addendum no. 2 november 17, 2021 to: all perspective

New Field House and Athletic Improvements Addendum No. 2
CRA Project No. 3447 November 17, 2021
TO: All Perspective Bidders and Other Recipients of Contract Drawings and Specifications
This Addendum is hereby made a part of the Contract Document, which will be the basis of the Contract.
The Addendum is issued to modify and/or correct the original Contract Documents dated November 3,
2021. Attach this Addendum to your Contract Documents. Receipt of this Addendum must be
acknowledged on the Proposal Form. Failure to do so may subject the bidder to disqualification.
GENERAL
a. Each Bid must be submitted on the form provided by the Architect/Engineer, and must
be accompanied by a bid bond, certified check, or cashier’s check equal to ten percent
of the total price submitted inclusive of add alternates. The Owner also reserves the
right to reject any or all Bids for any reason whatsoever.
b. The last day which Contractors can ask questions in writing will be five days prior to
receipt of bids. Questions will be answered by Addendum only.
c. All bidders are hereby notified that they are responsible to review all parts of this
addendum for conditions and requirements that may apply to their individual contracts.
All Plan Holders shall review their Bidding Documents against the Table of Contents and
List of Drawings to ensure that all Specifications Sections and Drawings are in your
possession
Northern Lebanon School District | New Field House and Athletic Improvements
CRA Project No. 3447
SPECIFICATIONS – VOLUME 1
SECTION 000302 – HC BID FORM
1. REPLACE this section in its entirety with the attached section.
SECTION 012300 – ALTERNATES
SECTION 012900 – APPLICATIONS FOR PAYMENT
1. REVISE Paragraph 1.3.C.5.b to read as follows:
5. Provide a separate line item in the Schedule of Values for each part of the Work where
Applications for Payment may include materials or equipment, purchased or fabricated
and stored, but not yet installed.
a. Differentiate between items stored on-site and items stored off-site (this is
permitted by the Owner for this project). Contractor to provide requirements for
insurance and bonded warehousing, as required, including, but not limited to the
following:
2) Photographs of the materials in question
3) Bill of laden or invoice confirming shipment of the materials
SECTION 101419 - DIMENSIONAL SIGNAGE
SECTION 102113 – TOILET COMPARTMENTS
1. DELETE paragraph 1.2.A.2 in its entirety; there is not an alternate bid for plastic laminate clad.
SECTION 104416 – FIRE EXTINGUISHERS
1. ADD paragraph 2.26 to read as follows:
2.26 ELECTRIC HEAT TRACING
A. Electric heat tracing for the purpose of freeze protection shall be installed on
condensate piping for cooler/freezer. See Plans.
Northern Lebanon School District ADD -3
B. The heat tracing shall be capable of maintaining a minimum water temperature of
40°F at an ambient air temperature of -10° with pipe covered by 1" fiberglass
insulation.
C. The electric heat tracing shall be of a self-regulating XL-Trace heater manufactured
by Raychem Corporation or equal by Thermon. The heater shall respond to varying
localized temperature conditions along the pipe by self-regulating its heat output
at each point along its length without reliance on thermostat controls.
D. Operating energy shall be conserved by the self-regulating feature of the heater
materials which automatically controls heat output in proportion to the heat
requirement. Operating safety shall be increased by the absolute heater
temperature limit built into the self-regulating heater material without a reliance
on thermostats. A constant wattage heater shall not be acceptable.
E. The electrical heat tracing shall consist of flat, flexible, low-heat density electric
heat tracing strip of parallel circuit construction, consisting of 16 AWG bus bars and
a continuous inner core of self-regulating conductive material, this core shall be
insulated with a radiation cross-linked polyolefin jacket. The heat tracing strip shall
be capable of being cut to the desired length in the field. Raychem SK components
shall be used for all power connection points, heat tracing tees, and end seal
terminations.
F. The heater shall operate on 120 volts. Electrical power for each heat tracing circuit
shall be routed through a 15-amp circuit breaker.
G. The self-regulating heater, in combination with the interconnect components, shall
have a UL System listing.
H. Furnish and install 1 ambient sensing thermostat (Model AMC-1A) set at 40°F
connected in series with a Model AMC-13 thermostat with a capillary tube attached
to pipe and set at 40°F. Electric heat tracing shall be energized when contacts on
both thermostats are closed. (ie – ambient temperature below 40°F and pipe wall
temperature below 40°F). Each pie run shall be furnished with separate circuit and
separate thermostat with capillary tube.
I. Plumbing Contractor shall provide all heat tracing and thermostats required for a
complete installation.
1. DELETE the words “Model RTGH-CM95DVLN” in paragraph 2.8.A.
2. ADD paragraph 2.12.H to read ‘H. Water Heaters – Rinnai, Bradford White, A.O. Smith, Navien’
CIVIL DRAWINGS
1. REPLACE the sheet in its entirety with the attached.
a. REVISE proposed 3” gas line connection to a point after the gas meter as shown.
b. ADD Pavement Restoration Detail.
c. REVISE proposed 2” gas line and 4” water line to connect to the building at the
southeastern corner of the building as shown.
ARCHITECTURAL DRAWINGS
DRAWING A1.3 – FIELD HOUSE FLOOR PLANS
1. ADD note ‘FE’ in rooms A006 and A008 at fire extinguisher symbol shown on plan.
DRAWING A4.1 – LARGE SCALE TOILET PLANS
2. REVISE Toilet Accessory Schedule item No. 3 model from B-700 to B-750.
DRAWING A4.2 – LARGE SCALE TEAM ROOMS
1. REVISE Toilet Accessory Schedule item No. 3 model from B-700 to B-750.
2. ADD the following not to Coaches Room A003:
a. LOCKER TYPE 'C'
c. 8 TOTAL LOCKERS @ 18"Wx18"Dx36"H
DRAWING A4.3 – LARGE SCALE STAIR PLANS AND DETAILS
a. ADDED top of wall elevations.
DRAWING A4.4 – LARGE SACEL RAMP AND STAIR PLANS AND DETAILS
a. ADDED top of wall elevations.
DRAWING I4.1 – LARGE SCALE – FIELD HOUSE CASEWORK & FINISH PLANS
1. REVISE Casework Schedule to match custom millwork specification and provided details 3/I4.1
for ADA Vanity Sink Base Cabinet Detail, 4/I4.1 Base & Wall Cabinet Detail and 5/I4.1 4-Drawer
Base Cabinet Detail.
a. REVISE column elevation at grid line B-4 as shown.
b. ADD wall foundation adjacent to grid line B-4 as shown.
DRAWING S3.1 – FOUNDATION SECTIONS
a. REVISE Section 10 as shown.
PLUMBING DRAWINGS
1. REVISE gas service as follows:
a. DELETE gas meter at building. Gas piping will tie into existing high school gas meter on
site, refer to revised site drawing C-10 in this addendum.
b. REVISE gas size of piping into the Concessions Building to be 2” and into the Fieldhouse
Building to be 2”. Extend 2” gas piping from each building to 5’-0” from building and
connect to site piping. Refer to revised site drawing C-10 in this addendum for
continuation of work.
DRAWING P2.1 – GROUND FLOOR PLAN - PLUMBING
a. REVISE gas main to building to be 2” (2 psi) instead of 3” (low pressure) on enlarged
plan 11. Furnish and install shutoff valve and gas pressure reducing valve in vertical
piping inside building at an accessible height. Run vent piping from gas pressure
reducing valve to exterior as high in room as possible and terminate with a sidewall
connection to exterior. Gas pressure regulator shall have an inlet pressure of 2 psi and
an outlet pressure of 10” w.c.
2. REVISE domestic water service as follows:
a. REVISE domestic water service to be drainable for winterization purposes. Furnish and
install hose bibb HB-2 just downstream of main shutoff valve at water service into
building on enlarged plan 11. Duplex heat trace (2 complete circuits and systems) and
double insulate all above grade domestic water piping upstream of this hose bibb
including the shutoff valve.
DRAWING P2.2 – FIRST FLOOR PLAN - PLUMBING
a. REVISE gas main to building to be 2” (2 psi) instead of 3” (low pressure) on enlarged
plan 3. Furnish and install shutoff valve and gas pressure reducing valve in vertical piping
inside building at an accessible height. Run vent piping from gas pressure reducing valve
to exterior as high in room as possible and terminate with a sidewall connection to
exterior. Gas pressure regulator shall have an inlet pressure of 2 psi and an outlet
pressure of 10” w.c.
2. REVISE domestic water service as follows:
a. REVISE domestic water service to be drainable for winterization purposes. Furnish and
install hose bibb HB-2 just downstream of main shutoff valve at water service into
building on enlarged plan 3. Duplex heat trace (two complete circuits and systems) and
double insulate all above grade domestic water piping upstream of this hose bibb
including the shutoff valve.
