satisfy
sustainability in bridge engineering?2. Wh is Education a si nificant com onent in sustainable
development?
3. Why are some aspects of current design specifications too
4. Do we know how to design a bridge with a capacity equal to or
slightly over the limit states?
. a s e ma or erence e ween owa e ress es gn
(ASD) and Load and Resistance Factors Design (LRFD)?
6. Probability (reliability) based formulation provides answers in
probabilitic terms. Design specifications are given as
deterministic limit state equations. How did this happen?