Appendix D: Geotechnical Study

City of Hayward—24493 Clawiter Road Industrial Building Project Initial Study/Mitigated Negative Declaration

FirstCarbon Solutions

Appendix D: Geotechnical Study

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www.mooretwining.comPH: 559.268.7021FX: 559.268.71262527 Fresno StreetFresno, CA 93721

PRELIMINARYGEOTECHNICAL ENGINEERING INVESTIGATION

PROPOSED WAREHOUSE24493 CLAWITER ROAD

HAYWARD, ALAMEDA COUNTY, CALIFORNIA

Project Number: G21411.01

For:

Duke Realty200 Spectrum Center Drive, Suite 1600

Irvine, CA 92618

January 31, 2020

www.mooretwining.comPH: 559.268.7021FX: 559.268.71262527 Fresno StreetFresno, CA 93721

January 31, 2020 G21411.01

Duke Realty200 Spectrum Center Drive, Suite 1600Irvine, CA 92618

Attention: Mr. Randy Dilag

Subject: Preliminary Geotechnical Engineering InvestigationProposed Warehouse24493 Clawiter RoadHayward, Alameda County, California

Dear Mr. Dilag:

We are pleased to submit this Preliminary Geotechnical Engineering Investigation report, preparedat your request, for the warehouse building proposed at 24493 Clawiter Road in Hayward, AlamedaCounty, California.

The contents of this report include the purpose of the investigation, scope of services, backgroundinformation, investigative procedures, our findings, evaluation, conclusions, and recommendations.It is recommended that those portions of the plans and specifications that pertain to earthwork,pavements, and foundations be reviewed by Moore Twining Associates, Inc. (Moore Twining) todetermine if they are consistent with our recommendations. A future design level geotechnicalinvestigation will need to be conducted to supplement the findings from this preliminarygeotechnical engineering investigation.

In addition, it is recommended that Moore Twining be retained to provide inspection and testingservices for the excavation, earthwork, pavement, and foundation phases of construction. Theseservices are necessary to determine if the subsurface conditions are consistent with those used in theanalyses and formulation of recommendations for this investigation, and if the construction complieswith our recommendations. These services are not, however, part of this current contractualagreement. We would appreciate the opportunity to provide a proposal for these additional servicesafter construction documents are completed. A representative with our firm will contact you in thenear future regarding these services.

Preliminary Geotechnical Engineering Investigation G21411.01Proposed Warehouse January 31, 202024493 Clawiter RoadHayward, Alameda County, California Page No. 2

We appreciate the opportunity to be of service. If you have any questions regarding this report, orif we can be of further assistance, please contact us at your convenience.

Sincerely,

MOORE TWINING ASSOCIATES, INC.Geotechnical Engineering Division

DRAFT

Read L. Andersen, RGEManager

EXECUTIVE SUMMARY

Moore Twining Associates, Inc. conducted this preliminary geotechnical engineering investigationfor the warehouse building proposed at 24493 Clawiter Road, in the City of Hayward, California.

The proposed project is anticipated to include a 210,000 square foot warehouse building with 38dock doors. It is anticipated the building will be single-story with possible mezzanine areas and willinclude a concrete slab on grade floor. It is anticipated the project will incorporate dock highconstruction (retaining walls) for truck loading and unloading. Appurtenant construction isanticipated to include asphalt concrete and/or Portland cement concrete pavements, concretewalkways, landscaped areas, and underground utilities.

According to the site plan provided, the net site area is about 9.9 acres. At the time of our fieldinvestigation, the site was in use for fabrication of steel materials for building construction. The siteincludes three existing buildings: a moderate-size warehouse building (approximately 27,000 squarefeet in plan area) in the western portion of the site, a larger-size warehouse building (approximately124,500 square feet in plan area) in the eastern portion of the site, and a smaller-size building(approximately 1,300 square feet in plan area) located on the north side of the larger-size warehousebuilding in the eastern portion of the site. Existing site improvements include asphalt and concretepaving, concrete walks and landscape areas. The remaining portions of the site are generallyoverlain by aggregate base type materials. Piles of steel were noted throughout several portions ofthe site.

On January 8 and 11, 2020, four (4) test borings were drilled within the proposed warehouse buildingand loading dock area to depths ranging from about 25 to 51½ feet BSG.

On January 11, 2020, nine (9) Cone Penetration Tests (CPTs) were advanced at the site generallyto depths of about 50 feet BSG. However, one of the CPTs (CPT-7) encountered refusal due to anapparent buried obstruction that could not be penetrated and encountered refusal at depths rangingbetween 2.6 to 3.9 feet BSG during four (4) attempts to advance the CPT.

The borings all encountered fill soils that extended to depths of about 2¾ to about 4½ feet BSG, withexception that boring B-2 encountered suspected fill soils extending to a depth of about 11 feet BSG.The fill soils encountered were variable. The fill soils encountered in boring B-1 included 6 inchesof aggregate base that was cement treated. Cement treated aggregate base was also suspected to beencountered in the areas of CPT-4 and CPT-5 in the western portion of the site as the aggregate basehad to be cored with a coring machine before the CPT could be advanced. The cement treatedaggregate base encountered in boring B-1 was underlain by silty sand fill soils with some graveloverlying queried fill soils consisting of lean clay with gravel that extended to a total depth of about3½ feet BSG. Below the Portland cement concrete pavement, boring B-2 encountered sandy leanclay fill soils to a depth of about 4¼ feet BSG. Below a depth of 4¼ feet BSG in boring B-2, layersof lean clay, poorly graded sand with silt and gravel, and silty sand were suspected to be fillextending to a depth of 11 feet BSG. The fill soils encountered in boring B-3 consisted of 12 inchesof aggregate base overlying lean clay with sand fill soils with wood debris and gravel and extendedto a depth of about 3½ feet BSG. The fill soils encountered in boring B-4 consisted of 6 inches ofaggregate base over lean clay with sand fill soils with brick debris and gravel overlying queried fill

EXECUTIVE SUMMARY (cont.)

soils consisting of a thin layer of silty sand soils; and the fill soils at this boring location extendedto a total depth of about 4½ feet BSG. Based on the penetration resistance of the CPTs, the CPTsgenerally indicate the upper soils consist of fill.

In addition to the fill soils encountered in the borings, Contractors should anticipate thatundocumented fill soils also exist in areas where Underground Storage Tanks were reportedlyremoved from the site in the early 1990s. The Phase I report provided by the client indicated a sumpstructure and six underground tanks ranging in size from 500 gallons to 6,000 gallons werepreviously removed and the excavations backfilled. Thus, as part of site preparation, a careful searchshould be conducted to expose the fill soils and remove and recompact these soils as engineered fillto reduce the potential for excessive settlement. The approximate locations of the formerunderground tanks and sump structure are noted on Drawing No. 2 in Appendix A, attached to thisreport.

The native soils encountered in the borings consisted of interbedded layers of lean clays with varyingamounts of sand, sandy lean clays, silty sands, poorly graded sands with silt and gravel, and clayeysands that extended to depths ranging from about 11 to 15 feet BSG. These layers were underlainby lean clays or fat clays with varying amounts of sand that extended to the maximum depthexplored, about 51½ feet BSG.

The near surface clayey soils include expansive soils with a low to moderate plasticity and lowexpansion potential. Due to the presence of expansive soils, concrete slabs on grade arerecommended to be underlain by a minimum of 18 inches of imported, non-expansive fill. It maybe possible to chemically treat the onsite soils for use as the non-expansive fill; however, this usewould need to be evaluated as part of the future design level geotechnical investigation.

Groundwater was encountered in all of the test borings drilled during our field investigation at depthsranging from about 10 to 13 feet BSG and the CPT soundings encountered groundwater at depthsranging from about 9 to 11 feet BSG. However, groundwater has been reported at shallower levelsat the subject site. The California State Water Resources Control Board Geotracker website alsoincluded several groundwater monitoring reports for the subject site issued between the years 2011through 2017. The latest report entitled, “Vapor Intrusion Investigation and Annual MonitoringReport, Former White Cap Facility, 24493 Clawiter Road, Hayward, California,” dated November2017, prepared by Golder Associates, included groundwater depth data from various monitoringwells between the years 2009 and 2017. The data indicates that the depth to groundwater at the sitebetween 2009 and 2017 has generally ranged from about 7.3 feet to about 15.24 feet below sitegrades (BSG).

Soils with high moisture contents were encountered directly above the groundwater which wasgenerally encountered in the borings and CPTs between the depths of about 9 and 12 feet.Contractors should anticipate that soil excavated within a few feet above the groundwater (such asmay be required for pad over-excavation and/or utility installations) will be overly moist and willrequire drying prior to being used as engineered fill. Also, it should be anticipated that the base ofexcavations to these depths will require stabilization prior to placement of engineered fill.

EXECUTIVE SUMMARY (cont.)

It should be noted that an area north of the proposed building was marked by others as containinga buried concrete slab below the ground surface. The approximate area with the buried concrete slabis shown on Drawing No. 2 in Appendix A. Due to the history of development on the property,buried obstructions should be anticipated that will require removal as part of the site preparation. Inaddition, existing foundations and underground features such as utilities should be removed and allbackfill placed as engineered fill. Also, as noted areas in the western portion of the site includedcement treated base where boring B-1 was drilled and CPT soundings CPT-4 and CPT-5 wereadvanced. These areas where cement treated base is present are anticipated to require more effortand cost to remove and dispose.

Due to the compressibility of the subsurface soils, the presence of undocumented fill and disturbanceof the soils due to excavation and removal of existing surface and subsurface improvements, over-excavation to establish engineered fill for support of the proposed structure is recommended. Therecommendations included in this report are intended to reduce the total static settlement of 1 inchand a differential settlement of ½ inch in 40 feet.

The results of the analysis indicate zones of granular soils encountered are susceptible to liquefactionunder the design earthquake event. Seismic settlement analyses indicate total seismic settlementsranging from about ¼ to 1½ inches and a differential seismic settlement of ¾ inches over 40 feet.

The site is not located in an Alquist-Priolo special studies zone. The nearest active fault with surfacerupture is the Hayward fault, which is located about 3.2 miles northeast of the site. Therefore, thepotential for fault rupture at the site is considered low.

Chemical testing of soil samples indicated the soils exhibit a “moderately corrosive”to “highlycorrosive” corrosion potential. The results of chemical analyses for sulfates are pending and shouldbe added to this report with regard to the potential for sulfate attack on concrete placed in contactwith the near surface soils.

This report did not include an environmental assessment. Due to the previous site remediation work,it is recommended an environmental professional be consulted regarding potential soils andgroundwater impacts.

This executive summary should not be used for design or construction and should be reviewed inconjunction with the attached report.

