appendix d - burlingame, california d - geotechnical report.pdfsand and silty sand up to 10 feet...

Initial Study 920 Bayswater Avenue

APPENDIX D

GEOTECHNICAL INVESTIGATION

Copyright © 2017 by ENGEO Incorporated. This document may not be reproduced in whole or in part by any means whatsoever, nor may it be quoted or excerpted without the express written consent of ENGEO Incorporated.

920 BAYSWATER BURLINGAME, CALIFORNIA

PRELIMINARY GEOTECHNICAL EXPLORATION

SUBMITTED TO Mr. Mark Pilarczyk

Fore Green Development, LLC 20 S. Santa Cruz Avenue, #300

Los Gatos, CA 95030

PREPARED BY ENGEO Incorporated

May 3, 2017

PROJECT NO.

13889.000.000

GEOTECHNICAL ENVIRONMENTAL

WATER RESOURCES CONSTRUCTION SERVICES

2010 Crow Canyon Place, Suite 250 San Ramon, CA 94583 (925) 866-9000 Fax (888) 279-2698 www.engeo.com

Project No. May 3, 2017 13889.000.000 Mr. Mark Pilarczyk Fore Green Development, LLC 20 S. Santa Cruz Avenue, #300 Los Gatos, CA 95030 Subject: 920 Bayswater Avenue Burlingame, California PRELIMINARY GEOTECHNICAL REPORT Dear Mr. Pilarczyk: With your authorization, we prepared this preliminary geotechnical report for your proposed project located across the following seven properties: 920 Bayswater Avenue (APN 029-235-170), 108 Myrtle Road (APN 029-235-180), 112 Myrtle Road (APN 029-235-190), 116 Myrtle Road (APN 029-235-200), 120 Myrtle Road (APN 029-235-210), 124 Myrtle Road (029-235-220), and 908 Bayswater Avenue (APN 029-235-160), collectively referred to as “920 Bayswater”, in Burlingame, California. The accompanying geotechnical feasibility assessment presents our conclusions and preliminary recommendations regarding residential development at the site. Our findings indicate that the study area is suitable for the proposed residential development provided the preliminary recommendations and guidelines provided in this report are implemented during project planning. The scope of this report was limited as an initial study. A design-level geotechnical exploration and collection of soil samples will be required to refine geotechnical hazards identified in this report, and develop geotechnical parameters for grading plan preparation and foundation design. The main geotechnical considerations at the site include (1) presence of undocumented fills, (2) presence of shallow groundwater, (3) presence of potentially liquefiable soils, and (4) proximity of the planned development with respect to nearby existing structures and infrastructure. We are pleased to have been of service to you on this project and are prepared to consult further with you and your design team as the project progresses. If you have any questions regarding the contents of this report, please do not hesitate to contact us. Sincerely, ENGEO Incorporated Eric M. Kiefer, PG James Yang, PE Jeff Fippin, GE ek/jyjf/jf

Fore Green Development, LLC 920 Bayswater Avenue, Burlingame 13889.000.000 Preliminary Geotechnical Exploration

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TABLE OF CONTENTS

Letter of Transmittal 1.0 INTRODUCTION .................................................................................................. 1

1.1 PURPOSE AND SCOPE .................................................................................................... 1 1.2 SITE LOCATION AND DESCRIPTION .............................................................................. 1 1.3 PROPOSED DEVELOPMENT ........................................................................................... 1

2.0 GEOLOGY AND SEISMICITY ............................................................................. 2

2.1 REGIONAL GEOLOGY ...................................................................................................... 2 2.2 FAULTING AND SEISMICITY ............................................................................................ 2

3.0 FIELD EXPLORATION ........................................................................................ 3

3.1 SURFACE CONDITIONS ................................................................................................... 3 3.2 CONE PENETRATION TESTS .......................................................................................... 3 3.3 SUBSURFACE CONDITIONS ............................................................................................ 3 3.4 GROUNDWATER CONDITIONS ....................................................................................... 3 3.5 LABORATORY TESTING ................................................................................................... 4

4.0 PRELIMINARY CONCLUSIONS ......................................................................... 4

4.1 EXISTING FILL ................................................................................................................... 4 4.2 SHALLOW GROUNDWATER ............................................................................................ 5 4.3 SOIL CORROSION POTENTIAL ........................................................................................ 5 4.4 EXCAVATABILITY .............................................................................................................. 5 4.5 SEISMIC HAZARDS ........................................................................................................... 5

4.5.1 Ground Rupture ..................................................................................................... 5 4.5.2 Ground Shaking ..................................................................................................... 5 4.5.3 Liquefaction-Induced Settlement ........................................................................... 6 4.5.4 2016 CBC Seismic Design Parameters ................................................................. 6

5.0 PRELIMINARY RECOMMENDATIONS .............................................................. 7

5.1 EARTHWORK RECOMMENDATIONS .............................................................................. 7

5.1.1 Demolition and Stripping ........................................................................................ 7 5.1.2 Existing Fill ............................................................................................................. 7 5.1.3 Selection of Materials ............................................................................................. 8 5.1.4 Fill Placement ......................................................................................................... 8

5.1.4.1 Expansive Fill Materials ............................................................................ 8 5.1.4.2 Low Expansive Fill Materials..................................................................... 8

5.1.5 Surface Drainage ................................................................................................... 9 5.1.6 Stormwater Infiltration ............................................................................................ 9

5.2 DEWATERING .................................................................................................................... 9 5.3 SHORING ......................................................................................................................... 10 5.4 PRE-CONSTRUCTION SURVEY AND CONSTRUCTION MONITORING ..................... 10 5.5 PRELIMINARY FOUNDATION DESIGN .......................................................................... 11 5.6 PAVEMENT DESIGN........................................................................................................ 11

5.6.1 Subgrade and Aggregate Base Compaction ....................................................... 12

6.0 DESIGN-LEVEL STUDY .................................................................................... 12

7.0 LIMITATIONS AND UNIFORMITY OF CONDITIONS ....................................... 12


TABLE OF CONTENTS (Continued)

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SELECTED REFERENCES FIGURES APPENDIX A – Cone Penetration Test Logs (Gregg Drilling, 2017)

APPENDIX B – Laboratory Test Data

APPENDIX C – Liquefaction Analysis


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1.0 INTRODUCTION 1.1 PURPOSE AND SCOPE We prepared this preliminary geotechnical report for your proposed residential development located on Bayswater Avenue in Burlingame, California. Our scope of services included a review of available published geologic maps, a field exploration consisting of four cone penetration tests (CPTs), and providing preliminary planning-level conclusions and recommendations for the project. Based on conversations with the client based on contractor availability and desired turnaround time, we updated the intended scope from two geotechnical soil borings to four CPTs with discrete soil samples. We selected the discrete sampling intervals using the preliminary data from the CPTs. For our use, we received the following: Submittal Package/Preliminary Design prepared by Withee Malcom Architects, LLP, dated

December 5, 2016. Offering Memorandum prepared by Colliers International, dated 2015. We prepared this preliminary report exclusively for Fore Green Development, LLC and their design team consultants. We should review any changes made in the character, design or layout of the development to modify the conclusions and recommendations contained in this report, as necessary. Design-level exploration and laboratory testing should be performed to facilitate construction drawings. This document may not be reproduced in whole or in part by any means whatsoever, nor may it be quoted or excerpted without our express written consent. 1.2 SITE LOCATION AND DESCRIPTION The “L”-shaped site comprises the following seven properties: 920 Bayswater Avenue (APN 029-235-170); 108 Myrtle Road (APN 029-235-180), 112 Myrtle Road (APN 029-235-190), 116 Myrtle Road (APN 029-235-200), 120 Myrtle Road (APN 029-235-210), 124 Myrtle Road (029-235-220), and 908 Bayswater Avenue (APN 029-235-160), collectively referred to as “920 Bayswater,” in Burlingame, California. The roughly 1.2-acre property is generally bounded by Bayswater Avenue to the southeast, Myrtle Road to the south and west, and residential development to the northeast and northwest (Figures 1 and 2). 1.3 PROPOSED DEVELOPMENT Based on review of the provided Submittal Package/Preliminary Design prepared by Withee Malcom Architects, LLP, dated December 5, 2016, site development will consist of: A residential podium structure – including:

o Four stories of wood construction above grade with 140 proposed units/apartments o Two below-grade parking stories comprising concrete construction

A community room/gym Two open courtyard areas Sidewalks and paved streets Underground utilities Landscaping


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Earthwork cut is assumed to be up to approximately 20 feet to facilitate the below-grade construction. Structural loads and grading are yet to be determined; however, we assume that structural loads will be representative for this type of construction and that subterranean grading will be required for the development. 2.0 GEOLOGY AND SEISMICITY 2.1 REGIONAL GEOLOGY The geology in the area of the subject property and vicinity has been mapped on a regional scale by Brabb, Graymer and Jones (1998; Figure 3). The geologic units mapped underlying the site are described as Pleistocene alluvial deposits (Qpaf). 2.2 FAULTING AND SEISMICITY The site is not located within a currently designated Alquist-Priolo Earthquake Fault Zone (Figure 4), and no known surface expression of active faults is believed to exist within the site. Fault rupture through the site, therefore, is not anticipated. Numerous small earthquakes occur every year in the San Francisco Bay Region and larger earthquakes have been recorded and can be expected to occur in the future. Figure 5 shows the approximate locations of these faults and significant historic earthquakes recorded within the Greater Bay Area Region. The most common nearby active faults within 35 miles of the site and their estimated maximum earthquake magnitudes are provided in the following table based on United States Geologic Survey (USGS) 2008 National Seismic Hazard Maps. An active fault is defined by the State Mining and Geology Board as one that has had surface displacement within Holocene time (about the last 11,000 years) (Hart, 1997). TABLE 2.2-1: Regional Faults Site: Latitude = 37.579051; Longitude = -122.341067

FAULT NAME APPROXIMATE

DISTANCE (MILES)

ESTIMATE OF MAXIMUM MAGNITUDE

(ELLSWORTH) N. San Andreas 2.8 7.9 San Gregorio 9.7 7.5 Monte Vista-Shannon 11.0 6.5 Hayward-Rodgers Creek 15.4 7.3 Calaveras 23.7 7.0 Mount Diablo Thrust 26.3 6.7 Green Valley 29.3 6.8 Greenville 34.7 7.0

The United States Geologic Survey evaluated the Bay Area seismicity through a study by the Working Group on California Earthquake Probabilities (WGCEP, 2014). WGCEP estimated the aggregate probability of a magnitude (Mw) of 6.7 or greater earthquake in the San Francisco Bay Area to be 72 percent in the San Francisco Region.