Attachments:
Specifications:
SECTION 012300 ALTERNATES
Drawings:
DRAWING A4.4 – LARGE SCALE RAMP AND STAIR PLANS AND DETAILS
DRAWING I4.1 – LARGE SCALE – FIELD HOUSE CASEWORK & FINISH PLANS
DRAWING S2.1 – GROUND FLOOR FOUNDATION PLAN
DRAWING S3.1 – FOUNDATION SECTIONS
Northern Lebanon High School Improvements
345 School Drive Fredericksburg, Lebanon County, Pennsylvania ECS Project Number 18:5194 April 2, 2021
April 2, 2021 Mr. Gary Messinger Northern Lebanon School District PO Box 100 Fredericksburg, PA 17026
ECS Project No. 18:5194 Reference: Geotechnical Engineering Report Northern Lebanon High School Improvements Fredericksburg, Pennsylvania Dear Mr. Messinger: ECS Mid-Atlantic, LLC (ECS) has completed the subsurface exploration and geotechnical engineering analyses for the above-referenced project. Our services were performed in general accordance with our Proposal No. 18:7793-GP, dated February 25, 2021. This report presents our understanding of the geotechnical aspects of the project, results of the field exploration, laboratory testing, and our design and construction recommendations. It has been our pleasure to be of service to Northern Lebanon School District and Steckbeck Engineering & Surveying, Inc. during this phase of this project. We would appreciate the opportunity to remain involved during the continuation of the design phase and to provide our services during construction phase operations as well to verify the assumptions of subsurface conditions made for this report. Should you have any questions concerning the information contained in this report, or if we can be of further assistance to you, please contact us. Respectfully submitted, ECS Mid-Atlantic, LLC Kyle T. Eldridge Geotechnical Staff Project Manager [email protected] J. Matthew Carroll, P.E. Principal Engineer [email protected] Derek G. Ridinger, P.E. Geotechnical Department Manager [email protected]
TABLE OF CONTENTS
3.0 FIELD EXPLORATION AND LABORATORY TESTING ........................................................................ 5 Subsurface Characterization ............................................................................................................... 5
3.1.1 Stormwater Infiltration Testing ..................................................................................................... 6 3.1.2 Dynamic Cone Penetrometer ........................................................................................................ 7
Karst Mapping .................................................................................................................................... 7 Groundwater Observations ................................................................................................................ 7 Laboratory Testing .............................................................................................................................. 8
4.0 DESIGN RECOMMENDATIONS ..................................................................................................... 9 Foundation Design .............................................................................................................................. 9 Floor Slabs ........................................................................................................................................ 10 Site Retaining Walls .......................................................................................................................... 11 Seismic Design Characteristics ......................................................................................................... 12 Stormwater Management Areas ...................................................................................................... 13
4.5.1 Stormwater Management Facilities ............................................................................................ 13 4.5.2 Stormwater Management Considerations .................................................................................. 14 4.5.3 Stormwater Management Facilities - Design Notes .................................................................... 14
Pavements ........................................................................................................................................ 15 5.0 SITE CONSTRUCTION RECOMMENDATIONS ............................................................................... 17
Karst Related – General Risk............................................................................................................. 17 Stormwater Construction Recommendations .................................................................................. 17
5.2.1 Demolition of Existing Structure ................................................................................................. 18 Subgrade Preparation ....................................................................................................................... 18
5.3.1 Stripping and Grubbing ............................................................................................................... 18 5.3.2 Proofrolling .................................................................................................................................. 18 5.3.3 Site Temporary Dewatering ........................................................................................................ 19
Earthwork Operations ...................................................................................................................... 20 5.4.1 Existing Man-Placed Fill ............................................................................................................... 20 5.4.2 Rock Excavation ........................................................................................................................... 20 5.4.3 Structural Fill Materials ............................................................................................................... 20 5.4.4 Proposed Fill Slopes..................................................................................................................... 21
Foundation and Slab Observations................................................................................................... 21 Utility Installations ............................................................................................................................ 22
6.0 CLOSING ................................................................................................................................... 23
Northern Lebanon High School Improvements April 2, 2021 ECS Project No. 18:5194 Page ii
APPENDICES Appendix A – Figures
Appendix B – Field Operations
• Subsurface Exploration Procedure: Standard Penetration Testing (SPT)
• Boring Logs B-1 through B-5 and IT 1 through IT-4
• Rock Core Photograph
• Infiltration Test Results
• Test Pit Photographs
Appendix D – Details
• Sinkhole Repair Details
Northern Lebanon High School Improvements April 2, 2021 ECS Project No. 18:5194 Page 1
EXECUTIVE SUMMARY The following summarizes the main findings of the exploration, particularly those that may have a cost impact on the planned development. Further, our principal foundation recommendations are summarized. Information gleaned from the Executive Summary should not be utilized in lieu of reading the entire geotechnical report.
• Groundwater depths measured at the time of drilling ranged from 6.0 to 13.0 feet below the existing ground surface, corresponding to approximate EL. 459.0 to EL 467.0 ft. These groundwater readings are likely indicative of perched water. Variations in the long-term water table may occur because of changes in precipitation, evaporation, surface water runoff, construction activities, and other factors.
• Existing fill materials were identified within the building footprints to depths of up to 13 feet. The fill is very loose and wet in some areas, and no documentation of engineering controls during placement was provided. Remediation of loose existing fill is recommended via either overexcavation, moisture conditioning, and replacement throughout the building footprints (Option 1), or select overexcavation in foundation areas to a depth of 3 feet and to a width of 4 feet wider than the footing, and the top 1 foot within the building slab areas, followed by replacement with select granular fill (Option 2).
• Supplemental test pit excavation around the proposed building pads to further delineate the extent of the existing fill prior to bidding is recommended.
• All existing foundation elements and utilities within the footprint of the proposed buildings should be removed and backfilled with compacted structural fill.
• The proposed buildings can be supported by conventional shallow foundations consisting of column and/or strip footings bearing on the existing soils. The foundations can be designed for an allowable soil bearing pressure of 2,500 psf based on anticipated design loads. The buildings should be designed based on a seismic site classification of C.
• Provided the evaluated bearing stratum and Granular Drainage Layer are completed per the recommendations discussed herein, the slab may be designed assuming a modulus of subgrade reaction, k1, of 100 pci (lbs/cu. Inch).
• Infiltration rates ranged between 1.06 in/hr to 12.75 in/hr, including a factor of safety of 2.0. We understand that the design infiltration rate for this facility is on the order of 0.75 in/hr and we recommend that an amended soil mixture be utilized to slow down the rate of infiltration through the existing materials. Suitable amended soils may consist of imported blends, or on-site soils blended with clay.
• This site is underlain by carbonate geology, which presents a risk of sinkhole development, especially within stormwater management facilities. Although the risk is low, careful site preparations and observation in accordance with this report, and proper repair of sinkholes will be key to site development.
Refer to the text of the report for site specific design and construction recommendations.
1.0 INTRODUCTION The purpose of this study was to provide geotechnical information for design and construction of two athletic buildings with associated access drives, parking areas, retaining walls, and stormwater management facilities. The recommendations developed for this report are based on project information supplied by Steckbeck Engineering & Surveying, Inc. Our services were provided in accordance with the Proposal No. 7793-GP, dated February 25, 2021, as authorized by Northern Lebanon School District which includes our Terms and Conditions of Service. This report contains the results of our subsurface exploration, site characterization, laboratory testing, engineering analyses, and recommendations for the design and construction of the proposed development. This report includes the following:
• A review of area and site geologic conditions.
• A review of surface topographical features and site conditions.
• A brief review and description of our field procedures.
• A brief review and description of our field and laboratory test procedures and the results of testing conducted.
• A review of subsurface soil stratigraphy with pertinent available physical properties.
• Final copies of our boring logs and test pit logs
• Infiltration testing results and recommendations for stormwater management.
• Recommendations for site preparation and construction of compacted fills, including an evaluation of on-site soils for use as compacted fills and identification of potentially unsuitable soils and/or soils exhibiting excessive moisture at the time of sampling.
• Recommended foundation type and allowable bearing pressure for foundation design.
• General recommendations for pavement design, including a recommended design CBR value.
• Discussion of parameters for slab on grade construction and modulus of subgrade reaction (k).
• Recommendations for seismic site classification and site seismic design coefficients based on the 2015 IBC parameters.
• Evaluation and recommendations relative to groundwater.
• Recommendations regarding stormwater management.
• A discussion of potential of karst geology features.
2.0 PROJECT INFORMATION
PROJECT LOCATION
The project site is located at the physical address of 345 School Drive in Fredericksburg, Pennsylvania. The site is located southwest of the intersection of Airport Road with School Road consisting of the Northern Lebanon High School with associated parking areas, athletic fields, and drive lanes. The site generally slopes downward in the southwest direction with a local topographic relief on the order of approximately ±22 feet. Refer to Figure 2.1.A and the Site Location Map in Appendix A for a detailed depiction of the project site location.