G21411.01

TABLE OF CONTENTSPage

1.0 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2.0 PURPOSE AND SCOPE OF INVESTIGATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122.1 Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.2 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

3.0 BACKGROUND INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33.1 Site Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33.2 Site History and Previous Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43.3 Foundation Plans for Existing Buildings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53.4 Anticipated Construction and Grading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

4.0 INVESTIGATIVE PROCEDURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74.1 Field Exploration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

4.1.1 Site Reconnaissance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74.1.2 Drilling Test Borings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74.1.3 Soil Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84.1.3 Cone Penetration Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

4.2 Laboratory Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

5.0 FINDINGS AND RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95.1 Surface and Subsurface Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95.2 General Geologic Soil Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95.3 Asphaltic Concrete (AC) Pavements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95.4 Portland Cement Concrete (PCC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105.5 Soil Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105.6 Soil Engineering Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115.7 Groundwater Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

6.0 EVALUATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146.1 Existing Surface and Subsurface Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146.2 Undocumented Fills and Buried Obstructions . . . . . . . . . . . . . . . . . . . . . . . . . . . 146.3 Shallow Groundwater and Stabilization of Wet Soils . . . . . . . . . . . . . . . . . . . . . 156.4 Expansive Soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156.5 Static Settlement and Bearing Capacity of Shallow Foundations . . . . . . . . . . . . 166.6 Seismic Ground Rupture and Design Parameters . . . . . . . . . . . . . . . . . . . . . . . . 166.7 Liquefaction and Seismic Settlement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176.8 Asphaltic Concrete (AC) Pavements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186.9 Portland Cement Concrete (PCC) Pavements . . . . . . . . . . . . . . . . . . . . . . . . . . . 186.10 Soil Corrosion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196.11 Sulfate Attack of Concrete . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

7.0 CONCLUSIONS AND PRELIMINARY RECOMMENDATIONS . . . . . . . . . . . . . . . 20

G21411.01

TABLE OF CONTENTSPage

8.0 DESIGN CONSULTATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

9.0 CONSTRUCTION MONITORING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

10.0 NOTIFICATION AND LIMITATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

APPENDICES

APPENDIX A - Drawings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

Drawing No. 1 - Site Location MapDrawing No. 2 - Test Boring and CPT Location Map

APPENDIX B - Logs of Test Borings and CPT Soundings . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1

APPENDIX C - Results of Laboratory Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1

PRELIMINARYGEOTECHNICAL ENGINEERING INVESTIGATION

PROPOSED WAREHOUSE24493 CLAWITER ROAD

HAYWARD, ALAMEDA COUNTY, CALIFORNIA

Project Number: G21411.01

1.0 INTRODUCTION

This preliminary geotechnical engineering investigation report was prepared for the warehousebuilding proposed at 24493 Clawiter Road in Hayward, Alameda County, California. MooreTwining Associates, Inc. (Moore Twining) was authorized by written agreement to perform thisgeotechnical engineering investigation.

The contents of this report include the purpose of the investigation and the scope of servicesprovided. The previous studies, site description, and anticipated construction are discussed. Inaddition, a description of the investigative procedures used and the subsequent findings obtained arepresented. Finally, the report provides an evaluation of the findings, general conclusions, and relatedrecommendations. The report appendices contain the drawings (Appendix A), the logs of borings(Appendix B), the results of laboratory tests (Appendix C), and graphical results of the liquefactionand seismic settlement analyses (Appendix D).

The Geotechnical Engineering Division of Moore Twining performed the investigation.

2.0 PURPOSE AND SCOPE OF INVESTIGATION

2.1 Purpose: The purpose of the investigation was to conduct a field exploration and alaboratory testing program, evaluate the data collected during the field and laboratory portions of theinvestigation, and provide the following:

2.1.1 A general description of the subsurface soil and groundwater conditionsencountered;

2.1.2 Recommendations for earthwork construction, including site and subgradepreparation, and engineered fill;

2.1.3 Recommendations for temporary excavations, trench excavation, trenchbackfill, and excavation stability;

2.1.4 Foundation design parameters including allowable soil bearing capacity,settlement, foundation depth, and lateral resistance;

2.1.5 Discussion of liquefaction potential and estimates of total and differentialseismic settlement;

2.1.6 Recommendations for Portland cement and asphaltic concrete pavements;


2.1.7 Evaluation of soil corrosivity potential; and

2.1.8 Final test boring logs and laboratory test results.

This preliminary geotechnical engineering investigation report is provided specifically for theproposed warehouse building and associated improvements referenced in the AnticipatedConstruction section of this report. A future design level geotechnical investigation will need to beconducted to supplement the findings from this preliminary geotechnical engineering investigation.This investigation did not include a flood plain investigation, on-site storm water infiltration study,compaction tests, environmental investigation, or environmental audit.

2.2 Scope: Our proposal, dated December 24, 2019, and contract amendment No. 1,dated January 9, 2020, outlined the scope of our services. The actions undertaken during theinvestigation are summarized as follows.

2.2.1 A Conceptual Site Plan, prepared by Duke Realty, dated November 20, 2019,was reviewed (herein referred to as “site plan”).

2.2.2 A visual site reconnaissance and subsurface exploration were conducted.

2.2.3 Several aerial images of the site between the years 1993 and 2019, fromonline sources, were reviewed.

2.2.4 A report entitled, “Phase I Environmental Site Assessment, 24493 ClawiterRoad, Hayward, California 94545,” prepared by Partner Engineering andScience, Inc., dated August 24, 2012, was reviewed. Other reports for thesubject site were reviewed on the California State Water Resources ControlBoard Geotracker website.

2.2.5 Mr. Adam Schmid (Duke Realty) and Mr. Randy Dilag (Duke Realty) wereconsulted during the investigation.

2.2.6 Laboratory tests were conducted to determine selected physical andengineering properties of the subsurface soils.

2.2.7 The data obtained from the investigation were evaluated to develop anunderstanding of the subsurface soil conditions and the engineering propertiesof the subsurface soils.

2.2.8 This report was prepared to present the purpose and scope, backgroundinformation, field exploration procedures, findings, evaluation, andconclusions and recommendations.


3.0 BACKGROUND INFORMATION

The site description, site history, previous studies, and the anticipated construction are summarizedin the following subsections.

3.1 Site Description: The project site is located at 24493 Clawiter Road, about 500 feetsouthwest of the intersection of Commerce Place and Clawiter Road, in the City of Hayward,California. A site location map, presented on Drawing No. 1 in Appendix A. The site is locatedabout 1b miles east of the San Francisco Bay.

At the time of our investigation, on January 8, 2020 and January 11, 2020, the site was occupied bya ConXtech facility, a steel fabrication business. According to the referenced site plan (see DrawingNo. 2 in Appendix A), the net site area is about 9.9 acres.

The site is bounded to the north by other warehouse-type building developments, to the east byClawiter Road, to the south by Bay Area Concrete Recycling facility, and to the west by railroadtracks.

The site is fully developed and includes three existing buildings, including a intermediate-sizedwarehouse building in the western portion of the site, a larger-size warehouse building in the easternportion of the site, and a smaller-size building located on the north side of the larger-size warehousebuilding in the eastern portion of the site.

The intermediate-sized warehouse building in the western portion of the site is approximately 27,000square feet in plan area which includes attached canopies and a garage with a roll-up door on thesouth side of the building. This warehouse building appeared to have concrete walls and a concreteslab-on-grade floor. The south side of this building includes areas of with raised concrete slabs thatare about 10 inches high.

The existing larger-size warehouse building is approximately 124,500 square feet in plan area whichincludes an attached garage with a roll-up door on the north side of the building at its western end.The larger-size warehouse building includes concrete slab-on-grade floors and generally includesconcrete masonry unit (CMU) walls, and the upper portions of the walls are typically covered bymetal sheeting. However, the east side and a portion of the north side of the larger-size warehousebuilding includes brick walls. The upper portion of the brick walls on the north side of the building,at its eastern end, was covered by metal sheeting.

Concrete pavements exist on the south side of the intermediate-size warehouse building and betweenthe intermediate-size and larger-size warehouse buildings.

The smaller-size building in the eastern portion of the site is approximately 1,300 square feet in planarea and was covered on the outside by metal sheeting.


An asphalt concrete paved driveway entrance and parking lot exists in the eastern side of the site.Concrete walkways and a landscaped area with a grass lawn, bushes and trees exist on the south sideof the asphalt concrete paved driveway entrance in the northeastern portion of the site. Theremaining portions of the site are generallyoverlain byaggregate base type materials. Steel materialswere noted throughout several portions of the site. The piles of steel were constantly being movedby various equipment during our investigation. Two stockpiles of soil, and a pile of wood, werenoted in the northwestern portion of the site. These features are shown on Drawing No. 2 inAppendix A.

Based on our site observations, the ground surface at the site is relatively flat. A topographic survey,or ALTA survey, was not available at the time this report was written. Based on elevations from arecent satellite image of the site from online sources, site surface elevations range from about 24 feetAMSL in the northwestern portion of the site to about 31 feet AMSL in the central and easternportions of the site.

Underground utilities for gas, fire water and sewer were marked at the site by a private utility locatorand member of Underground Service Alert (dig alert). Underground storm drain lines were alsonoted at the site. An overhead utility line was also noted as trending from the northern edge of thesite to the northeast portion of the larger-size building in the eastern portion of the site.

3.2 Site History and Previous Studies: A report provided by Duke Realty entitled,“Phase I Environmental Site Assessment, 24493 Clawiter Road, Hayward, California 94545,”prepared by Partner Engineering and Science, Inc. (Partner), dated August 24, 2012, was reviewed.Based on our review of this report, it is our understanding that the site was formerly used asagricultural land dating back to at least 1939 (oldest aerial photo referenced in the report) untildevelopment of the property began in 1964. The report indicated that the subject property wasexpanded in the early 1970s and again, to the current configuration, in the early 1980s. Historicalaerial photos were not included in the referenced Phase I Environmental Site Assessment report.However, based on our review of aerial photographs between the years 1993 and 2019 from onlinesources, the site development has remained relatively unchanged during that period of time, with theexception that the westernmost portion of the site, west of the intermediate-size building in thewestern portion of the site, was shown as vacant land with no apparent use between 1993 and early2004. Since 2004, this area in the westernmost portion of the site was covered by aggregate basetype materials and generally used for storage of steel materials.

In regards to the site’s historical use, the report indicated the following:

“From 1963 to 1997, White Cap (formerly known as Continental White Cap) manufacturedcontainer closures at the site. The products consisted of metal camps, typically for glass food andbeverage containers.....Six historical underground storage tanks (USTs), which were removed in theearly 1990s, were found to have leaked resulting in soil and groundwater contamination andimproper soil handling activities during removal contributed to the disbursement of contaminatedsoils to other parts of the site. These USTs consisted of: a 6,000-gallon waste thinner UST, a 500-


gallon waste thinner UST, three (3) 1,000-gallon virgin thinner USTs, and a 4,000-gallon reclaimedthinner UST. Additional soil and groundwater contamination was reported in the area of a formerdry sump, which was used for a short time in the 1960s, prior to the installation of the USTs.Constituents of Concern (COCs) consist primarily of xylenes and ethylbenzene.

Remedial actions have occurred at the subject property from as early as 1991 and activeremediation ceased in 2011. Groundwater monitoring continues currently at the subject property.In 2005, the Regional Water Quality Control Board (RWQCB) determined that remediation of thesouth portion of the subject property had been effective and further work was not needed. On April21, 2010, the RWQCB issued a no further action letter for the leaking underground storage tank(LUST) case associated with the former USTs, closing this case administratively in order to addresscontamination at the subject property under the Spills Leaks Incidents and Cleanups (SLIC) case(#1S0534) only. According to RWQCB documents, there are currently twenty-four (24) groundwatermonitoring wells installed at the subject property. Not all wells were observed by Partner duringthe on-site reconnaissance. Maximum contaminants of concern (COC) levels were reported fromW24, located in the west central portion of the property. The Responsible Party for thecontamination at the subject property is identified as Amcor Corporation; the current propertyowner is not the Responsible Party. The identified contamination at the subject property representsa recognized environmental condition.”

The California State Water Resources Control Board Geotracker website was reviewed for otherdocuments. The latest document addressed to Amcor LTD and entitled, “No Further Action, FormerWhite Cap Facility, 24493 Clawiter Road, Hayward, Alameda County,” dated July 16, 2018,prepared by the San Francisco BayRegional Water QualityControl Board, confirmed the completionof site investigation and remedial action for the pollutant releases at the subject site. The documentalso indicated that all remaining monitoring wells have now been abandoned and the case should beclosed. The document concluded that no further action related to the pollutant releases at the subjectsite is required.

No other previous geotechnical engineering, geological, or environmental studies conducted for thissite were provided for review during this investigation. If available, these reports should be providedfor review and consideration for this project.

