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HomeMy WebLinkAbout1818 Trousdale Drive - Technical Studyob k� KLEINFELDER RECEIVED JUL 1 3 Z005 CITY OF BURLINGAME PLANNING DEPT. FEASIBILITY -LEVEL GEOTECIINICAL INVESTIGATION PROPOSED SUNRISE ASSISTED LIVING FACILITY 1818 TROUSDALE DRIVE BURLINGAME, CALIFORNIA PREPARED FOR: Sunrise Development, Inc. 249 View Street Mountain View, California 94041 ATTENTION: Mr. Dan Zemanek Copyright 2004 Kleinfelder, Inc. All Rights Reserved Unauthorized use or copying of this document is strictly prohibited by anyone other than the client for the specific project. December 30, 2004 50968 (SJ04R582) bl w k" KLEINFELDER An employee owned company December 30, 2004 File: 50968 Sunrise Development, Inc. Mr. Dan Zemanek 249 View Street Burlingame, California 94041 SUBJECT: Feasibility -level Geotechnical Investigation for the Proposed Sunrise Assisted Living Project at 1818 Trousdale Drive, Burlingame, California Dear Mr. Zemanek: We are pleased to submit our feasibility -level geotechnical investigation report for the subject project. The accompanying report provides the results of our limited field investigation, laboratory testing and engineering analyses. Preliminary design guidelines for site earthwork, foundations, concrete slabs -on -grade, pavements, and site drainage are provided. The primary geotechnical considerations for the project are the presence of moderately expansive soils, relatively high groundwater table, and potentially liquefiable soils. Discussion on these issues and mitigation measures are presented in the text of this report. The design -level geotechnical investigation should include installation of piezometer(s) to monitor the groundwater table and a more refine evaluation of liquefaction potential at the site. Lime treatment, if found feasible, may be used for mitigation of expansion soil and stabilization of potential soft and wet subgrade soil at the subterranean parking level. Please refer to the text of the report for details, especially Section 4, "Preliminary Conclusions." If you have any questions, please contact us. Sincerely, KLEINFELDER, INC. a"61� Finnegan Mwape Staff Professional Chalerm "Beeson" Lian§,; Geotechnical Department cc: Addressee (5) Billy Shields (1), Sunrise Development Company (electronic copy only) Bill Lindstrom (1), Sunrise Development Company S. 140. 2031 50968 (SJ04R582) bl Page 1 of 1 December 30, 2004 Copyright 2004 Kleinfelder, inc. KLEINFELDER 1362 Ridder Park Drive, San Jose, CA 95131-1571 (408) 436-1155 (408) 436-1771 fax k'q KLEINFELDER FEASIBILITY -LEVEL GEOTECHNICAL INVESTIGATION PROPOSED SUNRISE ASSISTED LIVING FACILITY 1818 TROUSDALE DRIVE BURLINGAME, CALIFORNIA TABLE OF CONTENTS 1.0 INTRODUCTION................................................................................................................................1 1.1 PROJECT DESCRIPTION.....................................................................................................................1 1.2 SCOPE OF SERVICES.........................................................................................................................2 2.0 SEISMIC CONSIDERATIONS..........................................................................................................3 2.1 GEOLOGIC SETTING..........................................................................................................................3 2.2 FAULTING AND SEISMICITY..............................................................................................................3 2.3 SURFACE FAULT RUPTURE...............................................................................................................5 2.4 SEISMIC SHAKING.............................................................................................................................5 2.5 SITE CHARACTERIZATION................................................................................................................6 3.0 SITE INVESTIGATION......................................................................................................................7 3.1 SITE DESCRIPTION............................................................................................................................7 3.2 FIELD INVESTIGATION......................................................................................................................7 3.3 LABORATORY TESTING.................................................................................................................... 8 3.4 SUBSURFACE CONDITIONS...............................................................................................................8 4.0 PRELIMINARY CONCLUSIONS.....................................................................................................9 5.0 PRELIMINARY GEOTECIINICAL GUIDELINES.....................................................................11 5.1 DESIGN GROUNDWATER LEVEL.....................................................................................................11 5.2 EARTHWORK.................................................................................................................................. 11 5.2.1 Site Clearing and Stripping...............................................................................................11 5.2.2 Basement Excavation, Temporary Construction Slopes, Shoring and Dewatering ..........11 5.2.3 Subgrade Preparation.................................................................-.......................................12 "Non -expansive" Material.................................................................................................13 5.2.5 Material for Fill.................................................................................................................13 5.2.6 Trench Excavation and Backfill........................................................................................14 5.2.7 Surface Drainage...............................................................................................................14 5.2.8 Seepage Control................................................................................................................14 5.3 BUILDING FOUNDATIONS...............................................................................................................15 5.3.1 Conventional Footings......................................................................................................15 5.3.2 Strip Mat Foundations.......................................................................................................16 5.3.3 Structural Mat Foundations...............................................................................................17 5.4 BASEMENT FLOOR SLAB................................................................................................................17 5.5 EXTERIOR CONCRETE SLABS-ON-GRADE......................................................................................18 5.6 BASEMENT WALLS.........................................................................................................................18 5.7. PAVEMENTS ....................................................................................................................................19 6.0 ADDITIONAL SERVICES AND LIMITATIONS.........................................................................21 6.1 SUPPLEMENTAL GEOTECHNICAL INVESTIGATION.........................................................................21 6.2 PLAN REVIEW AND CONSTRUCTION OBSERVATION AND TESTING SERVICES..............................21 6.3 LIMITATIONS..................................................................................................................................22 50968 (SJ04R582) bl Page i of ii December 30, 2004 Copyright 2004 Kleinfelder, Inc. 1 ` KLEINFELDER FEASIBILITY -LEVEL GEOTECHNICAL INVESTIGATION PROPOSED SUNRISE ASSISTED LIVING FACILITY 1818 TROUSDALE DRIVE BURLINGAME, CALIFORNIA TABLE OF CONTENTS (CONTINUED) PLATES Plate 1 Site Vicinity Map Plate 2 Site Plan APPENDIX A Plate A-1 Boring Log Legend Plates A-2 and A-3 Boring Logs (B-1 and B-2) APPENDIX B Plate B-1 Plasticity Chart i Plate B-2 Unconfined Compression Test Plate B-3 Resistance Value Test Data APPENDIX C i Corrosion Test Results and Report from CERCO Analytical '-�j 50968 (SJ04R582) bl Page ii of ii December 30, 2004 Copyright 2004 Kleinfelder, Inc. — Geolechnical Engineering Report �, Geotechnical Services Are Performed for Specific Purposes, Persons, and Projects Geotechnical engineers structure their services to meet the specific needs of their clients. A geotechnical engineering study conducted for a civil engi- neer may not fulfill the needs of a construction contractor or even another civil engineer. Because each geotechnical engineering study is unique, each geotechnical engineering