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NNA16543413R

Amendment 5

Attachment A

“Geotechnical Investigation, N288 Biolab

Project NASA Ames Research Center”

July 13, 2016

Information on Geotechnical Investigation NASA Ames Biosciences Collaborative Facility

The report “Geotechnical Investigation N288 Biolab Project, NASA Ames Research Center, Mountain View, California”, dated May 7, 2015, is provided for informational purposes only. The report was prepared prior to the completion of design of this project. Some of the information and recommendations in the report have been superseded and are no longer applicable. The final drawings and specifications reflect full consideration of known soil conditions. Nothing in the geotechnical report shall be interpreted as changing any requirement of the contract drawings or specifications. Offerors shall base their proposals solely on the requirements shown on the drawings and described in the specifications.

The geotechnical report refers to existing buried foundations. The majority of the buried pile caps and tie beams within the project site were removed under a separate contract after the publication of the geotechnical report. The remaining abandoned piles and pile caps are shown on contract drawings C012 and S110.

There is an existing groundwater monitoring well northwest of the project site. The monitoring well is identified by keynote 24 on sheet C011. The groundwater elevation in this well is measured periodically.

Groundwater elevations measured over the past 25 years are shown on the attached sheet entitled “Historical Groundwater Elevation in Monitoring Well 15A04A”, dated July 11, 2016. The elevations provided are based on the project benchmark, C887 Reset 2009, located northwest of the project site and shown on sheet C011.

Material character deeper than approximately 5 feet below grade is reasonably indicated by the boring logs. Between existing grade and approximately 5 feet deep, the site has been highly disturbed by the demolition of the wind tunnel previously occupying this site. Soil in this upper layer may be imported material and contain pieces of broken concrete generally smaller than 4". Offerors may drill test borings on-site to characterize the existing soil conditions prior to submitting their proposals. Coordinate test hole drilling with the Contracting Officer and the COR.

Historical Groundwater Elevation in Monitoring Well 15A04A 11-Jul-16 Elevations based on Benchmark C887 Reset 2009

Measurement Date

Elevation of Groundwater

(ft.)

5/23/1990 6.47 2/24/2000 10.53 3/25/2010 9.95 5/23/1991 8.85 5/25/2000 9.21 11/18/2010 7.59 8/22/1991 8.01 8/24/2000 8.83 3/24/2011 10.8

11/26/1991 7.92 11/16/2000 9.02 9/15/2011 8.81 3/19/1992 9.55 2/22/2001 9.93 3/15/2012 9.08 5/28/1992 8.84 5/24/2001 9.05 9/20/2012 8.89 8/27/1992 8.02 8/23/2001 8.76 3/21/2013 9.58

11/19/1992 8.08 11/15/2001 8.92 9/19/2013 8.63 2/25/1993 10.33 2/28/2002 9.16 3/20/2014 9.35 5/20/1993 9.15 2/27/2003 9.77 9/18/2014 8.4 8/26/1993 8.48 5/22/2003 9.14 3/19/2015 9.54

11/18/1993 8.55 8/28/2003 8.51 9/17/2015 8.1 2/24/1994 9.7 11/20/2003 8.73 6/26/2016 8.07 5/19/1994 9.14 3/25/2004 9.45 8/25/1994 8.5 8/26/2004 8.34

11/17/1994 8.77 11/18/2004 9.14 2/23/1995 9.9 3/24/2005 10.47 5/25/1995 9.62 8/25/2005 8.52 7/5/1995 9.91 11/17/2005 8.44 9/27/1995 8.74 3/23/2006 10.66 2/22/1996 10.75 11/16/2006 8.58 5/23/1996 9.46 3/22/2007 9.45 8/22/1996 8.79 11/15/2007 8.61

11/21/1996 9.24 3/27/2008 9.47 2/20/1997 9.94 11/20/2008 8.4 5/22/1997 9.08 3/26/2009 9.87 8/28/1997 8.89 11/19/2009 8.49

11/20/1997 9.45 2/26/1998 10.77 5/28/1998 9.72 8/27/1998 9.07

11/19/1998 9.01 2/25/1999 10.27 5/27/1999 9.23 8/26/1999 8.93

11/18/1999 8.73 12/22/1999 8.73

Since 5/23/1990 Lowest Measured Groundwater Elevation 6.47 feet Highest Measured Groundwater Elevation 10.8 feet Average Groundwater Elevation 9.10 feet Median Groundwater Elevation 9.05 feet

Geotechnical Investigation

N288 Biolab Project NASA Ames Research Center

Mountain View, California

Prepared for AECOM Technical Services

May 7, 2015

#2014(107G

Rutherford + Chekene

55 Second Street, Suite 600

San Francisco, CA 94105

Geotechnical Investigation

N288 Biolab Project

NASA Ames Research Center

Mountain View, California

Prepared for

AECOM Technical Services

#2014!107G

Structural | Geotechnical Engineers 55 Second Street Suite 600 | San Francisco CA 94105 | T 415 568 4400 | F 415 618 0684 | www.ruthchek.com

David Moore, Project Manager

AECOM Technical Services

560 Mission Street, Suite 900

San Francisco, CA 94105

2014!107G

Subject: GEOTECHNICAL INVESTIGATION

N288 BIOLAB PROJECT

NASA AMES RESEARCH CENTER

MOUNTAIN VIEW, CALIFORNIA

Dear Mr. Moore:

We are pleased to transmit herewith an electronic copy of our Geotechnical Investigation Report

(GIR) covering the subject project.