Figure 2.1.A – Site Location
PROPOSED CONSTRUCTION
Based on the “Preliminary/Final Land Development” Plan, provided by Steckbeck Engineering & Surveying, Inc., dated January 4, 2021, we understand that the proposed construction will consist of demolishing the existing field building and constructing two (2) new athletic buildings and improving the existing soccer and practice fields. Development of the project will also include constructing new parking areas, drive lanes, site retaining walls, and a stormwater management facility. The stormwater management facility is anticipated to consist of an at grade basin. The following information explains our understanding of the buildings and assumed loads:
Single Story Buildings
Southern Building: 5,700 SF
Usage Athletic buildings Column Loads Assumed - 50 Kips maximum
Single Story Buildings
Lowest Finish Floor Elevation (FFE)
Northern Building: 479.00 ft
Southern Building: 469.00ft
3.0 FIELD EXPLORATION AND LABORATORY TESTING Our exploration procedures are explained in greater detail in Appendix B including the insert titled Subsurface Exploration Procedures. Our scope of work included drilling a total of five (5) geotechnical borings, excavating five (5) test pits, and performing four (4) infiltration tests. Our testing locations were located with a handheld GPS unit and their approximate locations are shown on the Exploration Location Plan in Appendix A.
SUBSURFACE CHARACTERIZATION
The following sections provide generalized characterizations of the soil strata. Please refer to the boring logs in Appendix B. According to the Pennsylvania Department of Conservation and Natural Resources Conservation Service Interactive Map the site is underlain by the Hamburg Sequence (OH). This formation is included in the Engineering Characteristics of the Rocks of Pennsylvania (Pennsylvania Geologic Survey, 1982). The Hamburg sequence consists of gray, greenish-gray, and maroon shale, silty and siliceous in many places with dark-gray impure sandstone and medium-to light-gray, finely crystalline limestone. Bedding within the formation is moderately thin well bedded; the sandstone is well bedded; and the limestone is well bedded as well. Fracturing in the shale has a seamy to platy pattern, close spacing, open and steeply dipping. The sandstone has a blocky pattern, moderately spaced, open and vertically oriented. The bedrock is moderately resistant to a deep depth, resulting in loose rubble of pencil-like to rectangular plates. The formation exhibits good surface drainage with the joints and bedding planes providing secondary porosity of moderate magnitude. Based on our review of the Soil Survey (USDA - Natural Resources Conservation Service (websoilsurvey.ncrs.usda.gov), the site soils are mapped as Comly silt loam, Clarksburg silt loam, and Berks channery silt loam. These soil types are described as having the following properties.
SUBSURFACE STRATIGRAPHY
Stratum Description
n/a Surficial Material: Topsoil 8.0 to 10.0 inches thick
I SANDY SILT (ML)/SILTY SAND (SM), varying amounts of gravel, moist, light brown, loose to medium dense, possible FILL extended up to 13 feet
II SILTY GRAVEL (GM) varying amounts of sand, moist, light brown, very loose to very dense
III Limestone, highly to slightly weathered, contains shale partings, hard, intensely to highly fracture, very rough, moderate angle dip, gray and white, resulted in auger refusal as shallow as 7.5 feet below existing grade
SOIL MAPPING SUMMARY
Mapped Soil Unit
slopes)
BkC
grained sandstone
lithic bedrock
CkA Residuum
to lithic bedrock
CmA Colluvium derived
to lithic bedrock
0.60)
Soil mapping of the site vicinity is presented in Appendix A.
3.1.1 Stormwater Infiltration Testing The subsurface exploration for stormwater management areas consisted of four (4) test pits paired with infiltration testing to explore the subsurface conditions and characterize the site relative to stormwater management. The test pits were conducted on-site under the supervision of ECS and infiltration testing was completed in four (4) of them. Infiltration testing was completed using the double ring infiltration methodology in general accordance with Appendix C of the Pennsylvania Stormwater Best Management Practices (PA BMP) Manual. Infiltration test results are provided in the following table.
INFILTRATION TESTING RESULTS
(Includes FS=2.0)
Note1: Elevations interpolated from provided plan.
3.1.2 Dynamic Cone Penetrometer The fifth test pit was completed in the footprint of the eastern retaining wall. In order to evaluate the bearing capacity of the proposed subgrade materials, a dynamic cone penetrometer (DCP) was utilizing near the anticipated bottom of wall elevation. DCP testing at this location and elevation revealed that the materials were relatively loose, having blow counts less than 5 for each interval. The table below briefly summarizes the results of DCP testing performed.
DYNAMIC CONE PENETROMETER RESULTS
3-3-4 1-3-4 3-4-5 2-2-5
KARST MAPPING
The Limestone of Hamburg Sequence is composed of carbonate bedrock that is prone to karst activity. Karst activity can take the form of soft and loose soils above the bedrock, uneven bedrock surfaces, closed surficial depressions, and sinkholes. The Karst Features Map located in Appendix A depicts a scale of the level of karst activity in the vicinity of the site. The Karst Features Map shows no sinkholes and no surface depressions within 0.5 miles of the project site; however, the data is incomplete as there is not a requirement within the state to track the naturally developing karst activity. Based on our experience in the area, the results of the boring exploration, and known karst features at nearby sites, the risk of sinkholes and related karst activity near this location is low.
GROUNDWATER OBSERVATIONS
Water levels were measured during the on-site exploration and are included on our boring/test pit logs in Appendix B. Groundwater seepage into our test pits was not observed during our exploration at the depths explored; however, groundwater was observed during drilling the geotechnical borings. In auger drilling operations, water is not introduced into the boreholes during soil drilling, and the groundwater position can often be determined by observing water flowing into or out of the borings. Groundwater depths measured at the time of drilling ranged from 6.0 to 13.0 feet below the existing ground surface, corresponding to approximate EL. 459.0 to EL 467.0 ft. Mottled soils that can possibly indicate a seasonal high water table or intermittent perched conditions, were not observed. This site may be subject to shallow perched water conditions over the underlying bedrock or less permeable soils. It is possible that water seepage and accumulation may be observed in deeper excavations that remain open for an extended duration.
The highest groundwater observations are normally encountered in late winter and early spring; therefore, our groundwater levels recorded are expected to be close to the seasonal maximum water table. Variations in the long-term water table may occur because of changes in precipitation, evaporation, surface water runoff, snow melt, construction activities, and other factors. Groundwater could potentially be encountered during construction of stormwater management facilities, deep utility installations, and areas of deep cuts.
LABORATORY TESTING
The laboratory testing consisted of selected tests performed on samples obtained during our field exploration operations. Classification and index property tests were performed on representative soil samples. Each sample was visually classified on the basis of texture and plasticity in accordance with ASTM D2488 Standard Practice for Description and Identification of Soils (Visual-Manual Procedures) and including USCS classification symbols, and ASTM D2487 Standard Practice for Classification for Engineering Purposes (Unified Soil Classification System (USCS)). After classification, the samples were grouped in the major zones noted on the boring logs in Appendix B. The group symbols for each soil type are indicated in parentheses along with the soil descriptions. The stratification lines between strata on the logs are approximate; in situ, the transitions may be gradual.
4.0 DESIGN RECOMMENDATIONS
FOUNDATION DESIGN
Provided subgrades and structural fills are prepared as discussed herein, the proposed structures can be supported by conventional shallow foundations consisting of column and continuous wall footings. The design of the foundations shall utilize the following parameters:
FOUNDATION DESIGN PARAMETERS
Net Allowable Bearing Pressure1 2,500 psf 2,500 psf
Acceptable Bearing Soil Material Stratum II, III, or
Structural Fill
Minimum Width 24 inches 24 inches
Minimum Footing Embedment Depth for Interior Foundations (below slab or finished grade) 30 inches 30 inches
Minimum Footing Embedment Depth for Exterior Foundations (below slab or finished grade)
36 inches 36 inches
Estimated Differential Settlement Less than 0.5 inches between columns
Less than 0.5 inches over 50 feet
Note1: Net allowable bearing pressure is the applied pressure in excess of the surrounding overburden soils above the base of the foundation.