report Is unique, prepared solelyfor the client. No one except you should rely on your geotechnical engineering report without first conferring with the geotechnical engineer who prepared it. And no one — not even you —should apply the report for any purpose or project except the one originally contemplated. Read the Full Report Serious problems have occurred because those relying on a geotechnical engineering report did not read it all. Do not rely on an executive summary. Do not read selected elements only. A Geotechnical Engineering Report Is Based on A Unique Set of Project -Specific Factors Geotechnical engineers consider a number of unique, project -specific fac- tors when establishing the scope of a study. Typical factors Include: the client's goals, objectives, and risk management preferences; the general nature of the structure involved, its size, and configuration; the location of the structure on the site; and other planned or existing site improvements, such as access roads, parking lots, and underground utilities. Unless the geotechnical engineer who conducted the study specifically indicates oth- erwise, do not rely on a geotechnical engineering report that was: • not prepared for you, • not prepared for your project, • not prepared for the specific site explored, or • completed before important project changes were made. Typical changes that can erode the reliability of an existing geotechnical engineering report include those that affect: • the function of the proposed structure, as when it's changed from a parking garage to an office building, or from a light industrial plant to a refrigerated warehouse, elevation, configuration, location, orientation, or weight of the proposed structure, composition of the design team, or project ownership. As a general rule, always inform your geotechnical engineer of project changes —even minor ones —and request an assessment of their impact Geotechnical engineers cannot accept responsibility or liabilityforproblems that occur because their reports do not consider developments of which they were not informed. Subsurface Conditions Can Change A geotechnical engineering report is based on conditions that existed at the time the study was performed. Do not rely on a geotechnical engineer- ing report whose adequacy may have been affected by: the passage of time; by man-made events, such as construction on or adjacent to the site; or by natural events, such as floods, earthquakes, or groundwater fluctua- tions. Always contact the geotechnical engineer before applying the report to determine if it is still reliable. A minor amount of additional testing or analysis could prevent major problems. Most Geotechnical Findings Are Professional Opinions Site exploration identifies subsurface conditions only at those points where subsurface tests are conducted or samples are taken. Geotechnical engi- neers review field and laboratory data and then apply their professional judgment to render an opinion about subsurface conditions throughout the site. Actual subsurface conditions may differ --sometimes significantly — from those indicated in your report. Retaining the geotechnical engineer who developed your report to provide construction observation is the most effective method of managing the risks associated with unanticipated conditions. A Report's Recommendations Are Not Final Do not overrely on'the construction recommendations included in your report. Those recommendations are not final, because geotechnical engi- neers develop them principally from judgment and opinion. Geotechnical engineers an finalize their recommendations only by observing actual KLEINFELDER kn KLEINFELDER FEASIBILITY -LEVEL GEOTECHNICAL INVESTIGATION PROPOSED SUNRISE ASSISTED LIVING FACILITY 1818 TROUSDALE DRIVE BURLINGAME, CALIFORNIA 1.0 INTRODUCTION This report presents the results of our feasibility -level geotechnical investigation performed for the proposed Sunrise Assisted Living project to be located at 1818 Trousdale Drive, Burlingame, California. The approximate location of the site is shown on the Site Vicinity Map, Plate 1. A layout of the proposed project is shown on the Site Plan, Plate 2. This report presents our preliminary conclusions and guidelines related to the geotechnical aspects of project design and construction. These preliminary conclusions and guidelines are based on the subsurface conditions encountered at the locations of our exploration and the provisions and requirements outlined in the Additional Services and Limitations section of this report. The preliminary conclusions and guidelines presented herein should not be used for final project design and cost estimating, and should not be extrapolated to other areas or used for other projects without our review. Kleinfelder is also performing a Phase I and Limited Phase H Environmental Site Assessment and an asbestos and lead containing paint survey for the project. The results of those studies are presented in separate reports. 1.1 PROJECT DESCRIPTION The present plan is to construct an assisted living facility consisting of a four-story structure over one level of subterranean parking. Details regarding building type and loads have not been finalized, but we anticipate the proposed building will be of reinforced concrete and/or steel construction. Other proposed site improvements include at -grade fire access lane, trash enclosure, underground utilities, concrete flatwork and landscaped areas. Site grading is expected to involve an excavation of 10 to 12 feet deep for the subterranean parking and cuts and fills of about 2 feet or less for the remaining areas. 50968 (SJ04R582) bl Page 1 of 23 Copyright 2004 Kleinfelder, Inc. December 30, 2004 kn KLEINFELDER 1.2 SCOPE OF SERVICES The purpose of this feasibility -level geotechnical investigation was to explore and evaluate the subsurface conditions at the site, identify geotechnical conditions that may impact development of the site, and to discuss general geotechnical guidelines for preliminary planning and i conceptual design of the proposed improvements. The scope of our services was summarized in our proposal dated October 5, 2004, and consisted of a review of geologic and geotechnical information in our office, site reconnaissance, subsurface exploration, laboratory testing, engineering analyses, and preparation of this report. Also included in this study was laboratory corrosivity testing of two selected soil samples from our borings. 50968 (SJ04R582) bl Page 2 of 23 December 30, 2004 Copyright 2004 Kleinfelder, Inc. g� KLEINFELDER 2.0 SEISMIC CONSIDERATIONS 2.1 GEOLOGIC SETTING The San Francisco Bay Area lies within the Coast Range Geomorphic Province, a more or less discontinuous series of northwestern trending mountain ranges, ridges and intervening valleys characterized by intense, complex folding and faulting. The general geologic framework of the San Francisco Bay Area is illustrated in studies by Schlocker (1971), as well as in studies by the California Division of Mines and Geology (1990), while the general regional setting with respect to active and potentially active faults is taken from Jennings (1994). The project site is situated on the broad alluvial plain surrounding San Francisco Bay. The site is essentially level, although the regional inclination gently slopes east toward the bay. Based on mapping by Braff and others (1998), the site is bisected by the geologic contact between Holocene age natural levee deposits and Pleistocene age Cohna Formation. Natural levee deposits (Qhl) consist of loose, moderately to well —sorted sandy or clayey silt grading to sandy or silty clay. These deposits are porous and permeable and provide conduits for transport of groundwater. Levee deposits border stream channels, usually both banks, and slope away to flatter floodplains and basins. Colma Formation (Qc) consists of yellowish -gray and gray to yellowish -orange and red -brown (where fresh), friable to loose, fine- to medium -grained arkosic sand with subordinate amounts of gravel, silt, and clay. Total thickness unknown, but may be as great as 180 ft. 2.2 FAULTING AND SEISMICITY The San Francisco Bay Area is seismically dominated by the active San Andreas Fault system, the general boundary between the northward moving Pacific Plate (west of the fault) and the southward moving North American Plate (east of the fault). This movement is distributed across a complex system of generally strike -slip, right -lateral, parallel and subparallel faults. Table 1 lists significant faults, which are considered by the Uniform Building Code (UBC) to be active or potentially active seismogenic sources and gives selected seismic parameters. The closest map distance from the site to these faults and associated parameters presented in Table 1 50968 (SJ04R582) bl Page 3 of 23 December 30, 2004 Copyright 2004 Kleinfelder, Inc. kn