3.3 Foundations Plans for Existing Buildings: Moore Twining conducted research atthe City of Hayward, Building Division, to search for previous geotechnical engineeringinvestigation reports and/or foundation plans related to the existing buildings.

A foundation plan for an addition to the larger-size warehouse building in the eastern portion of thesite was located during the review. The foundation plan (Sheet S-1), dated September 24, 1969,prepared by Ronald K. Kraft Consulting Civil Engineer, indicates that the warehouse buildingaddition was to be supported on conventional shallow spread foundations. The footings had a widthsranging from 3.5 to 5.5 feet, and elevations of the bottom of the footings were indicated on the plansto extend to depths of 2 feet to 7 feet below the top of the floor slab. The foundation plan indicates


a 6 inch thick floor slab reinforced with No. 4 reinforcement bars at 18 inches on center each way.A detail included on Sheet S-2 of the plans indicates select engineered fill to a depth of 24 inchesbelow the bottom of the foundation. The foundation plan also referenced that the design was basedon a soils report prepared by Woodward Clyde and Associates, Oakland, California, dated July 17,1969.

Plans were also reviewed for the intermediate-size warehouse building in the western portion of thesite. The Foundation Plan, dated November 10, 1980, prepared by Black & Veatch ConsultingEngineers, indicates the warehouse to have a finished floor elevation ranging from 28 feet AMSLalong the northern and southern edges to 28.5 feet AMSL along the center of the building. Thefoundation plan indicates a floor slab thickness of 10 inches which was to be reinforced with adouble mat of No. 4 reinforcing steel spaced at 12 inches each way, top and bottom. The Site Plan,dated November 10, 1980, prepared by Black & Veatch Consulting Engineers, indicatespreconstruction site grade elevations in the area of the intermediate-size warehouse building in thewestern portion of the site to range from about 24 to 28 feet AMSL. Thus, approximately 0.5 to 4.5feet of engineered fill would have been required to achieve the finished floor elevation. In addition,a detail on the site plan indicates that engineered fill - import material - was to extend to 12 inchesbelow the bottom of the footings. The detail also indicates that the bottom of the engineered fill wasto be 2.5 feet below finished grade elevations directly outside the building footings.

3.4 Anticipated Construction and Grading: The proposed project is anticipated toinclude a 210,000 square foot warehouse building with 38 dock doors located at 244930 ClawiterRoad in Hayward, Alameda County, California. The Appurtenant construction is anticipated toinclude asphalt concrete and/or Portland cement concrete pavements, concrete walkways, landscapedareas, and underground utilities.

Structural loads for the building were not available at the time of preparation of this report. Basedon our experience with similar projects, the maximum column and wall loads are anticipated to be75 kips and 4 kips per linear foot, respectively. Appurtenant construction is anticipated to includePortland cement and asphaltic concrete pavements, underground utilities, site lighting, exteriorconcrete slabs on grade, etc. It is anticipated the project will incorporate dock high construction(retaining walls) for truck loading and unloading located on the north of the building. Retainingwalls are not anticipated to exceed a retained height of 5 feet. No other site retaining walls areanticipated.

Finished floor elevations and the extent of grading were not known at the time of preparation of thisreport. Considering the site grades observed, cuts and fill (not including over-excavation) up toabout 3 to 4 feet are anticipated to achieve a level building pad and perimeter site grades.


4.0 INVESTIGATIVE PROCEDURES

The field exploration and laboratory testing programs conducted for this investigation aresummarized in the following subsections.

4.1 Field Exploration: The field exploration consisted of a site reconnaissance, drillingtest borings, conducting Cone Penetration Tests (CPTs), and soil sampling. Prior to our subsurfaceinvestigations, the site was marked for Underground Service Alert and drilling/CPT permits wereobtained from the San Joaquin County Environmental Health Department. In addition, a privateutility locator was used to mark the locations of underground utilities detected in the vicinity of theboring/CPT locations.

4.1.1 Site Reconnaissance: The site reconnaissance consisted of walking the siteand noting visible surface features. The reconnaissance was conducted by Mr. Allen Harker ofMoore Twining on January8, 2020. The features noted are described in the Background Informationsection of this report.

4.1.2 Drilling Test Borings: The depths and locations of the test borings wereselected based on the purpose of this report (preliminary investigation), the type of construction,estimated depths of influence of the anticipated foundation loads, and the subsurface soil conditionsencountered.

On January 8 and 11, 2020, four (4) test borings were drilled at the site to depths ranging from about25 to 51½ feet BSG.

The borings were drilled with a truck-mounted CME-75 drill rig equipped with 6-5/8 inch outsidediameter (O.D.) hollow-stem augers.

During the drilling of the test borings, bulk samples of soil were obtained for laboratory testing. Thetest borings were drilled under the direction of a Moore Twining project geologist. The soilsencountered in the test borings were logged during drilling by a representative of our firm. The fieldsoil classification was in accordance with the Unified Soil Classification System consisted of particlesize, color, and other distinguishing features of the soil.

The presence and elevation of free water in the borings were noted and recorded during drilling.

Test boring locations were determined by pacing and/or tape measure, with reference to existing sitefeatures. The approximate locations of the test borings are shown on Drawing No. 2 in AppendixA of this report. The test borings were backfilled with neat cement grout per Alameda County PublicWorks Agency requirements.


4.1.3 Soil Sampling: Standard penetration tests were conducted in the test borings,and both disturbed and relatively undisturbed soil samples were obtained. The standard penetrationresistance, N-value, is defined as the number of blows required to drive a standard split barrelsampler into the soil. The standard split barrel sampler has a 2-inch O.D. and a 1d-inch insidediameter (I.D.). The sampler is driven by a 140-pound weight free falling 30 inches. The sampleris lowered to the bottom of the bore hole and set by driving it an initial 6 inches. It is then drivenan additional 12 inches and the number of blows required to advance the sampler the additional 12inches is recorded as the N-value.

Relatively undisturbed soil samples for laboratory tests were obtained by pushing or driving aCalifornia modified split barrel ring sampler into the soil. The soil was retained in stainless steelrings, 2.5 inches O.D. and 1-inch in height. The lower 6-inch portion of the samples were placedin close-fitting, plastic, airtight containers which, in turn, were placed in cushioned boxes fortransport to the laboratory. Bulk samples of soil were also collected from the borings. Soil samplesobtained were taken to Moore Twining's laboratory for classification and testing.

4.1.4 Cone Penetration Tests: On January 11, 2020, nine (9) Cone PenetrationTests (CPTs) were advanced at the site generally to depths of about 50 feet BSG. However, CPT-7encountered an apparent buried obstruction that could not be penetrated and encountered refusal atdepths ranging between 2.6 to 3.9 feet BSG during four (4) attempts to advance CPT-7. The CPTlocations are shown on Drawing No. 2 in Appendix A.

The CPT soundings were performed byMiddle Earth Geo Testing, Inc. using an electronic piezoconewith a 60-degree apex angle and a diameter of 44.5 millimeters (about 1.75 inches). The CPTsoundings were hydraulically advanced using a 25-ton CPT rig in accordance with ASTM TestMethod D5778. Measurements of cone tip resistance and sleeve friction data were recorded atapproximate 2-inch intervals during penetration to provide nearly continuous data for interpretingthe engineering properties of the soils. The CPT logs are presented in Appendix B of this report.The CPT holes were backfilled with neat cement.

4.2 Laboratory Testing: The laboratory testing was programmed to determine selectedphysical and engineering properties of the soils underlying the site. The tests were conducted ondisturbed and relatively undisturbed samples representative of the subsurface soils.

The results of laboratory tests are summarized in Appendix C. These data, along with the fieldobservations, were used to prepare the final test boring logs in Appendix B.


5.0 FINDINGS AND RESULTS

The findings and results of the field exploration and laboratory testing are summarized in thefollowing subsections.

5.1 Surface and Subsurface Conditions: At the time of our investigation, the site wasoccupied by two warehouse type buildings, a smaller building, asphalt concrete and Portland cementconcrete pavements. Other areas of the site were covered by aggregate base, concrete walkways anda landscaped area that included a grass lawn, bushes and trees. Some stockpiles of soils and wood,and material storage (steel) were noted.

The existing larger-size warehouse building includes an attached garage with a roll-up door on thenorth side of the building at its western end. An area on the ground just northeast of this garage withthe roll-up door was marked by others as containing a buried concrete slab below the ground surface.The approximate area with the buried concrete slab is shown on Drawing No. 2 in Appendix A. Thearea of Cone Penetration Test CPT-7 on the eastern side of the larger-size building may also haveencountered a buried obstruction such as a concrete slab. Four attempts in four close-by areas weremade to push CPT-7, and all of the attempts encountered refusal at depths ranging from about 2½to nearly 4 feet BSG.

Additional information regarding the surface conditions at the site are described in the “SiteDescription” section of this report.

5.2 General Geologic and Soil Conditions: Based on our review of the CaliforniaGeological Survey website, the project site is located in an area of Quaternary Alluvium. Based onour review of the Earthquake Zones of Required Investigation, Hayward Quadrangle, prepared bythe California Geological Survey, dated September 21, 2012, the area is mapped in a liquefactionhazard zone. The nearest active fault with surface rupture is the Hayward fault, which is locatedabout 3.2 miles northeast of the site.

Based on our review of the soil survey maps prepared by the U.S. Department of Agriculture,Natural Resources Conservation Service, the near surface soils (upper 5 feet) are anticipated toconsist of high plasticity fat clays.

5.3 Asphalt Concrete (AC) Pavements: The asphalt concrete pavement encounteredwhere CPT-1 was advanced was not directly measured with a tape measure. However, the CPT dataindicated that the asphalt concrete thickness appeared to be about 8 to 10 inches in thickness.


5.4 Portland Cement Concrete (PCC) Pavements: Boring B-2 was drilled in an areaof Portland cement concrete (PCC) between the two warehouse buildings in the northern portion ofthe site and the Portland cement concrete (PCC) pavement was measured to be about 10 inches inthickness. The PCC pavement was underlain by the onsite soils at the location of boring B-2. CPT-6 was advanced in an area between the two warehouse buildings in the southern portion of the site,and the PCC pavement that was cored was measured to be about 6½ inches in thickness. The PCCpavement was underlain by the onsite soils at the location of CPT-6.

5.5 Soil Profile: The borings all encountered fill soils that extended to depths of about2¾ to about 4½ feet BSG, with exception that boring B-2 encountered suspected fill soils extendingto a depth of about 11 feet BSG. The fill soils encountered were variable. The fill soils encounteredin boring B-1 included of 6 inches of aggregate base that was cement treated as it reacted to theapplication of phenolphthalein. The cement treated aggregate base was also suspected to beencountered in the areas of CPT-4 and CPT-5 in the western portion of the site as the aggregate basehad to be cored with a coring machine before the CPT could be advanced. The cement treatedaggregate base encountered in boring B-1 was underlain by silty sand fill soils with some graveloverlying queried fill soils consisting of lean clay with gravel that extended to a total depth of about3½ feet BSG. Below the Portland cement concrete pavement, boring B-2 encountered sandy leanclay fill soils that had intermixed dark gray and olive colors and extended to a depth of about 4¼ feetBSG. Below a depth of about 4¼ feet BSG in boring B-2, layers of lean clay, poorly graded sandwith silt and gravel, and silty sand were suspected to be fill extending to a depth of 11 feet BSG.The fill soils encountered in boring B-3 consisted of 12 inches of aggregate base overlying lean claywith sand fill soils with wood debris and gravel and extended to a depth of about 3½ feet BSG. Thefill soils encountered in boring B-4 consisted of 6 inches of aggregate base over lean clay with sandfill soils with brick debris and gravel overlying queried fill soils consisting of a thin layer of siltysand soils; and the fill soils at this boring location extended to a total depth of about 4½ feet BSG.