The results of the test borings indicate that most of the footprint of the two proposed buildings are underlain by several feet of fill materials that appear to have been placed with very little compactive effort given their very loose and wet condition. Due to the presence of these materials, remediation of these materials is recommended to provide structural support of the foundations of the proposed buildings. Two options to remediate these materials are provided below for consideration: Option 1 (Low Risk): Overexcavate and Replace Fill within Building Footprint Overexcavate the fill materials to the depth of natural soils and replace the excavated materials in a controlled manner in accordance with the recommendations for site preparation and fill placement outlined in Sections 5.3 and 5.4 of this report. It should be noted that the moisture contents of the existing fill materials were elevated, therefore some drying of the materials should be anticipated to be needed prior to replacing them as structural fill. Total overexcavation depths are anticipated to vary between less than 1 foot, up to a depth of 13 feet. Overexcavation extents should include the building footprint plus a perimeter of a minimum of 10 feet beyond the building line. Supplemental test pits prior to bidding are recommended to further delineate the anticipated depths and associated volume of material that will require excavation and replacement. Option 2 (Low to Moderate Risk): Select Overexcavation and Replacement with Select Granular Material Provide overexcavation of the building pad subgrade to a minimum depth of 1 foot, and overexcavate all foundations to a minimum depth of 3 feet and replace with select granular material consisting of compacted 2A aggregate. Overexcavation of foundation areas should include widening of the excavation
beneath the footing area a minimum of 4 feet (2 feet wider than edge of footing on each side) through the depth of the 3-foot undercut. Depending on the condition of the soils at the undercut depth, poor quality bearing materials may require the use of geogrid reinforcement at the bottom of the aggregate layer.
FLOOR SLABS
It appears that the slabs for the structure will bear on natural materials composed of dominantly of SILT. As outlined in Section 4.1, some remediation of the on-site fill materials should be completed to provide adequate slab support. Slab subgrade preparation should consist of removal and then replacement of the on-site materials in a controlled fill, or select overexcavation of slab subgrade areas to provide a supplemental thickness of select granular fill. During subgrade preparation, areas of unsuitable fill, soft soils, or other unsuitable soils are encountered, they should be removed and replaced with compacted structural fill in accordance with the recommendations included in this report. The slab subgrade should be evaluated by proofrolling in accordance with Section 5.3.2. The following graphic depicts our soil- supported slab recommendations:
Figure 4.2.A 1. Drainage Layer Thickness: 6 inches minimum 2. Drainage Layer Material: graded aggregate base 3. Subgrade compacted to 95% maximum dry density per ASTM D698
Subgrade Modulus: Provided the evaluated bearing stratum and Granular Drainage Layer are completed per the recommendations discussed herein, the slab may be designed assuming a modulus of subgrade reaction, k1, of 100 pci (lbs/cu. inch). The modulus of subgrade reaction value is based on a 1 foot by 1 foot plate load test basis. Slab Isolation: Ground-supported slabs should be isolated from the foundations and foundation- supported elements of the structure so that differential movement between the foundations and slab will not induce excessive shear and bending stresses in the floor slab. Where the structural configuration prevents the use of a free-floating slab, the slab should be designed with suitable reinforcement and load transfer devices to preclude overstressing of the slab. Vapor Barrier: The granular layer below the slab will facilitate the fine grading of the subgrade and help prevent the rise of water through the floor slab. Before the placement of concrete, a vapor barrier maybe placed on top of the granular material to provide additional moisture protection. However, special attention should be given to the surface curing of the slab in order to minimize uneven drying of the slab and associated cracking. Depending on flooring material types, the structural engineer and/or the architect may choose to eliminate the vapor barrier.
Concrete Slab Vapor Barrier
Granular Capillary Break/Drainage Layer
Compacted Subgrade
SITE RETAINING WALLS
There are proposed retaining walls at this site consisting of cut walls. One retaining wall is located on the western side of the southern building and will retain materials to facilitate a stairway to the entrance of the building. Additionally, a series of walls are located east of this building to retain materials from the football field and support the northern most building area. The walls appear to have maximum wall heights above grade on the order of 9.0 feet high. Unlike below grade walls, site retaining walls are free to rotate at the top (not restrained). For these walls, the "Active" (ka) soil condition should be used along with a triangular distribution of earth pressures. In addition, site retaining walls should be designed to withstand lateral earth pressures exerted by the backfill and any surcharge loads within the “Critical Soil Zone”. The Critical Zone is defined as the area between the back of the retaining wall footing and an imaginary line projected upward and rearward at a 45-degree angle (see figure below).
RETAINING WALL BACKFILL IN THE CRITICAL SOIL ZONE
Soil Parameter Estimated Value
granular
Coefficient of Active Earth Pressure (Ka) 0.30
Retained Soil Moist Unit Weight (γ) 120 pcf
Cohesion (C) 0 psf
Friction Coefficient [Concrete on Soil] (μ) 0.30
Active Equivalent Fluid Pressure 40H (psf)
FOUNDATION SOILS
Wall 1
Minimum Wall Embedment Below Grade 24 inches
Coefficient of Passive Earth Pressure (Kp) 2.77
Soil Moist Unit Weight (γ) 115 pcf
Cohesion (C) 0 psf
Passive Equivalent Fluid Pressure 275H (psf)
It is critical that the soils used for backfill of the retaining walls meet the soil parameters recommended above. If the soils available do not meet those parameters, then ECS should be contacted to provide revised values, and to confirm that only suitable soils will be used for wall backfill.
Care should be used to avoid the operation of heavy equipment to compact the wall backfill since it may overload and damage the wall. In addition, such loads are not typically considered in the design of site retaining walls, and are not provided for in our recommendations. Similar to the building foundations, some overexcavation and stabilization of existing fill materials may be required along the foundation bearing zone of the retaining wall. Wall Drainage: Retaining walls should be provided with a wall and drainage system to relieve hydrostatic pressures which may develop behind the walls. This system should consist of weepholes through the wall and/or a 4-inch perforated, closed joint drain line located along the backside of the walls above the top of the footing. The drain line should be surrounded by a minimum of 6 inches of AASHTO #57 Stone wrapped with an approved non-woven geotextile, such as Mirafi 140-N or equivalent. Wall drains can consist of a 12-inch wide zone of free draining gravel, such as AASHTO #57 Stone, employed directly behind the wall and separated from the soils beyond with a non-woven geotextile.
SEISMIC DESIGN CHARACTERISTICS
The International Building Code (IBC) 2015 requires site classification for seismic design based on the upper 100 feet of a soil profile. At least two methods are utilized in classifying sites, namely the shear wave velocity (vs) method and the Standard Penetration Resistance (N-value) method. The latter method (Standard Penetration Resistance) was used in classifying this site.
SEISMIC SITE CLASSIFICATION
(ft./s) N value (bpf)
A Hard Rock Vs > 5,000 fps N/A
B Rock 2,500 < Vs ≤ 5,000 fps N/A
C Very dense soil and soft rock 1,200 < Vs ≤ 2,500 fps >50
D Stiff Soil Profile 600 ≤ Vs ≤ 1,200 fps 15 to 50
E Soft Soil Profile Vs < 600 fps <15
Based upon our interpretation of the subsurface conditions, the appropriate Seismic Site Classification is “C” as shown in the preceding table. Ground Motion Parameters: In addition to the seismic site classification noted above, ECS has determined the design spectral response acceleration parameters following the IBC 2015 methodology. The Mapped Reponses were estimated from the free seismic design maps available from Structural Engineers Association of California (SEAOC) (http://seismicmaps.org). The design responses for the short (0.2 sec, SDS) and 1-second period (SD1) are noted in bold at the far right end of the following table.
GROUND MOTION PARAMETERS [IBC 2015 METHOD]
Period (sec)
Design Spectral Response
16-40
GROUND MOTION PARAMETERS [IBC 2015 METHOD]
Period (sec)
Design Spectral Response
0.2 SS 0.164 Fa 1.2 SMS=FaSs 0.197 SDS=2/3
SMS 0.131
1.0 S1 0.057 Fv 1.7 SM1=FvS1 0.097 SD1=2/3
SM1 0.064
The Site Class definition should not be confused with the Seismic Design Category designation which the Structural Engineer typically assesses. If a higher site classification is beneficial to the project, we can provide additional testing methods that may yield more favorable results.
STORMWATER MANAGEMENT AREAS
4.5.1 Stormwater Management Facilities General: The plan provided to ECS displayed the proposed location for the stormwater management facilities. Stormwater management facilities are expected to consist at-grade basins. The recommendations presented below should be considered during design and construction.
4.5.1.a Infiltration Characteristics During our test pit exploration program, infiltration rates ranged from 1.06 to 12.75 in/hr through the onsite materials. Based on our correspondences, it is our understanding that a design infiltration rate for this facility is on the order of 0.75 in/hr. Although the infiltration rate achieved through the onsite soils exceeds the design value, we recommend that an amended soil blend be consider to slow down infiltration through the onsite materials and achieve a rate closer to the 0.75 in/hr design rate. The materials at proposed bottom of basin elevations appeared to be Sandy to gravelly (coarse grained). This material should be overexcavated 2 feet and replaced with finer grained materials approved by ECS. Based on the laboratory testing performed, the onsite materials are dominantly composed of Silty SAND soils. Suitable amended soils may consist of imported blends, or on-site soils with limited compactive effort applied. The onsite soils will need to be blended to meet the requirements in the below table before being considered.