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3.0 FIELD EXPLORATION 3.1 SURFACE CONDITIONS Surface conditions at the exploration locations generally consisted of flatwork, pavement, and landscaping. No bedrock outcrops were encountered during our site visit, as expected for the mapped geological unit dominating the site. Based on our site visit as part of exploration activities, the site is currently developed and consists of an auto-body repair shop, residential development (both single- and multi-family), concrete flatwork, and landscaping. Based on review of the existing topographic maps, the site is generally flat. Additionally, the site is located adjacent to an active CalTrain rail. The rail is approximately 70 feet from the property boundary in the southwest and approximately 150 feet from the rail to the property boundary in the northwest. There is a smaller tolerance for construction-related settlement or uplift with respect to CalTrain right-of-ways. 3.2 CONE PENETRATION TESTS As part of our scope of services, we performed subsurface exploration comprising four cone penetration tests (CPT) on April 14, 2017, at various locations on the site as depicted on Figure 2. The CPTs were performed to depths ranging from approximately 60 to 80 feet below the ground surface (bgs). Adjacent to the tests, we collected samples at discrete depths using direct push methods. The location of our explorations are approximate and were estimated by pacing from existing site features, and should be considered accurate only to the degree implied by the method used. The CPTs were performed in general accordance with ASTM D-5778. Measurements include the tip resistance to penetration of the cone (Qc), the resistance of the surface sleeve (Fs), and dynamic pore pressure (U). The CPT logs are located in Appendix B. The CPT holes were backfilled with cement-bentonite grout upon completion in accordance with San Mateo County guidelines. 3.3 SUBSURFACE CONDITIONS Based on empirical correlations of the CPT data to estimated soil type and strength, the subsurface conditions generally comprise dense sand, silty sand, and sandy silt in the upper 26 to 28 feet, with interbedded layers of stiff clay and silty clay. The sandy material is underlain by a clay and silty clay layer to an approximate depth of 66 to 68 feet, with interbedded layers of dense sand and silty sand up to 10 feet thick. Below the clayey layer, the CPTs encountered a dense sand, silty sand, and sandy silt layer to the terminus depth of the explorations. 3.4 GROUNDWATER CONDITIONS Based on the pore pressure dissipation test results for 1-CPT1, 1-CPT2, and 1-CPT4, groundwater was estimated at a depth of approximately 9½ to 11 feet below the ground surface at the time of our field exploration, which generally agrees with publically available data from the State Water Resources Control Board. Based on our experience in the region and the data produced during the CPT tests, perched groundwater conditions may exist onsite. This can occur when a generally permeable sandy or silty layer is underlain by a generally impermeable clayey


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layer. The impermeable clayey layer prevents the groundwater from infiltrating deeper into the strata, so some groundwater remains “perched” at a higher elevation. Fluctuations in the level of groundwater may occur due to variations in rainfall, irrigation practice, and other factors not evident at the time measurements were made. Furthermore, watering conditions of nearby properties can produce varying groundwater conditions. Perched groundwater and seeps from the adjacent properties may be encountered during excavations. 3.5 LABORATORY TESTING We performed laboratory tests on select soil samples to evaluate their engineering properties. For this project, we performed plasticity index, moisture content, unit weight, and sieve testing of select soil samples recovered from the direct push samples. Laboratory data are included in Appendix C of this report. 4.0 PRELIMINARY CONCLUSIONS Based upon this preliminary study, the project site is suitable for the proposed development. The preliminary recommendations in this report should be considered in the initial planning for the study area. A design-level geotechnical study should be performed as part of the design process, which may include borings and laboratory testing to provide data for preparation of specific recommendations regarding site grading, foundations, and drainage for the proposed development. The exploration will also allow for more detailed evaluation of the below-described geotechnical constraints and afford the opportunity to provide techniques and procedures to be implemented during construction to mitigate potential geotechnical/geological hazards. As summarized in the sections below, the potential geotechnical constraints for development of the site are as follows: Presence of existing fill materials Presence of shallow groundwater. Presence of potentially liquefiable soil Proximity of proposed development to existing structures and infrastructure 4.1 EXISTING FILL We did not evaluate the potential thickness of existing fill as part of our exploration activities, since we understand that a basement level of up to 20 feet below the ground surface is proposed for the subject project. We anticipate that excavation activities associated with the underground level will remove the existing fill at the site; however, the thickness should be confirmed with borings and/or test pits during a design-level study. Existing fill left in-place underneath structural areas could undergo settlement that is not easily characterized and could ultimately be inadequate to effectively support the proposed building loads. In general, existing non-engineered fill should be excavated, and if deemed suitable for reuse, replaced as engineered fill. The extent and quality of existing fill should be evaluated at the time of design-level study and mitigated during remedial grading activities.


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4.2 SHALLOW GROUNDWATER Based on the results of the pore pressure dissipation tests, the groundwater table below the site was as shallow as 9½ feet below ground surface at the time of our exploration. In addition, review of publically available data from the State Water Resources Control Board indicates that groundwater in the vicinity of the area is as shallow as 13 feet below ground surface. Since the proposed excavation for the site is approximately 20 feet deep, we anticipate that dewatering will be required during excavation and shoring activities. 4.3 SOIL CORROSION POTENTIAL Sampling and testing for corrosion potential was not performed as part of this preliminary study. Representative samples of the foundation grade soils should be obtained during the design-level study to determine the potential for corrosion on buried metal and the potential for sulfate attack on foundation concrete. Based on the test results, the corrosion potential can be described and the recommended concrete design parameters can be developed in accordance with the guidelines presented in the California Building Code (2016). If subsurface transformers are proposed for the development, we recommend that the subsurface samples be obtained and tested in accordance with recommendations set forth by Pacific Gas & Electric once the transformer locations and depths are determined. 4.4 EXCAVATABILITY Based upon our observations and experience, we believe conventional grading and backhoe equipment will be able to excavate the soil deposits to the depths required to develop the site for the current plan. We provide the above excavatability information for general planning purposes only. This information is not intended for bidding purposes. 4.5 SEISMIC HAZARDS Potential seismic hazards resulting from a nearby moderate to major earthquake can generally be classified as primary and secondary. The primary effect is ground rupture, also called surface faulting. The common secondary seismic hazards include ground shaking and ground lurching. The following sections present a discussion of these hazards as they apply to the site. Based on topographic and lithologic data, the risk of regional subsidence or uplift, tsunamis, lateral spreading, lurching, seismically induced land sliding, or seiches is considered low to negligible at the site. 4.5.1 Ground Rupture Since there are no known active faults crossing the property and the site is not located within an Earthquake Fault Special Study Zone, ground rupture is unlikely at the subject property. 4.5.2 Ground Shaking An earthquake of moderate to high magnitude generated within the San Francisco Bay Region could cause considerable ground shaking at the site, similar to that which has occurred in the past. To mitigate the shaking effects, all structures should be designed using sound engineering judgment and the current California Building Code (CBC) requirements, as a minimum. Seismic


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design provisions of current building codes generally prescribe minimum lateral forces, applied statically to the structure, combined with the gravity forces of dead-and-live loads. The code-prescribed lateral forces are generally considered to be substantially smaller than the comparable forces that would be associated with a major earthquake. Therefore, structures should be able to: (1) resist minor earthquakes without damage, (2) resist moderate earthquakes without structural damage but with some nonstructural damage, and (3) resist major earthquakes without collapse but with some structural as well as nonstructural damage. Conformance to the current building code recommendations does not constitute any kind of guarantee that significant structural damage would not occur in the event of a maximum magnitude earthquake; however, it is reasonable to expect that a well-designed and well-constructed structure will not collapse or cause loss of life in a major earthquake (SEAOC, 1996). 4.5.3 Liquefaction-Induced Settlement Liquefaction is a phenomenon in which saturated, cohesionless soil is subject to a temporary loss of shear strength because of pore pressure build-up under the reversing cyclic shear stresses associated with earthquakes. Soils most susceptible to liquefaction are clean, loose, saturated, uniformly graded, fine-grained sands below the groundwater level. As noted in Section 2.1, the site is underlain by Pleistocene alluvial deposits. These deposits are generally not considered susceptible to liquefaction due to their age; however, we evaluated the susceptibility of the onsite soil to liquefaction. Our analyses were performed using a Maximum Considered Earthquake Peak Ground Acceleration (PGAM) of 0.78 and a Moment Magnitude (Mw) 7.9 earthquake; the PGA value is based on the 2016 CBC, and the earthquake magnitude is associated with an earthquake on the San Andreas Fault. Based on the pore pressure dissipation tests, we considered a groundwater of 9½ feet below ground surface for our analysis. We evaluated liquefaction potential and settlement using procedures published by Idriss and Boulanger (2008) and Zhang et al. (2002). We also utilized screening procedures in accordance to methodologies presented by Bray and Sancio (2006) to set a site-specific Ic cut-off of 2.3, and accounted for the aging effects by utilizing a strength gain factor of 2 in accordance with the findings of Arango et al. (2000) for soils deposited at least 10,000 years ago. Our results, presented in Appendix C, indicate less than 1¾ inch of total liquefaction-induced settlement at the existing ground surface. We estimate that maximum differential settlement of the existing ground surface will be on the order of 1 inch over 50 feet. Much of the potentially liquefiable soil will be excavated to construct the planned basement. Assuming the depth of basement is approximately 20 feet, the settlement of the ground below the basement floor would be subject to approximately ½ inch or less of settlement with a nominal differential settlement. We consider these settlement values to be conservative since the site is underlain by Pleistocene alluvial deposits. 4.5.4 2016 CBC Seismic Design Parameters We characterized the site as Site Class C in accordance with the 2016 CBC. We provide the 2013 CBC seismic design parameters in Table 4.5.4-1 below, which include design spectral response acceleration parameters based on the mapped Risk-Targeted Maximum Considered Earthquake (MCER) spectral response acceleration parameters.