The native soils encountered in the borings consisted of interbedded layers of lean clays with varyingamounts of sand, sandy lean clays, silty sands, poorly graded sands with silt and gravel, and clayeysands that extended to depths ranging from about 11 to 15 feet BSG. These layers were underlainby lean clays or fat clays with varying amounts of sand that extended to the maximum depthexplored, about 51½ feet BSG.

The CPT soundings were in general agreement with the soils encountered in the borings, with theexception of some deeper granular layers that were encountered in some of the CPT soundings butnot in boring B-1 which extended to a depth of 51½ feet BSG. The CPT soundings generallyencountered soil behavior types described as silty clay to clay and clayey silt to silty clay extendingto the maximum depth explored. However, granular soil behavior types described as sands, or sandto silty sand, or silty sand to sandy silt were encountered in the upper 1 to 3 feet BSG. In addition,some of the CPT soundings encountered granular soil behavior types described as sands, or sand tosilty sand, or silty sand to sandy silt beginning at about 30 feet BSG and extending to depths of about35 to 40 feet BSG. Some of the CPT soundings also encountered granular layers described as sands,or sand to silty sand, or silty sand to sandy silt of varying thicknesses between the depths of 40 and50 feet BSG.


The foregoing is a general summary of the soil conditions encountered in the test borings drilled forthis investigation. Detailed descriptions of the soils encountered at each test boring location arepresented in the logs of borings in Appendix B. The stratification lines in the logs represent theapproximate boundary soil types; the actual in-situ transition may be gradual.

5.6 Soil Engineering Properties: The following is a description of the soil engineeringproperties as determined from our field exploration and laboratory testing.

Silty Sand Fill Soils: The silty sand fill soils encountered were described as medium dense, asdetermined by a standard penetration resistance (SPT) equivalent N-value (estimated by driving aCalifornia Modified split barrel sampler) of 20 blows per foot. The moisture content of a sampletested was about 10 percent. One (1) relatively undisturbed sample revealed a dry density of 108.5pounds per cubic foot. A sieve analysis conducted on a sample collected from depths of ½ foot to2¾ feet BSG from boring B-1 indicated 12.7 percent gravel, 56.2 percent sand and 31.1 percent fines(silt and clay). An Atterberg Limits test conducted on the same sample from boring B-1 indicateda liquid limit of 19 and a plasticity index of 3.

Lean Clay, Lean Clay with Sand and Sandy Lean Clay Fill Soils: The lean clay, lean clay withsand and sandy lean clay fill soils encountered were described as stiff to very stiff, as determinedby SPT, N-values, ranging from 11 to 23 blows per foot, and an SPT equivalent N-value (estimatedby driving a California Modified split barrel sampler) of 16 blows per foot. The moisture contentof the samples tested ranged from about 8 to 22 percent. One (1) relatively undisturbed samplerevealed a dry density of 113.6 pounds per cubic foot. A sieve analysis conducted on a near surfacesandy lean clay fill sample collected from depths of 1 to 3½ feet BSG from boring B-2 indicated 35.5percent sand and 64.5 percent fines (silt and clay). An Atterberg Limits test conducted on the samesample from boring B-2 indicated a liquid limit of 41 and a plasticity index of 22.

Native Lean Clays, Lean Clays with Sand, and Sandy Lean Clays: The native lean clays, leanclays with sand, and sandy lean clays encountered were described as soft to very stiff, as indicatedby SPT, N-values, ranging from 2 to 14 blows per foot. The moisture content of the samples testedranged from about 12 to 28 percent. Four (4) relatively undisturbed samples revealed dry densitiesof 116.9,108.0, 109.4 and 104.1 pounds per cubic foot. A sieve analysis conducted on a bulk samplecontaining lean clay fill and native soils collected from depths of about 2¾ to 4 feet BSG fromboring B-1 indicated 46.2 percent sand and 53.8 percent fines (silt and clay). An Atterberg Limitstest conducted on the same sample from boring B-1 indicated a liquid limit of 28 and a plasticityindex of 13. An Atterberg Limits test was also conducted on combined SPT and Modified Californiasamples collected at depths of 2¾ to 5 feet BSG and indicated a liquid limit of 29 and a plasticityindex of 14. A direct shear test conducted on a native lean clay sample collected from depths ofabout 5 to 6½ feet BSG from boring B-1 indicated an internal angle of friction of 38 degrees and 400pounds per square foot of cohesion. A sieve analysis conducted on a native lean clay samplecollected from depths of about 15 to 16½ feet BSG from boring B-1 indicated 39.5 percent sand and60.5 percent fines (silt and clay). An Atterberg Limits test conducted on the same sample fromboring B-1 indicated a liquid limit of 33 and a plasticity index of 16. A sieve analysis conducted on


a native lean clay sample collected from depths of about 5 to 6½ feet BSG from boring B-3 indicated30.1 percent sand and 69.9 percent fines (silt and clay). An Atterberg Limits test conducted on thesame sample from boring B-3 indicated a liquid limit of 35 and a plasticity index of 18.

Native Silty Sands: The native silty sands encountered were described as very loose to loose asindicated by SPT, N-values, ranging from 3 to 4 blows per foot, and an SPT equivalent N-value(estimated by driving a California Modified split barrel sampler) of 5 blows per foot. The moisturecontent of the samples tested directly above groundwater were very moist and ranged from about 19to 20 percent. One (1) relatively undisturbed sample collected at depths of 8½ to 10 feet BSG fromboring B-4 (containing lean clay soils in the upper ring of the ring sample and silty sand soils in thelower five rings of the ring sample) revealed a dry density of 98.4 pounds per cubic foot but wasconsidered to be disturbed. A sieve analysis conducted on a silty sand sample collected from depthsof 11 to 11½ feet BSG from boring B-1 indicated 71.5 percent sand and 28.5 percent fines (silt andclay).

Native Poorly Graded Sands with Silt and Gravel: The native poorly graded sands with silt andgravel, encountered only in boring B-2 from depths of 7 to 10¾ feet BSG, was described as mediumdense, as indicated by an equivalent N-value (estimated by driving a California Modified split barrelsampler) of 20 blows per foot. The moisture content of the samples tested ranged from about 4 to5 percent. One (1) relatively undisturbed sample collected at depths of 7 to 8½ feet BSG fromboring B-2 revealed a dry density of 114.8 pounds per cubic foot. A sieve analysis conducted on asample collected from depths of 7 to 8½ feet BSG form boring B-2 indicated 36.5 percent gravel,55.2 percent sand and 8.3 percent fines (silt and clay).

Native Fat Clays: The native fat clays encountered were described as soft to stiff, as indicated bySPT, N-values, ranging from 3 to 11 blows per foot. The moisture content of the samples testedranged from 23 to 34 percent.

Native Clayey Sands: The native clayey sands encountered were described as medium dense, asindicated by an SPT, N-value, of 14 blows per foot. The moisture content of a sample tested wasabout 13 percent.

Consolidation Tests: A consolidation test conducted on a lean clay sample collected from depthsof about 2 to 3½ feet BSG from boring B-1 (queried as fill) indicated high compressibilitycharacteristics (about 9.9 percent consolidation under a load of 16 kips per square foot). Aconsolidation test conducted on a native lean clay sample collected from depths of about 3½ to 5 feetBSG from boring B-2 indicated moderate compressibility characteristics (about 7.9 percentconsolidation under a load of 16 kips per square foot). A consolidation test conducted on a nativesandy lean clay sample collected from depths of about 5 to 6½ feet BSG from boring B-3 indicatedmoderate compressibility characteristics (about 7.9 percent consolidation under a load of 16 kips persquare foot). A consolidation test conducted on a native lean clay sample with high silt contentcollected from depths of about 8½ to 10 feet BSG from boring B-4 indicated moderatecompressibility characteristics (about 6.8 percent consolidation under a load of 16 kips per squarefoot).


Expansion Index Tests: An expansion index test conducted on a sandy lean clay bulk samplecollected from depths of 2¾ to 4 feet BSG from boring B-1 indicated an expansion index of 30. Anexpansion index test conducted on a lean to fat clay bulk sample collected from depths of about 1to 3 ½ feet BSG from boring B-2 indicated an expansion index test of 33.

R-value Tests: The results of two (2) R-value tests conducted on near surface samples collectedfrom borings B-2 and B-3 indicated R-values of 12 and 15.

Chemical Tests: The results of chemical tests performed on two (2) near surface soil samplesindicated pH values of 8.8 and 9.7, minimum resistivity values of 5,803 and 2,468 ohm-centimeter;0.0039 and 0.0041 percent by weight concentrations of soluble sulfates; and 0.0011 and less than0.00060 percent by weight concentrations of chloride.

5.7 Groundwater Conditions: Groundwater was encountered in all of the test boringsdrilled during our field investigation at depths ranging from about 10 to 13 feet BSG. The boringscould not be left open to check for stabilized groundwater levels since the borings had to be groutedas soon as the borings were completed per the boring requirements of Alameda CountyPublic WorksAgency. The CPT soundings encountered groundwater at depths ranging from about 9 to 11 feetBSG.

Based on the Seismic Hazard Zone Report for the Hayward 7.5-Minute Quadrangle, AlamedaCounties, California, dated 2003, prepared by the California Geological Survey, plate 1.2 indicatesa historic high groundwater depth of 10 feet at the subject site. However, groundwater has beenreported at shallower levels at the subject site. The California State Water Resources Control BoardGeotracker website also included several groundwater monitoring reports for the subject site issuedbetween the years 2011 through 2017. The latest report entitled, “Vapor Intrusion Investigation andAnnual Monitoring Report, Former White Cap Facility, 24493 Clawiter Road, Hayward, California,”dated November 2017, prepared by Golder Associates, included groundwater depth data fromvarious monitoring wells between the years 2009 and 2017. The data indicates that the depth togroundwater at the site between 2009 and 2017 has generally ranged from about 7.3 feet to about15.24 feet below site grades (BSG).

Based on our test boring data and review of the referenced Geotracker groundwater data, a highgroundwater elevation of 7.3 feet AMSL was used for liquefaction and seismic settlement analyses.

It should be recognized, however, that groundwater elevations fluctuate with time, since they aredependent upon seasonal precipitation, irrigation, land use, and climatic conditions as well as otherfactors. Therefore, water level observations at the time of the field investigation may vary fromthose encountered both during the construction phase and the design life of the project. Theevaluation of such factors was beyond the scope of this investigation and report.


6.0 EVALUATION

The data and methodology used to develop conclusions and recommendations for project design andpreparation of construction specifications are summarized in the following subsections. Theevaluation was based upon the subsurface soil conditions determined from this investigation and ourunderstanding of the proposed construction.

The conclusions obtained from the results of our evaluations are described in the Conclusions sectionof this report.

6.1 Existing Surface and Subsurface Conditions: At the time of our fieldinvestigation, on January 8 and 11, 2020, the site was developed and included two warehousebuildings, one smaller building, asphalt concrete and Portland cement concrete pavements, unpavedareas covered by aggregate base, concrete walkways and a landscaped area that included a grasslawn, bushes and trees. Two soil stockpiles in the northwestern portion of the site included a smallstockpile of soil and gravel and a larger stockpile of soil and gravel. A pile of wood was also notedadjacent to the soil stockpiles in the northwestern portion of the site.

As part of the site preparation, existing improvements encountered, including the existing buildingsand canopies, foundations, floor slabs, paving, underground utilities and associated backfill, etc. willneed to be removed. During removal of underground utilities and subsurface structures, the backfillsoils should also be removed. Care should be taken to over-excavate all soils which are disturbedfrom the demolition activities prior to backfilling the excavations with engineered fill. Allexcavations should be backfilled with engineered fill in accordance with the recommendations ofthis report, under the observation and testing of Moore Twining.