KLEINFELDER are based on modified data derived from Blake (2000) with attenuation factors based on Campbell & Bozorgnia (1994/1997) for soft rock conditions. TABLE 1 SIGNIFICANT FAULTS WITHIN ABOUT IOU MILES OF THE PROJECT SITE Fault Name Approximate Distance to Fault mi km Magnitude of Maximum Earthquake Peak Site Acceleration Modified Mercalli* San Andreas (1906) 2(2.5) 7.9 0.645 X San Gre orio 8 13 7.3 0.388 X Monte Vista - Shannon 14 (22) 6.8 0.199 VIII Hayward South 17(28) 6.9 0.144 VIlI Hayward (Total Length) 17 (28) 7.1 0.167 VIII Hayward(North) 17 28 6.9 0.144 VIII San Andreas (North Coast) 19 31 7.6 0.205 VIII Calaveras (No.of Calaveras Res) 26(41) 6.8 0.078 VII Hayward (Se Extension) 28 (46) 6.4 0.048 VI Concord - Green Valle 30 (49) 6.9 0.066 VI Calaveras (So.of Calaveras Res) 34 (55) 6.2 0.030 V Rodgers Creek 34 55 7.0 0.061 VI Point Reyes 35 (57) 6.8 0.050 VI Greenville 36 57 6.9 0.053 VI San Andreas (Santa Cruz Mtn.) 36 (57) 7.0 0.058 VI Great Valle 6 39 63 6.7 0.040 V Sargent 40 (64) 6.8 0.041 V West Napa 40 65 6.5 0.031 V Zayante-Vergeles 42 (67) 6.8 0.039 V Great Valle 5 43 70 6.5 0.029 V Great Valley 7 44 (70) 6.7 0.033 V Monterey Bay - Tularcitos 49 78 7.1 0.039 V Great Valle 4 52(83) 6.6 0.024 IV Palo Colorado - Sur 56 90 7.0 0.030 V San Andreas ajaro 58(94) 6.8 0.024 IV 50968 (SJ04R582) bl Page 4 of 23 December 30, 2004 Copyright 2004 Kleinfelder, Inc. g� KLEINFELDER TABLE 1 SIGNIFICANT FAULTS WITHIN ABOUT 100 MILES OF THE PROJECT SITE Fault Name Approximate Distance to Fault mi (km) Magnitude of Maximum Earthquake Peak Site Acceleration ( Modified Mercalli* Hunting Creek - Berryessa 60(97) 6.9 0.025 V Great Valle 8 63(102) 6.6 0.017 IV Orti alita 64(104) 6.9 0.022 IV Maacama South 70 113 6.9 0.020 IV San Andreas (Creeping) 72(116) 6.5 0.013 III Rinconada 72 116 7.3 0.027 V Quien Sabe 73 (117) 6.4 0.012 lII Great Valle 3 74 119 6.8 0.016 IV Great Valle 9 81 (130) 6.6 0.012 III Colla omi 84 135 6.5 0.011 III Bartlett Springs 93 (150) 7.1 0.016 IV Maacama Central 93 150 7.1 0.015 IV Foothills Fault System 97(157) 6.5 0.008 III 2.3 SURFACE FAULT RUPTURE The site is not located within a State of California Earthquake Fault Zone and no mapped active faults are known to transverse the site. Therefore, it is our opinion that the potential for fault - related surface rupture at the project site is low. 2.4 SEISMIC SHAKING The San Francisco Bay area is considered by geologists and seismologists to be one of the most seismically active regions in the United States. On the basis of current technology and historical evidence, it is reasonable to conclude that during its useful life, the proposed development will be subjected to at least one severe earthquake (magnitude 7 to 8+) that could cause considerable ground shaking at the site. It is also anticipated that the subject site will periodically experience small to moderate magnitude earthquakes. Some degree of structural damage due to strong 50968 (SJ04R582) bl Page 5 of 23 December 30, 2004 Copyright 2004 Kleinfelder, Inc. k'q KLEINFELDER seismic shaking at the site should be expected, but the risk can be reduced through adherence to seismic design codes. 2.5 SITE CHARACTERIZATION The project site is located in Seismic Zone 4. From a seismic standpoint based on the soil conditions encountered in our exploratory borings and on our knowledge of the site geology, the site may be classified as being a very dense soil and soft rock site. This corresponds to a soil profile of Sc according to Table 16-J of the 1997 Uniform Building Code, which is defined as a site with shear wave velocities between 1,200 feet/sec and 2,500 feet/sec, blowcount of 50 or higher, or undrained shear strength (Su) of 2,000 psf or higher for the upper 100 feet. 50968 (SJ04R582) bl Page 6 of 23 December 30, 2004 Copyright 2004 Kleinfelder, Inc. k'q KLEINFELDER 3.0 SITE INVESTIGATION 3.1 SITE DESCRIPTION The site is bordered by Trousdale Drive on the southeast, Ogden Drive on the southwest, and developed land on the northeast and northwest. The site is currently occupied by a one-story building in the south/southeastern portion. The remaining areas of the site consist of vehicle pavements and landscaping. 3.2 FIELD INVESTIGATION Our field investigation consisted of a surface reconnaissance and a subsurface exploration program that included drilling of two exploratory borings. The borings were drilled on November 16, 2004 using a truck -mounted drill rig equipped with hollow -stem augers to depths of approximately 44 to 45%2 feet below the existing ground surface. The materials encountered in the borings were visually classified in the field and a log of each boring was recorded by our engineering staff. Samples were obtained from the borings by driving a 2-inch inside diameter Modified California sampler up to a depth of 18 inches into the underlying soil using a 140-pound hammer falling 30 inches. The number of blows required to drive the samplers was recorded for each 6-inch penetration interval. The number of blows required to drive the sampler the last 12 inches was recorded as blows per foot and noted on the boring logs. As required by San Mateo County Environmental Health Department, the borings were backfilled with cement grout. The top of the borings was capped with cold patch asphalt. Visual field classification of the soils encountered in our exploratory borings was made in general accordance with the Unified Soil Classification System (ASTM D2488). The results of our laboratory testing were used to refine our field classifications. A key for the classification of the soil is presented in Appendix A on the Boring Log Legend, Plate A-1. The logs of the borings are presented on Plates A-2 and A-3 in Appendix A. The approximate locations of the borings, which were estimated by our personnel in the field based on existing site features, are shown on Plate 2. 50968 (SJ04R582) bl Page 7 of 23 Copyright 2004 Kleinfelder, Inc. December 30, 2004 k'q KLEINFELDER 3.3 LABORATORY TESTING Representative soil samples were obtained from the exploratory borings at selected depths. The samples were returned to our laboratory for further observation and testing. Laboratory testing performed on selected soil samples includes I natural moisture content, unit weight, unconfined compression, Atterberg Limits and percent passing a No. 200 sieve. The laboratory test results are presented on the boring logs at the corresponding sample depths. Two selected soil samples from the borings were sent for laboratory corrosivity testing. The test results are presented in a report from CERCO Analytical, included in Appendix C. 3.4 SUBSURFACE CONDITIONS The borings were located in the existing parking lot areas. The pavement section encountered in the borings consists of approximately 3 to 6 inches of asphalt concrete over approximately 6 inches of base. The pavement section is underlain by fill consisting of medium dense poorly graded sand to depths of about 1 %2 to 3 Y2 feet below ground surface (bgs). Below the fill are layers of stiff to very stiff lean clay, sandy lean clay and silt to depths of about 23 %2 to 30 feet bgs. These materials are underlain by channel (levee) deposits consisting of medium dense poorly graded sand to depths of 27 to 34%2 feet bgs, and by Colma Formation materials consisting of hard clay and medium dense to very dense poorly graded sand and silty sand to the maximum explored depths of 45%2 and 44 feet in Borings B-1 and B-2, respectively. Groundwater was initially encountered at a depth of about 24 feet in the borings during drilling. Groundwater rose to a depth of about 13 feet bgs in Boring B-2 about 10 minutes later, suggesting artesian pressure. It should be noted that fluctuations in groundwater level could occur due to variations in rainfall, temperature, pumping from wells and other factors that were not evident at the time of our investigation. If significant variations in the groundwater level are encountered during construction, it may be necessary for Kleinfelder to review the recommendations made herein and provide supplemental recommendations as necessary. The above is a general description of the subsurface conditions encountered at the site in the borings made for this investigation. For a more detailed description of the soil conditions encountered, refer to the boring logs presented in Appendix A. 50968 (S704R582) bl Page 8 of 23 December 30, 2004 Copyright 2004 Kleinfelder, Inc. kn KLEINFELDER 4.0 PRELIMINARY CONCLUSIONS Based on the information collected during this feasibility -level geotechnical investigation, the following preliminary conclusions can be made. Refer the following sections of the report for detailed guidelines and preliminary design parameters. 