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TABLE 4.5.4-1: 2016 CBC Seismic Design Parameters Latitude: 37.579051 / Longitude: -122.341067

PARAMETER VALUE

Site Class C Mapped MCER Spectral Response Acceleration at Short Periods, SS (g) 2.002 Mapped MCER Spectral Response Acceleration at 1-second Period, S1 (g) 0.942 Site Coefficient, FA 1.0 Site Coefficient, FV 1.3 MCER Spectral Response Acceleration at Short Periods, SMS (g) 2.002 MCER Spectral Response Acceleration at 1-second Period, SM1 (g) 1.224 Design Spectral Response Acceleration at Short Periods, SDS (g) 1.334 Design Spectral Response Acceleration at 1-second Period, SD1 (g) 0.816 Mapped MCE Geometric Mean (MCEG) Peak Ground Acceleration, PGA (g) 0.784

5.0 PRELIMINARY RECOMMENDATIONS The following recommendations are for initial land planning and preliminary estimating purposes. Final recommendations regarding site grading and foundation construction will be provided in a design-level geotechnical report after additional site-specific exploration has been undertaken. 5.1 EARTHWORK RECOMMENDATIONS 5.1.1 Demolition and Stripping Site demolition includes the removal of structures, foundations, and buried structures, including abandoned utilities, irrigation wells, septic tanks and leach fields, if any. Near-surface soft soil and surficial debris should be also removed from locations to be graded, from areas to receive fill or structures, or those areas to serve as borrow. The depth of removal of such materials should be determined by the Geotechnical Engineer in the field at the time of grading. Vegetation should also be removed from areas to receive fill or improvements, or those areas to serve for borrow. Tree roots should be removed down to a depth of at least 3 feet below existing grade. Subject to approval by the Landscape Architect, strippings and organically contaminated soils can be used in landscape areas. Otherwise, such soils should be removed from the project site. Any topsoil that will be retained for future use in landscape areas should be stockpiled in areas where it will not interfere with grading operations. All excavations should be cleaned to a firm undisturbed soil surface determined by our representative in the field. This surface should then be scarified, moisture conditioned, and backfilled with compacted engineered fill. The requirements for backfill materials and placement operations are the same as for engineered fill. Loose or uncontrolled backfilling of depressions resulting from demolition or stripping should not be allowed. 5.1.2 Existing Fill Existing fill is considered non-engineered and should be subexcavated, within the footprint of all areas to receive buildings and any settlement sensitive improvements, to expose underlying competent native soil that is approved by our field representative. The base of the excavations


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should be processed, moisture conditioned, as needed, and compacted in accordance with the recommendations for engineered fill. As previously indicated, the planned basement excavation should remove all existing fill. The fill material is suitable for use so long as it follows the recommendations set forth in Sections 5.1.3 and 5.1.4 of this report. 5.1.3 Selection of Materials With the exception of construction debris (wood, brick, asphalt, concrete, metal, etc.), trees, organically contaminated materials (soil which contains more than 3 percent organic content by weight), and environmentally impacted soil (if any), we anticipate the site soil is suitable for use as engineered fill provided any existing gravels are broken down to 6 inches or less in size. 5.1.4 Fill Placement 5.1.4.1 Expansive Fill Materials For preliminary land planning and cost estimating purposes, the following compaction control requirements should be anticipated for general fill areas utilizing materials with a PI greater than or equal to 20: Test Procedures: ASTM D-1557. Required Moisture Content: Not less than 4 percentage points above the optimum

moisture content. Minimum Relative Compaction: Between 87 and 92 percent relative compaction (R.C.) for

material within the upper 5 feet. Greater than 90 percent for anything deeper than 5 feet below proposed finished grade.

5.1.4.2 Low Expansive Fill Materials For preliminary land planning and cost estimating purposes, the following compaction control requirements should be anticipated for general fill areas utilizing materials with a PI less than 20: Test Procedures: ASTM D-1557. Required Moisture Content: Not less than 2 percentage points above optimum moisture

content. Minimum Relative Compaction: Minimum 90 percent R.C. for material within the upper

5 feet. Relative compaction refers to the in-place dry density of soil expressed as a percentage of the maximum dry density of the same material. Additional compaction requirements may be required that will be developed during our design-level exploration.


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5.1.5 Surface Drainage The project civil engineer is responsible for designing surface drainage improvements. With regard to geotechnical engineering issues, we recommend that finish grades be sloped away from buildings and pavements to the maximum extent practical to reduce the potentially damaging effects of expansive soil. The latest California Building Code Section 1804.3 specifies minimum slopes of 5 percent away from foundations. Where lot lines or surface improvements restrict meeting this slope requirement, we recommend that specific drainage requirements be developed. As a minimum, we recommend the following: 1. Discharge roof downspouts into closed conduits and direct away from foundations to

appropriate drainage devices. 2. Do not allow water to pond near foundations, pavements, or exterior flatwork. 5.1.6 Stormwater Infiltration Based on the anticipated fines content of near-surface soils, near-surface site soils are expected to have low permeability values for stormwater infiltration. Post-construction BMPs should not rely on infiltration; rather, we recommend BMPs receive subdrains that discharge treated stormwater into the planned storm drain system. If possible, we recommend bioswales/bioretention areas and other BMPs be planned a minimum of 5 feet away from structural site improvements. Where this is not practical, bioretention areas located within 5 feet of structural onsite or offsite improvements can either: 1. Be constructed with structural side walls capable of withstanding the loads from the adjacent

improvements, or 2. Incorporate filter material compacted to between 85 and 90 percent relative compaction

(ASTM D1557, latest edition). In addition, one of the following options should be followed: 1. Bioretention design should incorporate a waterproofing system lining the bioswale excavation

and a subdrain, or other storm drain system, to collect and convey water to an approved outlet. The waterproofing system should cover the bioretention area excavation in such a manner as to reduce the potential for moisture transmission beneath the adjacent improvements.

2. Alternatively, and with increased risk of movement of adjacent improvements, if minor

infiltration is desired, the perimeter of the bioretention areas should be lined with an HDPE tree root barrier that extends at least 1 to 2 feet below the bottom of the bioretention area.

5.2 DEWATERING Dewatering will be required for excavations extending below the groundwater table, to allow for construction under dry conditions. However, extensive dewatering could cause adjacent streets and other improvements to experience unacceptable settlement during construction. This is especially critical in the case of CalTrain infrastructure. CalTrain tolerances for settlement and/or uplift during construction activities tend to be much smaller than other general tolerances; CalTrain may require monitoring of their adjacent infrastructure during construction. The amount


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of dewatering required could be reduced significantly by using a relatively impervious shoring system and dewatering from inside the excavation. Ultimately, the selection and design of the dewatering system should be the responsibility of the contractor. There are a number of variables that will influence the effectiveness of a dewatering system including the number, depth, screened interval, and pumping rate of wells. The local sewer agency may prohibit the discharge of groundwater into the system or may charge a fee to do so. 5.3 SHORING Excavation shoring will be required to protect adjacent improvements and streets during excavation for the below-grade parking levels. The design of the shoring should be sufficiently rigid to prevent detrimental movement of the temporary shoring and possible damage of adjacent streets, facilities, or other improvements. Given the proposed excavation depth, it will likely be necessary to restrain the shoring by using a single-level or multi-level system of tie-back anchors or to provide internal bracing. Prior to tie-back design and construction, permission from the City of Burlingame, CalTrain, or other jurisdictions will have to be obtained if tie-backs are to encroach below those adjacent properties. Tie-back anchors should be designed to avoid adjacent underground utilities. Permanent or temporary tie-backs may be installed through the selected shoring system with 15 to 20 degree inclinations. Excavation, dewatering, and shoring are temporary works that are typically the responsibility of the contractor to design, install, maintain, and monitor. An experienced shoring and dewatering system designer should be retained to select and design these systems. The following sections provide some general considerations that should be incorporated into shoring and dewatering system design. Geotechnical shoring design recommendations are dependent on performance criteria, the type of system selected and construction sequencing. For preliminary design purposes, the following shoring systems may be considered suitable for the subject site: sheet piles, soldier pile and lagging, secant piles, diaphragm wall, and deep soil mixing (DSM). Sheet piles and soldier pile and lagging systems are not waterproof systems and some flow of groundwater into the excavation should be anticipated. During the design-level study, we can provide design-level recommendations and assist with the process of selection of shoring system and lateral support. Where possible, temporary construction slopes may be used above the groundwater level. The soil at the site are considered to be “Type B” soils according to OSHA criteria and as such, temporary slopes should be no steeper than 1:1½ (horizontal:vertical). The contractor should establish appropriate setback distances from the top of the slope for vehicles, equipment and spoil piles, and should establish appropriate protective measures for exposed slope faces. 5.4 PRE-CONSTRUCTION SURVEY AND CONSTRUCTION MONITORING Excavation dewatering and construction will take place adjacent to existing streets, improvements, and underground utilities. We recommend that a pre-construction survey (e.g. crack survey) for the surrounding improvements which may be affected by construction activities be performed before construction. This survey will form a basis for any damage claims and also assist the contractor in assessing the performance of the shoring. The pre-construction survey