Trees, bushes, organics, etc. should be removed from the site as part of stripping. The general depthof stripping should be sufficiently deep to remove the root systems and organic topsoils. Thesematerials will not be suitable for use as engineered fill; however, stripped topsoil may be stockpiledand reused in landscape areas at the discretion of the owner.

6.2 Undocumented Fill and Buried Obstructions: Undocumented fill soils wereencountered in all of the borings to depths of about 2¾ to about 4½ feet BSG, with exception thatboring B-2 encountered suspected fill soils extending to a depth of about 11 feet BSG. The fill soilsencountered were variable. All undocumented fill soils encountered during site preparation shouldbe removed and placed back as engineered fill.

The fill soils encountered in boring B-1 included of 6 inches of aggregate base that was cementtreated as it reacted to the application of phenolphthalein. The cement treated aggregate base wasalso encountered in the areas of CPT-4 and CPT-5 in the western portion of the site. These areaswhere cement treated base is present are anticipated to require more effort and cost to remove anddispose of the materials.


As indicated in the Background Information section of this report, the referenced “Phase IEnvironmental Site Assessment, 24493 Clawiter Road, Hayward, California 94545,” prepared byPartner Engineering and Science, Inc. (Partner), dated August 24, 2012, indicated numerousunderground storage tanks (USTs) previously existed at the site which have been removed. Thus,undocumented fill soils are anticipated in the areas of the former tanks. The areas of the former drysump and USTs are shown on Drawing No. 2 in Appendix A of this report based on our review ofFigure 2 from a report review on the California State Water Resources Control Board Geotrackerwebsite entitled, “Letter Report, Operation Summaryfor the Soil Vapor Extraction System CoveringPeriod: System Startup through 19 July 1997, Former White Cap Facility, 24493 Clawiter Road,Hayward, CA,” dated October 1, 1997, prepared by Streamborn. Undocumented fill soils used tobackfill the removed dry sump and USTs will need to be removed and replaced as engineered fillas part of the site preparation.

It should be noted that an area north of the proposed building was marked by others as containinga buried concrete slab below the ground surface. The approximate area with the buried concrete slabis shown on Drawing No. 2 in Appendix A. In addition, Cone Penetration Test CPT-7 on the easternside of the larger-size building appeared to encounter a buried obstruction such as a concrete slab.Four attempts in close-by areas were made to advance CPT-7, and all of the attempts encounteredrefusal due to an apparent obstruction at depths ranging from about 2½ to nearly 4 feet BSG. Inaddition to the obstructions noted, due to the history of development on the property, other buriedobstructions should be anticipated that will require removal as part of the site preparation. Inaddition, existing foundations, subsurface structures, and underground features such as utilitiesshould be removed as part of the site preparation.

6.3 Shallow Groundwater and Stabilization of Wet Soils: Near surface soils with highmoisture contents were encountered nearer to the groundwater, generally below a depth of about 8feet BSG. Thus, soil excavated near to groundwater (such as may be required for pad over-excavation and/or utility installations) should be anticipated to be overly moist and will requiredrying prior to being used as engineered fill. Also, it should be anticipated that the bottom of deeperexcavations will require stabilization prior to placement of engineered fill. Where wet, unstable soilconditions are experienced, methods such as aeration, mixing wet soils with drier soils, chemical(i.e., lime and/or cement) treatment of the soil, or over-excavation of an additional depth of 12 inchesand placement of a bridge lift of aggregate base and a geotextile stabilization fabric such as Mirafi600X, may be required to achieve a stable soil condition. Due to the climate in the site area, dryingusing only aeration may not be effective and special stabilization measures may likely be required.

6.4 Expansive Soils: One of the potential geotechnical hazards evaluated at this site isthe expansion potential of the near surface soils. Over time, expansive soils will experience cyclicdrying and wetting as the dry and wet seasons pass. Expansive soils experience volumetric changes(shrink/swell) as the moisture content of the clayey soils fluctuate. These shrink/swell cycles canimpact foundations and lightly loaded slabs-on-grade when not designed for the anticipatedexpansive soil pressures. Expansive soils cause more damage to structures, particularly light


buildings and pavements, than anyother natural hazard, including earthquakes and floods (Jones andHoltz, 1973). Expansion potential may not manifest itself until months or years after construction.The potential for damage to slabs-on-grade and foundations supported on expansive soils can bereduced by placing non-expansive fill underlying foundations and slabs-on-grade.

In evaluation of the potential for expansive soils at the site, expansion index testing was performedon representative samples of the near surface soils which are anticipated to be within the zone ofinfluence of the planned improvements. The expansion index (EI) testing was performed inaccordance with ASTM D4829 and is summarized in Appendix C of this report. Expansive soilswere encountered during the investigation. The result of two (2) expansion index tests conductedon the near surface sandy lean clay soil samples indicated expansion indices of 30 and 33. TheAtterberg Limits data from the near surface clayey soils tested from borings B-1, B-2 and B-3 in theupper 6½ feet BSG indicated low to medium plasticity based on plasticity indices of 13, 14, 18 and22. Due to the presence of expansive soils, concrete slabs on grade are recommended to be underlainby imported, non-expansive fills.

6.5 Static Settlement and Bearing Capacity of Shallow Foundations: The potentialfor excessive total and differential static settlement of foundations and slabs-on-grade is ageotechnical concern that was evaluated for this project. The increases in effective stress tounderlying soils which can occur from new foundations and structures, placement of fill, withdrawalof groundwater, etc. can cause vertical deformation of the soils, which can result in damage to theoverlying structure and improvements. The differential component of the settlement is often themost damaging. In addition, the allowable bearing pressures of the soils supporting the foundationswere evaluated for shear and punching type failure of the soils resulting from the imposed foundationloads.

The net allowable soil bearing pressure is the additional contact pressure at the base of thefoundations caused by the structure. The weight of the soil backfill and weight of the footing maybe neglected. A net allowable soil bearing pressure of 2,000 pounds per square foot for dead-plus-live loads was selected using the Terzaghi bearing capacity equations for spread foundationsconsidering a minimum factor of safety of 3.0 and based on the anticipated static settlements notedin this report. On a preliminary basis, to reduce the estimated static settlements to 1 inch total and½ inch differential in 40 feet, the on-site soils should be over-excavated to support the foundationson a minimum of 2 feet of engineered fill.

6.6 Seismic Ground Rupture and Design Parameters: The site is not located in anAlquist-Priolo Earthquake Fault Zone. The nearest active fault with surface rupture is the Haywardfault, which is located about 3.2 miles northeast of the site. Therefore, the potential for fault ruptureat the site is considered low.

It is our understanding that the 2019 CBC will be used for structural design, and that seismic sitecoefficients are needed for design.


Based on the 2019 CBC, a Site Class E represents the on-site soil conditions with the average ofstandard penetration resistance, N-values, in the upper 100 feet below site grade being less than 15blows per foot.

A table providing the recommended seismic coefficient and earthquake spectral responseacceleration values for the project site is included in the Conclusions and Recommendations sectionof this report. A Maximum Considered Earthquake (geometric mean) peak ground accelerationadjusted for site effects (PGAM) of 0.818g was determined for the site using the Ground MotionParameter Calculator provided by SEOAC and OSHPD (http://seismicmaps.org). A MaximumConsidered Earthquake magnitude of 6.9 was applied in the analysis based on deaggregation analysis(United States Geological Survey deaggregation website, Dynamic Conterminous U.S. 2014,V4.2.0).

6.7 Liquefaction and Seismic Settlement: Liquefaction and seismic settlement areconditions that can occur under seismic shaking from earthquake events. Liquefaction describes aphenomenon in which a saturated, cohesionless soil loses strength during an earthquake as a resultof induced shearing strains. Lateral and vertical movements of the soil mass, combined with lossof bearing can result in the event of liquefaction. Fine, well sorted, loose sand, shallow groundwaterconditions, higher intensity earthquakes, and particularly long duration of ground shaking are therequisite conditions for liquefaction.

Based on our review of the Earthquake Zones of Required Investigation, Hayward Quadrangle,prepared by the California Geological Survey, dated September 21, 2012, the area is mapped in aliquefaction hazard zone. The For the purpose of the liquefaction and seismic settlement analyses,an historic high groundwater depth of 7.3 feet BSG was used (see Section 5.5 of this report).

Liquefaction and seismic settlement analyses were conducted based on soil properties revealed bythe cone penetration test (CPT) soundings using the computer program LiquefyPro, developed byCivilTech Software. A Maximum Considered Earthquake (geometric mean) peak groundacceleration adjusted for site effects (PGAM) of 0.818g was determined for the site using the GroundMotion Parameter Calculator provided by SEOAC and OSHPD (http://seismicmaps.org). AMaximum Considered Earthquake magnitude of 6.9 was applied in the analysis based ondeaggregation analysis (United States Geological Survey deaggregation website, DynamicConterminous U.S. 2014, V4.2.0).

Soil parameters, such as wet unit weight, tip resistance, and sleeve friction were input from the CPTdata for the soil layers encountered throughout the depths explored.


The findings of the liquefaction analyses indicate that numerous layers of granular soils, withthicknesses ranging from less than a foot to about 7 feet thick, are susceptible to liquefaction as aresult of the Maximum Considered Earthquake. The results of the seismic settlement analysesindicate a total seismic settlements ranging from about ¼ to 1½ inches and a differential seismicsettlement of ¾ inches. The majority of the liquefiable zones typically occur below a depth of 28feet BSG. However, some of the CPTs encountered thin layers (typically less than 1 foot thick)which are susceptible to liquefaction within the upper about 12 feet BSG. Due to the limitedthickness of these layers and the fine-grained behavior indicated by the CPT data, the potentialimpacts of liquefaction of relatively shallow thin layers (if realized) are anticipated to be limited toseismic settlement.

6.8 Asphaltic Concrete (AC) Pavements: Recommendations for onsite asphalticconcrete pavement structural sections are presented in the "Recommendations" section of this report.The structural sections were designed using the gravel equivalent method in accordance with theCalifornia Department of Transportation Highways Design Manual. The analysis was based ontraffic index values ranging from 5.0 to 10.0. The appropriate paving section should be determinedby the project civil engineer or applicable design professional based on the actual vehicle loading(traffic index) values. If traffic loading is anticipated to be greater than assumed, the pavementsections should be re-evaluated.

It should be noted that if the pavements are constructed prior to the building construction, theadditional construction truck traffic should be considered in the selection of the traffic index value.If more frequent or heavier traffic is anticipated and higher Traffic Index values are needed, MooreTwining should be contacted to provide additional pavement section designs.

The results of the R-value testing conducted on the near surface soils indicated R-values of 12 and15. Based on the results of the testing and the procedures in the Caltrans Highway Design Manual,an R-value of 10 was used for the preliminary pavement design. Additional R-value testing shouldbe conducted during a design level geotechnical engineering investigation.

6.9 Portland Cement Concrete (PCC) Pavements: Recommendations for Portlandcement concrete (PCC) pavement structural sections are presented in the "Recommendations"section of this report. The PCC pavement sections are based upon the amount and type of trafficloads being considered and the strength of the subgrade soils which will support the pavement. Themeasure of the amount and type of traffic loads are based upon an index of equivalent axle loads(EAL) from the loading of heavy trucks called a traffic index (T.I).

The results of R-value testing performed in accordance with California Test Method 301 were usedto estimate the pavement subgrade modulus. The results of the R-value testing conducted on thenear surface soils indicated R-values of 12 and 15. Based on the results of the testing and reviewof the test boring logs, an R-value of 10 was used for preliminary design. Additional R-value testingshould be conducted during a design level geotechnical engineering investigation. The R-value testresults are summarized in Appendix C of this report.


A modulus of subgrade reaction, K-value, for the pavement section, of 200 psi/in was used for thepavement design, for pavement slabs placed directly12 inches of aggregate base. The aggregate baseis recommended to help reduce the potential for expansive soil movement.