1. Both borings encoutered fill material under the pavement section to depths of 1 %2 and 3%2 feet below ground surface. The geologic map we reviewed also indicates artificial fill in the area. The vertical and lateral extents of the fill should be confirmed during the design -level geotechnical investigation. Most of the fill would be removed for construction of the subterranean parking. The remaining fill, expected to be relatively thin, could be processed during site preparation at the time of construction and should not have a significant impact on the proposed development. 2. The near -surface. clay soil has a low to intermediate plasticity and a moderate expansion potential. The clay extends to depths of about 18 to 19%2 fet below ground surface. Concrete slabs -on -grade, including the basement floor slab and exterior flatwork, constructed on this clay should be underlain by a layer of "non -expansive" material. Non -expansive material may consist of imported fill or lime treated on -site soil provided laboratory testing is performed to verify the on -site clay can be treated with lime to reduce its expansion potential. 3. Our analysis suggests that the sands encountered in Boring B-1 between depths of about 30 and 37%2 feet has a high liquefaction potential whereas the sands encountered in Boring B-2 are essentially non -liquefiable. During the design -level geotechnical investigation, additonal borings and/or Cone Penetrometer Testing should be performed to refine the liquefaction potential at the site. Based on the current information, we have estimated the potential ground settlement as a result of soil liquefaction in Boring B-1 could be on the order of 1 inch. This magnitude of settlement should be within tolerable limits of a structural mat foundation, but not for conventional footings. 4. The proposed subterranean parking, expected to be about 10 to 12 feet deep, will extend into stiff to very stiff clay soil which has sufficient shear strength to support the anticipated building loads. However, the appropriate foundation type will depend on the results of further analysis on soil liquefaction. If the site soils are found to be non -liquefiable, the 50968 (SJ04R582) bl Page 9 of 23 December 30, 2004 Copyright 2004 Kleinfelder, Inc. hn KLEINFELDER proposed building may be supported on either conventional footing, structural mat or strip mat foundation. If the site soils are found to be liquefiable, foundation type may be limited to structural mat or deep foundation such as drilled piers, unless ground improvements are implemented to mitigate the potential for liquefaction. 5. We did not encounter highly compressible material in our borings which would require special civil and foundation design. 6. Groundwater was measured as shallow as 13 feet below ground surface during our exploration in October 2004. The groundwater table is likely to be higher in the rainy months, which could be above the basement parking elevation. Piezometer(s) should be installed to monitor fluctuation in the groundwater level and to established a design groundwater level for final project design. If the design groundwater level is above the basement elevation, it will be necessary to design the basement walls and slab for hydrostatic pressure, water -proof the basement, and provide dewatering during construction. 7. The basement excavation will require shoring or sloping of the side slopes in accordance with OSHA and Cal -OSHA requirements. 8. Evaluation of flood hazard is beyond the scope of our investigation. 9. A design -level geotechnical investigation is recommended for the design phase of the project when specific details regarding building type, loads and dimensions have been finalized. The supplemental investigation should include additional subsurface exploration, laboratory testing and engineering analyses to check the preliminary conclusions and guidelines made in this feasibility -level investigation and to develop project specific design recommendations. Of special considerations are the potential for liquefaction and groundwater level at the site. 50968 (SJ04R582) bl Page 10 of 23 December 30, 2004 Copyright 2004 Kleinfelder, Inc. k" KLEINFELDER 5.0 PRELIMINARY GEOTECHNICAL GUIDELINES 5.1 DESIGN GROUNDWATER LEVEL A design groundwater level should be established for final project design and for construction, based on information from piezometer(s) installed at the site. Periodic measurement of the groundwater level should be made in the piezomater(s). Typically, measurements can be taken weekly or less during the rainy months, and less frequently during the summer months. Information on the groundwater level will help establish criteria for excavating support and dewatering, waterproofing of structure, and hydrostatic pressure on the basement wall and the basement. 5.2 EARTHWORK 5.2.1 Site Clearing and Stripping Site clearing should include removal of buildings, foundations, concrete slabs, pavements, abandoned and designated underground utilities, stumps and primary roots of trees and brush, and other below -grade obstructions and deleterious material. Surface vegetation and organic laden soil should be stripped. Depressions, voids and holes (including those from removal of underground improvements) that extend below proposed finish grades should be cleaned and backfilled with acceptable material compacted to project specifications. The existing asphalt concrete may be pulverized into fragments no larger than 2 inches in size and mixed with the underlying aggregate base. The mixture, if meets project requirements and approves by the Geotechnical Engineer, may be used as engineered fill. 5.2.2 Basement Excavation, Temporary Construction Slopes, Shoring and Dewatering Construction of the subterranean parking will require an excavation of roughly 10 to 12 feet deep below ground surface. The excavation should be readily accomplished with conventional earth - moving equipment. The perimeter of the excavation may be constructed vertical or at a slope if sufficient area is available. Vertical temporary construction slopes should be properly shored and/or braced for stability and personnel protection. The excavation should comply with OSHA and Cal -OSHA guidelines and local jurisdictions. 50968 (SJ04R582) bl Page I 1 of 23 December 30, 2004 Copyright 2004 Kleinfelder, Inc. KLEINFELDER Design, installation, maintenance and removal of temporary shoring and bracing are the responsibility of the contractor, and may involve soldier piles and lagging (with or without tiebacks), or other appropriate systems. A sheet pile shoring system may not be preferred because of the proximity of existing improvements (vibration associated with driving sheet piles). The presence of existing streets, structures, pavements, and underground utilities adjacent to the basement excavation must not be overlooked and must be incorporated in the design of the shoring system. Groundwater was measured in our borings as shallow as 13 feet below ground surface. Piezometers are recommended in the design -level investigation phase to monitor fluctuation in groundwater level and to establish a design groundwater level. If the groundwater table is higher than the depth of excavation, dewatering will be necessary so construction can proceed in a relatively "dry" condition. Design, installation, maintenance, and removal of the dewatering system should be the responsibility of the contractor. The dewatering system should be capable of lowering the groundwater table at least 2 feet below the bottom of the excavation. 5.2.3 Subgrade Preparation Proper preparation of soil subgrade should be performed in areas to receive engineered fills, concrete slabs -on -grade and pavements. For the basement areas, the subgrade soil is anticipated to be wet and possible "pumping." In view of the potential wetness and the moderate expansion potential of the soil, consideration should be given to treating the top 18 inches of the subgrade soil with lime to help "dry" the soil, to create a more stable working platform, and to reduce the expansion potential of the soil. The actual percentage of lime to be used will depend on the soil type and the type of lime, and should be determined during the design phase of the project. For preliminary planning and budgeting purposes, 4 to 5 percent of high calcium or dolomitic quicklime may be assumed. The treatment should include the entire basement area. For at -grade exterior flatwork and pavement areas, the upper 12 inches of subgrade soil should be scarified, moisture conditioned and compacted as recommended below under "Fill Placement and Compaction." Where not restricted by existing improvements or limits of work, subgrade 50968 (SJ04R582) bl Page 12 of 23 December 30, 2004 Copyright 2004 Kleinfelder, Inc. k'q KLEINFELDER preparation should extend laterally no less than 2 feet beyond the back of curbs or the edge of pavement where no curbs are constructed, or limits of flatwork. After the subgrades are properly prepared, the areas may be raised to