This report contains a summary of geotechnical recommendations developed for the design of the project. The recommendations have been developed based on the data presented in the report and a number of interactions, mostly with the Project Structural and Civil Engineers, as the design evolved.

The recommendations contained herein have mostly been communicated previously to the

Project Structural and/or Civil Engineer. This report therefore serves primarily as a more detailed documentation of those recommendations.

We greatly appreciate the opportunity to be of service to you on this project. If you have questions regarding this report, please contact us.

Sincerely, RUTHERFORD + CHEKENE

Gyimah Kasali, Ph.D., G.E. Laurel Jiang, G.E.

Principal Associate

Geotechnical Investigation – #2014!107G May 7, 2015

N288 Biolab Project, NASA Ames Research Center, Mountain View, California Page i

TABLE OF CONTENTS

Topic Page No.

Letter of Transmittal

Table of Contents ............................................................................................................................. i

List of Figures ................................................................................................................................ iv

List of Tables ................................................................................................................................. iv

SECTION 1 SITE AND PROJECT INFORMATION

INTRODUCTION

General

Site Description

Site Elevations

Project Description

Summary of Field Exploration and Laboratory Testing

Organization of Report

Limitations

GEOLOGY AND SEISMICITY

Regional Geology

Local Geology

Faulting in the Site Vicinity

Seismicity

SUBSURFACE CONDITIONS AND GEOLOGIC HAZARDS

Soil Conditions

Groundwater Conditions

Seismic and Geologic Hazards

Conclusions

FACTORS RELEVANT TO THE DEVELOPMENT OF DESIGN RECOMENDATIONS

Mitigation of Potential Impacts of Identified Hazards

Site Development History

SECTION 2 STRUCTURAL DESIGN ISSUES

DESIGN RECOMMENDATIONS FOR STRUCTURES

Preface

Seismic Design Criteria

Foundation Design

Design of Ground Improvement System

Estimated Settlement

Construction of Footings

Tiedowns

Slabs!on!Grade

N288 Biolab Project, NASA Ames Research Center, Mountain View, California Page ii

SECTION 3 CIVIL DESIGN ISSUES

PAVEMENTS

Asphalt Concrete and Other Paving

Pavement Subgrade Preparation and Drainage

Aggregate Base Materials

EARTHWORK, DRAINAGE AND UTILITIES

Site Preparation and Demolition

Excavation and Slopes

Subgrade Preparation

Engineered Fill and Backfill Placement

Fill and Backfill Materials

Site!Derived Recycled Materials

Drain Rock and Filter Fabric

Surface Drainage and Erosion Control

Bioretention

Utility Trench Backfilling

SECTION 4 MULTIDISCIPLINARY DESIGN ISSUES

AUGER CAST GROUTED COLUMNS

Preparation for Installation

Pilot Installation

Preparation for Drilling and Grouting

Drilling

Grouting and Auger Withdrawal

Post!Installation Checks and Miscellaneous Items

CORROSION POTENTIAL AND BELOW GRADE CONSTRUCTION

Summary

SECTION 5 CONSTRUCTION:RELATED ISSUES

IMPACT OF SITE CONDITIONS ON CONSTRUCTION

General

Winter Construction

Other Issues

CONSTRUCTION OBSERVATION

Summary

SECTION 6 REFERENCES

REFERENCES

Reports and Publications

N288 Biolab Project, NASA Ames Research Center, Mountain View, California Page iii

APPENDICES

Appendix A

Figures for This Report

Appendix B

Boring Log Information from Previous Project

Appendix C

Laboratory Test Results from Previous Project

N288 Biolab Project, NASA Ames Research Center, Mountain View, California Page iv

LIST OF FIGURES

Figure No. Title Page No.

1 Site Vicinity Map ...................................................................................................... A1

2 Site and Exploration Location Plan ........................................................................... A2

3 Local Geologic Map .................................................................................................. A3

4 Generalized Subsurface Profile A!A ......................................................................... A4

5 Generalized Subsurface Profile B!B ......................................................................... A5

6 Proposed Construction Relative to Abandoned Pile Foundation System .................. A6

7 Types of Auger Cast Grouted Column (ACGC) Configuration ................................ A7

LIST OF TABLES

Table No. Title Page No.

Table 1 Regional Faults and Seismicity

Table 2 Summary of Potential Geologic Hazards

Table 3 Major Earthquake Sources in San Francisco Bay Area

Table 4 Recommended Seismic Design Parameters for NASA Biolab

Table 5 Allowable Bearing Pressures for Footings With Auger Cast Grouted Columns

Table 6 Parameters for Calculating Lateral Load Resistance

Table 7 Estimated Settlement from Plaxis Analysis

Table 8 Load Sequence for Performance and Proof Testing for Micropiles or Tiedowns

Table 9 Recommended Pavement Sections

Geotechnical Investigation: #2014!107G May 7, 2015

N288 Biolab Project, NASA Ames Research Center, Mountain View, California Page 1

SECTION 1

SITE AND PROJECT INFORMATION

N288 Biolab Project, NASA Ames Research Center, Mountain View, California Page 2

INTRODUCTION

General

This report summarizes the results of the findings of the geotechnical investigation, which we performed for the N288 Biolab Project.

The overall geotechnical investigation program consists of the following two phases:

1. Gathering of geotechnical data from a previous geotechnical investigation performed by

Kleinfelder (2008) on the site.