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should record the elevation and horizontal position of all existing improvements within 50 feet minimum and may consist of photographs, video recordings, topographic survey, etc. We also recommend that a system of construction monitoring be installed. This may consist of inclinometers and groundwater monitoring wells that are installed within a distance of 5 to 15 feet from the excavation towards the existing improvements. Vibration monitoring should be considered during operations of heavy equipment such as pile driving, demolition, etc. In addition, a settlement survey should initially be performed on a weekly basis during excavation and on a monthly basis, approximately one month after the excavation has been completed, at a minimum. 5.5 PRELIMINARY FOUNDATION DESIGN For preliminary purposes, a rigid mat foundation system is feasible for the proposed structure. The thickness of the mat will be driven by the structural design. The structural mat should be designed for an average allowable bearing pressure of 3,000 pounds per square foot (psf) for dead-plus-live loads. The allowable bearing capacity may be increased to 3,500 psf in areas of loading concentration. These values may be increased by one-third when considering transient loads, such as wind or seismic. If a spring constant is needed for design, a modulus of subgrade reaction (ks) of 150 pounds per square inch per inch of deflection (psi/in) can be used. Resistance to lateral loads may be provided by frictional resistance between the foundation concrete and the subgrade soil, and by passive earth pressure acting against the side of the foundation. A coefficient of friction of 0.35 can be used between concrete and subgrade. The foundation should be designed for the anticipated settlement in Section 4.5. 5.6 PAVEMENT DESIGN As applicable, the following preliminary pavement sections for new streets have been determined for a Traffic Index of 4 through 6, an assumed R-value of 5 based on our experience in the project area and in accordance with the design methods contained in Topic 633 of Caltrans Highway Design Manual (including the asphalt factor of safety). TABLE 4.4-1: Preliminary Flexible Pavement Design

TRAFFIC INDEX (TI) AC (inches) AB (inches)

4.0 3.0 8.0 5.0 3.0 10.0 6.0 3.5 13.0

Notes: AC – Asphalt Concrete AB – Caltrans Class 2 aggregate base (R-value of 78 or greater)

The above preliminary pavement sections are provided for estimating only. We recommend the actual subgrade material be tested for R-value once established and the Traffic Index and minimum pavement section(s) should be confirmed by the Civil Engineer and the appropriate regulatory agencies.


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5.6.1 Subgrade and Aggregate Base Compaction The subgrade soil should be compacted to 90 percent relative compaction under sidewalks and 95 percent relative compaction under streets and roadways. The Aggregate base (AB) should meet the requirements for 3/4-inch maximum Class 2 AB in accordance with Section 26-1.02 of the latest Caltrans Standard Specifications and should be compacted to 95 percent relative compaction at a moisture content at least equal to the optimum. 6.0 DESIGN-LEVEL STUDY This report presents preliminary geotechnical findings, conclusions, and recommendations intended for preliminary planning purposes only. A design-level geotechnical exploration and assessment should be performed when development plans are finalized to further evaluate the potential geotechnical issues for the site as discussed above in Section 3.0. Soil samples should be obtained and tested for engineering properties to evaluate geotechnical hazards of the site soil. Specific recommendations for site grading and the design and construction of the foundations and utilities should be included in the design-level report. 7.0 LIMITATIONS AND UNIFORMITY OF CONDITIONS This report presents geotechnical recommendations for design of the improvements discussed in Section 1.3 for the project in Burlingame, California. If changes occur in the nature or design of the project, we should be allowed to review this report and provide additional recommendations, if any. It is the responsibility of the owner to transmit the information and recommendations of this report to the appropriate organizations or people involved in design of the project, including but not limited to developers, owners, buyers, architects, engineers, and designers. The conclusions and recommendations contained in this report are solely professional opinions and are valid for a period of no more than 2 years from the date of report issuance. We strived to perform our professional services in accordance with generally accepted geotechnical engineering principles and practices currently employed in the area; no warranty is expressed or implied. There are risks of earth movement and property damages inherent in building on or with earth materials. We are unable to eliminate all risks or provide insurance; therefore, we are unable to guarantee or warrant the results of our services. This report is based upon field and other conditions discovered at the time of report preparation. We developed this report with limited subsurface exploration data. We assumed that our subsurface exploration data is representative of the actual subsurface conditions across the site. Considering possible underground variability of soil, rock, and groundwater, additional costs may be required to complete the project. We recommend that the owner establish a contingency fund to cover such costs. If unexpected conditions are encountered, notify us immediately to review these conditions and provide additional and/or modified recommendations, as necessary. Our services did not include excavation sloping or shoring, soil volume change factors, flood potential, or a geohazard exploration. In addition, our preliminary geotechnical exploration did not include work to determine the existence of possible hazardous materials. If any hazardous materials are encountered during construction, notify the proper regulatory officials immediately.


Page | 13 May 3, 2017

This document must not be subject to unauthorized reuse; that is, reusing without our written authorization. Such authorization is essential because it requires us to evaluate the document’s applicability given new circumstances, not the least of which is passage of time.


May 3, 2017

SELECTED REFERENCES

Arango I., Lewis, M. R., and Kramer, C., 2000, Updated Liquefaction Potential Analysis Eliminates

Foundation Retrofitting of Two Critical Structures, Soil Dynamics and Earthquake Engineering, Vol. 20, 17-25.

Brabb, E.E., Graymer, R.W., and Jones, D.L., 1998, Geology of the Onshore Part of San Mateo

County, California: Derived from the Digital Database Open-File 98-137. Bray, J. D. and Sancio, R. B., September 2006, Assessment of the Liquefaction Susceptibility of

Fine-Grained Soils, Journal of Geotechnical and Geoenvironmental Engineering. California Building Code, 2016. Hart, E. W., and Bryant, W. A., 1997, Fault rupture hazard in California: Alquist-Priolo earthquake

fault zoning act with index to earthquake fault zone maps: California Division of Mines and Geology Special Publication 42.

Idriss, I.M. and Boulanger, R.W., 2008, Soil Liquefaction During Earthquakes, Earthquake

Engineering Research Institute, Monograph MNO-12. SEAOC, 1996, Recommended Lateral Force Requirements and Tentative Commentary. Working Group on California Earthquake Probabilities, 2013, The Uniform California Earthquake

Rupture Forecast, Version 3 UCERF 3, USGS Open File Report 2013. Zhang, G., Robertson, P. K., and Brachman, R. W. I., 2002, Estimating Liquefaction-Induced

Ground Settlements from CPT for Level Ground, Can. Geotech. J. 39, 1168-1180.

FIGURES FIGURE 1: Vicinity Map FIGURE 2: Site Plan FIGURE 3: Regional Geologic Map FIGURE 4: Earthquake Fault Zone Map FIGURE 5: Regional Faulting and Seismicity

0

0 FEET

METERS

20001000

VICINITY MAP920 BAYSWATER AVENUE

BURLINGAME, CALIFORNIA

13889.000.000

AS SHOWN 1

SITE

1-CPT1

1-CPT4

1-CPT2

1-CPT3

EXPLANATION

0

0 FEET

METERS

5025

CONE PENETROMETER TEST (ENGEO, 2017)

SITE PLAN920 BAYSWATER AVENUE


13889.000.000

AS SHOWN 2

SITE

1-CPT4

EXPLANATION

REGIONAL GEOLOGIC MAP920 BAYSWATER AVENUE


13889.000.000

AS SHOWN 3

SITE

ARTIFICIAL FILL

BASIN DEPOSITS (HOLOCENE)

ALLUVIAL FAN AND FLUVIAL DEPOSITS (HOLOCENE)

ALLUVIAL FAN AND FLUVIAL DEPOSITS (PLEISTOCENE)

COLMA FORMATION (PLEISTOCENE)

0

0 FEET

METERS

40002000

EXPLANATION

FAULTS CONSIDERED TO HAVE BEEN ACTIVE DURING HOLOCENETIME AND TO HAVE A RELATIVELY HIGH POTENTIAL FOR SURFACERUPTURE; SOLID LINE WHERE ACCURATELY LOCATED, LONG DASHWHERE APPROXIMATELY LOCATED, SHORT DASH WHERE INFERRED,DOTTED WHERE CONCEALED; QUERY (?) INDICATES ADDITIONALUNCERTAINTY. EVIDENCE OF HISTORIC OFFSET INDICATED BY YEAROF EARTHQUAKE-ASSOCIATED EVENT OR C FOR DISPLACEMENTCAUSED BY CREEP OR POSSIBLE CREEP

EARTHQUAKE FAULT ZONE BOUNDARIES; DELINEATED AS STRAIGHT-LINE SEGMENTS THAT CONNECT ENCIRCLED TURNING POINTS SOAS TO DEFINE EARTHQUAKE FAULT ZONE SEGMENTS