RECOMMENDED AMENDED SOILS BLEND
Permissible Soil Types for Amended Soil, based on UDSA Classification
Ranges of USDA Particle Size Percentages Typical Infiltration
Rates for Permissible Soil Types (in/hr)*
Sand Silt Clay Min Max
Min Max Min Max Min Max
Sand, Loamy Sand, Sandy Loam, Loam
50 100 0 50 0 20 0.5 6.0
ECS recommends that specific construction notes appear on the plans requiring full-time observation of the excavation of the basins by the authorized ECS representative to verify suitable conditions are present. ECS can assist in developing these notes once plans become more final.
4.5.1.b Embankment/Outlet Structures/Slopes Embankment construction or cut slopes to facilitate basin construction should incorporate side slopes of 3(H):1(V) or flatter. If steeper slopes are necessary, ECS should be contacted to review the proposed slope geometry. Fill materials should be placed to a minimum of 95% of the maximum dry density of the material, as determined by the Standard Proctor method (ASTM D698). The moisture content of the materials should be within ± 3% of the optimum. Storm water management facilities with embankments should include the construction of a clay core having a minimum thickness of 2 feet. Clay suitable for this use should consist of CL or CH materials, having a minimum of 70% fines (passing #200 sieve), a minimum liquid limit (LL) of 40 and minimum plasticity index (PI) of 20. This material should be approved by the Geotechnical Engineer. Clay materials should be compacted to 95% of the standard proctor maximum dry density at a moisture content that is at or up to 3% above the optimum. Limited lab testing of the on-site material did not meeting the requirements presented above.
4.5.1.c Temporary Sediment Basin Fill Embankments Soils used in temporary sediment basin fill embankments should satisfy the requirements for fill discussed below and should be placed and compacted to the specification requirements for Structural Fill. Care should be taken not to track heavy equipment over the basin bottom during construction. 4.5.2 Stormwater Management Considerations The property is underlain by carbonate geology which is prone to sinkhole development. The owner should understand that the concentrated influx of stormwater to a select area will increase the potential of sinkhole development. In order to reduce the rate of sinkhole development, and in keeping with the guidelines and recommendations of the PA BMP Manual, we recommend that the following design principles be incorporated.
• Use existing drainage patterns
• Keep stormwater away from known sinkholes or problematic subsidence areas
• Avoid concentrating stormwater
• Use broad shallow basins
• Maintain the facilities post construction
• Provide underdrains in all stormwater management facilities if needed 4.5.3 Stormwater Management Facilities - Design Notes It has been our experience that construction of basins may encounter conditions that were not anticipated as a result of the subsurface exploration. As a result, we have developed the following sequence of items for addressing construction related difficulties or discrepancies with the design assumptions. We recommend that these recommendations be included in the stormwater management feature construction notes on the plans.
A) If redoximorphic features (soil mottling and coloration patterns formed by the reduction of iron and/or manganese from saturated conditions in the soil) are encountered:
• A qualified professional should determine if the features observed are associated with a historic condition (associated with fill, previous site condition, or natural coloration) or are associated with conditions that could presently occur (seasonal variations in the water table).
• Evaluate the elevation of the features relative to the proposed design elevation of the SWM feature and determine if the size and elevation of the SWM feature can be adjusted to alleviate the conflict.
• Retain the ECS and Civil Engineer to evaluate alternate design concepts. Alternate designs proposed by the Professional should be sealed and submitted to the Township for approval.
B) If the field verified infiltration rates are excessively low (less than 0.1 in/hr):
• Determine the extent of the materials exhibiting the low infiltration rates through a combination of visual-manual classification, hand probing, density testing, or other suitable methods as determined by the ECS.
• Overexcavate the materials to the depth where the material type changes or a maximum depth of 2 feet, whichever is encountered first.
• If rock is encountered, the rock should be removed to a minimum depth of 2 feet below the bottom of basin and should be examined by the ECS, prior to replacement of suitable material.
• Replace the excavated material with more coarsely grained materials approved by the ECS. Suitable soil mixtures can consist of a blend of on-site and/or off-site materials available to the Contractor, and subject to testing and approval of the ECS.
• Suitable soil mixtures may consist of materials blended by volume ratios as determined by the ECS.
• Materials should be lightly tracked into place in non-structural areas. If material replacement is required in structural areas (Ex: below-grade SWM facilities in paved areas), material placement specifications, including materials type, mix ratio, compactive effort and required density should be determined by the ECS. Suitable soil mixtures can consist of a blend of on-site and/or off-site materials available to the Contractor generally conforming the table above, with field infiltration rates post placement determined and approved by the ECS.
PAVEMENTS
Subgrade Characteristics: Based on the results of our borings and test pits, it appears that the pavement subgrades in cuts will consist mainly of silty SAND or finer materials. Remediation of the subgrade soils , including moisture adjustments or removal and replacement, may be required. California Bearing Ratio (CBR) testing was not performed as part of this study. Therefore, we have assumed a CBR value of 3 for preliminary design purposes. Based on the anticipated use of the planned pavement areas associated with the proposed development, we have assumed only a light duty and medium duty pavement section will be required. However, a heavy duty pavement section can be provided at the request of the Client. The light duty pavement section can be utilized in parking areas that will support primarily passenger vehicle traffic and occasional light maintenance vehicle traffic. We have calculated approximate equivalent axle loadings of 10,000 and 100,000 for light-duty and medium-duty pavements, respectively. In addition, we have assumed an initial
serviceability of 4.2, terminal serviceability of 2.2, a reliability of 90 percent, a standard deviation of 0.45 for flexible pavements, and a design life of 20 years. The design analyses for pavements have been based on methodology from the American Association of State Highway and Transportation Officials’ (AASHTO) Guide of Design of Pavement Structures, 1993 and guidelines established for SUPERPAVE as outlined in the Pavement Design Guide from the Pennsylvania Asphalt Pavement Association. The preliminary pavement sections below are guidelines that may or may not comply with local jurisdictional minimums.
PROPOSED PAVEMENT SECTIONS
Portland Cement Concrete (f’c = 4000 psi)
- - 6.0 in. 5.0 in.
1.5 in 1.5 in - -
3.0 in 2.5 in - -
Crushed Stone Base 8.0 in 6.0 in 6.0 in 5.0 in
In general, medium duty sections are areas that will be subjected to trucks, buses, or other similar vehicles including main drive lanes of the development. Light duty sections are appropriate for vehicular traffic and parking areas. Large, front loading trash dumpsters frequently impose concentrated front wheel loads on pavements during loading. This type of loading typically results in rutting of asphalt pavement and ultimately pavement failures. For preliminary design purposes, we recommend that the pavement in trash pickup areas consist of a 6-inch thick, 4,000 psi, reinforced concrete slab over 6-inches of dense graded aggregate. When traffic loading becomes available ECS or the Civil Engineer can design the pavements. Prior to subbase placement and paving, CBR testing of the subgrade soils (both natural and fill soils) should be performed to determine the soil engineering properties for final pavement design.
5.0 SITE CONSTRUCTION RECOMMENDATIONS
KARST RELATED – GENERAL RISK
If any subsidence features such as sinkholes, surface depressions, and exposed rock pinnacles are encountered, ECS should be consulted to provide a recommendation for repair on a case by case basis. Although sinkholes stem from geologic conditions within the underlying rock, they are often triggered by changes in the surface and subsurface drainage patterns. In order to reduce the potential for future sinkhole development which could impact foundation performance, positive surface drainage should be maintained both during and after construction. We recommend that the following preventative measures be followed to reduce the potential inducement of sinkhole formation in proposed development areas and to incorporate good construction practices.
1. Earthwork operations should be graded to drain away from structures at all times. Upon
completion of daily earthwork operations, the ground surface should be sealed by thorough rolling to reduce infiltration of precipitation and facilitate runoff.
2. Sediment control management facilities should be located outside of planned construction areas. Inlets associated with storm drain systems should not be utilized as temporary sediment control devices during construction.
3. During construction, care should be taken to reduce the ponding of surface water in and/or adjacent to the buildings. The foundations should be excavated and poured the same day, if possible, or the founding soils should be provided with a mud mat (lean concrete).
4. Visual observations during all earthwork operations should be carried out in order to detect any previous unexposed or recently created collapse features. Any such feature should be called to ECS’s attention for remedial improvement.
5. Final site grading should include sloping grades and piping of downspouts away from the building.
6. Storm piping should be designed such that joints and structure tie-ins remain watertight with allowance for some settlement. Leaking storm pipes promote subsurface seepage and can instigate sinkhole development in the form of surficial dropouts with little or no warning. It may be beneficial to use bentonite clay around all pipe joints to reduce the potential for long-term leaking.
Areas identified to be suspect during the initial earthwork phase should be further explored during construction to determine the extent, both vertically and horizontally, of possible solution activity. We recommend that all available geotechnical data be made available to ECS during earthwork operations.