2. Interpretation and analysis of the geotechnical data for the sole purpose of developing recommendations for design.

Site Description

The site is part of the NASA Ames Research Center, which is located in Mountain View, California. The site is bounded to the north by Warner Road, to the south by Durand Road, to the east by McCord Avenue and to the west by De France Avenue. The location of the site is shown in Figure 1, "Site Vicinity Map" and in Figure 2, "Site and Boring Location Plan".

Site Elevations

We based the site elevations in this report on the topographic survey shown on the existing conditions plan, prepared by BKF, which we received from AECOM. The elevations on the survey are reported to be based on the 1988 North American Vertical Datum (NAVD). We have therefore based all elevations in this report on the NAVD, unless otherwise noted.

The horizontal data, on the other hand, are based on the North American Datum (NAD).

Project Description

The proposed N288 Biolab project is planned to be a two!story concrete structure that will house a biosciences research facility. The structure includes the utility building, which will be structurally continuous with the rest of the building. The first floor will have a slab on grade floor and the second floor will be a flat slab supported by concrete columns.

Gravity columns are likely to be supported by isolated spread footings. The footings may also be combined where adjacencies between columns provides greater economy. The lateral force resisting system will be specially reinforced concrete shear/bearing walls distributed evenly along the length and width of the building to minimize torsion in the overall system and reduce the demand on collectors and diaphragms locally at the shear walls.

N288 Biolab Project, NASA Ames Research Center, Mountain View, California Page 3

The south façade of the building will have a canopy at the roof level. This canopy consists of a steel framing supported on steel pipe columns. The columns are likely to be supported on isolated spread footings.

Proposed site work includes the following:

1. Site Preparation – This will mostly involve clearing and grubbing and removal of existing foundations.

2. Rerouting of Existing and Installation of New Utilities – This will involve rerouting of existing utilities that fall within the footprint of the proposed facility and the installation of new utility lines associated with the project.

3. Staging and Parking Area – This will involve the creation of areas for storing construction materials and parking during the construction phase.

4. Stormwater Drainage – This will involve stormwater control during and after construction.

Summary of Field Exploration and Laboratory Testing

Field Exploration: We used field exploration and laboratory test data from a previous project

(Kleinfelder, 2008), which was originally slated for the site. We used the data for subsequent engineering analysis of the various components of the project.

The field exploration data include logs of five exploratory borings drilled and cone penetration test profiles obtained on January 11 and 14, 2008. The borings and the cone penetration tests ranged in depth from approximately 31 feet to 100 feet below existing grade.

During the field exploration, Kleinfelder obtained estimates of undrained shear strengths and unconfined compressive strength of selected soil samples using a hand!held penetrometer or torvane, as appropriate. The strength estimates are noted on the boring logs, which are presented in Appendix B.

The cone penetration tests (CPTs) were performed in accordance with ASTM D5778. The CPTs were extended to a depth 100 feet. Data from the CPT are presented in Appendix B.

Laboratory Testing: The laboratory testing program consists of index and strength tests.

Consolidation and R value tests were also performed. The results of the laboratory tests are presented in Appendix C.

N288 Biolab Project, NASA Ames Research Center, Mountain View, California Page 4

Organization of Report

The report has been organized into six sections as follows:

Section 1 – Introduction

Contains a summary of background information.

Section 2 – Structural Design Issues

Covers recommendations relating to structures.

Section 3 – Civil Design Issues

Covers recommendations relating to the design of proposed pavements, earthwork, drainage, and utilities.

Section 4 – Multidisciplinary Design Issues

Covers recommendations relating to ground improvement, and corrosion protection.

Section 5– Construction!Related Issues

Discusses potential constructability issues and construction observation services.

Section 6 – References

Contains a list of references used in the course of the investigation.

This report also contains the following appendices:

Appendix A: Contains figures relating to this report.

Appendix B: Contains logs of historical borings drilled and cone penetration tests performed by Kleinfelder (2008) on this project site.

Appendix C: Contains results of laboratory tests performed by Kleinfelder (2008) on samples from aforementioned historical borings.

Limitations

1. This report has been prepared for the exclusive use of AECOM Architect and its consultants for specific application to the NASA AMES N288 Biolab as described herein. In the event that there are any changes in ownership, nature, location or design of the project, the information contained in this report shall not be considered valid unless the project changes are reviewed by Rutherford + Chekene.

2. Any conclusions contained in this report are based in part upon the data obtained from exploratory borings and laboratory testing performed as part of a previous investigation.

The nature and extent of variations between the borings may not become evident until

N288 Biolab Project, NASA Ames Research Center, Mountain View, California Page 5 construction. If variations are discovered, it will be necessary to re!evaluate any conclusions contained in this report.

3. Simplified interpretations of geotechnical data have been made to facilitate the geotechnical analysis performed for this project. Such interpretations, while adequate for the analysis performed, are inadequate for estimating quantities for the purposes of developing construction costs or submitting bids for this project. These interpretations should therefore not be used for purposes other than the stated intended purpose.

4. This report should not be part of the contract documents for the proposed project described herein. Instead, the report should serve as a guide for preparing design drawings and specifications that are part of the contract documents.

5. We cannot be responsible for the impacts of any changes in geotechnical or geologic standards, practices, or regulations subsequent to the performance of our services if we are not consulted subsequent to the changes.

6. We can neither vouch for the accuracy of information supplied by others, nor accept consequences for use of segregated portions of this report without consultation with our office.

7. The opinions set forth in this report are not based upon an examination of the location or condition of utility lines or other subsurface structures on the property. Those performing the construction must assume any risks arising from the locations or conditions of such lines.