The recommendations provided in this report for PCC pavements are based on traffic indices rangingbetween 5.0 and 10.0 and the design procedures contained in the Portland Cement Association"Thickness Design of Highway and Street Pavements.”

The PCC pavement sections were designed for a life of 20 years and a load safety factor of 1.1. Thesection thicknesses for a traffic index of 5.0 were evaluated for light vehicular loading and the othertraffic indexes were evaluated based on a truck loading consisting of a single axle weight of 12,000pounds and two tandem axles (36,000 pounds each).

6.10 Soil Corrosion: The risk of corrosion of construction materials relates to thepotential for soil-induced chemical reaction. Corrosion is a naturally occurring process whereby thesurface of a metallic structure is oxidized or reduced to a corrosion product such as iron oxide (i.e.,rust). The metallic surface is attacked through the migration of ions and loses its original strengthby the thinning of the member.

Soils make up a complex environment for potential metallic corrosion. The corrosion potential ofa soil depends on numerous factors including soil resistivity, texture, acidity, field moisture andchemical concentrations. In order to evaluate the potential for corrosion of metallic objects incontact with the onsite soils, chemical testing of soil samples was performed by Moore Twining aspart of this report. The test results are included in Appendix C of this report. Conclusions regardingthe corrosion potential of the soils tested are included in the Conclusions section of this report basedon the National Association of Corrosion Engineers (NACE) corrosion severity ratings listed inTable No. 1, below.

Table No. 1Soil Corrosion Potential Rating

Soil Resistivity (ohm-cm) Corrosion Potential Rating

>20,000 Essentially non-corrosive

10,000 - 20,000 Mildly corrosive

5,000 - 10,000 Moderately corrosive

3,000 - 5,000 Corrosive

1,000 - 3,000 Highly corrosive

<1,000 Extremely corrosive


The results of soil sample analyses indicate that the near-surface soils exhibit a “moderatelycorrosive” to “highly corrosive” corrosion potential to buried metal objects.

If the manufacturers or suppliers cannot determine if materials are compatible with the soil corrosionconditions, a professional consultant, i.e., a corrosion engineer, with experience in corrosionprotection should be consulted to provide design parameters. Moore Twining does not providecorrosion engineering services.

6.11 Sulfate Attack of Concrete: Degradation of concrete in contact with soils due tosulfate attack involves complex physical and chemical processes. When sulfate attack occurs, theseprocesses can reduce the durability of concrete by altering the chemical and microstructural natureof the cement paste. Sulfate attack is dependent on a variety of conditions including concretequality, exposure to sulfates in soil/groundwater and environmental factors. The standard practicefor geotechnical engineers in evaluation of the soils anticipated to be in contact with concrete is toperform testing to determine the sulfates present in the soils. The test results are then compared withthe provisions of ACI 318, section 4.3 to provide guidelines for concrete exposed to sulfate-containing solutions. Common methods used to resist the potential for degradation of concrete dueto sulfate attack from soils include, but are not limited to the use of sulfate-resisting cements, air-entrainment and reduced water to cement ratios.

The soil corrosion data should be provided to the manufacturers or suppliers of materials that willbe in contact with soils (pipes or ferrous metal objects, etc.) to provide assistance in selecting theprotection and materials for the proposed products or materials. If the manufacturers or supplierscannot determine if materials are compatible with the soil corrosion conditions, a professionalconsultant, i.e., a corrosion engineer, with experience in corrosion protection should be consultedto provide design parameters.

7.0 CONCLUSIONS AND PRELIMINARY RECOMMENDATIONS

Based on the data collected during the field and laboratory investigations, our geotechnicalexperience in the vicinity of the project site, and our understanding of the anticipated construction,the following conclusions and preliminary recommendations are presented. A future design levelgeotechnical investigation will need to be conducted to supplement the findings from thispreliminary geotechnical engineering investigation.

7.1 The site is considered suitable for the proposed construction with regard to supportof the proposed warehouse building, provided the recommendations contained in thispreliminary report and the future design level geotechnical engineering investigationreport are followed. It should be noted that the recommended design consultationand observation of clearing, and earthwork activities by Moore Twining are integralto this conclusion.


7.2 The borings all encountered fill soils that extended to depths of about 2¾ to about 4½feet BSG, with exception that boring B-2 encountered suspected fill soils extendingto a depth of about 11 feet BSG. The fill soils encountered were variable. The fillsoils encountered in boring B-1 included of 6 inches of aggregate base that wascement treated as it reacted to the application of phenolphthalein. The cement treatedaggregate base was also suspected to be encountered in the areas of CPT-4 and CPT-5 in the western portion of the site as the aggregate base had to be cored with a coringmachine before the CPT could be advanced. The cement treated aggregate baseencountered in boring B-1 was underlain by silty sand fill soils with some graveloverlying queried fill soils consisting of lean clay with gravel that extended to a totaldepth of about 3½ feet BSG. Below the Portland cement concrete pavement, boringB-2 encountered sandy lean clay fill soils that had intermixed dark gray and olivecolors and extended to a depth of about 4¼ feet BSG. Below a depth of 4¼ feet BSGin boring B-2, layers of lean clay, poorly graded sand with silt and gravel, and siltysand were suspected to be fill extending to a depth of 11 feet BSG. The fill soilsencountered in boring B-3 consisted of 12 inches of aggregate base overlying leanclay with sand fill soils with wood debris and gravel and extended to a depth of about3½ feet BSG. The fill soils encountered in boring B-4 consisted of 6 inches ofaggregate base over lean clay with sand fill soils with brick debris and graveloverlying queried fill soils consisting of a thin layer of silty sand soils; and the fillsoils at this boring location extended to a total depth of about 4½ feet BSG. As partof the site preparation, undocumented fill soils are recommended to be excavated andre-compacted as engineered fill to reduce the potential for excessive settlement.

The native soils encountered in the borings consisted of interbedded layers of leanclays or lean clays with sand or sandy lean clays, silty sands, silty gravel with sand,and clayey sands that extended to depths ranging from about 11 to 15 feet BSG.These layers were underlain by lean clays or fat clays with varying amounts of sandthat extended to the maximum depth explored, about 51½ feet BSG.

7.3 Undocumented fill soils were encountered in all of the borings and extended todepths of about 2¾ to about 4½ feet BSG, with exception that boring B-2encountered suspected fill soils extending to a depth of about 11 feet BSG. The fillsoils encountered were variable. All undocumented fill soils encountered during sitepreparation should be removed and placed back as engineered fill. In addition to thefill soils encountered in the borings, Contractors should anticipate that undocumentedfill soils also exist in areas where Underground Storage Tanks were reportedlyremoved from the site in the early 1990s. The referenced Phase I report provided bythe client indicated a sump structure and six underground tanks ranging in size from500 gallons to 6,000 gallons were previously removed and the excavations backfilled.Thus, as part of site preparation, a careful search should be conducted to expose thefill soils and remove and compact them as engineered fill to reduce the potential forexcessive settlement. The areas of the former dry sump and USTs are shown on


Drawing No. 2 in Appendix A of this report based on our review of Figure 2 from areport review on the California State Water Resources Control Board Geotrackerwebsite entitled, “Letter Report, Operation Summary for the Soil Vapor ExtractionSystem Covering Period: System Startup through 19 July 1997, Former White CapFacility, 24493 Clawiter Road, Hayward, CA,” dated October 1, 1997, prepared byStreamborn.

7.4 The near surface clayey soils tested exhibited low expansion potential and low tomoderate plasticity characteristics. Due to the expansion characteristics, on apreliminary basis, it is recommended concrete slabs on grade be underlain by aminimum of 18 inches of imported, non-expansive fill, over subgrade soils preparedas part of the building pad preparation as recommended herein. It may be possibleto chemically treat the onsite soils for use as the non-expansive fill material;however, this use would need to be evaluated as part of the future design levelgeotechnical investigation. On a preliminary basis, considering the imported, non-expansive fill is placed below the slab on grade, a modulus of subgrade reaction of100 pounds per cubic inch may be used for slab design. This value is based on a 1foot square plate and should be adjusted for design of aerial static loading to the slabbased on the size effects of the loaded area(s).

7.5 Groundwater was encountered in all of the test borings drilled during our fieldinvestigation at depths ranging from about 10 to 13 feet BSG. The borings could notbe left open to check for stabilized groundwater levels since the borings had to betremie grouted as soon as the borings were completed per the boring requirements ofAlameda County Public Works Agency. The CPT soundings encounteredgroundwater at depths ranging from about 9 to 11 feet BSG. However, groundwaterhas been reported at shallower levels at the subject site. The California State WaterResources Control Board Geotracker website also included several groundwatermonitoring reports for the subject site issued between the years 2011 through 2017.The latest report entitled, “Vapor Intrusion Investigation and Annual MonitoringReport, Former White Cap Facility, 24493 Clawiter Road, Hayward, California,”dated November 2017, prepared by Golder Associates, included groundwater depthdata from various monitoring wells between the years 2009 and 2017. The dataindicates that the depth to groundwater at the site between 2009 and 2017 hasgenerally ranged from about 7.3 feet to about 15.24 feet below site grades (BSG).

7.6 It should be noted that an area north of the proposed building was marked by othersas containing a buried concrete slab below the ground surface. The approximate areawith the buried concrete slab is shown on Drawing No. 2 in Appendix A. Due to thehistoryof development on the property, buried obstructions should be anticipated thatwill require removal as part of the site preparation. In addition, existing foundationsand underground features such as utilities should be removed and all backfill placedas engineered fill. It should also be noted that areas in the western portion of the site


included cement treated base where boring B-1 was drilled and CPT soundings CPT-4 and CPT-5 were advanced. These areas where cement treated base is present areanticipated to require more effort and cost to remove and dispose.

7.7 The subject site is located in a liquefaction hazard zone. Based on the analysisconducted as part of this preliminary report, some of the granular soils encounteredare susceptible to liquefaction under the design earthquake event. The results of theseismic settlement analyses indicate total seismic settlements ranging from about ¼to 1½ inches and a differential seismic settlement of ¾ inches over 40 feet.

7.8 Soils with high moisture contents were encountered directly above the groundwaterwhich was generally encountered in the borings and CPTs between the depths ofabout 9 and 12 feet. Contractors should anticipate that soil excavated within a fewfeet above the groundwater table (such as may be required for pad over-excavationand/or utility installations) will be overly moist and will require aerating prior tobeing used as engineered fill. Also, it should be anticipated that the base ofexcavations to these depths will require stabilization prior to placement of engineeredfill. Where wet, unstable soil conditions are experienced, methods such as aeration,mixing wet soils with drier soils, chemical (i.e., lime and/or cement) treatment of thesoil, or over-excavation of an additional depth of 12 inches and placement of a bridgelift of aggregate base and a geotextile stabilization fabric such as Mirafi 600X, maybe required to achieve a stable soil condition. The actual method employed tostabilize the bottom of the excavation or pavement subgrade should be selected at thetime of construction. Due to the climate in the site area, drying using only aerationmay not be effective and special stabilization measures may likely be required.

7.9 On a preliminary basis, after site stripping and removal of existing surface andsubsurface improvements, the on-site soils should be over-excavated within theproposed building area and below all foundations to a depth of at least 2 feet belowthe bottom of the proposed foundations, to the depth required to remove all fill soils(encountered as extending to depths ranging from 2¾ to about 4½ feet BSG, with theexception of boring B-2 where fill was queried to a depth of 11 feet BSG), and to atleast 1 foot below subsurface structures to be removed (note that the foundation plansfor an addition to one of the existing warehouse buildings indicated the deepestfootings may extend to 7 feet below top of slab), whichever is greater. The zone ofover-excavation should extend laterally a minimum of 5 feet beyond the edges of theperimeter foundations and concrete walks adjacent to the building, or to a horizontaldistance equal to the depth of fill below the foundations, whichever is greater. Thebottom of the over-excavation should be scarified to a depth of 8 inches, moistureconditioned to between one (1) and four (4) percent above optimum moisture contentand compacted as engineered fill, or stabilized by placement of a bridge lift ofgeotextile fabric and rock, or lime/cement treatment.