EARTHQUAKE FAULT ZONE MAP920 BAYSWATER AVENUE


13889.000.000

AS SHOWN 4

0

0 FEET

METERS

40002000

SITE

ORTIGALITA

GREENVILLE

SANG

REG

OR

IO

SANANDREAS

HAYWARD

POINTREYES

SANANDREAS

CONCORD

GR

EENV

ALLEY

VACA

SANJOAQUIN

ORTIGALITA

TOLAY

RODGERSCREEK

CO

RD

ELIA

MIDWAY

SILVERCREEK

SANJOSE

MONTE VISTA SHANNON

BERROCAL

ZAYANTE

VERGELES

SARGENT

DUNNIGAHHILLS

MAACAMA

CALAVERAS

CARNEGIE CORAL HOLLOW

WEST

NAPA

BENNETTVALLEY

HU

NTING

CR

EEK- BER

RYESSA

ALEXANDER-REDWOOD

HILL

GEYSERPEAK

COLLAYOMI

ANTIOCH

BEARM

OUN

TAINS

BEARMOUNTAINS

MELONES

BEARMOUNTAINS

TAHOE

- SIERRAFRONTAL

GR

EA

TV

AL

LE

YF

AU

LT

GR

EA

TV

AL

LE

YF

AU

LT

SAN ANDREAS

Santa Cruz Santa Clara

Merced

San MateoMariposa

Alameda

Stanislaus

Contra CostaSan Joaquin

MarinTuolumne

CalaverasSolano

AmadorSacramento

NapaSonoma Alpine

YoloEl Dorado

Lake

SanFrancisco

0

0

MILES

KILOMETERS

15

30

EXPLANATION

MAGNITUDE 7+

MAGNITUDE 6-7

MAGNITUDE 5-6

HISTORIC FAULT

HOLOCENE FAULT

QUATERNARY FAULT

HISTORIC BLIND THRUST FAULTZONE

SITE

REGIONAL FAULTING AND SEISMICITY920 BAYSWATER AVENUE


13889.000.000

AS SHOWN 5

APPENDIX A CONE PENETRATION TEST LOGS (GREGG DRILLING & TESTING, INC., 2017)

GREGG DRILLING & TESTING, INC. GEOTECHNICAL AND ENVIRONMENTAL INVESTIGATION SERVICES

950 Howe Rd Martinez, California 94553 (925) 313-5800 FAX (925) 313-0302 www.greggdrilling.com

April 17, 2017 Engeo Attn: Erik Kiefer Subject: CPT Site Investigation 920 Bayswater Burlingame, California GREGG Project Number: 17-054MA Dear Mr. Kiefer: The following report presents the results of GREGG Drilling & Testing’s Cone Penetration Test investigation for the above referenced site. The following testing services were performed:

1 Cone Penetration Tests (CPTU) 2 Pore Pressure Dissipation Tests (PPD) 3 Seismic Cone Penetration Tests (SCPTU) 4 UVOST Laser Induced Fluorescence (UVOST) 5 Groundwater Sampling (GWS) 6 Soil Sampling (SS) 7 Vapor Sampling (VS) 8 Membrane Interface Probe (MIP) 9 Vane Shear Testing (VST) 10 Dilatometer Testing (DMT)

A list of reference papers providing additional background on the specific tests conducted is provided in the bibliography following the text of the report. If you would like a copy of any of these publications or should you have any questions or comments regarding the contents of this report, please do not hesitate to contact our office at (925) 313-5800. Sincerely, GREGG Drilling & Testing, Inc.

Mary Walden Operations Manager



Cone Penetration Test Sounding Summary

-Table 1-

CPT Sounding Identification

Date Termination Depth (feet)

Depth of Groundwater Samples (feet)

Depth of Soil Samples (feet)

Depth of Pore Pressure Dissipation

Tests (feet) 1-CPT01 4/14/17 80 - 30 24.6, 45.4 1-CPT02 4/14/17 60 - 20 - 1-CPT03 4/14/17 74 - - 42.8 1-CPT04 4/14/17 60 - 26 44.3



Bibliography Lunne, T., Robertson, P.K. and Powell, J.J.M., “Cone Penetration Testing in Geotechnical Practice” E & FN Spon. ISBN 0 419 23750, 1997 Roberston, P.K., “Soil Classification using the Cone Penetration Test”, Canadian Geotechnical Journal, Vol. 27, 1990 pp. 151-158. Mayne, P.W., “NHI (2002) Manual on Subsurface Investigations: Geotechnical Site Characterization”, available through www.ce.gatech.edu/~geosys/Faculty/Mayne/papers/index.html, Section 5.3, pp. 107-112. Robertson, P.K., R.G. Campanella, D. Gillespie and A. Rice, “Seismic CPT to Measure In-Situ Shear Wave Velocity”, Journal of Geotechnical Engineering ASCE, Vol. 112, No. 8, 1986 pp. 791-803. Robertson, P.K., Sully, J., Woeller, D.J., Lunne, T., Powell, J.J.M., and Gillespie, D.J., "Guidelines for Estimating Consolidation Parameters in Soils from Piezocone Tests", Canadian Geotechnical Journal, Vol. 29, No. 4, August 1992, pp. 539-550. Robertson, P.K., T. Lunne and J.J.M. Powell, “Geo-Environmental Application of Penetration Testing”, Geotechnical Site Characterization, Robertson & Mayne (editors), 1998 Balkema, Rotterdam, ISBN 90 5410 939 4 pp 35-47. Campanella, R.G. and I. Weemees, “Development and Use of An Electrical Resistivity Cone for Groundwater Contamination Studies”, Canadian Geotechnical Journal, Vol. 27 No. 5, 1990 pp. 557-567. DeGroot, D.J. and A.J. Lutenegger, “Reliability of Soil Gas Sampling and Characterization Techniques”, International Site Characterization Conference - Atlanta, 1998. Woeller, D.J., P.K. Robertson, T.J. Boyd and Dave Thomas, “Detection of Polyaromatic Hydrocarbon Contaminants Using the UVIF-CPT”, 53rd Canadian Geotechnical Conference Montreal, QC October pp. 733-739, 2000. Zemo, D.A., T.A. Delfino, J.D. Gallinatti, V.A. Baker and L.R. Hilpert, “Field Comparison of Analytical Results from Discrete-Depth Groundwater Samplers” BAT EnviroProbe and QED HydroPunch, Sixth national Outdoor Action Conference, Las Vegas, Nevada Proceedings, 1992, pp 299-312. Copies of ASTM Standards are available through www.astm.org

Revised 02/05/2015 i

Cone Penetration Testing Procedure (CPT)

Gregg Drilling carries out all Cone Penetration Tests

(CPT) using an integrated electronic cone system,

Figure CPT.

The cone takes measurements of tip resistance (qc),

sleeve resistance (fs), and penetration pore water

pressure (u2). Measurements are taken at either 2.5 or

5 cm intervals during penetration to provide a nearly

continuous profile. CPT data reduction and basic

interpretation is performed in real time facilitating on‐

site decision making. The above mentioned

parameters are stored electronically for further

analysis and reference. All CPT soundings are

performed in accordance with revised ASTM standards

(D 5778‐12).

The 5mm thick porous plastic filter element is located

directly behind the cone tip in the u2 location. A new

saturated filter element is used on each sounding to

measure both penetration pore pressures as well as

measurements during a dissipation test (PPDT). Prior

to each test, the filter element is fully saturated with

oil under vacuum pressure to improve accuracy.

When the sounding is completed, the test hole is

backfilled according to client specifications. If grouting

is used, the procedure generally consists of pushing a

hollow tremie pipe with a “knock out” plug to the

termination depth of the CPT hole. Grout is then

pumped under pressure as the tremie pipe is pulled

from the hole. Disruption or further contamination to

the site is therefore minimized.

Figure CPT

Revised 02/05/2015 ii

Gregg 15cm2 Standard Cone Specifications

Dimensions

Cone base area 15 cm2

Sleeve surface area 225 cm2

Cone net area ratio 0.80

Specifications

Cone load cell

Full scale range 180 kN (20 tons)

Overload capacity 150%

Full scale tip stress 120 MPa (1,200 tsf)

Repeatability 120 kPa (1.2 tsf)

Sleeve load cell

Full scale range 31 kN (3.5 tons)


Full scale sleeve stress 1,400 kPa (15 tsf)

Repeatability 1.4 kPa (0.015 tsf)

Pore pressure transducer

Full scale range 7,000 kPa (1,000 psi)


Repeatability 7 kPa (1 psi)

Note: The repeatability during field use will depend somewhat on ground conditions, abrasion,

maintenance and zero load stability.

Revised 2/05/2015 i

Cone Penetration Test Data & Interpretation The Cone Penetration Test (CPT) data collected are presented in graphical and electronic form in the

report. The plots include interpreted Soil Behavior Type (SBT) based on the charts described by

Robertson (1990). Typical plots display SBT based on the non‐normalized charts of Robertson et al

(1986). For CPT soundings deeper than 30m, we recommend the use of the normalized charts of

Robertson (1990) which can be displayed as SBTn, upon request. The report also includes

spreadsheet output of computer calculations of basic interpretation in terms of SBT and SBTn and

various geotechnical parameters using current published correlations based on the comprehensive

review by Lunne, Robertson and Powell (1997), as well as recent updates by Professor Robertson

(Guide to Cone Penetration Testing, 2015). The interpretations are presented only as a guide for

geotechnical use and should be carefully reviewed. Gregg Drilling & Testing Inc. does not warranty

the correctness or the applicability of any of the geotechnical parameters interpreted by the

software and does not assume any liability for use of the results in any design or review. The user

should be fully aware of the techniques and limitations of any method used in the software. Some

interpretation methods require input of the groundwater level to calculate vertical effective stress.

An estimate of the in‐situ groundwater level has been made based on field observations and/or CPT

results, but should be verified by the user.

A summary of locations and depths is available in Table 1. Note that all penetration depths

referenced in the data are with respect to the existing ground surface.

Note that it is not always possible to clearly identify a soil type based solely on qt, fs, and u2. In these

situations, experience, judgment, and an assessment of the pore pressure dissipation data should be

used to infer the correct soil behavior type.