design grades by placement of engineered fill. Soft or wet soil encountered during construction should be stabilized prior to placement of new fill and further construction. The method of stabilization should be evaluated by a representative of Kleinfelder at the time of construction depending on the exposed conditions. Moisture conditioning of subgrade and fill soils will consist of adding water if the soils are too dry and allowing the soils to dry if the soils are too wet. 5.2.4 "Non -expansive" Material Because the near -surface clay soil has a moderate expansion potential, concrete slabs -on -grade constructed on the soil should be supported on a layer of "non -expansive" material meeting the requirements presented below under "Materials for Fill." The "non -expansive" material for at -grade exterior flatwork should be at least 6 inches thick and should extend at least 2 feet laterally beyond the outer limits of the slabs. If the subgrade soil for the subterranean parking is to be lime treated, additional "non -expansion" material may not be required for the basement slab. 5.2.5 Material for Fill In general, on -site soils with an organic content of less than 3 percent by weight and free of any hazardous or deleterious materials may be used as general engineered fill to achieve project grades, except where "non -expansive" fill is required. Imported fill material should be predominantly granular, should not contain rocks or lumps larger than 3 inches in greatest dimension, should not contain more than 15 percent of the material larger than 1-1/2 inches, should contain at least 20 percent passing the No. 200 sieve, and should have a low expansion potential (as indicated by Plasticity Index or Expansion Index). "Non -expansive" material should have a Plasticity Index of 15 or less. 50968 (SJO4R582) bl Page 13 of 23 December 30, 2004 Copyright 2004 Kleinfelder, Inc. kn KLEINFELDER 5.2.6 Trench Excavation and Backfill Trenches should be constructed in accordance with OSHA and Cal -OSHA Safety Standards and local jurisdictions. Safety in and around utility trenches is the responsibility of the underground contractors. Trench stability should be evaluated prior to occupation by construction personnel. Dewatering will be necessary where trenches extend below groundwater. Bedding for utility pipes should consist of free -draining sand, unless otherwise specified by the utility company. Sand bedding should extend from the trench bottom to at least 1 foot above the top of pipe. Trench backfill material above the bedding may consist of on -site soil or imported soil, compacted to project specifications by mechanical means. 5.2.7 Surface Drainage Final site grading should provide surface drainage away from the building, concrete slabs -on - grade and pavements to reduce the percolation of water into the underlying soils. The ground surface for a horizontal distance of at least 5 feet from the building should be sloped away from the building a minimum of 4 percent in landscaped and flatwork areas and a minimum of 2 percent in paved areas. Rainwater collected on the roof of building should be transported through gutters, downspouts and closed pipes that discharge onto pavement or lead directly to the site storm sewer system. If discharging onto the pavement, safety of pedestrian traffic should be considered. 5.2.8 Seepage Control Where utility lines extend through or beneath perimeter foundations, or curbs at the pavement areas, permeable backfill should be terminated at least one foot from the footing or curb. Concrete should be used around the pipe to act as a seepage cutoff. Beneath footings, the pipe should be "sleeved" through concrete cut-offs, and the annular space around. the pipe should be filled with a waterproof caulk. This will help reduce the amount of water seeping through the pervious trench backfill and collecting under the building or pavements. 50968 (SJ04R582) bl Page 14 of 23 December 30, 2004 Copyright 2004 Kleinfelder, Inc. h5l KLEINFELDER Where slabs or pavements abut against landscaped areas, the base rock layer and subgrade soil should be protected against saturation. If landscape water or surface runoff is allowed to seep into the pavement section, the service life of the pavement will be reduced. Subdrains behind curbs in landscape areas or vertical cut-offs, such as a deepened curb section, or equivalent, extending at least 2 inches below the base rock/subgrade interface, would help reduce the amount of lateral seepage under pavements or slabs from adjacent landscaped areas. Subdrains should discharge directly to the site storm sewer system. Cut-offs should be carefully constructed such that they extend below the base rock section and are poured neat against undisturbed native soil or compacted clayey fill. The cut-offs should be continuous. Utility trenches (irrigation lines, electrical conduit, etc.) that extend through or under the curbs should be sealed with compacted clayey soil or concrete. In addition, care should be taken to prevent over -watering of landscaped areas. 5.3 BUILDING FOUNDATIONS Final selection of building foundation will depend on the results of the supplemental evaluation of liquefaction potential at the site and the groundwater level. If liquefaction is found not to be a concern at this site, consideration may be given to conventional footing, strip mat or structural mat foundation. If liquefaction is found to be a concern at this site, building foundation type may be limited to structural mat and deep foundation, unless mitigation measure is implemented to reduce liquefaction and its impact. Mitigation measures may involve stone columns and grouting. Deep foundations may include drilled piers or piles (such as auger -cast piles). Preliminary design guidelines for conventional footings, strip mats and structural mat are discussed below. Foundation settlements should be evaluated when building loads are available. 5.3.1 Conventional Footings Conventional footings should consist of continuous footings for perimeter and interior load - bearing walls and isolated footings for columns, all founded on undisturbed native soil or engineered fill. For preliminary design, footing embedment depth should be at least 24 inches below rough pad grade. Rough pad grade is defined as the top of the "non -expansive" fill (or lime treated subgrade) or the bottom of the capillary break material. Footings should have a 50968 (SJ04R582) bl Page 15 of 23 December 30, 2004 Copyright 2004 Kleinfelder, Inc. f� KLEINFELDER minimum width of 24 inches. For preliminary sizing of the footings, a net allowable bearing pressure of 3,500 pounds per square foot (psf) may be assumed for dead loads and 4,000 psf for dead plus live loads. The allowable bearing pressures may be increased by one-third when considering transient loads such as wind or seismic. Lateral loads may be resisted by a combination of friction between the bottom of foundations and the supporting subgrade, and by passive resistance acting against the vertical sides of the foundations. For preliminary engineering, an ultimate friction coefficient of 0.3 may be used for friction between the foundations and supporting subgrade. Ultimate passive resistance equal to an equivalent fluid weight of 350 pounds per cubic foot (pcf) acting against the embedded sides of the foundations may be used for design purposes. The passive pressure can be assumed to act starting at the top of the lowest adjacent grade in paved areas. In unpaved areas, the passive pressure can be assumed to act starting at a depth of one foot below grade. It should be noted that the passive resistance value discussed above is only applicable where the concrete is either placed directly against undisturbed soil. Voids created by the use of forms should be backfilled i with soil compacted to the requirements given in this report or with concrete. Footings located adjacent to utility trenches should be deepened so that their bearing surfaces are below an imaginary plane having an inclination of 1.5 horizontal to 1.0 vertical, extending downward from the bottom edge of the footing. 5.3.2 Strip Mat Foundations Strip mat foundations are continuous foundations designed to distribute the building loads, generally under a wall or a line of columns, relatively uniform on the supporting soil. The strip mats should be founded on undisturbed native soil or engineered fill. For preliminary engineering, strip mat foundations may be evaluated using the net allowable bearing pressures, minimum embedment depth and minimum dimension provided above for conventional foundations. The parameters given above for conventional foundations may be assumed in the preliminary evaluation of resistance to lateral loads for strip mat foundations. 