7.10 Provided the site preparation recommended in this report and the future design levelinvestigation is followed, a preliminary maximum net allowable soil bearing pressureof 2,000 pounds per square foot for dead-plus-live loads. These values may beincreased by one-third for short duration wind or seismic loads. On a preliminarybasis, perimeter foundations should have a minimum depth of 18 inches below thebottom of the slab-on-grade and 18 inches below the lowest finished adjacent grade.On a preliminary basis, interior foundations should have a minimum depth of 18inches below the bottom of the slab-on-grade. On a preliminary basis, all footingsshould have a minimum width of 18 inches, regardless of load. The foundationsshould be designed and reinforced for the anticipated settlements and heave. Astructural engineer experienced in foundation design should recommend thethickness, design details and concrete specifications for the foundations and slabs ongrade based on: 1) a total static settlement of 1 inch, 2) a differential static settlementof ½ inch in 40 linear feet, 3) a total seismic settlement of 1½ inches, and 4) adifferential seismic settlement of ¾ inches in 40 lineal feet.

7.11 Based on the data obtained from this geotechnical investigation, a Site Class Erepresents the on-site soil conditions with the average of standard penetrationresistance, N-values, in the upper 100 feet below site grade being less than 15 blowsper foot.

The following seismic factors were developed for the site using the Ground MotionParameter Calculator provided by SEOAC and OSHPD (http://seismicmaps.org),based upon a site latitude of 37.6417 degrees and a site longitude of -122.1217degrees. The data provided in Table No. 3 are based upon the procedures of Sections1613.2.1 through 1613.2.4 of the 2019 California Building Code, ASCE 7-16. Thedata in Table No. 3 were not determined based upon a ground motion hazardanalysis. The structural engineer should review the values in Table No. 2 anddetermine whether a ground motion hazard analysis is required for the projectconsidering the seismic design category, structural details, and requirements of ASCE7-16 (Section 11.4.8 and other applicable sections). If required, Moore Twiningshould be notified and requested to conduct the additional analysis, develop updatedseismic factors for the project, and update the following values.


Table No. 2Seismic Factors

Seismic Factor 2019 CBC Value

Site Class E

Maximum Considered Earthquake (geometricmean) peak ground acceleration adjusted for

site effects (PGAM)0.818

Mapped Maximum Considered Earthquake(geometric mean) peak ground acceleration,

ASCE 7-16 (PGA)0.744

Spectral Response At Short Period (0.2Second), Ss

1.769

Spectral Response At 1-Second Period, S1 0.672

Site Coefficient (based on Spectral ResponseAt Short Period), Fa

See Note

Site Coefficient (based on spectral response at1-second period) Fv

See Note

Maximum considered earthquake spectralresponse acceleration for short period, SMS

See Note

Maximum considered earthquake spectralresponse acceleration at 1 second, SM1

See Note

Five percent damped design spectral responseaccelerations for short period, SDS

1.415

Five percent damped design spectral responseaccelerations at 1-second period, SD1

See Note

Note: Requires ground motion hazard analysis per ASCE Section 21.2 (ASCE 7-16, Section11.4.8), unless the structural engineer determines that an Exception of Section 11.4.8 ofASCE 7-16 is applicable for the project design.

7.12 The following asphalt concrete pavement sections are based on an preliminary designR-value of 10, and traffic index values ranging from 5.0 to 10.0. Additional R-valuetesting should be conducted during a design level geotechnical engineeringinvestigation. It should be noted that if pavements are constructed prior to thebuilding construction, the traffic index value should account for construction traffic.


The actual traffic index values applicable to the site should be determined by theproject civil engineer. Preparation of the subgrade soils in pavement areas shouldinclude removal of existing surface and subsurface improvements, over-excavationto remove undocumented fill, followed by scarification and compaction of theunderlying soils prior to placement of fill. The upper 12 inches of the subgrade soilsshould be compacted to a minimum of 95 percent of the maximum dry densitydetermined in accordance with ASTM D1557.

Table No. 3Asphaltic Concrete Pavements

TrafficIndex

ACthickness,

inches

ABthickness,

inches

CompactedSubgrade,

inches

5.0 2.5 10.0 12

5.5 3.0 10.5 12

6.0 3.0 12.5 12

6.5 3.5 13.5 12

7.0 4.0 14.0 12

7.5 4.0 16.0 12

8.0 4.5 17.0 12

8.5 5.0 18.0 12

9.0 5.5 19.0 12

9.5 5.5 20.5 12

10.0 6.0 21.5 12

AC - The asphaltic concrete, including the joint density, should be compactedto an average relative compaction of 93 percent, with no single test valuebeing below a relative compaction of 91 percent and no single test valuebeing above a relative compaction of 97 percent of the referencedlaboratory density according to ASTM D2041.

AB - Class 2 aggregate base, CAB, or CMB compacted to at least 95 percentrelative compaction (ASTM D1557)

7.13 The following Portland cement concrete pavement sections are based on anpreliminary design R-value of 10, and traffic index values ranging from 5.0 to 10.0.Additional R-value testing should be conducted during a design level geotechnicalengineering investigation. The following PCC pavement section thicknesses were


prepared based on a preliminary design k-value of 200 psi/in for pavement slabsplaced directly12 inches of aggregate base and a range of average daily truck trafficfrom about 2 to 142 trucks per pad. The design thicknesses were prepared based onthe procedures outlined in the Portland Cement Association (PCA) document,“Thickness Design for Concrete Highway and Street Pavements,” assuming thefollowing: 1) minimum modulus of rupture of 550 psi for the concrete, 2) loadtransfer by aggregate interlock or dowels, 3) a concrete shoulder, 4) a load safetyfactor of 1.1, 5) vehicular loading only for a traffic index of 5.0 and 6) truck loadingconsisting of 1 single axle load of 12 kips and two tandem axle loads of 36 kips eachfor traffic indexes of 6.0 and higher. Preparation of the subgrade soils in pavementareas should include removal of existing surface and subsurface improvements, over-excavation to remove undocumented fill, followed by scarification and compactionof the underlying soils prior to placement of fill. The upper 12 inches of the subgradesoils should be compacted to a minimum of 95 percent of the maximum dry densitydetermined in accordance with ASTM D1557.

Table No. 4Portland Cement Concrete Pavement Sections

Traffic Index ADTT(Trucks/day)

PCCThickness(inches)

AggregateBase

Thickness(inches)

Compacted Subgrade(inches)

5.0 N/A1 4.0 12.0 12.0

6.0 1.9 5.5 12.0 12.0

7.0 7 6.0 12.0 12.0

8.0 21 6.5 12.0 12.0

9.0 58 7.0 12.0 12.0

10.0 142 7.5 12.0 12.01 - Passenger Vehicular Loading

7.14 The near surface soils encountered are generally clayey soils with a high waterholding capacity and low permeability. In addition, shallow groundwater occurs atthis site. Thus, it is not recommended to use stormwater infiltration systems at thesubject site.


7.15 Buried metal objects should be protected in accordance with the manufacturer'srecommendations based on a “moderately corrosive” to “highly corrosive” corrosionpotential (soil resistivity values of 5,803 and 2,468 ohm-cm). The evaluation waslimited to the effects of soils to metal objects; corrosion due to other potentialsources, such as stray currents and groundwater, was not evaluated. If piping orconcrete are placed in contact with deeper soils or engineered fill, these soils shouldbe analyzed to evaluate the corrosion potential of these soils.

7.16 Corrosion of concrete due to sulfate attack is “negligible” as indicated by 0.0039 and0.0041 percent by weight concentrations of soluble sulfates. According to theCalifornia Building Code, the concentration of sulfates falls in the negligibleclassification (0.00 to 0.10 percent by weight) for concrete. Therefore, restrictionsare not required regarding the type, water-to-cement ratio, or strength of the concreteused for foundation and slabs due to the sulfate content. However, a low water tocement ratio of 0.52 lb./lb. or less in the concrete for slabs-on-grade is recommendedto reduce the potential for shrinkage cracking and curling of slabs.

7.17 The site is not located in an Alquist-Priolo special studies zone. The nearest activefault with surface rupture is the Hayward fault, which is located about 3.2 milesnortheast of the site. Therefore, the potential for fault rupture at the site is consideredlow.

8.0 DESIGN CONSULTATION

8.1 This report presents the results of a preliminary geotechnical engineeringinvestigation. A future design level geotechnical investigation will need to beconducted to supplement the findings from this preliminary geotechnical engineeringinvestigation. Moore Twining should be retained to review those portions of thecontract drawings and specifications that pertain to earthwork operations andfoundations prior to finalization to determine whether they are consistent with ourrecommendations. This service is not part of this current contractual agreement.

8.2 It is the client's responsibility to provide plans and specification documents for ourreview prior to their issuance for construction bidding purposes.

8.3 If Moore Twining is not retained for the plan review, we assume no liability for themisinterpretation of our conclusions and recommendations. This review isdocumented by a formal plan/specification review report provided by MooreTwining.

9.0 CONSTRUCTION MONITORING

9.1 It is recommended that Moore Twining be retained to observe the excavation,earthwork, and foundation phases of work to determine that the subsurface conditionsare compatible with those used in the analysis and design.


9.2 Moore Twining can conduct the necessary observation and field testing to provideresults so that action necessary to remedy indicated deficiencies can be taken inaccordance with the plans and specifications. Upon completion of the work, awritten summary of our observations, field testing and conclusions will be providedregarding the conformance of the completed work to the intent of the plans andspecifications. This service is not, however, part of this current contractualagreement.

9.3 In the event that the earthwork operations for this project are conducted such that theconstruction sequence is not continuous, (or if construction operations disturb thesurface soils) it is recommended that the exposed subgrade that will receive floorslabs be tested to verify adequate compaction and/or moisture conditioning. Ifadequate compaction or moisture contents are not verified, the fill soils should beover-excavated, scarified, moisture conditioned and compacted are recommended inthe Recommendations of this report.

9.4 The construction monitoring is an integral part of this investigation. This phase ofthe work provides Moore Twining the opportunity to verify the subsurface conditionsinterpolated from the soil borings and make alternative recommendations if theconditions differ from those anticipated.

9.5 If Moore Twining is not afforded the opportunity to provide engineering observationand field-testing services during construction activities related to earthwork,foundations, pavements and trenches; then, Moore Twining will not be responsiblefor compliance of any aspect of the construction with our recommendations orperformance of the structure or improvements if the recommendations of this reportare not followed. It is recommended that if a firm other than Moore Twining isselected to conduct these services that they provide evidence of professional liabilityinsurance of at least $3,000,000 and review this report. After their review, the firmshould, in writing, state that they understand and agree with the conclusions andrecommendations of this report and agree to conduct sufficient observations andtesting to ensure the construction complies with this report's recommendations.Moore Twining should be notified, in writing, if another firm is selected to conductobservations and field-testing services prior to construction.

9.6 Upon the completion of work, a final report should be prepared by Moore Twiningto identify whether the recommendations presented in this report are incorporatedinto the project construction, and to note any deviations from the project plans andspecifications. This service is not, however, part of this current contractualagreement.


10.0 NOTIFICATION AND LIMITATIONS

10.1 The conclusions and recommendations presented in this report are based on theinformation provided regarding the proposed construction, and the results of the fieldand laboratory investigation, combined with interpolation of the subsurfaceconditions between boring locations. The nature and extent of subsurface variationsbetween borings may not become evident until construction.