8. Rutherford + Chekene assumes no responsibility for the management of contaminated or hazardous materials that may be found on the site.

a. Rutherford + Chekene has not performed investigations to determine the presence of contaminated or hazardous materials. The Owner must provide the results of any such investigations to the Contractor.

b. The Construction Contractor is responsible for ensuring that personnel within the work area are protected from hazardous materials. If hazardous materials are discovered, the Contractor must immediately notify the Owner and cease work until conditions can be maintained in accordance with all applicable regulations.

N288 Biolab Project, NASA Ames Research Center, Mountain View, California Page 6

GEOLOGY AND SEISMICITY

Regional Geology

The site is located in the northwest trending Santa Clara Valley, which is bounded on the southwest by the Santa Cruz Mountains and on the northeast by the Diablo Range. These topographic boundaries have been created in large part by movement within the San Andreas fault system; principally, along the San Andreas (west) and the Hayward and Calaveras (east) faults. This movement has produced a structural block which has subsided over time (forming a

“graben”) and allowed the accumulation of both marine and continental deposits. The tectonic activity which has produced the structural block accelerated in the late Miocene and has operated essentially continuously through the Pliocene and Pleistocene to the present day.

Basement rock in the block is the metamorphic complex of the Franciscan formation

(Cretaceous!Jurassic age), which is overlain unconformably by continental alluvium and lake beds of the Santa Clara formation (late Pliocene!Pleistocene age). In turn, the Santa Clara formation is overlain by several hundred feet of Pleistocene as well as Recent alluvium and marine sediments: bay muds, silts and sands.

Local Geology

Figure 3 ! Local Geologic Map ! depicts the distribution of the alluvial materials in the general area of the site. Going eastward toward the bay, these materials have been categorized as:

Qyf – young alluvial fan deposits of silt, sand and clay with minor amounts of gravel;

Qyfl – fluvial deposits of fine!grained sand, silt, and clay at the outer edges of fans;

Qb – interfluvial fresh water basin deposits of fossiliferous, organic clay and silty clay;

Qbm – highly compressible, estuarine organic clay and silty clay commonly referred to as

“bay mud”.

The site is situated in the interfluvial fresh water basin deposits (Qb) unit and near the contact with the fluvial deposits (Qyfl).

The site is underlain by a Quaternary alluvium layer about 1,400 feet thick. The alluvium deposit forms a cone extending from the toe of the steeper hill slope about four miles to the southwest to submergence under the present bay level at the northern boundary of Moffett Field.

The uppermost horizon of the cone is composed of outwash deposits from the ridge system to the southwest. This alluvium deposit interfingers with and grades into flood plain deposits at the periphery of San Francisco Bay. Underlying the uppermost horizon are older deposits and alluviums that are in turn underlain by bedrock of Pliocene age.

Data from previous investigation at nearby Moffett Field indicate that the alluvium deposit is composed of peat, silt, clay, sand, and gravel. Generally, the surface soil is a stiff, highly plastic clay and silty clay. The surface soil is underlain by a predominantly silty clay layer often containing traces of sand. Near the northern boundary of Moffett Field, soft Bay Mud and peat

N288 Biolab Project, NASA Ames Research Center, Mountain View, California Page 7 interfingers with this silty clay layer. Zones of predominantly sandy soils underlie this silty clay layer. These sand zones are sandwiched between the upper silty clay layer and a lower stiff, blue!gray clay layer.

Faulting in the Site Vicinity

Major Active Faults: The San Andreas Fault Zone lies approximately 14 km southwest of the site. The Fault Zone splits from a very linear trace in Central California approximately 95 km southwest of the San Francisco Peninsula. The Hayward–Calaveras fault systems trend up the east side of the San Francisco Bay while the San Andreas proper follows the Peninsula on the west side of the Bay. A third strike!slip fault zone, the San Gregorio, crosses the westernmost part of the Peninsula at Año Nuevo and Pillar Point and then trends offshore toward the Golden

Gate where it merges with the San Andreas fault before the main trace trends north through

Bolinas and Tomales Bays.

At the southern end of the Peninsula lies the Santa Cruz Mountains that are the result of compression associated with the prominent westward bend in the San Andreas Fault. The length of the Peninsula segment of the San Andreas Fault is associated with a prominent ridgeline.

The broadest part of this uplift, the Santa Cruz Mountains, is closest to the westward bend in the

San Andreas Fault. Although the topographic spine of the Peninsula is maintained along its length, it narrows markedly and drops in elevation to the north towards the Golden Gate. At the northern end of the Peninsula, south of San Francisco, the San Andreas Fault trends offshore toward the Golden Gate.

Monte Vista Fault and the Foothills Thrust System: The thrust and reverse faulting that has been mapped along the northeastern foot of the Santa Cruz Mountains are geologic structures, subsidiary to the San Andreas Fault Zone, and can be attributed to the compressional tectonic environment. At the southern end of the Peninsula, the northeast flank of the Santa Cruz

Mountains marks the start, and widest expression, of the northwest trending Foothills Thrust

System. At the northern end of the Peninsula, the Foothills Thrust System appears to die out to the north in a narrow band of two or three surface traces of the Serra Fault Zone. No trace of the thrust system has been mapped.

The Monte Vista fault is a potentially active fault mapped crossing southwest of the NASA

Ames site, approximately 10 km from the site. Several sub!parallel, generally southwest!dipping faults including the Monte Vista fault (Dibblee, 1966; Sorg and McLaughlin, 1975;

William Cotton and Associates 1978) trend along the northeast flank of the Santa Cruz

Mountains from the vicinity of Los Gatos/Highway 17 northwest to just northwest of Page Mill

Road in Palo Alto. These faults expose older rocks in their southwest walls suggestive of thrusting or reverse!slip. The fault geometry is compatible with uplift of the Santa Cruz

Mountains relative to the Santa Clara Valley.