50968 (SJ04R582) bl Page 16 of 23 December 30, 2004 Copyright 2004 Kleinfelder, Inc. k'q KLEINFELDER 5.3.3 Structural Mat Foundations A structural mat is a reinforced concrete slab/mat designed to distribute the building loads relatively uniformly on the supporting soil. Structural mat also can tolerable higher total and differential settlements than conventional footings or strip mat foundations. Mat foundation should be constructed on properly prepared soil subgrade (lime treated subgrade per Earthwork section of this report). For preliminary design of the mat foundation, a net allowable soil bearing pressure of 4,000 pounds per square foot. (psf) may be assumed for dead plus live loads. This net allowable soil bearing pressure may be increased by one-third when transient loads such as wind or seismic loads are included. The mat may also be evaluated using a modulus of subgrade reaction of 200 pounds per square inch per inch (psi/in). Mat foundation should have a minimum thickness of 10 inches. If the mat extends below groundwater level, the mat will have to be designed for hydrostatic pressure. For preliminary design purposes, the parameters given above under "Conventional Foundations" may be assumed for calculation of preliminary ultimate resistance to lateral loads. 5.4 BASEMENT FLOOR SLAB If a mat foundation is to be used for the proposed building, the basement floor will be the structural mat. If conventional footings or strip mat foundations can be used for the proposed building (that is, liquefaction is not a concern at the project site), the basement floor may consist of a conventional concrete slab -on -grade. This slab should be constructed on lime treated subgrade per the "Earthwork" section of this report. The subgrade should be non -yielding when proof rolled with a fully loaded water truck or similar weight equipment. Thickness and reinforcement for the slab should be determined by the project Structural Engineer, but we suggest the slab to be a minimum of 5 inches thick. Because the groundwater level is very close to the anticipated bottom of the basement slab, we suggest the slab be water -proofed. It will be necessary to design the slab for hydrostatic pressure if highest groundwater level is found to be above the basement level. 50968 (SJ04R582) bl Page 17 of 23 December 30, 2004 Copyright 2004 Kleinfelder, hic. k%J KLEINFELDER 5.5 EXTERIOR CONCRETE SLABS -ON -GRADE Concrete slabs -on -grade constructed at grade are expected to consist of primarily exterior walkway and flatwork. See section above regarding the basement floor slab. Exterior slabs should be constructed on a layer of "non -expansive" material as recommended earlier in this report. Exterior flatwork will be subjected to edge effects due to the drying out or wetting of subgrade soils where adjacent to landscape or vacant area To protect against edge effects lateral cutoffs such as an inverted curb is suggested. Control joints and steel reinforcement should also be provided in the slabs as determined by the project structural engineer. 5.6 BASEMENT WALLS The perimeter walls of the subterranean parking level will serve as retaining walls. The walls should be designed to resist lateral earth pressure due to adjacent soil and surcharge pressures caused by seismic and loads applied behind the walls. It is recommended the walls be designed for lateral earth pressures presented below, which are expressed as equivalent fluid weights. The pressures are for level ground surface behind the walls and a fully drained backfill. For preliminary design of the basement retaining walls, the average total (moist) unit weight of the backfill soil may be assumed 110 pounds per cubic foot. The walls should be designed for an at -rest earth pressure of 60 pounds per cubic foot (pcf) for that portion above the design groundwater level (drained condition) and 92 pcf for that portion below the groundwater level (undrained condition). The design groundwater level should be determined with information from piezometers to be installed during the design level investigation. The effects of surcharge loads close to the basement walls should be included in the wall design, including foundation and floor loads from adjacent buildings, traffic loads from adjacent streets and parking, etc. Design parameters for surcharge loads should be determined during the project design stage. Backfill behind the retaining walls should be compacted to project specifications. 50968 (SJ04R582) bl Page 18 of 23 December 30, 2004 Copyright 2004 Kleinfelder, Inc. k'q KLEINFELDER To simulate the effect of seismic loading, the walls may be evaluated using an active lateral soil pressure plus a horizontal seismic line force of 20H2 pounds per lineal foot (where H is the height of the wall from the wall base to the ground surface above). The active soil pressure may be calculated using an equivalent fluid weight of 40 pounds per cubic foot. The resultant of the active lateral soil pressure should be applied at H/3 above the wall base and the resultant of the seismic line force should be applied at 2/3H above the wall base. A reduced factor of safety for overturning and sliding may be used in seismic design. The retaining walls should be designed with adequate backdrains to reduce the potential for build-up of hydrostatic pressure. A typical backdrain system consists of a 1 to 2 foot wide zone of crushed, free draining gravel (with less than 5 percent fines) wrapped in a geotextile filter fabric (Mirafi 140N or equivalent) or Caltrans Class 2 Permeable Material (Caltrans Standard Specifications, Section 68) immediately adjacent to the walls. Geotextile filter fabric is not required if Class 2 Permeable material is used. As an alternative, a prefabricated drainage board such as Mirdrain G100W or equivalent may be used in lieu of the Class 2 Permeable Material or filter wrapped drain rock. A minimum 4-inch diameter, rigid, perforated pipe should be placed in the lower portion of the drainage material to collect and discharge water to a storm drain or other discharge facility. The pipe should be PVC Schedule 40 or ABS with an SDR of 35 or better. The pipes should be sloped to drain by gravity to the outlets. For that portion of the basement walls which is designed for undrained soil pressure (below groundwater level), a subdrain system will not be necessary. 5.7 PAVEMENTS Some at -grade vehicle pavements will be required for the project. It is anticipated that traffic for this project will be limited to automobiles with occasional delivery and garbage trucks. For this project, we have included pavement sections for Traffic Indices (TIs) of 4.5 to 6.5. A bulk sample of the near surface soil was obtained, and laboratory testing resulted in an R-Value of 38 at an exudation pressure of 300 psi. For calculation of the pavement sections presented below, an R-Value of 35 was used. 50968 (SJ04R582) bl Page 19 of 23 December 30, 2004 Copyright 2004 Kleinfelder, Inc. k'q KLEINFELDER FLEXIBLE PAVEMENT SECTION ALTERNATIVES RNALUE = 35 Traffic Index Asphalt Concrete (inches) Class 2 Aggregate Base inches Class 2 Aggregate Sub- base inches Total Thickness inches 4.5 2.5 5 --- 7.5 5.0 2.5 6 --- 8.5 5.5 3 6 --- 9 6.0 3.5 7 --- 10.5 6.5 3.5 8 --- 11.5 The anticipated traffic and alternate pavement sections presented in this section should be reviewed by the project civil engineer in consultation with the owner during the development of the final grading plans. If site grading exposes soil other than that utilized in our analysis, additional testing should be prepared to confirm or revise the recommended pavement sections. Subgrade preparation for pavements should extend a minimum of 3 feet laterally beyond the face of the curb and should comply with the recommendations provided in the "Earthwork" Section of this report. Compacted pavement subgrade should be non -yielding. The top 12 inches of subgrade soil in vehicle pavement areas should be moisture conditioned to about 1 to 3 percent above the laboratory optimum value and compacted to a minimum of 95 percent relative compaction based on ASTM D 1157, latest edition. Wet subgrade soils will require special handling and treatment before the required compaction can be achieved. Asphalt concrete should meet the requirements for 1/2- or 3/4-inch maximum, medium Type B asphalt concrete in vehicle areas, Section 39, Caltrans Standard Specifications, latest edition. The Class 2 Aggregate Base material should conform to Section 26 of the Caltrans Standard Specifications. ASTM test procedures should be used to assess the percent relative compaction of soils, aggregate base and asphalt concrete. Asphalt concrete should be compacted to a minimum of 96 percent of the maximum laboratory compacted (Hveem) unit weight. 50968 (SJ04R582) bl Page 20 of 23 December 30, 2004 Copyright 2004 Kleinfelder, Inc. k'% KLEINFELDER 6.0 ADDITIONAL SERVICES AND LIMITATIONS 6.1 SUPPLEMENTAL GEOTECHNICAL INVESTIGATION A supplemental geotechnical investigation should be performed during the design phase of the project, when details regarding building type, estimated loads and dimensions have been finalized. The supplemental investigation should include additional subsurface exploration, laboratory testing and engineering analyses. The supplemental investigation is for development of geotechnical recommendations specific to the project including, but not limited to, foundation type and design parameters, anticipated building settlement, compaction requirements, and pavement sections. Kleinfelder would be pleased to prepare a scope of services and cost estimate for this supplemental geotechnical investigation as the details of your project are developed. - 6.2 PLAN REVIEW AND CONSTRUCTION OBSERVATION AND TESTING SERVICES The review of project plans and specifications and the observation and testing of earthwork related construction activities by Kleinfelder are an integral part of the preliminary conclusions and preliminary guidelines presented in this report. If Kleinfelder is not retained for these services, the client will be assuming our responsibility for any potential claims that may arise during or after construction. The required tests, observations and consultation by Kleinfelder during construction include, but are not limited to: • Review of plans and specifications • Review of shoring design • Observation of site clearing and stripping • Observation during installation of shoring system • Construction observation and density testing during subgrade preparation, placement of fill material, including trench backfill • Observation of foundation excavations and foundation construction • Observation of pavement construction 50968 (SJ04R582) bl Page 21 of 23 December 30, 2004 Copyright 2004 Kleinfelder, Inc. k'q KLEINFELDER 6.3 LIMITATIONS The , services provided under this contract as described in this report include professional opinions and preliminary conclusions based on the data collected. These services have been performed according to generally accepted geotechnical engineering practices that exist in the project area at the time the report was written. This report is issued with the understanding that the owner chooses the risk they wish to bear by the expenditures involved with the construction alternatives and scheduling that is chosen. No warranty is express or implied. This report may be used only by Sunrise Development, Inc. and their project consultants, and only for the purposes stated, within a reasonable time from its issuance, but in no event later than 3 years from the date of the report. Land or facility use, on and off -site conditions, regulations, or other factors may change over time, and additional work may be required with the passage of time. Based on the intended use of the report, Kleinfelder may require that additional work be performed and that an updated report be issued. Non-compliance with any of these requirements by the client or anyone else will release Kleinfelder from any liability resulting from the use of this report by any unauthorized party and client agrees to defend, indemnify, and hold harmless Kleinfelder from any claim or liability associated with such unauthorized use or non-compliance The preliminary conclusions and guidelines of this report are for the planning of the Sunrise Assisted Living Facility project in Palo Alto, California, as described in the text of this report. The preliminary conclusions and preliminary guidelines in this report are invalid if any of the following conditions occurs. • The anticipated building loads change • The proposed building location changes • The report is used for adjacent or other property • The Additional Services section of this report is not followed particularly the observation of subgrade preparation and "non -expansive" fill placement • If changes of grades occur between the issuance of this report and construction • Any other change is implemented that materially alters the project from that proposed at the time this report was prepared 50968 (SJ04R582) bl Page 22 of 23 December 30, 2004 Copyright 2004 Kleinfelder, Inc. k'9 KLEINFELDER The preliminary conclusions and preliminary guidelines presented in this report are based on information obtained from the following. • Two borings made within the site • The observations of our engineer • The results of laboratory tests • Our experience on similar projects with similar soil conditions The logs of the exploratory borings do not provide a warranty as to the conditions that may exist beneath the entire site. The extent and nature of subsurface soil and groundwater variations may not become evident until construction begins. It is possible that variations in soil and bedrock conditions and depth to groundwater could exist beyond the points of exploration that may require additional studies, consultation, and possible design revisions. If conditions are encountered in the field during construction that differ from those described in this report, our firm should be contacted immediately to provide any necessary revisions to these recommendations. ;I 50968 (SJ04R582) bl Page 23 of 23 December 30, 2004 Copyright 2004 Kleinfelder, Inc. -V O� �1�� SOPS 01 Z VU San Franci Internatio�c1 o rt San FranciscoB Bay SITE c�UF°R�jq O,Q 2000 0 2000 © by Kleinfelder Inc., 2004 APPROXIMATE SCALE (feet) � KLEINFELDER SITE VICINITY MAP PLATE ` 1362 Ridder Park Drive A San Jose, CA 95131 SUNRISE BURLINGAME 1 r PH. (408) 436-1155 FAX. (408) 436-1771 1818 TROUSDALE DRIVE DRAFTED BY: L. Sue CHECKED BY: F. Mwa a BURL.INGAME, CALIFORNIA DATE: 12 29 04 1 REVISION DATE: PROJECT NO. 50968—GEO QW FILE D:,PROJECf5�50988�CEO\517E—V[C.drq LAYOUT: Layoull PLOUED: 1q O.c 10i1, 3:1* LEGEND — — — — PROPERTY BOUNDARY SOIL BORING (by Kleinfelder, Dec. 2004) NOTE: Locations are approximate. 50 2,5 0 50 APPROXIMATE SCALE (feet) REFERENCE: Mithun, "Site Plan," dated December 9, 2004. ©by Kleinfelder Inc., 2004 CAD FILE &IP-,.-.., rn..v— n.w.... ! t cY / �. 7+rir:.' �/ ahirPr .'•q%w.q:� ( ;:16A75XS,L' :� wuo mv- a 7QUNIT4STORY I ASSISTED LIVING - FACILITY A. '. vznc: ;:,ter ! � !', . �a�:>�� ; ja:,�� `'•••• TRCUSDALE DRIVE KLEINFELDER SITE PLAN 1362 Ridder Park Drive Son Jose, CA 95131 SUNRISE BURLINGAME PH. (408) 436-1771 FAX. (408) 436-1155 1818 TROUSDALE DRIVE DRAFTED BY: L. Sue ICHECKED BY: F. Mwo a BURLINGAME CALIFORNIA DATE: 12/29/04 1 REVISION DATE: PRn.IF(:T Nn -90968— PLATE 2 U1TWT: LW/WA1 A7TACMED 1WbE$ Imp--: IIiEPIAN.IP9 PLOrrED: 29 Dee 2W. 2:12p. IIINIFIFII Still rl ACCI1:IrATInAI cyeTGM MAJOR DIVISIONS LTR ID DESCRIPTION MAJOR DIVISIONS LTR ID DESCRIPTION a.•,q •:C. GW • ' 'a. :::�. Well -graded grovels or grovel with sand; little ML 6-manic sills and very fine sands, rod, flour or clayey or no tines. sks with slight plasticity. SILTS AND GP b• •o- o' o, R.Q ..O � or- ems.ded wits or grant with sand, CL Inorganic lean days of low to medium plasticity, gravelly GRAVEL CLAYS days, sandy days, silty days. ° AND GRAVELLY GM 00 1 Silty grovels, silly gravel with send mWure. GL Organic sits and organic sill -days of low plaswAy. FINE f , f GRAINED COARSE GC Clayey gravels, clayey gravel with sand mWure. SOILS MH GRAINED Inorganic elastic slits, mkareolus or dialomaceous � or silly sots. SOILS SW '..>•:::; �::; Weggraded sands or gravelly sands, Mile or +=;!•;•.'.'A no lines. SILTS AND CH Inorganic rat clan (high plasticity). SP Poodygraded sands or groveily sands, little CLAYS SAND Brno fires. AND OH Organic days of medium high to high plasticity. SANDY SM Silly sand. SC Clayey sand. HIGHLY ORGANIC SOILS Pt . f �t rr Peat and other highly organic sots. Standard Penetration Split Spoon Sampler 2.0 inch, 1.4 inch I.D. Modified California Sampler 2.5 inch O.D., 2.0 inch I.D. Bulk Sample California Sampler, 3.0 inch O.D., 2.5 inch I.D. Shelby Tube 3.0 inch O.D. —"1e00, Approximate water level first observed in boring. Time recorded in reference to a 24 hour clock. 5131 Approximate water level observed in boring following drilling — 0800, 5131 PEN Pocket Pentrometer reading, in tsf TV:Su Torvane shear strength, in ksf LL LIQUID LIMIT TX TRIAXIAL SHEAR PI PLASTICITY INDEX CONSOL CONSOLIDATION %-#200 SIEVE ANALYSIS (#200 SCREEN) R-Value RESISTANCE VALUE DS DIRECT SHEAR SE SAND EQUIVALENT C COHESION (PSF) El EXPANSION EQUIVLANT PHI FRCITION ANGLE FS FREE SWELL (U.S.B.R.) Notes: Blow counts represent the number of blows a 140-pound hammer falling 30 inches required to drive a sampler through the last 12 inches of an 18 inch penetration, unless otherwise noted. The lines separating strata on the logs represent approximate boundaries only. The actual transition may be gradual. No warranty is provided as to the continuity of soil strata between borings. Logs represent the soil section observed at the boring location on the date of drilling only. k4 K L E I N F E L D E R PROJECT NO. 50968 BORING LOG LEGEND I PLATE Sunrise Burlingame 1818 Trousdale Drive A-1 Burlingame, California a UAGINI Y>RWc'CTSZOWS.GPJ O o cn o in o u+ Depth, ft c c O 0 y 3 0 m n 0 n Sample 2 'n , v � 3 - „ Blows/ft e m m a r a Dry Density o m pcf + co 0 0 a, N rn Moisture c Z w c'o °i Content T % r- i m �, Compress. CD `D p \ Strength a r tsf D 1 v oy O A Other Tests W cw O w Pen, tsf w w N <t) YJ LE D m n 0 p C W 0 (D 0 N ai C -n M O H y 0 0 O T c n al fD 7 O N 3 CD -ri Za O O D Z O O O ;a Li a x m 0 W �_ CD" N N CD 7 N < r N -< r m O �, 2 Iril T p > .n a ( Z v O a y Z D n Z' N 3 K n c' D > m 0 0 a ego +n o r o a '� 3 °m > n m CL n Z A 3 < G j to H 7 m m m O L , A v 2 0> d m c c d a v ? fD w 0.m y d W �<, < m 0 fD � U X 10 o A H n A N it � `° 0 1 x 3 �.22 B fD N d d y 0 3 C S d CDm i fD O O O a m c m M N 0 S rn Z v O o N N < CL y 'n N �+ n N r o Q csu fA 0 m ,2. m CD r3 � o G a o A g Cr 0 N O m CD > N - 3:":in rm FIELD LABORATORY N DESCRIPTION •N GI N 4) L N �' y N F Y (Continued from previous plate) a N 3 Co 4) C n N m 0 o 20 n o O fn `� m O `m a C-,.. POORLY GRADED SAND WITH CLAY AND GRAVEL o: (SP-SC)- grayish green, wet, medium dense, fine to coarse sand, fine to coarse gravel (channel deposit) 0 o. 35 28 Passing POORLY GRADED SAND (SP)- grayish green, wet, medium -#200=8% dense, fine to coarse sand (Colma Formation) SANDY LEAN CLAY (CL)- grayish green, moist, hard, fine to coarse sand, trace fine gravel (Colma Formation) LEAN CLAY (CL)- mottled olive to grayish green, wet, hard 40 80 (Colma Formation) - silt with fine sand below 43.5' 50/5" SILTY SAND WITH GRAVEL (SM)- mottled olive to grayish as green, wet, very dense, fine to coarse sand, fine to coarse gravel (Colina Formation) -grades coarser below 45' Bottom of boring at 45.5' Boring backfilled with cement grout 50 55 60 65 LOG OF BORING NO. B-1 PLATE XTK L E I N F E L D E R Sunrise Burlingame 1818 Trousdale Drive Burlingame, California A-2 (cont'd) PROJECT NO. 5osss Date Completed: 11/16/04 Sampler. Modified California 2.5 inch O.D., 2.0 Inch I.D. Logged By: F. Mwape Total Depth: 44.0 ft Hammer Wt. 140 lbs., 30" drop Method: 8" Hollow Stem Auger FIELD LABORATORY DESCRIPTION t n N Z. m ! w m L F w w o Z m o 0 ELrn o m L Surface Elevation: Estimated feet (Above MSL) v� m oo a �c�o U in N o 0 ASPHALT CONCRETE- a roximatel 3 inches AGGREGATE BASE- approximate 6 inches LL=32; PI=17 POORLY GRADED SAND WITH SILT (SP-SM)- brown, moist, 21 116 11 medium dense fine sand Fill LEAN CLAY WITH SAND (CL)- black, moist, hard, fine to >4.5 coarse sand, some organics 5 25 101 14 - brown, moist, very stiff, fine to coarse sand, trace fine gravel, trace organics 2.3 10 14 111 18 10:08 - mottled gray brown, moist, stiff to very stiff, some fine to coarse 1 v1 2.0 sand 15 17 -sand cla la er with fine sand ockets 19' to 19.5' 20 23 SANDY LEAN CLAY (CL)- mottled olive gray, moist, very stiff, fine to coarse sand - some silt 9:51 POORLY GRADED SAND WITH GRAVEL (SP) - gray, wet, 25 50/ dense, fine to coarse sand, fine to coarse gravel, some clay 11t stow p; (channel deposit) o,. POORLY GRADED SAND (SP)- gray, wet, very dense, fine to coarse sand (Colma Formation) 50/4" 30 LOG OF BORING NO. B-2 PLATE u klq-- K L E I N F E L D E R Sunrise Burlingame d 1818 Trousdale Drive Burlingame, California A-3 c �L C PROJECT NO. 60968 FIELD LABORATORY DESCRIPTION N `y- T C 4J N L y F a o E vi o3 m c o o n N C M U o E w U U) °' O .y. a (Continued from previous plate) Poorly Graded Sand- Continued 35 LEAN CLAY (CL)- grayish green with olive mottling, damp to wet, hard, trace fine sand (Colma Formation) - sand lens, fine to coarse -grained from 38' to 38.5' 50/5.5" SANDY LEAN CLAY (CL) - grayish green, wet, hard, fine sand 40 (Colma Formation) SILTY SAND WITH GRAVEL (SM)- grayish green, wet, very dense, fine to coarse sand, fine to coarse gravel (Colma 45 Formation Bottom of boring at 44'1" Boring backfilled with cement grout so 55 60 LOG OF BORING NO. B-2 PLATE K L E I N F E L D E R Sunrise Burlingame 1818 Trousdale Drive Burlingame, California A-3 , (cont'd) PROJECT NO. 50968 60 55 50 CH 45 a 40 W 35 CL Lu Z_ 30 V 25 va7 20 a 15 m MH 10 or 5 ML or OH CL - ML 1 7. 0-- 1 1 ---r I OL - 0 25 50 75 100 LIQUID LIMIT (LL) Symbol Boring Depth ft LL PL PI Sample Description El B-1 4.5 41 18 23 Black to Olive Brown Lean Clay with Sand (CL) m B-2 1.5 32 15 17 Black Lean Clay with Sand (CL) Symbol LL < 50 s mbol LL > 50 Inorganic clayey sifts to very fine sands Inorganic silts and clayey silts ML of slight plasticity MFi of high plasticity CL inorganic clays of low to medium plasticity CH Inorganic clays of high plasticity Organic silts and organic silty clays of Organic clays of medium to OL low plasticity OH high plasticity, organic silts 12r"2004 3:15:16 PM 4.5 4.0 3.5 3.0 w x 2.5 a 2.0 E+ 1.5 1.0 0.5 0. 4 6 6 STRAIN - % BORING NO. B-1 DRY DENSITY - pcf 104 DEPTH - ft 14.5 WATER CONTENT - % 23 SOIL DESCRIPTION Mottled Olive Brown/Grayish Green Lean Clay with Sand MAX. UC STRENGTH= 4.06 ksf At 13.0 % STRAIN UNCONFINED COMPRESSION TEST PLATE k" KLEINFELDER Sunrise Burlingame 1818 Trousdale Drive Burlingame, California B-2 PROJECT NO. 50968 Completed: 1228/2004 4:26:58 PM 10 91 81 71 v 60 LLJ _I Q 50 LU 0 40 Q H () 30 LU W 20 10 0 4. i , 1 I , I i I i f �—i I i i It...._..i . _' ff _ 3 —` 7 -- i— - 7 ! -{ T ' « t 11 �._....._.......�_... 1,000 800 600 400 EXUDATION PRESSURE 200 (psi) 0 SPECIMEN NO. m MOISTURE CONTENT (%) 12.4 11.1 9.7 DRY DENSITY (PCF) 121.8 123.8 121.9 EXUDATION PRESSURE (PSI) 160 320 680 EXPANSION PRESSURE (PSF) 0 0 26 RESISTANCE VALUE (R) 17 41 80 Date Received: 121612004 SAMPLE SOURCE CLASSIFICATION SAND EQUIVALENT EXPANSION PRESSURE R-VALUE B-1 (1' - 3') Brown Poorly Graded Sand with Silt 0 psf 38 ASTM D 2844, Cal Test 301 RESISTANCE VALUE TEST DATA PLATE KLEINFELDER Sunrise Burlingame 1818 Trousdale Drive B_3 PROJECT NO. 50968 Burlingame, California J California State Certified Laboratory No.2153 20 December IV analytical, inc. Job No.0412062 UEC .Z 2 2004 Cust. No. 10781 3942-A Valley Avenue Pleasanton, CA 94566-4715 Tel: 925.462.2771 Mr. Nasir ER �A� :�� Fax: 925.462.2775 Kleinfelder 1362 Ridder Park Drive San Jose, CA 95131 Subject: Project No.: 5128 Project Name: Sunrise, Burlingame Corrosivity Analysis — ASTM Test Methods Dear Mr. Ahmad: Pursuant to your request, CERCO Analytical has analyzed the soil samples submitted on December 07, 2004. Based on the analytical results, a brief corrosivity evaluation is enclosed for your consideration. Based upon the resistivity measurements, both samples are classified as "moderately corrosive". All buried iron, steel, cast iron, ductile iron, galvanized steel and dielectric coated steel or iron should be properly protected against corrosion depending upon the critical nature of the structure. All buried metallic pressure piping such as ductile iron firewater pipelines should be protected against corrosion. The chloride ion concentrations reflect none detected with a detection limit of 15 mg/kg. The sulfate ion concentrations reflect none detected with a detection limit of 15 mg/kg and are determined to be insufficient to damage reinforced concrete structures and cement mortar -coated steel at these locations. The pH of the soils range from 7.2 to 7.6 which does not present corrosion problems for buried iron, steel, mortar -coated steel and reinforced concrete structures. The redox potentials range from 460 to 470-mV, which is indicative of aerobic soil conditions. This corrosivity evaluation is based on general corrosion engineering standards and is non-specific in nature. For specific long-term corrosion control design recommendations or consultation, please call JDH Corrosion Consultants, Inc. at (925) 927-6630. We appreciate the opportunity of working with you on this project. If you have any questions, or if you require further information, please do not hesitate to contact us. Very truly yours, ANALYTIC l W J arby Howard, Jr. P.E. r ident JDH/jdl Enclosure CERCO Analytical, Inc. 3942-A Valley Avenue, Pleasanton, CA 94566-4715 (925) 462-2771 Fax (925) 462-2775 FINAL RESULTS Client: Kleinfelder Date Sampled: Not Indicated Client's Project No.: 5128 Date Received: 7-Dec-2004 Client's Project Name: Sunrise, Burlingame Date of Report: 20-Dec-2004 Authorization: Signed Chain of Custody Matrix: Soil Resistivity Redox Conductivity (100% Saturation) Sulfide Chloride Sulfate jum3ampie r4o. 6ampie i.li. (mv) ph (umhos/cm)- (ohms -cm) (mg/kg)* (mg/kg)* (mg/kg)* 0412062-001 B1-3 460 1 7.6 - 3,400 - N.D. N.D. 0412062-002 B2-5 470 1 7.2 1 3,300 - N.D. N.D. Method: ASTM D1498 ASTM D4972 ASTM D1125M ASTM G57 ASTM D4658M ASTM D4327 ASTM D4327 Detection Limit: - - 10 - 50 15 15 Date Analyzed: n 14-Dec-2004 15-Dec-2004 - 17-Dec-2004 - 15-Dec-2004 I 15-Dec-2004 * Results Reported on "As Received" Basis N.D. -None Detected Cheryl McMil Laboratory Director Ouality Control Summary - All laboratory quality control parameters were found to be within established limits Page No. 1