STORMWATER CONSTRUCTION RECOMMENDATIONS
It is recommended that verification of the subgrade conditions at the time of construction be conducted by an authorized ECS representative. During excavation of the basin, the materials at the bottom of basin should be verified to be consistent with those encountered in the exploration. Proper performance of infiltration facilities will be influenced
by the variability in the subsurface. It will be important that construction equipment does not traffic on the materials at the infiltration bed elevation, and that hand probing on an approximately 25 foot grid or isolated test pits be provided to evaluate proper offset distances from bedrock limiting zones. Stormwater management facilities should generally not be located within 30 feet of a building. If site constraints prohibit this recommendation, the facility may be located closer to a building subject to the review and approval of ECS. 5.2.1 Demolition of Existing Structure Development of the project will include demolishing the existing Concession building. All existing foundation elements and utilities within the footprint of the proposed buildings should be removed and backfilled with compacted structural fill. Existing foundations or slabs situated within the proposed parking areas and drive lanes should be over-excavated such that the top of the concrete is a minimum of 2 feet below the finished subgrade elevation. If the existing building has a basement, the existing basement slab should be removed beneath proposed building foundations or stormwater facilities. If the slab is to remain, it should be broken up on a minimum spacing grid of 3.0 feet on center to allow for proper drainage prior to placement of structural fill. All basement walls should be completely removed prior to the new building construction. The foundations, slabs, and pavements may be processed for reuse as structural fill provided all steel reinforcement separated, it is well blended, and no larger than 4-inches in diameter.
SUBGRADE PREPARATION
5.3.1 Stripping and Grubbing The subgrade preparation should consist of stripping all vegetation, rootmat, topsoil, unsuitable existing fill, asphalt, and any soft or unsuitable materials from the 10-foot expanded building and 5-foot expanded pavement limits, and 5 feet beyond the toe of Structural Fills. Borings and test pits performed in “undisturbed” areas of the site contained an observed 6 to 10 inches of topsoil. Deeper topsoil or organic laden soils may be present in wet, low-lying, and poorly drained areas. It is worth mentioning that there are areas of pavement that will need to be removed prior to construction. Borings revealed that asphalt was approximately 6 inches thick followed by about 2 inches of gravel subbase. ECS should be retained to verify that topsoil and other unsuitable surficial materials have been removed prior to the placement of structural fill or construction of structures. 5.3.2 Proofrolling Prior to fill placement or other construction on subgrades, the subgrades should be evaluated by an ECS field technician. The exposed subgrade should be thoroughly proofrolled with construction equipment having a minimum axle load of 10 tons [e.g. fully loaded tandem-axle dump truck]. Proofrolling should be traversed in two perpendicular directions with overlapping passes of the vehicle under the observation of an ECS technician. This procedure is intended to assist in identifying any localized yielding materials. Where proofrolling identifies areas that are unstable or “pumping” subgrade those areas should be repaired prior to the placement of any subsequent Structural Fill or other construction materials. Methods of stabilization include undercutting, moisture conditioning, or chemical stabilization. The situation should be discussed with ECS to determine the appropriate procedure. Test pits may be excavated to explore the shallow subsurface materials to help in determining the cause of the observed
unstable materials, and to assist in the evaluation of appropriate remedial actions to stabilize the subgrade. 5.3.3 Site Temporary Dewatering The contractor shall make their own assessment of temporary dewatering needs based upon the limited subsurface groundwater information presented in this report. Soil sampling is not continuous, and thus soil and groundwater conditions may vary between sampling intervals (typically 5 feet). If the contractor believes additional subsurface information is needed to assess dewatering needs, they should obtain such information at their own expense. ECS makes no warranties or guarantees regarding the adequacy of the provided information to determine dewatering requirements; such recommendations are beyond our scope of services. Dewatering systems are a critical component of many construction projects. Dewatering systems must be selected, designed, and maintained by a qualified and experienced (specialty or other) contractor familiar with the succinct geotechnical and other aspects of the project. The failure to properly design and maintain a dewatering system for a given project can result in delayed construction, unnecessary foundation subgrade undercuts, detrimental phenomena such as ‘running sand’ conditions, internal erosion (i.e., ‘piping’), the migration of ‘fines’ down-gradient towards the dewatering system, localized settlement of nearby infrastructure, foundations, slabs-on-grade and pavements, etc. Water discharged from any site dewatering system shall be discharged in accordance with all local, state and federal requirements. Strategies for Addressing Perched Groundwater: The typical primary strategy for addressing perched groundwater seeping into excavations is pumping from trench (or French) and sump pits with sump pumps. A typical sump pump drain (found in a sump pit or along a French drain) is depicted below. The inlet of the sump pump is placed at the bottom of the corrugated pipe and the discharge end of the sump is directed to an appropriate stormwater drain.
Sump Pit/Pump Diagram Details of a typical French drainage installation are included in Appendix D. A typical French drain consists of an 18 to 24-inch wide by 18 to 24-inch deep bed of AASHTO #57 (or similar open graded aggregate)
aggregate wrapped in a medium duty, non-woven geotextile and (sometimes) containing a 6-inch diameter, Schedule 40 PVC perforated or slotted pipe. Actual dimensions should be as determined necessary by ECS during construction. After the installation has been completed, the geotextile should be wrapped over the top of the aggregate and pipe followed by placement of backfill. The top of the drain should be positioned at least 18 inches below the design subgrade elevations. Drains should not be routed within the expanded building limits. Pumping wells or a vacuum system could also be used to address perched groundwater. These techniques often are only effective during the initial depletion of the perched water quantity and may quickly be ineffective at addressing accumulation of water from rain, snow, etc.
EARTHWORK OPERATIONS
5.4.1 Existing Man-Placed Fill Fill Content: Up to approximately 13 feet of existing possible fill was noted within the proposed building footprint during the subsurface exploration. Due to the presence of fill on-site, select over-excavation of existing fill material should be anticipated in accordance with Option 1 or Option 2 as described in Section 4.1. 5.4.2 Rock Excavation Bedrock was encountered in all of the borings performed onsite, signified by auger refusal, as shallow as 7.5 feet below existing grade which corresponds to approximate El. between 453.0 and 468.5 ft. Rock coring was performed in B-4 and B-5, with samples indicating that the underlying rock was composed of light gray Limestone that is highly to slightly weathered, hard, and highly fractured. When rock is found during construction, especially in areas of deep utility installation and basin construction, significant excavation difficulties which may slow down the construction process may occur. Usually, rock saws employed for trench excavations are capable of exceeding our refusal depths by several feet, but with some difficulty. The use of hydraulic rams on heavy duty excavation equipment, or the use of blasting, should be anticipated. We do not recommend straight line interpolation of bedrock surfaces for the estimation of excavation quantities due to the variable bedrock surface that is common in this geology. 5.4.3 Structural Fill Materials Prior to placement of Structural Fill, representative bulk samples (about 50 pounds) of on-site and/or off- site borrow should be submitted to ECS for laboratory testing, which will typically include Atterberg limits, natural moisture content, grain-size distribution, and moisture-density relationships (i.e., Proctors) for compaction. Import materials should be tested prior to being hauled to the site to determine if they meet project specifications. Satisfactory Structural Fill Materials: Materials satisfactory for use as Structural Fill should consist of inorganic soils with the following engineering properties and compaction requirements.
STRUCTURAL FILL INDEX PROPERTIES
Max. Particle Size 4 inches
Minimum Dry Density 105 pcf
Max. organic content 5% by dry weight
STRUCTURAL FILL COMPACTION REQUIREMENTS
Required Compaction 95% of Max. Dry Density
Moisture Content -1 to +3 % points of the soil’s
optimum value
Loose Thickness 8 inches prior to compaction
On-Site Borrow Suitability: Natural deposits of soils that meet the definition of Satisfactory Structural Fill do appear to be present on the site at possible excavation depths, however, some moisture conditioning will likely be necessary. Fill Placement: Fill materials should not be placed on frozen soils, on frost-heaved soils, and/or on excessively wet soils. Borrow fill materials should not contain frozen materials at the time of placement, and all frozen or frost-heaved soils should be removed prior to placement of Structural Fill or other fill soils and aggregates. Excessively wet soils or aggregates should be scarified, aerated, and moisture conditioned. 5.4.4 Proposed Fill Slopes Slopes comprised of engineered fill may be constructed at a slope of 3:1 or flatter. Slopes steeper than 3:1 should be evaluated by ECS. All slopes should be properly vegetated to reduce the likelihood of surficial erosion and sloughing.