10.2 If variations or undesirable conditions are encountered during construction, MooreTwining should be notified promptly so that these conditions can be reviewed andour recommendations reconsidered where necessary.

10.3 If the proposed construction is relocated or redesigned, or if there is a substantiallapse of time between the submission of our report and the start of work (over 12months) at the site, or if conditions have changed due to natural cause or constructionoperations at or adjacent to the site, the conclusions and recommendations containedin this report should be considered invalid unless the changes are reviewed and ourconclusions and recommendations modified or approved in writing.

10.4 Changed site conditions, or relocation of proposed structure, may require additionalfield and laboratory investigations to determine if our conclusions andrecommendations are applicable considering the changed conditions or time lapse.

10.5 The conclusions and preliminary recommendations contained in this report are validonly for the project discussed in the Background Information section of this report.The use of the information and recommendations contained in this report forstructures on this site not discussed herein or for structures on other sites notdiscussed in this report is not recommended. The entity or entities that use or causeto use this report or any portion thereof for another structure or site not covered bythis report shall hold Moore Twining, its officers and employees harmless from anyand all claims and provide Moore Twining’s defense in the event of a claim.

10.6 This report is issued with the understanding that it is the responsibility of the clientto transmit the information and recommendations of this report to developers,owners, buyers, architects, engineers, designers, contractors, subcontractors, andother parties having interest in the project so that the steps necessary to carry outthese recommendations in the design, construction and maintenance of the project aretaken by the appropriate party.

10.7 Our professional services were performed, our findings obtained, and ourrecommendations prepared in accordance with generally-accepted engineeringprinciples and practices. This warranty is in lieu of all other warranties eitherexpressed or implied.


10.8 Reliance on this report by a third party (i.e., that is not a party to our writtenagreement) is at the party's sole risk. If the project and/or site are purchased byanother party, the purchaser must obtain written authorization and sign an agreementwith Moore Twining in order to rely upon the information provided in this report fordesign or construction of the project.

We appreciate the opportunity to be of service to Duke Realty. If you have any questions regardingthis report, or if we can be of further assistance, please contact us at your convenience.

Sincerely,MOORE TWINING ASSOCIATES, INC.Geotechnical Engineering Division

DRAFT

Allen H. Harker, PGProfessional Geologist

DRAFT

Read L. Andersen, RGEManager

A-1 G21411.01

APPENDIX A

DRAWINGS

Drawing No. 1 - Site Location Map

Drawing No. 2 - Test Boring and CPT Location Map

SITE

20000

IN FEETAPPROXIMATE SCALE

SOURCE: U.S.G.S. TOPOGRAPHIC MAP, 7 ½ MINUTE SERIES

DATE:

APPROVED BY:

1DRAWING NO.

FILE NO.:

DRAWN BY:

PROJECT NO.

RM

G21411.01

HAYWARD, CALIFORNIA QUADRANGLE 1993

SITE LOCATION MAPPROPOSED WAREHOUSE BUILDING24493 CLAWITER ROADHAYWARD, CALIFORNIA

21411-01-01 01/15/20

01

/15

/20

DR

AW

ING

NO

.

AP

PR

OV

ED

BY

:

DA

TE

DR

AW

N:

PR

OJE

CT

NO

.

G2

14

11

.01

RM

DR

AW

N B

Y:

FIL

E N

O.

2

21

41

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B-1 G21411.01

APPENDIX B

LOGS OF BORINGS AND CONE PENETROMETER SOUNDINGS

This appendix contains the final logs of borings and cone penetrometer soundings. These logsrepresent our interpretation of the contents of the field logs and the results of the field and laboratorytests.

The logs and related information depict subsurface conditions only at these locations and at theparticular time designated on the logs. Soil conditions at other locations may differ from conditionsoccurring at these test boring and test pit locations. Also, the passage of time may result in changesin the soil conditions at these test boring and test pit locations.

In addition, an explanation of the abbreviations used in the preparation of the logs and a descriptionof the Unified Soil Classification System are provided at the end of Appendix B.

Moore Twining AssociatesProject Proposed Warehouse in Hayward Operator JM-AJ Filename SDF(238).cptJob Number G21411.01 Cone Number DDG1489 GPSHole Number CPT-01 Date and Time 1/11/2020 7:16:18 AM Maximum Depth 50.69 ftEST GW Depth During Test 10.00 ft

Net Area Ratio .8

Cone Size 10cm squared Soil Behavior Referance*Soil behavior type and SPT based on data from UBC-1983

0

5

10

15

20

25

30

35

40

45

50

0 500 TIPTSF 0 10

FRICTIONTSF 0 10

Fs/Qt% 0 100

SPT N0 12

1 - sensitive fine grained

2 - organic material

3 - clay

4 - silty clay to clay

5 - clayey silt to silty clay

6 - sandy silt to clayey silt

7 - silty sand to sandy silt

8 - sand to silty sand

9 - sand

10 - gravelly sand to sand

11 - very stiff fine grained (*)

12 - sand to clayey sand (*)

CPT DATA

DEPTH

(ft)

SOIL

BEHAVIOR

TYPE


Net Area Ratio .8


0

5

10

15

20

25

30

35

40

45

50

0 500 TIPTSF 0 10

FRICTIONTSF 0 10

Fs/Qt% 0 100

SPT N0 12



3 - clay






9 - sand




CPT DATA

DEPTH

(ft)

SOIL

BEHAVIOR

TYPE


Net Area Ratio .8


0

5

10

15

20

25

30

35

40

45

50

0 500 TIPTSF 0 10

FRICTIONTSF 0 10

Fs/Qt% 0 100

SPT N0 12



3 - clay






9 - sand




CPT DATA

DEPTH

(ft)

SOIL

BEHAVIOR

TYPE


Net Area Ratio .8


0

5

10

15

20

25

30

35

40

45

50

0 500 TIPTSF 0 10

FRICTIONTSF 0 10

Fs/Qt% 0 100

SPT N0 12



3 - clay






9 - sand




CPT DATA

DEPTH

(ft)

SOIL

BEHAVIOR

TYPE


Net Area Ratio .8


0

5

10

15

20

25

30

35

40

45

50

0 500 TIPTSF 0 10

FRICTIONTSF 0 10

Fs/Qt% 0 100

SPT N0 12



3 - clay






9 - sand




CPT DATA

DEPTH

(ft)

SOIL

BEHAVIOR

TYPE

Moore Twining AssociatesProject Proposed Warehouse in Hayward Operator JM-AJ Filename SDF(245).cptJob Number G21411.01 Cone Number DDG1489 GPSHole Number CPT-06 Date and Time 1/11/2020 1:04:39 PM Maximum Depth 50.69 ftEST GW Depth During Test 14.52 ft

Net Area Ratio .8


0

5

10

15

20

25

30

35

40

45

50

0 500 TIPTSF 0 10

FRICTIONTSF 0 10

Fs/Qt% 0 100

SPT N0 12



3 - clay






9 - sand




CPT DATA

DEPTH

(ft)

SOIL

BEHAVIOR

TYPE


Net Area Ratio .8


0

5

10

15

20

25

30

35

40

45

50

0 500 TIPTSF 0 10

FRICTIONTSF 0 10

Fs/Qt% 0 100

SPT N0 12



3 - clay






9 - sand




CPT DATA

DEPTH

(ft)

SOIL

BEHAVIOR

TYPE

Moore Twining AssociatesProject Proposed Warehouse in Hayward Operator JM-AJ Filename SDF(247).cptJob Number G21411.01 Cone Number DDG1489 GPSHole Number CPT-07A Date and Time 1/11/2020 2:04:13 PM Maximum Depth 3.77 ftEST GW Depth During Test 12.00 ft

Net Area Ratio .8


0

5

10

15

20

25

30

35

40

45

50

0 500 TIPTSF 0 10

FRICTIONTSF 0 10

Fs/Qt% 0 100

SPT N0 12



3 - clay






9 - sand




CPT DATA

DEPTH

(ft)

SOIL

BEHAVIOR

TYPE

Moore Twining AssociatesProject Proposed Warehouse in Hayward Operator JM-AJ Filename SDF(248).cptJob Number G21411.01 Cone Number DDG1489 GPSHole Number CPT-07B Date and Time 1/11/2020 2:15:39 PM Maximum Depth 3.77 ftEST GW Depth During Test 12.00 ft

Net Area Ratio .8


0

5

10

15

20

25

30

35

40

45

50

0 500 TIPTSF 0 10

FRICTIONTSF 0 10

Fs/Qt% 0 100

SPT N0 12



3 - clay






9 - sand




CPT DATA

DEPTH

(ft)

SOIL

BEHAVIOR

TYPE

Moore Twining AssociatesProject Proposed Warehouse in Hayward Operator JM-AJ Filename SDF(249).cptJob Number G21411.01 Cone Number DDG1489 GPSHole Number CPT-07C Date and Time 1/11/2020 2:25:41 PM Maximum Depth 2.62 ftEST GW Depth During Test 12.00 ft

Net Area Ratio .8


0

5

10

15

20

25

30

35

40

45

50

0 500 TIPTSF 0 10

FRICTIONTSF 0 10

Fs/Qt% 0 100

SPT N0 12



3 - clay






9 - sand




CPT DATA

DEPTH

(ft)

SOIL

BEHAVIOR

TYPE


Net Area Ratio .8


0

5

10

15

20

25

30

35

40

45

50

0 500 TIPTSF 0 10

FRICTIONTSF 0 10

Fs/Qt% 0 100

SPT N0 12



3 - clay






9 - sand




CPT DATA

DEPTH

(ft)

SOIL

BEHAVIOR

TYPE


Net Area Ratio .8


0

5

10

15

20

25

30

35

40

45

50

0 500 TIPTSF 0 10

FRICTIONTSF 0 10

Fs/Qt% 0 100

SPT N0 12



3 - clay






9 - sand




CPT DATA

DEPTH

(ft)

SOIL

BEHAVIOR

TYPE

C-1 G21411.01

APPENDIX C RESULTS OF LABORATORY TESTS

This appendix contains the individual results of the following tests. The results of the moisturecontent and dry density tests are included on the test boring logs in Appendix B. These data, alongwith the field observations, were used to prepare the final test boring logs in Appendix B.

These Included: To Determine:

Moisture Content(ASTM D2216)

Moisture contents representative of field conditions at thetime the sample was taken.

Dry Density(ASTM D2216)

Dry unit weight of sample representative of in-situ or in-placeundisturbed condition.

Expansion Index(ASTM D4829)

Swell potential of soil with increases in moisture content.

Consolidation(ASTM D2435)

The amount and rate at which a soil sample compresses whenloaded, and the influence of saturation on its behavior.

Direct Shear(ASTM D3080)

Soil shearing strength under varying loads and/or moistureconditions.

Atterberg Limits(ASTM D4318)

Determines the moisture content where the soil behaves as aviscous material (liquid limit) and the moisture content atwhich the soil reaches a plastic state.

Grain-Size Distribution(ASTM D422)

Size and distribution of soil particles, i.e., sand, gravel andfines (silt and clay).

R-Value(CTM 301)

The capacity of a subgrade or subbase to support a pavementsection designed to carry a specified traffic load.

Moisture-DensityRelationship(ASTM D1557)

The optimum (best) moisture content for compacting soil andthe maximum dry unit weight (density) for a given compactiveeffort.

Sulfate Content(ASTM D4327)

Percentage of water-soluble sulfate as (SO4) in soil samples.Used as an indication of the relative degree of sulfate attackon concrete and for selecting the cement type.

Chloride Content(ASTM D4327)

Percentage of soluble chloride in soil. Used to evaluate thepotential attack on encased reinforcing steel.

Resistivity(ASTM G187)

The potential of the soil to corrode metal.

pH (ASTM D4972)The acidity or alkalinity of subgrade material.

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Appendix D: Geotechnical Study

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