Figure SBT (After Robertson et al., 1986) – Note: Colors may vary slightly compared to plots

ZONE SBT 12

3456789

101112

Sensitive, fine grainedOrganic materials ClaySilty clay to clayClayey silt to silty claySandy silt to clayey siltSilty sand to sandy siltSand to silty sand Sand

Gravely sand to sand Very stiff fine grained*Sand to clayey sand*

*over consolidated or cemented


Cone Penetration Test (CPT) Interpretation Gregg uses a proprietary CPT interpretation and plotting software. The software takes the CPT data and

performs basic interpretation in terms of soil behavior type (SBT) and various geotechnical parameters

using current published empirical correlations based on the comprehensive review by Lunne, Robertson

and Powell (1997). The interpretation is presented in tabular format using MS Excel. The interpretations

are presented only as a guide for geotechnical use and should be carefully reviewed. Gregg does not

warranty the correctness or the applicability of any of the geotechnical parameters interpreted by the

software and does not assume any liability for any use of the results in any design or review. The user

should be fully aware of the techniques and limitations of any method used in the software.

The following provides a summary of the methods used for the interpretation. Many of the empirical

correlations to estimate geotechnical parameters have constants that have a range of values depending

on soil type, geologic origin and other factors. The software uses ‘default’ values that have been

selected to provide, in general, conservatively low estimates of the various geotechnical parameters.

Input:

1 Units for display (Imperial or metric) (atm. pressure, pa = 0.96 tsf or 0.1 MPa)

2 Depth interval to average results (ft or m). Data are collected at either 0.02 or 0.05m and

can be averaged every 1, 3 or 5 intervals.

3 Elevation of ground surface (ft or m)

4 Depth to water table, zw (ft or m) – input required

5 Net area ratio for cone, a (default to 0.80)

6 Relative Density constant, CDr (default to 350)

7 Young’s modulus number for sands, α (default to 5)

8 Small strain shear modulus number

a. for sands, SG (default to 180 for SBTn 5, 6, 7)

b. for clays, CG (default to 50 for SBTn 1, 2, 3 & 4)

9 Undrained shear strength cone factor for clays, Nkt (default to 15)

10 Over Consolidation ratio number, kocr (default to 0.3)

11 Unit weight of water, (default to γw = 62.4 lb/ft3 or 9.81 kN/m3)

Column

1 Depth, z, (m) – CPT data is collected in meters

2 Depth (ft)

3 Cone resistance, qc (tsf or MPa)

4 Sleeve resistance, fs (tsf or MPa)

5 Penetration pore pressure, u (psi or MPa), measured behind the cone (i.e. u2)

6 Other – any additional data

7 Total cone resistance, qt (tsf or MPa) qt = qc + u (1‐a)


8 Friction Ratio, Rf (%) Rf = (fs/qt) x 100%

9 Soil Behavior Type (non‐normalized), SBT see note

10 Unit weight, γ (pcf or kN/m3) based on SBT, see note

11 Total overburden stress, σv (tsf) σvo = σ z

12 In‐situ pore pressure, uo (tsf) uo = γ w (z ‐ zw)

13 Effective overburden stress, σ'vo (tsf ) σ'vo = σvo ‐ uo

14 Normalized cone resistance, Qt1 Qt1= (qt ‐ σvo) / σ'vo

15 Normalized friction ratio, Fr (%) Fr = fs / (qt ‐ σvo) x 100%

16 Normalized Pore Pressure ratio, Bq Bq = u – uo / (qt ‐ σvo)

17 Soil Behavior Type (normalized), SBTn see note

18 SBTn Index, Ic see note

19 Normalized Cone resistance, Qtn (n varies with Ic) see note

20 Estimated permeability, kSBT (cm/sec or ft/sec) see note

21 Equivalent SPT N60, blows/ft see note

22 Equivalent SPT (N1)60 blows/ft see note

23 Estimated Relative Density, Dr, (%) see note

24 Estimated Friction Angle, φ', (degrees) see note

25 Estimated Young’s modulus, Es (tsf) see note

26 Estimated small strain Shear modulus, Go (tsf) see note

27 Estimated Undrained shear strength, su (tsf) see note

28 Estimated Undrained strength ratio su/σv’

29 Estimated Over Consolidation ratio, OCR see note

Notes:

1 Soil Behavior Type (non‐normalized), SBT (Lunne et al., 1997 and table below)

2 Unit weight, γ either constant at 119 pcf or based on Non‐normalized SBT (Lunne et al.,

1997 and table below)

3 Soil Behavior Type (Normalized), SBTn Lunne et al. (1997)

4 SBTn Index, Ic Ic = ((3.47 – log Qt1)2 + (log Fr + 1.22)2)0.5

5 Normalized Cone resistance, Qtn (n varies with Ic)

Qtn = ((qt ‐ σvo)/pa) (pa/(σvo)n and recalculate Ic, then iterate:

When Ic < 1.64, n = 0.5 (clean sand)

When Ic > 3.30, n = 1.0 (clays)

When 1.64 < Ic < 3.30, n = (Ic – 1.64)0.3 + 0.5

Iterate until the change in n, ∆n < 0.01

Revised 02/05/2015 iii

6 Estimated permeability, kSBT based on Normalized SBTn (Lunne et al., 1997 and table below)

7 Equivalent SPT N60, blows/ft Lunne et al. (1997)

60

a

N

)/p(qt

= 8.5

4.6

I1 c

8 Equivalent SPT (N1)60 blows/ft (N1)60 = N60 CN,

where CN = (pa/σvo)0.5

9 Relative Density, Dr, (%) Dr2 = Qtn / CDr

Only SBTn 5, 6, 7 & 8 Show ‘N/A’ in zones 1, 2, 3, 4 & 9

10 Friction Angle, φ', (degrees) tan φ ' =

29.0'

qlog

68.2

1

vo

c

Only SBTn 5, 6, 7 & 8 Show’N/A’ in zones 1, 2, 3, 4 & 9

11 Young’s modulus, Es Es = α qt

Only SBTn 5, 6, 7 & 8 Show ‘N/A’ in zones 1, 2, 3, 4 & 9

12 Small strain shear modulus, Go

a. Go = SG (qt σ'vo pa)1/3 For SBTn 5, 6, 7

b. Go = CG qt For SBTn 1, 2, 3& 4

Show ‘N/A’ in zones 8 & 9

13 Undrained shear strength, su su = (qt ‐ σvo) / Nkt

Only SBTn 1, 2, 3, 4 & 9 Show ‘N/A’ in zones 5, 6, 7 & 8

14 Over Consolidation ratio, OCR OCR = kocr Qt1

Only SBTn 1, 2, 3, 4 & 9 Show ‘N/A’ in zones 5, 6, 7 & 8

The following updated and simplified SBT descriptions have been used in the software:

SBT Zones SBTn Zones

1 sensitive fine grained 1 sensitive fine grained

2 organic soil 2 organic soil

3 clay 3 clay

4 clay & silty clay 4 clay & silty clay

5 clay & silty clay

6 sandy silt & clayey silt

Revised 02/05/2015 iv

7 silty sand & sandy silt 5 silty sand & sandy silt

8 sand & silty sand 6 sand & silty sand

9 sand

10 sand 7 sand

11 very dense/stiff soil* 8 very dense/stiff soil*

12 very dense/stiff soil* 9 very dense/stiff soil*

*heavily overconsolidated and/or cemented

Track when soils fall with zones of same description and print that description (i.e. if soils fall

only within SBT zones 4 & 5, print ‘clays & silty clays’)

Revised 02/05/2015 v

Estimated Permeability (see Lunne et al., 1997)

SBTn Permeability (ft/sec) (m/sec)

1 3x 10‐8 1x 10‐8

2 3x 10‐7 1x 10‐7

3 1x 10‐9 3x 10‐10

4 3x 10‐8 1x 10‐8

5 3x 10‐6 1x 10‐6

6 3x 10‐4 1x 10‐4

7 3x 10‐2 1x 10‐2

8 3x 10‐6 1x 10‐6

9 1x 10‐8 3x 10‐9

Estimated Unit Weight (see Lunne et al., 1997)

SBT Approximate Unit Weight (lb/ft3) (kN/m3)

1 111.4 17.5

2 79.6 12.5

3 111.4 17.5

4 114.6 18.0

5 114.6 18.0

6 114.6 18.0

7 117.8 18.5

8 120.9 19.0

9 124.1 19.5

10 127.3 20.0

11 130.5 20.5

12 120.9 19.0

Revised 02.05.2015 i

Pore Pressure Dissipation Tests (PPDT) Pore Pressure Dissipation Tests (PPDT’s) conducted at various intervals can be used to measure equilibrium water pressure (at the time of the CPT). If conditions are hydrostatic, the equilibrium water pressure can be used to determine the approximate depth of the ground water table. A PPDT is conducted when penetration is halted at specific intervals determined by the field representative. The variation of the penetration pore pressure (u) with time is measured behind the tip of the cone and recorded. Pore pressure dissipation data can be interpreted to provide estimates of:

Equilibrium piezometric pressure

Phreatic Surface

In situ horizontal coefficient of

consolidation (ch)

In situ horizontal coefficient of

permeability (kh)

In order to correctly interpret the equilibrium piezometric pressure and/or the phreatic surface, the pore pressure must be monitored until it reaches equilibrium, Figure PPDT. This time is commonly referred to as t100, the point at which 100% of the excess pore pressure has dissipated. A complete reference on pore pressure dissipation tests is presented by Robertson et al. 1992 and Lunne et al. 1997. A summary of the pore pressure dissipation tests are summarized in Table 1.