The Foothills Thrust System is believed to place Franciscan Complex bedrock over alluvial deposits in the Santa Clara Valley. The age of the youngest alluvial deposits juxtaposed with Franciscan Complex rocks is estimated at approximately 20,000 years old (Late Pleistocene;

N288 Biolab Project, NASA Ames Research Center, Mountain View, California Page 8

CDMG, 1980). Mapping of the fault zone characteristically shows Santa Clara Formation gravels cut by the faulting, indicating an age of younger than 1 million years.

Seismicity

The major active faults in the region include the San Andreas, San Gregorio, Hayward, Rodgers Creek, Concord!Green Valley, and Calaveras faults. A list of major active faults in the region, including their distances from the site and maximum moment magnitudes, is provided in Table 1.

The site lies in the seismically active San Francisco Bay region and is subject to frequent ground shaking. The active faults nearest to the site are the San Andreas (14 km southwest), Monte Vista (10 km southwest), San Gregorio (17 km southwest), Hayward (18 km northeast), and Calaveras (25 km east).

Table 1

Regional Faults and Seismicity

Fault Segment Approximate Distance

(kilometers)

Direction

From Site

Maximum Moment

Magnitude

San Andreas (Peninsula) 14 Southwest 8.05

Monte Vista ! Shannon 10 Southwest 6.8

Hayward 18 Northeast 6.9

Calaveras 25 Northeast 6.9

San Gregorio 33 Southwest 7.4

A number of historical earthquakes have affected the area, including the 1906 earthquake and the more recent Loma Prieta earthquake. During a major earthquake on any one of the nearby active faults, the site may experience strong ground shaking.

The 1906 San Francisco earthquake had an estimated Moment Magnitude (Mw) of 7.8 and created a surface rupture along the San Andreas Fault approximately 270 miles long, with a maximum lateral displacement of about 21 feet. The epicenter of the 1906 event is estimated to be offshore of the San Francisco coastline approximately 48 km northwest of the site. Strong shaking occurred at many sites in the East Bay and extensive damage was documented. The recent Loma Prieta Earthquake (Mw 6.9) was centered on or near the San Andreas Fault about 40 km southeast of the site. It produced horizontal ground shaking of 0.28 g, and minor damage at the site.

The U.S. Geological Survey’s 2007 Working Group on California Earthquake Probabilities (2008) has compiled the earthquake fault research for the San Francisco Bay area in order to estimate the probability of fault segment rupture. They have determined that the overall probability of moment magnitude 6.7 or greater earthquake occurring in the San Francisco Bay Region during the next 30 years is 63 percent. The highest probabilities are assigned to the Hayward/Rodgers Creek and the Northern segment of the San Andreas faults. These probabilities are 31 and 21 percent, respectively (USGS, 2008).

N288 Biolab Project, NASA Ames Research Center, Mountain View, California Page 9

SUBSURFACE CONDITIONS AND GEOLOGIC HAZARDS

Soil Conditions

Based on the logs of borings performed on the site by Kleinfelder (2008), the project site is underlain by the following three categories of soils:

1. The top layer consists of an uncontrolled fill layer of expansive clay ranging in thickness from 2 to 5 feet.

2. The uncontrolled fill layer is underlain by Bay deposits of varying consistency to a depth of about 27 feet below existing grade. In general, strength of the materials increases with depth. However, there is a soft layer at a depth of about 10 to 18 feet below the ground surface.

3. Interbedded sand and silt with gravels are present in the Bay deposits.

Generalized profiles showing the various earth materials encountered are shown in Figures 4 and 5.

Groundwater Conditions

We gathered and reviewed groundwater data from California Geological Survey (CGS) and previous explorations at the site. According to the CGS maps, the historical high groundwater level in the area is approximately 4 feet below ground surface. The CPT logs showed groundwater to be 7 feet below ground surface. Groundwater level was not determined in the boring logs because the rotary method of drilling masked the presence of groundwater. We note that the reported ground water level may fluctuate due to seasonal rainfalls. We note that the reported ground water level may fluctuate due to seasonal rainfalls. Based on the preceding information, we estimate that the design groundwater elevation on the site would be close to elevation !4.0 feet below existing grade.

Seismic and Geologic Hazards

Table 2 shows a summary of the results of our geologic hazards evaluation of the site. The potential for occurrence of each identified hazard is rated on a scale of increasing probability:

low, moderate, and high.

N288 Biolab Project, NASA Ames Research Center, Mountain View, California Page 10

Table 2

Summary of Potential Geologic Hazards

Possible Geologic Hazard Potential Occurrence at Site

Fault Rupture Low

Strong Ground Shaking High

Liquefaction in Localized Zones High

Uncontrolled Fill and Obstructions High

Consolidating Soils High

Expansive Soil Moderate to High

Compaction Settlement (Large Scale) Low

Flooding and Reservoir Failure Low

Slope Stability Low

Tsunamis Low

Seiches Low

Erosion Low

Soil Corrosivity High

The hazards summarized in Table 2 are briefly discussed as follows:

Fault Rupture: The site is located outside the Alquist!Priolo Special Studies Zone, the nearest active mapped fault being the Monte!Vista Shannon fault, which is located about 10 kilometers to the southwest.

No active faults have been mapped within the project site, nor has a known active fault been projected to traverse the site. Therefore the hazard due to direct fault rupture within the site is considered low.

Ground Shaking: The San Andreas and Hayward faults dominate the seismicity of the region.

The likelihood of very strong ground shaking at the site during a major (magnitude 7 or larger) earthquake is high, in keeping with the generally high seismicity of the vicinity. This is consistent with the rest of the San Francisco Bay area and is due to the site’s proximity to active faults. The potential sources of a major earthquake and their estimated slip rates and recurrence intervals are presented in Table 3.

1 The term “active” fault refers to a fault exhibiting evidence of movement within the past 10,000 years.

N288 Biolab Project, NASA Ames Research Center, Mountain View, California Page 11

Table 3

Major Earthquake Sources in San Francisco Bay Area

Fault Slip Rate Recurrence Interval

San Andreas 24+3 mm/yr. 250 yrs.

Hayward 9+2 mm/yr. 167 yrs.

Rodgers Creek 6.4 ! 10.4 mm/yr. 131 ! 370 yrs.

Calaveras 8+3 mm/yr. 200 ! 900 yrs.

Concord 3 mm/yr. !

Green Valley 6 mm/yr. !

Greenville 0.6+0.1 mm/yr. !

San Gregorio 7+1 mm/yr. !

The U.S. Geological Survey's Working Group on California Earthquake Probabilities (2008) has compiled the earthquake fault research for the San Francisco Bay area in order to estimate the probability of fault segment rupture. They have determined that the overall 30!year probability of moment magnitude 6.7 or greater earthquake occurring is 63 percent.

The site has been subjected to strong ground shaking from moderate to large earthquakes on the

San Andreas and Hayward faults, indicating that there is a high potential for strong ground shaking affecting the site in the future. We therefore judge the potential for strong ground shaking to be high.

Liquefaction: Seismic!induced liquefaction is a phenomenon whereby loose, saturated, granular sediments lose a significant portion of their shear strength due to the generation of excess pore water pressure resulting from cyclic loading during an earthquake event. Liquefaction can result in loss of foundation support, failures due to lateral spreading, and differential compaction of affected soils. The requisite condition for liquefaction is the presence of loose, cohesionless, granular soils below the water table.

Seismic hazard mapping by the California Geological Survey (formerly the California Division of Mines and Geology or CDMG) identified zones in the site vicinity considered susceptible to earthquake!induced liquefaction (CDMG, 2006). The map shows that the project site is within the liquefaction hazard zone.

We performed a simple site!specific liquefaction analysis to evaluate the potential for liquefaction, using historical information from Kleinfelder (2008). We concluded that liquefaction occurred in non contiguous localized pockets. Based on the seismic hazard map, the soil and groundwater conditions encountered, and the results of the liquefaction analysis, we conclude that the potential for liquefaction in non contiguous localized pockets is high.

N288 Biolab Project, NASA Ames Research Center, Mountain View, California Page 12

Uncontrolled Fill and Obstructions: The site development history has led to the presence of two to five feet of uncontrolled fill as well as buried foundation elements that might interfere with the proposed development.

Based on the site history, we conclude that the potential for uncontrolled fill and obstructions impacting the project is high.

Consolidating Soils: The site is underlain by soft soils in the upper 25 feet. Some of the soft soils are susceptible to consolidation under vertical loads from a building supported on shallow foundation or from fill placed to raise the existing grade.

Given this subsurface condition, we judge the potential for consolidation!induced settlement to be high.

Expansive Soils: Based on information from previous investigation, there is a clay layer at the surface of the site that is considered as moderately to highly expansive. Therefore, we judge the potential for expansive soils at the site to be high.

Compaction Settlement: Compaction settlement, or seismic densification, occurs when loose granular soils above the water table increase in density as a result of earthquake shaking. The soil densification can result in differential settlement because of variations in soil composition, thickness and initial density.

Given the predominately clayey nature of the materials at the site, we judge the potential for compaction settlement affecting the proposed construction on a large scale to be low.

Flood Inundation: The site is not located within a designated flood prone area, as mapped by

FEMA. However, FEMA has designated areas adjacent to the existing levees in the site vicinity as areas susceptible to the 100!year flood. The site is not located within an area of possible inundation due to reservoir failure. We therefore judge that the potential for inundation of the site is low.

Slope Stability: The site is relatively flat, therefore, we judge the potential for future instability of the site slopes to be low.

Tsunamis: Tsunamis are transient long!period sea waves generated by submarine earthquakes or volcanic eruptions. According to the “Tsunami Inundation Emergency Planning Map for the

San Francisco Bay Region (2009)”, the site is not within projected areas of inundation resulting from a tsunami. Therefore, we judge the potential for tsunami inundation at the site to be low.

Seiches: Seiches occur as large waves within enclosed bodies of water such as lakes or reservoirs and result from violent earthquake shaking. Based on the absence of enclosed water bodies adjacent to the site, we judge the potential for seiche inundation at the site to be low.

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Erosion: The site is relatively flat. Assuming the site will be covered with hardscape in association with surface drainage provisions, we judge the potential for substantial erosion at the site to be low.

Soil Corrosivity: As part of the previous investigation a corrosivity analysis was performed on a sample of the site soils. The results of the analysis indicate that the soil at the site is corrosive.

Therefore, we judge that the corrosivity potential of the site soils is high.

Conclusions

Based on the results of the geologic hazard evaluation, we developed the following conclusions regarding the potential impacts of the following identified hazards on the proposed project:

1. Ground Shaking: Strong ground shaking should be expected at the site during a major earthquake. Ground shaking will induce seismic forces in structures.

2. Liquefaction: Liquefaction of the interbedded sandy materials should be expected at the site during a seismic event. Liquefaction will induce settlement on the proposed improvements.

3. Uncontrolled Fill and Buried Foundation Elements: Uncontrolled fill and buried foundation elements should be expected, depending on the depth of construction. The uncontrolled fill would not be suitable for support of structural elements without remedial work. Where construction deeper than that of new footings is required, the buried foundation elements could become obstructions to the proposed work.

4. Consolidating Soils: Consolidating soils in the upper 25 feet could lead to total and differential settlement of the new building if it is supported on shallow foundation. The potential for settlement would also dictate that the ground floor should be as close to the existing grade as possible.

5. Expansive Soils: Expansive soils will shrink and swell with changes in moisture content and could cause damage to overlying structures bearing in or on this layer.

6. Soil Corrosivity: Results of corrosivity tests performed on one sample from the site indicate that the sample is corrosive. Soil corrosivity can lead to corrosion of buried iron, steel, cast iron, ductile iron, galvanized steel, and dielectric coated steel or iron.

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FACTORS RELEVANT TO THE DEVELOPMENT OF DESIGN RECOMENDATIONS

Mitigation of Potential Impacts of Identified Hazards

General: The following brief discussions pertain to potential mitigation options for the groups of hazards with moderate to high probability of occurrence – strong ground shaking, liquefaction, uncontrolled fill and buried structures, consolidating soils, expansive soils and soil corrosivity.

Ground Shaking: The primary approach to mitigating the potential impacts of ground shaking on the proposed surface structures is to design the structures in accordance with the seismic design requirements of the 2013 California Building Code Criteria for the seismic design of these structures are presented in Section 2: Structural Design Issues.

Liquefaction: The primary approach to mitigating the potential impacts of liquefaction on a surface structure supported on footings is to design the structure to sustain liquefaction!induced bearing capacity reduction and/or anticipated differential settlement.

Uncontrolled Fill and Buried Foundation Elements: Uncontrolled fill that would be supporting structural elements should be removed partially or fully and be properly compacted as recommended for engineered fill.

Consolidating Soils: Recommendations for mitigating the potential impacts of consolidating soils on overlying surface structures are presented in Sections 2 and 4.

Expansive Soils: Expansive soils directly below structural elements should be either be removed and replaced with non expansive soils or be lime!treated.

Soil Corrosivity: Recommendations for mitigating the potential impacts of soil corrosivity on concrete and foundation elements are presented in Section 4.

Site Development History

The site was previously occupied by several structures, including wind tunnels and bunker buildings, which have since been demolished. Remnants of a pile foundation system, which was used to support some of the demolished structures, still remain and must be partially removed where they would interfere with the proposed improvements.

Figure 6 shows the proposed footprint of the new building and the overall development relative to the approximate locations of the abandoned pile foundation system.

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SECTION 2

STRUCTURAL DESIGN ISSUES

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DESIGN RECOMMENDATIONS FOR STRUCTURES

Preface

This section contains design recommendations pertaining to the following aspects of structural design:

1. Seismic design of structures

2. Foundation design

3. Tiedown design

4. Slabs!on!grade

Seismic Design Criteria

General: The primary approach to mitigating the potential impacts of ground shaking on the proposed building is to design the building in accordance with the current seismic design code. We have therefore developed recommendations for seismic design parameters per the

2013 California Building Code (CBC).

Site Coordinates: As previously noted, the project site has the following coordinates:

37.415 degrees North and 122.061 degrees West.

Site Class: Based on the subsurface information that we have gathered, we conclude that the site class is D.

Seismic Design Parameters for Site Class C Based on Mapped Spectral Accelerations:

The seismic design parameters for Site Class D based on 2013 CBC mapped spectral accelerations are presented in Table 2. We obtained the parameters from the United

States geological survey website: (http://geohazards.usgs.gov/designmaps/us/application.php), “Seismic Design Maps.”

The recommended seismic design parameters for the NASA Biolab, based on ASCE 7!10, are presented in Table 4.

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Table 4

Recommended Seismic Design Parameters for NASA Biolab

Site Class D

Mapped Spectral Response Acceleration Parameters

SS

(From CBC 2013) 1.50

S1

(From CBC 2013) 0.60

Site Coefficients

Fa

(From Table 11.4!1 of ASCE/SEI 7!10) 1.0

Fv

(From Table 11.4!2 of ASCE/SEI 7!10) 1.5

Adjusted MCE Spectral Acceleration Parameters SMS = FaSS 1.50

SM1 = FvS1 0.90

Design Spectral Acceleration Parameters

SDS = 2/3SMS 1.00

SD1 = 2/3SM1 0.60

Foundation Design

Foundation System: Based on our discussion with the Project Structural Engineer, we understand that the building would be subjected to uplift forces that cannot be resisted using the weight of the structure alone. Uplift!resisting elements would therefore be required to resist these uplift loads. Based on these facts, we initially considered two potential options for the building foundation system:

1. Support the building on shallow foundations and use tiedowns to resist uplift loads.

2. Support the building on drilled piers or piles and use the drilled piers or piles to resist both axial compression and tensile or uplift loads.

Based on estimated costs, we concluded that the first option may be more economical. We therefore started developing recommendations for that option.

Building on Shallow Foundations: Two of the geologic hazards identified at the site would have major potential impacts on the use of a shallow foundation system to support the building. These hazards are: 1) uncontrolled fill near the surface, and 2) consolidating soils below grade. The uncontrolled fill layer could have potential settlement impacts on the building foundation and the consolidating soils layer is likely to cause the building to settle. These potential impacts would therefore need to be mitigated if a shallow foundation system is used.

We considered various mitigation options including: 1) a mat foundation system, and 2) footings with ground improvement elements. Ground improvement options considered include removal and recompaction of about 5 feet of the existing uncontrolled fill and installation of auger cast grouted columns through existing fill and native soils. Based on our previous experience with similar site conditions and a preliminary cost analysis performed by the project team, we

N288 Biolab Project, NASA Ames Research Center, Mountain View, California Page 18 concluded that a shallow foundation system with ground improvement would be the preferred system from the performance and cost points of view.

Footing Design: Allowable bearing pressures for isolated and continuous footings supported on ground improved with auger cast grouted columns, which are presented in Table 5, should be used to design the new footings. We assumed that the footings would be at least 24 inches wide and have an embedment of 18 inches or greater.

Table 5

Allowable Bearing Pressures for Footings With Auger Cast Grouted Columns

Load Condition Allowable Bearing Pressure (psf)

Dead Load 3,000

Dead + Live Loads 3,400

Total Loads (Including Wind or Seismic) 4,530

At column locations where the isolated square footing dimensions exceed 10 feet by 10 feet, based on the allowable dead load of 3,000 psf, strip footings should be used instead of isolated columns footings.

To obtain ultimate bearing pressures from the allowable values given in the Table 5, the allowable dead plus live load bearing pressure should be multiplied by 3.

Lateral Resistance: Lateral loads on footings can be resisted by 1) passive pressure on the side of the footing perpendicular to the applied force, and 2) friction at the base of the footing. These components of resistance may be assumed to act together at the limit state, and so may be added to estimate the total resistance available.

The procedure for estimating the lateral resistance of a footing is presented below.

1. Passive soil pressure against the side of the footing: Passive pressure against a footing perpendicular to the applied force should be taken as a pressure of Pt psf at the top of the footing and increasing as an equivalent fluid pressure of Efp pcf.

2. Friction at the base of the footing: If the footing is not underlain by a waterproofing element, the allowable horizontal frictional resistance, Fbase, at the interface between the mat and the underlying earth materials may be taken as:

Fbase = fs x Actual Dead Load Pressure at Base of Footing (psf)

If a waterproofing element is present, the friction factor, fswp, should be substituted for

fs. The value of fswp will be dependent on the type of waterproofing element used and is likely to have a value less than fs. After a waterproofing element is selected, the manufacturer should be consulted for guidance on an appropriate friction factor fswp.

Geotechnical Investigation- #2014-107G May 7, 2015

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The values of Pt, Efp and fs for the earth materials in or on which the footings bear are presented in Table 6.

Table 6

Parameters for Calculating Lateral Load Resistance

Footing Bearing in or on Indicated

Earth Material

Pt

(psf)

Efp

(pcf) fs

Partially Compacted Artificial Fill 0 250 -

Class 2 Aggregate Base - - 0.35

To obtain ultimate lateral resistance components from the allowable values given above, the allowable lateral resistance should be multiplied by 1.5.

Design of Ground Improvement System

General: The ground improvement system would involve the installation of auger cast grouted columns (ACGCs) under the footings in one or more of the arrangements shown in Figure 7, depending on the size of the footing.

Auger Cast Grouted Column Dimensions: These grouted columns should be 18 to 24 inches in diameter and extend about 20 feet below existing grade. This 20-foot depth below grade corresponds to a tip elevation of -3.0 feet (Mean Sea Level) or lower for the grouted columns.

The top of grouted column should be 6 to 8 inches lower than the elevation of the bottom of the overlying footing.

Layout: Each building column footing should have four ACGCs installed symmetrically around the columns unless otherwise noted. The ACGCs should have a minimum spacing of 4 feet and a maximum spacing of 6 feet on center.

At column footing and/or strip footing locations where a tiedown is required, the ACGCs should be located so that the tiedown is at the center of the grouted column layout. For strip footings, the ACGCs should be located on gridlines in groups of four at the locations where the footings are enlarged.

Decoupling Layer: A 6- to 8-inch decoupling layer of compacted Class 2 aggregate base should be placed between the top of the grouted columns and the bottom of the overlying footings to prevent bonding between the footing and the grouted columns. Where grouted columns are installed along a strip footing, the entire strip footing should be underlain by the decoupling gravel layer. The Class 2 aggregate should be compacted to 95 percent relative compaction.

Special Condition: There have been previous efforts to locate the building in such a way that proposed footings would either be wholly underlain by abandoned piles or zero abandoned piles.

Where new footings land wholly on abandoned piles, grouted columns would not be required.

In that case, the piles, which are currently being partially demolished under a separate contract to

N288 Biolab Project, NASA Ames Research Center, Mountain View, California Page 20 an elevation, which is about 3 feet below the bottom of the overlying footing, should be incorporated into the ground improvement system. This incorporation should be accomplished by placing a minimum 12!inch layer of Class 2 aggregate base compacted to 95 percent relative compaction above the neatly cut piles that fall within the footprint of the new footing. New footings can then bear on the aggregate base layer, which would serve to decouple the footing from the piles. The Project Geotechnical Engineer should be giving the opportunity to review the subgrade conditions above previously demolished piles before the decoupling layer is placed.

Where footings are partially landing on existing piles, the footing should be combined with nearby ones to create a strip footing in order to avoid a mixture of existing piles and ACGCs under a column footing.

Installation: Guidelines for the installation of the auger cast grouted columns are presented in

Section 4:…