FOUNDATION AND SLAB OBSERVATIONS
Protection of Foundation Excavations: Exposure to the environment may weaken the soils at the footing bearing level if the foundation excavations remain open for too long a time. Therefore, foundation concrete should be placed the same day that excavations are made. If the bearing soils are softened by surface water intrusion or exposure, the softened soils must be removed from the foundation excavation bottom immediately prior to placement of concrete. If the excavation must remain open overnight, or if rainfall becomes imminent while the bearing soils are exposed, a 1 to 3-inch thick “mud mat” of “lean” concrete should be placed on the bearing soils before the placement of reinforcing steel. Footing Subgrade Observations: Most of the soils at the foundation bearing elevation are anticipated to be suitable for support of the proposed structure. It is important to have ECS observe the foundation subgrade prior to placing foundation concrete, to confirm the bearing soils are what was anticipated.
Slab Subgrade Verification: Prior to placement of a drainage layer, the subgrade should be prepared in accordance with the recommendations found in Section 5.3.2 Proofrolling.
UTILITY INSTALLATIONS
Utility Subgrades: The soils encountered in our exploration are expected to be generally suitable for support of utility pipes. The pipe subgrades should be observed and probed for stability by ECS. Any loose or unsuitable materials encountered should be removed and replaced with suitable compacted Structural Fill, or pipe stone bedding material. Utility Backfilling: The granular bedding material should be at least 4 inches thick, but not less than that specified by the civil engineer’s project drawings and specifications. We recommend that the bedding materials be placed up to the springline of the pipe. Fill placed for support of the utilities, as well as backfill over the utilities, should satisfy the requirements for Structural Fill and Fill Placement. Utility Excavation Dewatering: It is possible that perched water may be encountered by utility excavations which extend below existing grades. It is expected that removal of perched water which seeps into excavations could be accomplished by pumping from sumps excavated in the trench bottom and which are backfilled with AASHTO No. 57 Stone or open graded bedding material. Should water conditions beyond the capability of sump pumping be encountered, the contractor should submit a Dewatering Plan in accordance with project specifications. Excavation Safety: All excavations and slopes should be constructed and maintained in accordance with OSHA excavation safety standards. The contractor is solely responsible for designing, constructing, and maintaining stable temporary excavations and slopes. The contractor’s responsible person, as defined in 29 CFR Part 1926, should evaluate the soil exposed in the excavations as part of the contractor’s safety procedures. In no case should slope height, slope inclination, or excavation depth, including utility trench excavation depth, exceed those specified in local, state, and federal safety regulations. ECS is providing this information solely as a service to our client. ECS is not assuming responsibility for construction site safety or the contractor’s activities; such responsibility is not being implied and should not be inferred.
6.0 CLOSING ECS has prepared this report to guide the geotechnical-related design and construction aspects of the project. We performed these services in accordance with the standard of care expected of professionals in the industry performing similar services on projects of like size and complexity at this time in the region. No other representation, expressed or implied, and no warranty or guarantee is included or intended in this report.
The description of the proposed project is based on information provided to ECS by Steckbeck Engineering and Surveying, Inc. If any of this information is inaccurate, either due to our interpretation of the documents provided or if the site’s design changed, ECS should be contacted immediately to review the report in light of the changes and provide additional or alternate recommendations as required to reflect the proposed construction. We recommend that ECS review the project plans and specifications so we can confirm that those plans/specifications are in accordance with the recommendations of this geotechnical report. Field observations, and quality assurance testing during earthwork and foundation installation are an extension of, and integral to, the geotechnical design. We recommend that ECS be retained to apply our expertise throughout the geotechnical phases of construction, and to provide consultation and recommendation should issues arise. ECS is not responsible for the conclusions, opinions, or recommendations of others based on the data in this report.
APPENDIX A – Diagrams & Reports
Site Location Map Exploration Location Plan Geologic Map Karst Features Map Soil Survey Map Subsurface Profile A-A’ and B-B’
3/2 /20
E a rt
STECKBECK ENGINEERING & SURVEYING, INC.
Hamburg Sequence Rock Main Rock Type: Shale
SOURCE
DATE
3/2/2021
STECKBECK ENGINEERING & SURVEYING, INC.
0 Sinkhole(s)
E a rt
50 /4
50 /1
*B-4
APPENDIX B – Field Operations
Reference Notes for Boring Logs and Rock Cores Subsurface Exploration Procedure: Standard Penetration Testing (SPT) Boring Logs B-1 through B-5 Rock Core Photograph Test Pit Logs TP-1 through TP-5 Infiltration Test Results Test Pit Photographs
REFERENCE NOTES FOR BORING LOGS
MATERIAL1,2
1Classifications and symbols per ASTM D 2488-17 (Visual-Manual Procedure) unless noted otherwise. 2To be consistent with general practice, “POORLY GRADED” has been removed from GP, GP-GM, GP-GC, SP, SP-SM, SP-SC soil types on the boring logs. 3Non-ASTM designations are included in soil descriptions and symbols along with ASTM symbol [Ex: (SM-FILL)]. 4Typically estimated via pocket penetrometer or Torvane shear test and expressed in tons per square foot (tsf). 5Standard Penetration Test (SPT) refers to the number of hammer blows (blow count) of a 140 lb. hammer falling 30 inches on a 2 inch OD split spoon sampler required to drive the sampler 12 inches (ASTM D 1586). “N-value” is another term for “blow count” and is expressed in blows per foot (bpf). SPT correlations per 7.4.2 Method B and need to be corrected if using an auto hammer.
6The water levels are those levels actually measured in the borehole at the times indicated by the symbol. The measurements are relatively reliable when augering, without adding fluids, in granular soils. In clay and cohesive silts, the determination of water levels may require several days for the water level to stabilize. In such cases, additional methods of measurement are generally employed.
7Minor deviation from ASTM D 2488-17 Note 14. 8Percentages are estimated to the nearest 5% per ASTM D 2488-17.
Reference Notes for Boring Logs (03-24-2021).doc © 2021 ECS Corporate Services, LLC. All Rights Reserved
COHESIVE SILTS & CLAYS UNCONFINED
STRENGTH, QP4
<0.25 0.25 - <0.50 0.50 - <1.00 1.00 - <2.00 2.00 - <4.00 4.00 - 8.00
>8.00
SPT5
(BPF)
CONSISTENCY7
(COHESIVE)
DENSITY
PARTICLE SIZE IDENTIFICATION DESIGNATION PARTICLE SIZES
Hollow Stem Auger Power Auger (no sample) Bulk Sample of Cuttings Wash Sample Shelby Tube Sampler Split Spoon Sampler
Rock Quality Designation % Rock Sample Recovery % Rock Core, NX, BX, AX Rock Bit Drilling Pressuremeter TestSS
ST WS BS PA
Coarse Fine Coarse
0.074 mm to 0.425 mm (No. 200 to No. 40 sieve) <0.074 mm (smaller than a No. 200 sieve)
0.425 mm to 2.00 mm (No. 40 to No. 10 sieve) 2.00 mm to 4.75 mm (No. 10 to No. 4 sieve) 4.75 mm to 19 mm (No. 4 sieve to ¾ inch) ¾ inch to 3 inches (19 mm to 75 mm) 3 inches to 12 inches (75 mm to 300 mm) 12 inches (300 mm) or larger
>50 31 - 50 16 - 30
9 - 15 5 - 8 3 - 4 <2
Very Hard Hard
SILTY GRAVEL gravel-sand-silt mixtures
CLAYEY GRAVEL gravel-sand-clay mixtures
SILTY SAND sand-silt mixtures
CLAYEY SAND sand-clay mixtures
ELASTIC SILT high plasticity
FAT CLAY high plasticity
ORGANIC SILT or CLAY high plasticity
PEAT highly organic soils
FILL AND ROCK
REFERENCE NOTES FOR ROCK CORES
*ASTM D6032 Reference Notes for Rock Cores (03-15-2019) © 2019 ECS Corporate Services, LLC. All Rights Reserved
Rock Quality Designation (RQD(%))*
RQD% Description of Rock Quality
0-25% Very Poor
>25%-50% Poor
>50%-75% Fair
>75%-90% Good
DIABASE DIORITE GABBRO GRANITE PEGMATITE PERIDOTITE SYANITE
Fine Grained ANDESITE BASALT RHYOLITE TRACHYTE
Pyroclastic OBSIDIAN
Chemically Formed DOLOSTONE GYPSUM HALITE LIMESTONE
Organic Remains CHALK COAL COQUINA
Foliated GNEISS PHYLLITE SCHIST SLATE
Non-Foliated AMPHIBOLITE HORNFELS MARBLE QUARTZITE
PUMICE TUFF
Massive >3 ft.
Slightly Weathered
Moderately Weathered
Discoloring evident, surface pitted and altered with alteration penetrating well below rock surfaces, weathering 'halos' evident. 10 to 50 percent of the rock altered.
Highly Weathered
Entire mass discolored, alteration pervading nearly all of the rock, with some pockets of slightly weathered rock noticeable, some minerals leached away.