Figure PPDT


Seismic Cone Penetration Testing (SCPT) Seismic Cone Penetration Testing (SCPT) can be conducted at various intervals during the Cone

Penetration Test. Shear wave velocity (Vs) can then be calculated over a specified interval with depth. A

small interval for seismic testing, such as 1‐1.5m (3‐5ft) allows for a detailed look at the shear wave profile

with depth. Conversely, a larger interval such as 3‐6m (10‐20ft) allows for a more average shear wave

velocity to be calculated. Gregg’s cones have a horizontally active geophone located 0.2m (0.66ft) behind

the tip.

To conduct the seismic shear wave test, the penetration of the cone is stopped and the rods are decoupled

from the rig. An automatic hammer is triggered to send a shear wave into the soil. The distance from the

source to the cone is calculated knowing the total depth of the cone and the horizontal offset distance

between the source and the cone. To calculate an interval velocity, a minimum of two tests must be

performed at two different

depths. The arrival times

between the two wave traces

are compared to obtain the

difference in time (∆t). The

difference in depth is

calculated (∆d) and velocity

can be determined using the

simple equation: v = ∆d/∆t

Multiple wave traces can be

recorded at the same depth

to improve quality of the

data.

A complete reference on

seismic cone penetration

tests is presented by

Robertson et al. 1986 and

Lunne et al. 1997.

A summary the shear wave velocities, arrival times and wave traces are provided with the report.

Figure SCPT

(S)

1

2

t 1

2

1 2

12

12

Revised 3/09/2015 i

Groundwater Sampling Gregg Drilling & Testing, Inc. conducts groundwater sampling using a sampler as shown in Figure GWS. The groundwater sampler has a retrievable stainless steel or disposable PVC screen with steel drop off tip. This allows for samples to be taken at multiple depth intervals within the same sounding location. In areas of slower water recharge, provisions may be made to set temporary PVC well screens during sampling to allow the pushing equipment to advance to the next sample location while the groundwater is allowed to infiltrate. The groundwater sampler operates by advancing 44.5mm (1¾ inch) hollow push rods with the filter tip in a closed configuration to the base of the desired sampling interval. Once at the desired sample depth, the push rods are retracted; exposing the encased filter screen and allowing groundwater to infiltrate hydrostatically from the formation into the inlet screen. A small diameter bailer (approximately ½ or ¾ inch) is lowered through the push rods into the screen section for sample collection. The number of downhole trips with the bailer and time necessary to complete the sample collection at each depth interval is a function of sampling protocols, volume requirements, and the yield characteristics and storage capacity of the formation. Upon completion of sample collection, the push rods and sampler, with the exception of the PVC screen and steel drop off tip are retrieved to the ground surface, decontaminated and prepared for the next sampling event.

For a detailed reference on direct push groundwater

sampling, refer to Zemo et. al., 1992. Figure GWS


Soil Sampling Gregg Drilling & Testing, Inc. uses a piston‐type

push‐in sampler to obtain small soil samples

without generating any soil cuttings, Figure SS.

Two different types of samplers (12 and 18 inch)

are used depending on the soil type and density.

The soil sampler is initially pushed in a "closed"

position to the desired sampling interval using

the CPT pushing equipment. Keeping the sampler

closed minimizes the potential of cross

contamination. The inner tip of the sampler is

then retracted leaving a hollow soil sampler with

inner 1¼” diameter sample tubes. The hollow

sampler is then pushed in a locked "open"

position to collect a soil sample. The filled

sampler and push rods are then retrieved to the

ground surface. Because the soil enters the

sampler at a constant rate, the opportunity for

100% recovery is increased. For environmental

analysis, the soil sample tube ends are sealed

with Teflon and plastic caps. Often, a longer "split

tube" can be used for geotechnical sampling.

For a detailed reference on direct push soil

sampling, refer to Robertson et al, 1998.

Figure SS


Ultra‐Violet Induced Fluorescence (UVOST) Gregg Drilling conducts Laser Induced Fluorescence (LIF)

Cone Penetration Tests using a UVOST module that is

located behind the standard piezocone, Figure UVOST. The

laser induced fluorescence cone works on the principle that

polycyclic aromatic hydrocarbons (PAH’s), mixed with soil

and/or groundwater, fluoresce when irradiated by ultra

violet light. Therefore, by measuring the intensity of

fluorescence, the lateral and vertical extent of hydrocarbon

contamination in the ground can be estimated.

The UVOST module uses principles of fluorescence

spectrometry by irradiating the soil with ultra violet light

produced by a laser and transmitted to the cone through

fiber optic cables. The UV light passes through a small

window in the side of the cone into the soil. Any

hydrocarbon molecules present in the soil absorb the light

energy during radiation and immediately re‐emit the light

at a longer wavelength. This re‐emission is termed

fluorescence. The UVOST system also measures the

emission decay with time at four different wavelengths

(350nm, 400nm, 450nm, and 500nm). This allows the

software to determine a product “signature” at each data

point. This process provides a method to evaluate the type

of contaminant. A sample output from the UVOST system

is shown in Figure Output. In general, the typical detection

limit for the UVOST system is <100 ppm and it will operate

effectively above and below the saturated zone.

With the capability to push up to 200m (600ft) per day, laser induced fluorescence offers a fast and

efficient means for delineating PAH contaminant plumes. Color coded logs offer qualitative information

in a quick glance and can be produced in the field for real‐time decision making. Coupled with the data

provided by the CPT, a complete site assessment can be completed with no samples or cuttings, saving

laboratory costs as well as site and environmental impact.

Figure UVOST Figure UVOST


Figure Output

Revised 02/05/2015 iii

Hydrocarbons detected with UVOST

Gasoline

Diesel

Jet (Kerasene)

Motor Oil

Cutting fluids

Hydraulic fluids

Crude Oil

Hydrocarbons rarely detected using UVOST

Extremely weathered gasoline

Coal tar

Creosote

Bunker Oil

Polychlorinated bi‐phenols (PCB’s)

Chlorinated solvent DNAPL

Dissolved phase (aqueous) PAH’s

Potential False Positives (fluorescence observed)

Sea‐shells (weak‐medium)

Paper (medium‐strong depending on color)

Peat/meadow mat (weak)

Calcite/calcareous sands (weak)

Tree roots (weak‐medium)

Sewer lines (medium‐strong)

Potential False Negatives (do not fluoresce)

Extremely weathered fuels (especially gasoline)

Aviation gasoline (weak)

“Dry” PAHs such as aqueous phase, lamp black, purifier chips

Creosotes (most)

Coal tars (most) gasoline (weak)

Most chlorinated solvents

Benzene, toluene, zylenes (relatively pure)

Info Box :Contains pertinent loginfo including name andlocation.

Callouts :Waveforms fromselected depths ordepth ranges showingthe multi-wavelengthwaveform for thatdepth.

The four peaks are dueto fluorescence at fourwavelengths andreferred to as“channels”. Eachchannel is assigned acolor.

V

elativeamplitude of the fourchannels and/orbroadening of one ormore channels.

Basic waveformstatistics and anyoperator notes aregiven below the callout.

arious NAPLs willhave a uniquewaveform "fingerprint"due to the r

Main Plot :Signal (total fluorescence) versus depth where signal is relative to theReference Emitter (RE). The total area of the waveform is divided by the totalarea of the Reference Emitter yielding the %RE. This %RE scales with theNAPL fluorescence. The fill color is based on relative contribution of eachchannel's area to the total waveform area (see callout waveform). The channel-to-color relationship and corresponding wavelengths are given in the upper rightcorner of the main plot.

Note A :Time is along the x axis. No scaleis given, but it is a consistent320ns wide.The y axis is in mV and directlycorresponds to the amount oflight striking the photodetector.

Note B :These two waveforms are clearlydifferent. The first is weathereddiesel from the log itself while thesecond is the Reference Emitter(a blend of NAPLs) always takenbefore each log for calibration.

Dakota Technologies

UVOST Log Reference

Rate Plot :The rate of probeadvancement. ~ 0.8in(2cm) per second ispreferred.

A noticeable decrease inthe rate of advancementmay be indicative ofdifficult probingconditions (gravel,angular sands, etc.)such as that seen hereat ~5 ft.

Notice that this log wasterminated arbitrarily, notdue to "refusal", whichwould have beenindicated by a suddenrate drop at final depth.

Note C :Callouts can be a single depth(see 3rd callout) or a range (see4th callout). The range is notedon the depth axis by a bold line.When the callout is a range, theaverage and standard deviationin %RE is given below thecallout.

Note C

Note A

Note B

Conductivity Plot :The ElectricalConductivity (EC) of thesoil can be loggedsimultaneously with theUVOST data. EC oftenprovides insight into thestratigraphy.Note the drop in EC from10 - 13 ft, indicating ashift from consolidated tounconsolidatedstratigraphy. Thiscorrelates with theobserved NAPLdistribution.

2008-12-12

Data Files

*.lif.raw.bin

*.lif.plt

*.lif.jpg

*.lif.dat.txt

*.lif.sum.txt

*.lif.log.txt

Raw data file. Header is ASCII format and contains information stored when the file was initiallywritten (e.g. date, total depth, max signal, gps, etc., and any information entered by the operator). Allraw waveforms are appended to the bottom of the file in a binary format.

Stores the plot scheme history (e.g. callout depths) for associated Raw file. Transfer along with theRaw file in order to recall previous plots.

A jpg image of the OST log including the main signal vs. depth plot, callouts, information, etc.

Data export of a single Raw file. ASCII tab delimited format. No string header is provided for thecolumns (to make importing into other programs easier). Each row is a unique depth reading. Thecolumns are: Depth, Total Signal (%RE), Ch1%, Ch2%, Ch3%, Ch4%, Rate, Conductivity Depth,Conductivity Signal, Hammer Rate. Summing channels 1 to 4 yields the Total Signal.

A summary file for a number of Raw files. ASCII tab delimited format. The file contains a stringheader. The summary includes one row for each Raw file and contains information for each fileincluding: the file name, gps coordinates, max depth, max signal, and depth at which the max signaloccured.

An activity log generated automatically located in the OST application directory in the 'log' subfolder.Each OST unit the computer operates will generate a separate log file per month. A log file containsmuch of the header information contained within each separate Raw file, including: date, total depth,max signal, etc.

Reference Emitter Example

CH1482021.7

CH2810836.6

CH3624928.2

CH4298413.5

Total22161100%

CH1492322.3

CH2574325.9

CH3416618.8

CH417357.8

Total1658775%

ChannelArea (pVs)Percent RE

Common Waveforms

Diesel Gas Kerosene Motor Oil

Waveform Signal Calculation

(highly dependent on soil, weathering, etc.)

+++ =+++ =

APPENDIX B LABORATORY TEST DATA (ENGEO, 2017)

Tested By: M. Quasem Checked By: W. Miller

4/21/17

(no specification provided)

PL= LL= PI=

D90= D85= D60=D50= D30= D15=D10= Cu= Cc=

USCS= AASHTO=

*

See exploration logs#4#10#20#40#60

#100#140#200

100.0100.0100.0100.0

98.087.576.967.7

20 36 16

0.1641 0.1378

CL A-6(9)

GS: ASTM D6913PI: ASTM D4318, Wet methodUSCS: ASTM D2487

Fore Property Company

920 Bayswater Ave

13889.000.000

Soil Description

Atterberg Limits

Coefficients

Classification

Remarks

Sample Number: 1-CPT01 @ 30 Depth: 30.0-31.0 feetDate:

Client:

Project:

Project No:

SIEVE PERCENT SPEC.* PASS?

SIZE FINER PERCENT (X=NO)

PE

RC

EN

T F

INE

R

0

10

20

30

40

50

60

70

80

90

100

GRAIN SIZE - mm.

0.0010.010.1110100

% +75mmCoarse

% Gravel

Fine Coarse Medium

% Sand

Fine Silt

% Fines

Clay

0.0 0.0 0.0 0.0 0.0 32.3 67.7

6 in.

3 in.

2 in.

1½

in.

1 in.

¾ in.

½ in.

3/8

in.

#4

#10

#20

#30

#40

#60

#100

#140

#200

Particle Size Distribution Report


4/21/17


PL= LL= PI=

D90= D85= D60=D50= D30= D15=D10= Cu= Cc=

USCS= AASHTO=

*

See exploration logs1

3/41/23/8#4#10#20#40#60

#100#140#200

100.095.292.189.475.647.131.225.021.719.718.617.9

23 57 34

10.0160 7.0812 2.96732.2037 0.7651

SC A-2-7(1)



920 Bayswater Ave

13889.000.000

Soil Description

Atterberg Limits

Coefficients

Classification

Remarks


Client:

Project:

Project No:



PE

RC

EN

T F

INE

R

0

10

20

30

40

50

60

70

80

90

100

GRAIN SIZE - mm.

0.0010.010.1110100

% +75mmCoarse

% Gravel

Fine Coarse Medium

% Sand

Fine Silt

% Fines

Clay

0.0 4.8 19.6 28.5 22.1 7.1 17.9

6 in.

3 in.

2 in.

1½

in.

1 in.

¾ in.

½ in.

3/8

in.

#4

#10

#20

#30

#40

#60

#100

#140

#200



4/21/17


PL= LL= PI=

D90= D85= D60=D50= D30= D15=D10= Cu= Cc=

USCS= AASHTO=

*

See exploration logs1

3/41/23/8#4#10#20#40#60

#100#140#200

100.089.284.677.368.154.640.630.022.918.316.114.7

16 35 19

19.6623 13.0561 2.71881.5207 0.4249 0.0819

SC A-2-6(0)



920 Bayswater Ave

13889.000.000

Soil Description

Atterberg Limits

Coefficients

Classification

Remarks


Client:

Project:

Project No:



PE

RC

EN

T F

INE

R

0

10

20

30

40

50

60

70

80

90

100

GRAIN SIZE - mm.

0.0010.010.1110100

% +75mmCoarse

% Gravel

Fine Coarse Medium

% Sand

Fine Silt

% Fines

Clay

0.0 10.8 21.1 13.5 24.6 15.3 14.7

6 in.

3 in.

2 in.

1½

in.

1 in.

¾ in.

½ in.

3/8

in.

#4

#10

#20

#30

#40

#60

#100

#140

#200


1-CPT01 1-CPT02 1-CPT04

30-31 20-21 26-27

25.0 17.5 13.8

99.4 115.8 125.1

PROJECT NAME: 920 Bayswater Ave DATE: 04/21/17PROJECT NUMBER: 13889.000.000

CLIENT: Fore Property Company

PHASE NUMBER: GEX

Tested by: M. Quasem Reviewed by: W. Miller

DEPTH (ft.):

BORING ID:

DEPTH (ft.):

MOISTURE CONTENT (%):

DRY DENSITY (lbs/ft3):

BORING ID:

DEPTH (ft.):



BORING ID:

DEPTH (ft.):





Testing remarks: For moisture content only, ASTM D2216

MOISTURE-DENSITY DETERMINATIONASTM D7263

BORING ID:

DEPTH (ft.):



BORING ID:

Laboratory address: 3420 Fostoria Way, Suite E, San Ramon, CA 94583. Phone No. (925) 355-9047.


See exploration logs 36 20 16 100.0 67.7 CL

See exploration logs 57 23 34 25.0 17.9 SC

See exploration logs 35 16 19 30.0 14.7 SC

13889.000.000 Fore Property Company

MATERIAL DESCRIPTION LL PL PI %<#40 %<#200 USCS

Project No. Client: Remarks:

Project:

Depth: 30.0-31.0 feet Sample Number: 1-CPT01 @ 30



PL

AS

TIC

ITY

IN

DE

X

0

10

20

30

40

50

60

LIQUID LIMIT0 10 20 30 40 50 60 70 80 90 100 110

CL-ML

CL or O

L

CH or O

H

ML or OL MH or OH

Dashed line indicates the approximateupper limit boundary for natural soils

4

7

LIQUID AND PLASTIC LIMITS TEST REPORT

PI: ASTM D4318, Wet methodGS: ASTM D6913USCS: ASTM D2487PI: ASTM D4318, Wet methodGS: ASTM D6913USCS: ASTM D2487PI: ASTM D4318, Wet methodGS: ASTM D6913USCS: ASTM D2487

920 Bayswater Ave

APPENDIX C LIQUEFACTION ANALYSIS

L I Q U E F A C T I O N A N A L Y S I S R E P O R T

Input parameters and analysis dataI&B (2008)R&W (1998)Based on Ic value7.900.78

G.W.T. (in-situ):G.W.T. (earthq.):Average results interval:Ic cut-off value:Unit weight calculation:

Project title : 920 Bayswater Avenue Location : Burlingame, California

ENGEO Incorporated2010 Crow Canyon Place, Suite 250San Ramon, California 94583www.engeo.com

CPT file : 1-CPT01

9.50 ft9.50 ft32.30Based on SBT

NoN/AN/ANoYes

Clay like behaviorapplied:Limit depth applied:Limit depth:MSF method:

Sand & ClayNoN/AMethod based

Summary of liquefaction potential

CLiq v.1.7.6.34 - CPT Liquefaction Assessment Software - Report created on: 5/1/2017, 3:48:36 PMProject file: G:\Active Projects\_12000 to 13999\13889\13889000000\Analysis\Liquefaction\13889 Bayswater CLiq.clq

1

This software is licensed to: ENGEO Incorporated CPT name: 1-CPT01

C P T b a s i c i n t e r p r e t a t i o n p l o t s ( n o r m a l i z e d )

CLiq v.1.7.6.34 - CPT Liquefaction Assessment Software - Report created on: 5/1/2017, 3:48:36 PM 2Project file: G:\Active Projects\_12000 to 13999\13889\13889000000\Analysis\Liquefaction\13889 Bayswater CLiq.clq

SBTn legend1. Sensitive fine grained

2. Organic material

3. Clay to silty clay

4. Clayey silt to siltyl5. Silty sand to sandy silt

6. Clean sand to silty sand

7. Gravely sand to sand

8. Very stiff sand tol d9. Very stiff fine grained

Input parameters and analysis data

I&B (2008)R&W (1998)Based on Ic value7.900.789.50 ft

Depth to GWT (erthq.):Average results interval:Ic cut-off value:Unit weight calculation:Use fill:Fill height:

9.50 ft32.30Based on SBTNoN/A

N/ANoYesSand & ClayNoN/A


L i q u e f a c t i o n a n a l y s i s o v e r a l l p l o t s







F.S. color scheme LPI color scheme

Almost certain it will liquefy

Very likely to liquefy

Liquefaction and no liq. are equally likely

Unlike to liquefy

Almost certain it will not liquefy

Very high risk

High risk

Low risk






CPT file : 1-CPT02


NoN/AN/ANoYes





4





2. Organic material























Unlike to liquefy


Very high risk

High risk

Low risk






CPT file : 1-CPT03


NoN/AN/ANoYes





7





2. Organic material























Unlike to liquefy


Very high risk

High risk

Low risk






CPT file : 1-CPT04


NoN/AN/ANoYes





10





2. Organic material























Unlike to liquefy


Very high risk

High risk

Low risk

SAN RAMON

SAN FRANCISCO

SAN JOSE

OAKLAND

LATHROP

ROCKLIN

SANTA CLARITA

IRVINE

CHRISTCHURCH

WELLINGTON

AUCKLAND

appendix d - burlingame, california d - geotechnical report.pdfsand and silty sand up to 10 feet...

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