Decomposed Rock reduced to a soil with relict rock structure remaining (i.e. saprolite). Generally molded and crumbled by hand (friable).
Recovery (REC(%))
Total rock recovered from run Total Run Length
HARDNESS Very Soft Deformed by hand Soft Scratched with a fingernail
Moderately Hard Scratched easily with a knife
Hard Scratched with difficulty with a knife
Very Hard Cannot be scratched with a knife
JOINT/FRACTURE SPACING
Slightly 3 - 10 feet
Moderately 1 - 3 feet
Intensely < 2 inches
JOINT/FRACTURE ORIENTATION The range or average orientation of each joint set or fracture trend shall be measured in degrees from a horizontal plane where possible. If no measurement is possible, the qualitative terms High, Moderate or Low- angle shall be used. Record whether the joints are present in Conjugate sets (i.e. having an opposite sense of dip)
High 61-90 degree
Moderate 31-60 degree
Low-angle 0-30 degree
WALL ROCK CONDITION
The qualitative terms 'hard wall rock' or 'soft wall rock' shall be used to describe the condition of the parent rock on either side of the joint or fracture.
JOINT OR FRACTURE CONTINUITY It shall be noted whether the joints or fractures are continuous or discontinuous. If continuity of joints is not discernable at the scale of the rock core, continuous joints or fractures shall be assumed.
Description Sequence Example Rock Classification Description Type, [REC=_%,RQD=_%], Weathering, Hardness, Bedding, Fracturing/Jointing, Condition, Wall Rock Condition, Continuity, Dip, Color, Additional Features
LIMESTONE, [REC=95%,RQD=60%], Moderately Weathered, Hard, Thickly Bedded, Slightly Fractured/Jointed, Slightly Rough, Hard Wall Rock, Discontinuous, Moderate-angle Dip, Gray White
JOINT/FRACTURE SURFACE CONDITION The following qualitative terms shall be used to describe surface condition of joints and fractures. Multiple terms can be used. Very rough Slightly rough Slickensided Gouge
SUBSURFACE EXPLORATION PROCEDURE:
Split-Barrel Sampling
Standard Penetra on Tes ng, or SPT, is the most frequently used
subsurface explora on test performed worldwide. This test provides
samples for iden fica on purposes, as well as a measure of penetra on
resistance, or N-value. The N-Value, or blow counts, when corrected and
correlated, can approximate engineering proper es of soils used for
geotechnical design and engineering purposes.
• Involves driving a hollow tube (split-spoon)
into the ground by dropping a 140-lb hammer
a height of 30-inches at desired depth
• Recording the number of hammer blows re-
quired to drive split-spoon a distance of 12
inches (in 3 or 4 Increments of 6 inches each)
• Auger is advanced* and an addi onal SPT is
performed
two to five feet
*Drilling Methods May Vary— The predominant drilling
methods used for SPT are open hole fluid rotary drilling and
hollow-stem auger drilling.
DESCRIPTION OF MATERIAL
Topsoil Thickness[8.00"] (GM PROBABLE FILL) PROBABLE FILL, SILTY GRAVEL WITH SAND, brown to orange, moist, loose to medium dense
(GM) SILTY GRAVEL WITH SAND, dark brown, moist to wet, very loose
Refusal encountered at 18.5 feet. END OF DRILLING AT 18.5 FT
W AT
ER L
EV EL
9
23
5
8
9
2
5
50/4"
22.2
25.1
40.5
44.3
36.3
23.9
8.7
8.5
[38.5%]
CLIENT: Steckbeck Engineering and Surveying, Inc. PROJECT NAME: Northern Lebanon High School Improvements
PROJECT NO.: BORING NO.: 18:5194 B-1 DRILLER/CONTRACTOR: Eichelbergers, Inc.
SHEET: 1 of 1
LOSS OF CIRCULATION
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL TYPES. IN-SITU THE TRANSITION MAY BE GRADUAL
WL (First Encountered)
WL (Comple on)
Mar 16 2021
Mar 16 2021
LOGGED BY: RJR2
CAVE IN DEPTH:
DE PT
H (F
Topsoil Thickness[6.00"] (ML FILL) FILL, SANDY SILT WITH GRAVEL, brown, moist, loose to medium dense
(GP) GRAVEL, dark gray to dark brown, moist to dry, very dense
W AT
ER L
EV EL
10
16
9
50/4"
SHEET: 1 of 1
LOSS OF CIRCULATION
WL (Comple on)
Mar 16 2021
Mar 16 2021
LOGGED BY: KTE
CAVE IN DEPTH:
DE PT
H (F
Topsoil Thickness[8.00"] (SM FILL) FILL, SILTY SAND, brown, moist, very loose to loose
(ML) SANDY SILT WITH GRAVEL, dark gray, moist, very loose, saprolite
(SM) SILTY SAND WITH GRAVEL, dark gray, moist to wet, very loose
(GM) SILTY GRAVEL WITH SAND, dark gray, moist to wet, very dense
W AT
ER L
EV EL
9
5
2
2
4
2
2
50/1"
SHEET: 1 of 1
LOSS OF CIRCULATION
WL (Comple on)
Mar 16 2021
Mar 16 2021
LOGGED BY: KTE
CAVE IN DEPTH:
DE PT
H (F
Asphalt Thickness[6.00"] Gravel Thickness[2.00"] (ML FILL) FILL, SANDY SILT WITH GRAVEL, brown, moist, loose to medium dense (SM) SILTY SAND, brown, moist, loose to medium dense
(GM) SILTY GRAVEL WITH SAND, dark gray, moist to wet, loose
LIMESTONE, [REC=97%,RQD=10%], Moderately Weathered, Hard, Highly Fractured/Jointed, Moderate-angle Dip, Gray to Dark Gray
END OF DRILLING AT 15.5 FT
W AT
ER L
EV EL
1 0 97
SHEET: 1 of 1
LOSS OF CIRCULATION
WL (Comple on)
Mar 16 2021
Mar 16 2021
LOGGED BY: KTE
CAVE IN DEPTH:
DE PT
H (F
Gravel Thickness[8.00"] (SM) SILTY SAND WITH GRAVEL, orangish brown, moist, loose
(GM) SILTY GRAVEL WITH SAND, brown, moist to wet, medium dense LIMESTONE, [REC=28%,RQD=0%], Highly Weathered, Hard, Intensely Fractured/ Jointed, Very Rough, Moderate-angle Dip, Gray and White
END OF DRILLING AT 12.7 FT
W AT
ER L
EV EL
28
10
7
11
27
SHEET: 1 of 1
LOSS OF CIRCULATION
WL (Comple on)
Mar 16 2021
Mar 16 2021
LOGGED BY: KTE
CAVE IN DEPTH:
B -4
B -5
R o
ck C
o re
P h
o to
Topsoil Thickness[10.00"]
(SM) SILTY SAND WITH GRAVEL, light brown, moist, coarse fragments- 30%, 7.5YR 5/6
END OF TEST PIT AT 4.0 FT
EX CA
VA TI
O N
E FF
O RT
CLIENT: PROJECT NO.: Steckbeck Engineering and Surveying, Inc. 18:5194 PROJECT NAME: TEST PIT NO.: Northern Lebanon High School Improvements TP-1 SITE LOCATION: 345 School Drive, Fredericksburg, Pennsylvania 17026 NORTHING: 403175.6 EASTING:
SHEET: 1 of 1 SURFACE ELEVATION: 473.0 STATION:
2330778.7
REMARKS:
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDRY LINES BETWEEN SOIL TYPES. IN-SITU THE TRANSITION MAY BE GRADUAL
EXCAVATION EFFORT: E - EASY M - MEDIUM D - DIFFICULT VD - VERY DIFFICULT
WL (First Encountered) WL (Seasonal High) CONTRACTOR: OPERATOR: MAKE/MODEL:
WL (Comple on) Be er Way Excava ng Charles Mustang
ECS REP.: DATE COMPLETED: UNITS: CAVE-IN-DEPTH:
Rees Roberts Mar 08 2021 English
TEST PIT LOG
EX CA
VA TI
O N
E FF
O RT
2330979.0
REMARKS:
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDRY LINES BETWEEN SOIL TYPES. IN-SITU THE TRANSITION MAY BE GRADUAL
EXCAVATION EFFORT: E - EASY M - MEDIUM D - DIFFICULT VD - VERY DIFFICULT
WL (First Encountered) WL (Seasonal High) CONTRACTOR: OPERATOR: MAKE/MODEL:
WL (Comple on) Be er Way Excava ng Charles Mustang
ECS REP.: DATE COMPLETED: UNITS: CAVE-IN-DEPTH:
Rees Roberts Mar 08 2021 English
TEST PIT LOG
Not enc.Not enc.
EX CA
VA TI
O N
E FF
O RT
2331147.2
REMARKS: