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HomeMy WebLinkAboutGrading & Drainage GEOTECHNICAL INVESTIGATION FOR MIXED-USE BUILDING DILLON AVENUE/EAST CAMPBELL AVENUE -SENWMCCE, CALIFORNIA October 2015 RECEIVED NOV 232016 CITY OF CAMPBELL PLANNING DEPT. Prepared for Mr. Chris Russell Cresleigh Homes Corporation 3005 Douglas Boulevard, Suite 110 Roseville, California 95661 Project No. 3578-1 ROMIG ENGINEERS, INC. GEOTECHNICAL&ENVIRONMENTAL SERVICES Y f . ROMIG ENGINEERS, INC. GEOTECHNICAL&ENVIRONMENTAL SERVICES October 28, 2015 3578-1 Cresleigh Homes Corporation RE: GEOTECHNICAL INVESTIGATION 3005 Douglas Boulevard, Suite 110 MIXED-USE BUILDING Roseville, California 95661 DILLON AVENUE/EAST CAMPBELL AVENUE CAMPBELL,CALIFORNIA Attention: Mr. Chris Russell: Gentlemen: As requested, we have performed a geotechnical investigation for the proposed mixed-use building to be constructed southeast of the intersection of Dillon Avenue and East Campbell Avenue in Campbell, California. The accompanying report summarizes the results of our field exploration, laboratory testing, and engineering analysis, and presents geotechnical recommendations for the proposed project. We refer you to the text of our report for specific recommendations. Thank you for the opportunity to work with you on this project. If you have any questions or comments about our findings or recommendations for the project, please call. Very truly yours, FEss 0,0a ROMIG ENGINEERS,IN *FEgS/• /'kC•) N A. R Nq! , /441`PS I. 0TT490 � l� (2 0 6" /fv yy l&oty + 002157rn 111 ' esti4 • No.84234 m c Lucas J. Ottoboni, P.E.��rF• • crv►t ,,a`� Glenn A. Romig, P. '., G.E. -F CAItCo`--' F� l Copies: Addressee (4) GAR:LO:dr 1390 El Camino Real, Second Floor • San Carlos, California 94070 • (650)591-5224 • Fax(650)591-5251 GEOTECHNICAL INVESTIGATION MIXED-USE BUILDING DILLON AVENUE/EAST CAMPBELL AVENUE CAMPBELL,CALIFORNIA 95008 PREPARED FOR: MR. CHRIS RUSSELL CRESLEIGH HOMES CORPORATION 3005 DOUGLAS BOULEVARD, SUITE 110 ROSEVILLE, CALIFORNIA 95661 PREPARED BY: ROMIG ENGINEERS, INC. 1390 EL CAMINO REAL, SECOND FLOOR SAN CARLOS, CALIFORNIA 94070 OCTOBER 2015 ROMIG ENGINEERS, INC. • TABLE OF CONTENTS Page No. Letter of transmittal Title Page TABLE OF CONTENTS INTRODUCTION 1 Project Description 1 Scope of Work 1 Limitations 2 SITE EXPLORATION AND RECONNAISSANCE 2 Surface Conditions 3 Subsurface Conditions 3 Ground Water 4 GEOLOGIC SETTING 4 Faulting and Seismicity 4 Table 1. Earthquake Magnitudes and Historical Earthquakes 5 Earthquake Design Parameters 6 Geologic Hazards 6 CONCLUSIONS 7 FOUNDATIONS 8 Mat Foundation 8 Basement Water Proofing 9 Lateral Loads 9 Settlement 9 RETAINING WALLS 9 SLABS-ON-GRADE 11 General Slab Considerations 11 Exterior Flatwork 11 Interior Mat 11 VEHICLE PAVEMENTS 12 Table 2. Pavement Sections 13 PORTLAND CEMENT CONCRETE PAVEMENT 13 EARTHWORK 14 Clearing and Subgrade Preparation 14 Material For Fill 14 Compaction 14 Table 3. Compaction Recommendations 15 Temporary Slopes, Excavations and/or Shoring 15 Basement Excavation Support 16 Finished Slopes 16 Surface Drainage 16 FUTURE SERVICES 17 Plan Review 17 Construction Observation and Testing 18 ROMIG ENGINEERS, INC. TABLE OF CONTENTS (Continued) REFERENCES FIGURE 1 - VICINITY MAP FIGURE 2 - SITE PLAN FIGURE 3 - VICINITY GEOLOGIC MAP APPENDIX A-FIELD INVESTIGATION Figure A-1 -Key to Exploratory Boring Logs Exploratory Boring Logs EB-1, EB-2, and EB-3 APPENDIX B - SUMMARY OF LABORATORY TESTS Figure B-1 -Plasticity Chart ROMIG ENGINEERS, INC. , d GEOTECHNICAL INVESTIGATION FOR MIXED-USE BUILDING DILLON AVENUE/EAST CAMPBELL AVENUE CAMPBELL, CALIFORNIA INTRODUCTION This report presents the results of our geotechnical investigation for the proposed mixed- use building to be constructed southeast of the intersection of Dillon Avenue and East Campbell Avenue, in Campbell California. The location of the site is shown on the Vicinity Map, Figure 1. The purpose of this investigation was to evaluate subsurface conditions at the site and to provide geotechnical recommendations for design and construction of the proposed project. I I/milli Ot f ikon 6 1 Project Description 5. 641 MN, VSe The project consists of constructing a ' our-sto mixed-use building at the subject site. The building will be constructed over one evel of below-grade parking. The street level will be for commercial/retail use and the upper three floors will be residential. We assume that the basement elevation will be at a depth of approximately 10 to 13 feet below existing grade. The existing buildings that occupy the property will be dei TT hed prior to construction. Scove of Work Our scope of work for this investigation was presented in our agreement with Cresleigh Homes Corporation dated August 6, 2015. In order to complete our investigation, we performed the following work. • Review of geologic and geotechnical literature in our files pertinent to the general area of the site. • Subsurface exploration consisting of drilling, sampling, and logging three exploratory borings in the area of the proposed building. • Laboratory testing of selected soil samples to aid in soil classification and to help evaluate the engineering properties of the soils encountered at the site. ROMIG ENGINEERS, INC. Cresleigh Homes Corporation Mixed-Use Building Page 2 of 18 • Engineering analysis and evaluation of the surface and subsurface data to develop earthwork guidelines and foundation design criteria for the proposed building. • Preparation of this report presenting our findings and geotechnical recommendations for the proposed construction. Limitations This report has been prepared for the exclusive use of Cresleigh Homes Corporation for specific application to developing geotechnical design criteria for the proposed mixed-use building to be constructed southeast of the intersection of Dillon Avenue and East Campbell Avenue in Campbell, California. We make no warranty, expressed or implied, for the services performed for this project. Our services are performed in accordance with the geotechnical engineering principles generally accepted at this time and location. This report was prepared to provide engineering opinions and recommendations only. In the event there are an re.han� 'the nature, design, or location oft the project, or if any future improvements are planned, the conc usions an recommen ations presented in this --\ report should not be considered valid unless 1) the project changes are reviewed by us, and 2) the conclusions and recommendations presented in this report are modified or verified in writing. The analysis, conclusions, and recommendations presented in this report are based on site conditions as they existed at the time of our investigation; the currently planned improvements; review of readily available reports relevant to the site conditions; and laboratory test results. In addition, it should be recognized that certain limitations are inherent in the evaluation of subsurface conditions, and that certain conditions may not be detected during an investigation of this type. Changes in the information or data gained from any of these sources could result in changes in our conclusions or recommendations. If such changes occur, we should be advised so that we can review our report in light of those changes. SITE EXPLORATION AND RECONNAISSANCE Site reconnaissance and subsurface exploration were performed on October 13, 2015. Subsurface exploration was performed using a Simco 2400 SK-1 truck-mounted drill equipped with 6-inch diameter solid flight augers. Three exploratory borings were advanced to depths ranging from 22.3 to 28 feet. The approximate locations of the borings are presented on the Site Plan, Figure 2. The boring logs and the results of our laboratory tests are attached in Appendices A and B, respectively. ROMIG ENGINEERS, INC. . Cresleigh Homes Corporation Mixed-Use Building Page 3 of 18 Surface Conditions The overall subject property includes five individual lots and is located i mixed a residential and commercial area along the southeast side of the intersection of Dillon Avenue and East Campbell Avenue. Approximately one third of the site was developed and the remaining two thirds were vacant or used as a parking lot. Along Campbell Avenue and at the corner of Campbell Avenue and Dillon Avenue, there were a row of e story commercial buildings, which appeared to be mostly empty. Along Dillon n n enue, there was a single family residence, which appeared to be abandoned, surrounded by vacant property. The site as a whole is relatively flat. Based on the age of the buildings, we expect that they are supported on a conventional shallow foundation systems, although the depth and width of the foundations are unknown. The exterior stem wall of the buildings (commercial and single family) were generally covered by the siding and were not visible. Subsurface Conditions At the location of our Borings EB-1 and EB-2, we encountered 10 to 12 feet of firm to stiff sandy lean clay underlain by medium dense to very dense clayey gravel to the maximum depth explored of 28 and 25 feet in Borings EB-1 and EB-2, respectively. At Boring EB-3, we encountered 15 feet of firm to stiff sandy lean clay underlain by medium dense to very dense clayey gravel to the maximum depth explored of 22.3 feet, where auger refusal was met. We note that the top of the medium dense clayey gravel strata in Borings EB-1 and EB-2 appeared to be approximately at or just below elevation of the basement parking level; whereas the gravel layer in Boring EB-3 appeared to be encountered several feet below the elevation of the basement parking level. These medium dense clayey gravel strata appeared to be approximately 5 to 8 feet thick and may be prone to dynamic densification during a moderate to strong earthquake. Details of our dynamic settlement evaluation are included in the section titled "Dynamic Densification." Gasoline odors were also noticed during drilling and sampling, as noted on the boring logs. A Liquid Limit of 29 and a Plasticity Index of 9 were measured on a sample of surface soil obtained from our Boring EB-3. These test results indicate that the near surface soil has low plasticity and a low potential for expansion. ROMIG ENGINEERS, INC. Cresleigh Homes Corporation Mixed-Use Building Page 4 of 18 Ground Water Free ground water was not encountered in our borings during or immediately following our field exploration. The borings were backfilled with grout shortly after drilling, therefore a stabilized ground water level may not have been obtained. Please be cautioned that fluctuations in the level of ground water can occur due to variations in rainfall, landscaping, surface and subsurface drainage patterns, and other factors. Information presented in Seismic Hazard Zone Report 058 for the San Jose West Quadrangle (California Geological Survey, 2002) indicates the historical high ground water level near the site is greater than 50 feet below the ground surface. GEOLOGIC SETTING As part of our investigation, we briefly reviewed our local experience and geologic information in our files pertinent to the general area of the site. Geologic information for the area indicates that the site is underlain by Holocene-age older alluvial fan deposits, Qhf2 (Blake, Graymer, McLaughlin and Wentworth, 1999). These principal Holocene fans and associated terraces are generally found to consist of brown gravelly sand and sandy and clayey gravel, grading upward to sandy and silty clay. The geology of the site vicinity is shown on the Vicinity Geologic Map, Figure 3. The lot and the immediate site vicinity are located in an area that slopes gently to the north toward the San Francisco Bay. The site is located at an elevation of approximately 195 feet above sea level. Faulting and Seismicity There are no mapped through-going faults within or adjacent to the site and the site is not located within a State of California Earthquake Fault Zone (formerly known as a Special Studies Zone), an area where the potential for fault rupture is considered probable. The closest active fault is the San Andreas fault, located approximately 7.6 miles southwest of the property. Thus, the likelihood of surface rupture occurring from active faulting at the site is remote. ROMIG ENGINEERS, INC. Cresleigh Homes Corporation Mixed-Use Building Page 5 of 18 The San Francisco Bay Area is, however, an active seismic region. Earthquakes in the region result from strain energy constantly accumulating because of the northwestward movement of the Pacific Plate relative to the North American Plate. On average about 1.6-inches of movement occur per year. Historically, the Bay Area has experienced large, destructive earthquakes in 1838, 1868, 1906 and 1989. The faults considered most likely to produce large earthquakes in the area include the San Andreas, Hayward, Calaveras, and San Gregorio faults. The Hayward and Calaveras faults are located approximately 9.8 and 13 miles northeast of the site, respectively. The San Gregorio fault is located approximately 23 miles southwest of the site. These faults and significant earthquakes that have been documented in the Bay Area are listed below in Table 1. Table 1. Earthquake Magnitudes and Historical Earthquakes Mixed-Use Building Campbell,California Maximum Historical Estimated Fault Magnitude(Mw) Earthquakes Nlaanitude San Andreas 7.9 1989 Loma Prieta 6.9 1906 San Francisco 7.9 1865 N. of 1989 Loma Prieta Earthquake 6.5 1838 San Francisco-Peninsula Segment 6.8 1836 East of Monterey 6.5 Hayward 7.1 1868 Hayward 6.8 1858 Hayward 6.8 Calaveras 6.8 1984 Morgan Hill 6.2 1911 Morgan Hill 6.2 1897 Gilroy 6.3 San Gregorio 7.3 1926 Monterey Bay 6.1 In the future, the subject property will undoubtedly experience severe ground shaking during moderate and large magnitude earthquakes produced along the San Andreas fault or other active Bay Area fault zones. The Working Group On California Earthquake Probabilities, a panel of experts that are periodically convened to estimate the likelihood of future earthquakes based on the latest science and ground motion prediction modeling, concluded there is a 72 percent chance for at least one earthquake of Magnitude 6.7 or larger in the Bay Area before 2045. The Hayward fault has the highest likelihood of an earthquake greater than or equal to magnitude 6.7 in the Bay Area, estimated at 14 percent, while the likelihood on the San Andreas and Calaveras faults is estimated at approximately 6 and 7 percent, respectively(Working Group, 2015). ROMIG ENGINEERS, INC. Cresleigh Homes Corporatior Mixed-Use Building Page 6 of 18 Earthquake Design Parameters The State of California currently requires that buildings and structures be designed in accordance with the seismic design provisions presented in the 2013 California Building Code and in ASCE 7-10, "Minimum Design Loads for Buildings and Other Structures." Based on site geologic conditions and on information from our subsurface exploration at the site, the site may be classified as Site Class D, stiff soil, in accordance with Chapter 20 of ASCE 7-10. Spectral acceleration response parameters Ss and Si, and site coefficients Fa and Fv, may be taken directly from the figures and tables in the 2013 California Building Code and in the lookup tables at the U.S.G.S. website based on the latitude and longitude of the site. For the site latitude (37.2867) and longitude (-121.9404)and Site Class D, SDs= 1.056 and SD1 =0.601. Geologic Hazards As part of our investigation, we reviewed the potential for geologic hazards to impact the site and the proposed building, considering the geologic setting and the soils encountered during our investigation. The results of our review are presented below and in the following sections of our report. • Fault Rupture - The site is not located in a State of California Earthquake Fault Zone or area where fault rupture is considered likely. Therefore, active faults are not believed to exist beneath the site and the potential for fault rupture at the site is considered low. • Ground Shaking - The site is located in an active seismic area. Moderate to large earthquakes are probable along several active faults in the greater Bay Area over a 30 to 50 year design life. Strong ground shaking should therefore be expected several times during the life of the building, as is typical for sites throughout the Bay Area. The building should be designed in accordance with current earthquake resistance standards. • Liquefaction -Liquefaction occurs when saturated sandy soils lose strength during earthquake shaking. Ground settlement often accompanies liquefaction. Soils most susceptible to liquefaction are saturated, loose, sandy silts, silty sands, and uniformly graded sands. Since saturated sands were not encountered in our borings and since the ground water level is expected to be relatively deep, in our opinion, the likelihood of liquefaction occurring in the soils encountered in our borings at the site is low. In addition, the site is not located within a State designated liquefaction hazard zone. ROMIG ENGINEERS, INC. Cresleigh Homes Corporatior. Mixed-Use Building Page 7 of 18 • Dynamic Densification -Dynamic densification occurs during moderate and large earthquakes when soft or loose, natural or fill soils densify and settle, often unevenly across a site. To evaluate the potential for earthquake-induced dynamic densification of the medium dense clayey sands encountered at the site, we performed an analysis of the data from our borings following the methods presented in the US Army Corps of Engineers EM1110-1-1904. Medium dense clayey gravel strata ranging from 5 to 8 feet thick were encountered in Borings EB-1, EB-2, and EB-3 at a similar depth below the bottom of the assumed basement mat. Based on the results of our analysis, we estimate that total dynamic settlement up to about 1/2- to 3/4- inch may occur beneath the basement mat due to dynamic densification of the medium dense sand when subjected to a peak ground acceleration (PGA) of 0.603g, the PGAM for maximum considered earthquake based on ASCE 7-10. In our opinion, differential settlement on the order of 1/2- to 3/4-inch across the building is possible from the above estimated dynamic settlement. The estimated dynamic settlement should be considered during the structural design of the building and its foundation system. CONCLUSIONS From a geotechnical viewpoint, the site is suitable for the proposed mixed-use building provided the recommendations presented in this report are followed during design and construction. Specific geotechnical recommendations for the project are presented in the following sections of this report. The primary geotechnical concerns for the proposed construction are the presence of the medium dense clayey gravel strata encountered at or just below the assumed basement elevation that are susceptible to dynamic densification during strong seismic shaking, and the potential for severe ground shaking at the site during a major earthquake. As discussed above, on the order of about 1/2- to 3/4- inch of differential dynamic settlement from dynamic densification is estimated below the basement mat. In order to reduce the potential impact on the proposed building from differential movement/settlement from dynamic densification, in our opinion, the proposed building and basement retaining walls should be supported on a relatively rigid structural mat foundation. We note however, that once the layout and finished floor elevation of the basement and the magnitude and placement/spacing of the building loads have been finalized, we could be contacted to evaluate whether an alternative foundation type such as spread footings is feasible. ROMIG ENGINEERS, INC. Cresleigh Homes Corporatior. Mixed-Use Building Page 8 of 18 Depending on the depth of the basement excavation, we note that portions of the medium dense gravel strata encountered in the borings were judged to have limited cohesion and may be prone to sloughing and/or caving if excavated near-vertical. Temporary basement excavation shoring should be designed and installed accordingly. This information should be considered by the contractor when establishing temporary shoring/slope criteria for basement excavation, as needed. Providing adequate waterproofing of the basement mat/slab and walls is essential for the success of the basement. Please note however that providing water proofing recommendations is outside of our scope of services and expertise. Because subsurface conditions may vary from those encountered at the location of our borings, and to observe that our recommendations are properly implemented, we recommend that we be retained to: 1) review the grading and foundation plans for conformance with the recommendations presented in this report and, 2) observe and test during earthwork, foundation, shoring, drainage and slab construction. FOUNDATIONS Mat Foundation In our opinion, the proposed mixed-use building may be supported on a mat foundation at the basement level. The mat may be designed for an average allowable bearing pressure of 2,000 pounds per square foot for combined dead plus live loads, with maximum localized bearing pressures of 3,500 pounds per square foot at column or wall loads. These pressures may be increased by one-third for total loads including wind or seismic forces. These pressures are net values; the weight of the mat may be neglected in design. A water-proofing system designed by others should be installed below and around the edges of the mat foundation (and behind the basement walls). A modulus of subgrade reaction (Kvl) of 125 pounds per cubic inch may be assumed for the basement subgrade. This value is based on a 1-foot square bearing area and should be scaled to account for mat foundation size effects. Alternatively, when the building loads are known, we could be contacted to provide a modulus of subgrade reaction based on the anticipated building load and differential settlement, (Kv). ROMIG ENGINEERS, INC. Cresleigh Homes Corporatior. Mixed-Use Building Page 9 of 18 The mat should be reinforced to provide structural continuity and to permit spanning of local irregularities. The bottom of the mat excavation should be cleaned of loose and soft soil and debris. Our representative should observe the mat excavation to evaluate whether scarification and compaction or proof rolling of the excavation bottom is needed. Basement Water Proofing We have not provided recommendations regarding the method or details for basement damp-proofing since design of damp-proofing systems is outside of our scope of services and expertise. Installing adequate damp-proofing below and behind the edges of the basement floor and behind the basement walls is essential for the success of the basement structure. Placing concrete with a low water cement ratio should be considered as one step of good damp-proofing. The damp-proofing system below the basement mat may be placed directly on the prepared subgrade soils, a 6- inch section of crushed rock or on a thin working slab, as determined by the water-proofing consultant and design team. Lateral Loads Lateral loads may be resisted by friction between the bottom of the mat and the supporting subgrade. A coefficient of friction of 0.30 may be assumed for design. In addition to friction, lateral resistance may also be provided by passive soil pressure acting against the sides of foundations cast neat in excavations or backfilled with properly compacted structural fill. We recommend assuming an equivalent fluid pressure of 300 pounds per cubic foot for passive soil resistance, where appropriate. Settlement At this time, the column layout and structural loads on the basement mat are not available. On a preliminary basis, we estimate that the 30 year post-construction differential settlement due to static loads is not expected to exceed about 3/4-inch across the building supported on a mat foundation, provided that the foundations are designed and constructed as recommended. In addition, as stated in the above sections, we estimate that differential dynamic settlement up to about 3/4-inch could occur across the basement mat as a result of the analyzed seismic event. The estimated dynamic settlement should be considered during the structural design of the building and its foundation system. The settlement estimates should be updated during the design when structural loads are available. RETAINING WALLS Retaining walls should be designed to support adjacent native material and backfill. Retaining walls with level backfill that are not free to deflect or rotate, such as the retaining walls as part of the building, should be designed to resist an equivalent fluid ROMIG ENGINEERS, INC. Cresleigh Homes Corporatior, Mixed-Use Building Page 10 of 18 pressure of 45 pounds per cubic foot plus an additional uniform lateral pressure of 8H in pounds per square foot, where H is the height of the wall in feet. Where retaining walls will be subjected to surcharge loads, such as from adjacent foundations, vehicle loads, or construction, the walls should be designed for an additional uniform lateral pressure equal to one-half of the surcharge pressure. Based on the site peak ground acceleration (PGA), on Seed and Whitman (1970); Al Atik and Sitar (2010), and Lew et al. (2010); seismic loads on retaining walls that can yield may be simulated by a line load of 4H2 (in pounds per foot, where H is the wall height in feet). Seismic loads on walls that cannot yield, such as the basement retaining walls, may be subjected to a seismic load as high as about 10H2. This seismic surcharge line load should be assumed to act at 1/3H above the base of the wall (in addition to the active wall design pressure of 45 pounds per cubic foot). To prevent buildup of water pressure from surface water infiltration, a subsurface drainage system should be installed behind the basement walls. The drainage system should consist of a 4-inch diameter perforated pipe (perforations placed down) embedded in a section of 1/2- to 3/4-inch, clean, crushed rock at least 12 inches wide. Backfill above the perforated drain line should also consist of 1/2-to 3/4-inch, clean, crushed rock to within about 1'/z to 2 feet below exterior finished grade. A filter fabric should be wrapped around the crushed rock to protect it from infiltration of native soil. The upper 11/2 to 2 feet of backfill should consist of compacted native clayey soil. The perforated pipe should discharge into a sump that pumps to a suitable location. Damp-proofing of the basement walls should be included in areas where wall dampness and efflorescence would be undesirable. Miradrain, Enkadrain or other drainage fabrics approved by our office may be used for wall drainage as an alternative to the gravel drainage system described above. If used, the drainage fabric should extend from a depth of about 1 foot below the top of the wall backfill down to the drain pipe at the base of the wall. A minimum 12-inch wide section of '/z-inch to 3/4-inch clean crushed rock and filter fabric should be placed around the drainpipe, as recommended previously. Backfill placed behind the walls should be compacted to at least 90 percent relative compaction using light compaction equipment. If heavy equipment is used for compaction of wall backfill, the walls should be temporarily braced. Basement retaining walls should be supported on a mat foundation designed in accordance with the recommendations presented previously. ROMIG ENGINEERS, INC. Cresleigh Homes Corporatior. Mixed-Use Building Page 11 of 18 SLABS-ON-GRADE General Slab Considerations The surface and near surface soils at this site have a low potential for expansion. To reduce the potential for movement of the slab subgrade, at least the upper 6-inches of subgrade soil should be scarified and compacted at a moisture content above the laboratory optimum. The native or fill soil subgrade should be kept moist up until the time the non-expansive fill and/or aggregate base is placed. Slab subgrades and non expansive fill should be prepared and compacted as recommended in the section of this report titled "Earthwork." Exterior flatwork should be underlain by a layer of non expansive fill as discussed below. The non expansive fill should consist of aggregate base rock, granular soil, or a clayey soil with a plasticity index of 15 or less. Considering the potential for expansive soil movements of the surface soils, we expect that a reinforced slab will perform better than an unreinforced slab. Consideration should also be given to using a control joint spacing on the order of 2 feet in each direction for each inch of slab thickness. Exterior Flatwork Near surface concrete walkways and exterior flatwork should be at least 4 inches thick and should be constructed on at least 6 inches of Class 2 aggregate base. We recommend that exterior slabs-on-grade be constructed with a thickened edge to improve edge stiffness and to reduce the potential for water seepage under the edge of the slabs. Interior Mat Slab The basement mat slab should be constructed on a layer of to 3/4-inch crushed rock or class 2 aggregate base at least 6 inches thick. In areas where dampness of concrete floor slabs would be undesirable, such as within the garage and/or building interior, concrete slabs should be underlain by at least 6 inches of free-draining gravel, such as '/z- to 3/4- inch clean crushed rock with no more than 5 percent passing the ASTM No. 200 sieve. Pea gravel should not be used for this capillary break material. The crushed rock layer should be densified and leveled with vibratory equipment, and may be considered as the non-expansive fill section recommended above. As discussed above, the basement mat should be underlain by a high-quality water- proofing membrane. The membrane should be selected by your water proofing consultant. ROMIG ENGINEERS, INC. Cresleigh Homes Corporation. Mixed-Use Building Page 12 of 18 To reduce vapor transmission up through at-grade concrete floor slabs, the crushed rock section should be covered with a high quality, UV-resistant vapor barrier conforming to the requirements of ASTM E 1745 Class A, with a water vapor transmission rate less than or equal to 0.01 perms (such as 15-mil thick "Stego Wrap Class A"). The vapor barrier should be placed directly below the concrete slab. Sand above the vapor barrier is not recommended. The vapor barrier should be installed in accordance with ASTM E 1643. All seams and penetrations of the vapor barrier should be sealed in accordance with manufacturer's recommendations. The permeability of concrete is effected significantly by the water:cement ratio of the concrete mix, with lower water:cement ratios producing more damp-resistant slabs and stronger concrete. Where moisture protection is important and/or where the concrete will be placed directly on the vapor barrier, the water:cement ratio should be 0.45 or less. To increase the workability of the concrete, mid-range plasticizers can be added to the mix. Water should not be added to the concrete mix unless the slump is less than specified and the water:cement ratio will not exceed 0.45. Other steps that may be taken to reduce moisture transmission through the concrete slabs-on-grade include moist curing for 5 to 7 days and allowing the slab to dry for a period of two months or longer prior to placing floor coverings. Also, prior to installation of the floor covering, it may be appropriate to test the slab moisture content for adherence to the manufacturer's requirements and to determine whether a longer drying time is necessary. VEHICLE PAVEMENTS Based on the anticipated composition of the native surface soils, and an estimated traffic index for the proposed pavement loading conditions, we developed the minimum pavement sections presented in Table 2 on the following page based on Procedure 630 of the Caltrans Highway Design Manual. An assumed R-value of 12 was used. The Traffic Indices used in our pavement thickness calculations are considered reasonable values for this development and are based on engineering judgment rather than on detailed traffic projections. Asphalt concrete and aggregate base should conform to and be placed in accordance with the requirements of the Caltrans Standard Specifications, latest edition, except that compaction should be based on ASTM Test D1557. ROMIG ENGINEERS, INC. 1 •' Cresleigh Homes Corporatior. Mixed-Use Building Page 13 of 18 Table 2. Pavement Sections Mixed-Use Building Campbell,California Traffic Design Asphalt Aggregate . Total Loading Traffic Concrete Base* Thickness Condition Index (inches) (inches) (inches) Automobile Parking 4.0 3.0 6.0 9.0 Automobile Access 4.5 3.0 7.0 10.0 Light Truck Traffic 5.0 3.0 10.0 13.0 Moderate Truck Traffic 6.0 3.5 12.0 15.5 Heavy Truck Traffic 6.5 3.5 14.0 17.5 *Caltrans Class 2 Aggregate Base (minimum R-value = 78). We recommend that measures be taken to limit the amount of surface water that seeps into the aggregate base and subgrade below vehicle pavements, particularly where the pavements are adjacent to landscape areas. Seepage of water into the pavement base material tends to soften the subgrade, increasing the amount of pavement maintenance that is required and shortening the pavement service life. Deepened curbs extending 4-inches below the bottom of the aggregate base layer are generally effective in limiting excessive water seepage. Other types of water cutoff devices or edge drains may also be considered to maintain pavement service life. PORTLAND CEMENT CONCRETE PAVEMENT If the driveway and/or entrance ramp to the lower parking level will be constructed with Portland cement concrete (PCC), we recommend the driveway pavement consist of at least 5 inches of PCC on at least 8 inches of Class 2 aggregate base. Un-reinforced concrete for the 5-inch-thick driveway pavement should have a 28-day compressive strength of at least 3,500 psi. PCC pavements should be laterally constrained with curbs or shoulders and sufficient control joints should be incorporated in the design and construction to limit and control cracking. The soil subgrade and aggregate base below the pavement section should be prepared and compacted as recommended below. The use of a moisture cut-off or thickened edge along the edges of the driveway would be desirable in order to reduce water seepage below the edges of the driveway and into the underlying aggregate base and subgrade, which can lead to premature pavement distress. ROMIG ENGINEERS, INC. Cresleigh Homes Corporatior. Mixed-Use Building Page 14 of 18 EARTHWORK Clearing and Subgrade Preparation All deleterious materials, such as existing pavements, existing foundations, utilities to be abandoned, vegetation, root systems, surface fills, topsoil, etc. should be cleared from areas of the site to be built on or paved. The actual stripping depth should be determined by a member of our staff in the field at the time of construction. Excavations that extend below finished grade should be backfilled with structural fill that is water-conditioned, placed, and compacted as recommended in the section of this report titled "Compaction." After the site has been properly cleared, stripped, and excavated to the required grades, exposed soil surfaces in areas to receive structural fill or slabs-on-grade should be scarified to a depth of 6 inches, moisture conditioned, and compacted as recommended for structural fill in the section of this report titled "Compaction." On-site soils, foundation and utility trench excavations, and slab and pavement subgrades should be kept in a moist condition throughout the construction period. A member of our staff should observe the basement excavation to evaluate whether scarification and compaction or proof rolling of the excavation bottom is needed. If a temporary ramp is constructed to access portions of the basement excavation, the ramp should be properly backfilled with compacted on-site soil as recommended in this report for structural fill. A member of our staff should observe and test during backfilling of the temporary entrance ramp. Material For Fill All on-site soil containing less than 3 percent organic material by weight (ASTM D2974) may be suitable for use as structural fill. Structural fill should not contain rocks or pieces larger than 6 inches in greatest dimension and no more than 15 percent larger than 2.5 inches. Imported, non-expansive fill should have a Plasticity Index no greater than 15, should be predominately granular, and should have sufficient binder so as not to slough or cave into foundation excavations or utility trenches. A member of our staff should approve proposed import materials prior to their delivery to the site. Compaction Scarified soil surfaces and all structural fill should be compacted in uniform lifts no thicker than 8-inches in uncompacted thickness, conditioned to the appropriate moisture content, and compacted as recommended for structural fill in Table 3 on the following page. The relative compaction and moisture content recommended in Table 3 is relative to ASTM Test D1557, latest edition. ROMIG ENGINEERS, INC. Cresleigh Homes Corporatior. Mixed-Use Building Page 15 of 18 Table 3. Compaction Recommendations Mixed-Use Building Campbell,California Relative Compaction* Moisture Content* General • Scarified subgrade in areas 90 percent Above optimum to receive structural fill. • Structural fill composed 90 percent Above optimum of native soil. • Structural fill composed 90 percent Above optimum of non-expansive fill. • Structural fill below a 92 percent Above optimum depth of 5 feet. Pavement Areas • Upper 6-inches of soil 95 percent Near optimum below aggregate base. • Aggregate base. 95 percent Near optimum Utility Trench Backfill • On-site soil. 90 percent Near optimum • Imported sand 95 percent Near optimum • Relative to ASTM Test D 1557,latest edition. Temporary Slopes,Excavations and/or Shoring The contractor should be responsible for the design and construction of all temporary slopes and any required shoring. Shoring and bracing should be provided in accordance with all applicable local, state and federal safety regulations, including the current OSHA excavation and trench safety standards. Due to the limited space between the basement excavation and the surrounding roadways and adjacent development, unsupported cut slopes may not be feasible during the basement excavation so that shoring or bracing in accordance with OSHA standards will likely be required. This information should be considered by the contractor when establishing temporary shoring/slope criteria for the basement excavation and other temporary slopes and cuts. In addition, protection of the roadways and structures near cuts and excavations should also be the responsibility of the contractor. ROMIG ENGINEERS, INC. Cresleigh Homes Corporatior. Mixed-Use Building Page 16 of 18 Portions of the medium dense gravels encountered at the site were judged to have limited cohesion and will be prone to sloughing and/or caving if excavated near-vertical. This information should be considered by the contractor when establishing temporary shoring/slope criteria for basement excavation. Protection of structures and slopes near cuts should also be the responsibility of the contractor. In our experience, a preconstruction survey is generally performed to document existing conditions prior to construction, with intermittent monitoring of the structures during construction. The contractor should be responsible for staging the required cuts and wall construction and the design of temporary cut slopes and/or required shoring. Basement Excavation Support Based on the assumed finished floor elevation of the basement, temporary excavations up to approximately 12 to 14 feet deep (depending on the finished floor elevation and foundation depth) will be required in order to construct the basement. The walls of the basement excavation may be supported by several methods including tiebacks, soldier beams and wood lagging, soil nails, braced shoring or potentially other methods. The choice should be left to the contractor's judgment since economic considerations and/or the individual contractor's construction experience may determine which method is more economical and/or appropriate. Support of any adjacent existing structures and improvements without distress should also be the contractor's responsibility. We recommend that the contractor forward his plan for the support system to the structural engineer and geotechnical engineer for preconstruction review. In addition, it should be the contractor's responsibility to undertake a preconstruction survey with benchmarks and photographs of the adjacent properties. Finished Slopes Finished slopes should be cut or filled to an inclination preferably no steeper than 2.5:1 (horizontal:vertical). Exposed slopes may be subject to minor sloughing and erosion that may require periodic maintenance. We recommend that all slopes and soil surfaces disturbed during construction be planted with erosion-resistant vegetation. Surface Drainage Finished grades should be designed to prevent ponding of water and to direct surface water runoff away from foundations, and edges of slabs and pavements, and toward suitable collection and discharge facilities. Slopes of at least 2 percent are recommended for flatwork and pavement areas with 5 percent preferred in landscape areas within 8 feet of the structures, where possible. ROMIG ENGINEERS, INC. Cresleigh Homes Corporatior. Mixed-Use Building Page 17 of 18 At a minimum, splash blocks should be provided at the discharge ends of roof downspouts to carry water away from perimeter foundations. Preferably, roof downspout water from the building should be collected in a closed pipe system that is routed to a storm drain system. Drainage facilities should be observed to verify that they are adequate and that no adjustments need to be made, especially during the first two years following construction. We recommend preparing an as-built plan showing the locations of surface and subsurface drain lines and clean-outs. The drainage facilities should be periodically checked to verify that they are continuing to function properly. It is likely the drainage facilities will need to be periodically cleaned of silt and debris that may build up in the lines. FUTURE SERVICES Plan Review Romig Engineers should review the completed grading and foundation plans for conformance with the recommendations presented in this report. We should be provided with these plans as soon as possible upon their completion in order to limit the potential for delays in the permitting process that might otherwise be attributed to our review. In addition, it should be noted that many of the local building and planning departments now require "clean" geotechnical plan review letters prior to acceptance of plans for their final review. Since our plan reviews typically result in recommendations for modification of the plans, our generation of a "clean" review letter often requires two iterations. At a minimum, we recommend the following note be added to the plans. "Earthwork, slab subgrade and non-expansive fill preparation, foundation and slab construction, retaining wall drainage and backfilling, utility trench backfilling, tieback/soil nail installation and testing, shoring pier installation, pavement subgrade and aggregate base construction and site drainage should be performed as recommended in the geotechnical report, dated October 28, 2015, prepared by Romig Engineers, Inc. Romig Engineers should be notified at least 48 hours in advance of any earthwork and foundation construction, and should observe and test during earthwork and foundation construction as recommended in the geotechnical report." ROMIG ENGINEERS, INC. Cresleigh Homes Corporatior. Mixed-Use Building Page 18 of 18 Construction Observation and Testing The earthwork and foundation phases of construction should be observed and tested by us to 1) confirm that subsurface conditions are compatible with those used in the analysis and design; 2) observe compliance with the design concepts, specifications, and recommendations; and 3) allow design changes in the event that subsurface conditions differ from those anticipated. The recommendations presented in this report are based on a limited amount of subsurface exploration. The nature and extent of variation across the site may not become evident until construction. If variations are exposed during construction, it will be necessary to reevaluate our recommendations. ♦♦♦ ♦♦♦ ♦♦♦ ♦♦♦ ♦♦♦ ROMIG ENGINEERS, INC. REFERENCES Al Atik, L., and Sitar, N., 2010, Seismic Earth Pressures on Cantilever Retaining Structures, Journal of Geotechnical and Geoenvironmental Engineering, ASCE Vol. 136,No. 10. American Society of Civil Engineers, 2010, Minimum Design Loads for Buildings and Other Structures.,ASCE Standard 7-10. Blake, M.C., Graymer R.W., McLaughlin, R.J., Wentworth, C.M., 1999, Preliminary Geologic Map of the San Jose 30 x 60 Minute Quadrangle, California. California Building Standards Commission, and International Code Council, 2013 California Building Code, California Code of Regulations, Title 24, Part 2. , California Geological Survey, 2002, Seismic Hazard Zone Report for the San Jose West 7.5-Minute Quadrangle, Santa Clara County, California, Seismic Hazard Zone Report 058. Lew, M., Al Atik, L., Sitar, N., Pourzanjani, M., &Hudson, M., 2010, Seismic Earth Pressures on Deep Building Basements, SEAOC 2010 Convention Proceedings. U.S. Army Corps of Engineers, 1990, Engineering and Design, Settlement Analysis, Engineer Manual 1110-1-1904, Department of the Army, Washington, DC, September 30, 1990. U.S.G.S., 2014, U.S. Seismic Design Maps, Earthquake Hazards Program, http://earthquake.usgs.govidesignmaps/us/applicati on.php Working Group on California Earthquake Probabilities (WGCEP), 2015, Long-Term Time- Dependent Probabilities for the Third Uniform California Earthquake Rupture Forecast, Version 3 (UCERF 3),_U.S. Geological Survey Open File Report 2013-1165. •♦♦ ♦♦i ♦♦♦ •♦'• ♦♦♦ ♦ ♦ •♦ ♦ ROMIG ENGINEERS, INC. s 14 t 9 t Li i _ . . \ , 3RE EA- 1 a.m. "'� „ f r_ rr�r ad. , , in JilliNW fililliwonaiiiiiii raga 10111.1110 /440 Fr- ,t, lik ,,,- . ,„,, us „a 4.5..0, jib. w., 1 / I 111-915111111 11.3 I ON!di _ ! I : .I . is i mil 'alum - . � 1 i=les, .1 jJJnjhfI% L ...,, .. SITE �1 �1c�11a /i 1 / _ om iim , ,.....;;.--- II .. / ol.if, c 4,4rink 1 ... .. . 16.100. Ohms if -now / ' ' 2 if iii4,"4 „pm 0 100`00 4000 feet r r , , Scale: 1 inch=2000 feet Base is United States Geological Survey San Jose West 7.5 Minute Quadrangle.dated 1978. VICINITY MAP FIGURE 1 CRESLEIGH HOMES MIXED-USE BUILDING OCTOBER 2015 CAMPBELL, CALIFORNIA PROJECT NO. 3578-1 ROMIG ENGINEERS, INC. D I LLOI)• 14- M • P F p c-H ES \\\ °Ps 5 I l EB-2• H uctt.trt SvIPPok...T ^� f • • • • EB-1 IIII: .• E IIIII ' r I PRA J ter it PoRi — \ &ti 4A)rJ ME 0 EB-3 -- Approximate Location of Exploratory Boring. 25J Approximate Scale: 1 inch = 50 feet. Base is site plan prepared by LPAS Deisgn, dated October 26, 2015. SITE PLAN CRESLEIGH HOMES MIXED-USE BUILDING CAMPBELL, CALIFORNIA Legend Mimi Qhfl-Younger alluvial fan deposits(Holocene) NW I 4 S5 Qhf2-Older alluvial fan deposits(Holocene) -�„ Bali . Wan 0 i ;f 2 11ji aim mmilm 1 i er +' INIIIIIIIIIN (6' C7 . ■■IINI, a liti I I 111 SITE :,.; . iiipliggi 1 1, m'it ' iiii 1 6 a• -. Ek III litiTill'gill'M I ow. 114/ 'i ' 1 ar am am /,' / 4 anwilima 1 i , , mom / ,,,.., ,.- it _ iti ,,,,, ram AL „, '1MM. "ii 41. ":" Ili IMO. 1.....1... '''-':-- ':::-."/ .. i irook •/:: --' . ; ik a fill', Ill illigi ,.. In_ 4., ,A, , ,i Atillo,4 I.awl $ , Mill IN ,vp..„„,,, ' ,, ..,., ,. ai pet , um=j 1 Iall'-A ',I , 5 3 , ,..,;.."+� 3 . Ili illigsP.ir III AM I; ii.,,, .. _ .!. ',I ," _ ,. ,, Al♦: - .. / J.-: ' 0 1000 2000 4000 feet Base is Geologic Map of San Jose 30 x 60 Minute Quadrangle(Blake,Graymer,McLaughlin,and Wentworth, 1999). Scale: 1 inch=2000 Feet. VICINITY GEOLOGIC MAP FIGURE 3 CRESLEIGH HOMES MIXED-USE BUILDING OCTOBER 2015 CAMPBELL, CALIFORNIA PROJECT NO. 3578-1 ROMIG ENGINEERS, INC. APPENDIX A FIELD INVESTIGATION The soils encountered during drilling were logged by our representative and samples were obtained at depths appropriate to the investigation. The samples were taken to our laboratory where they were evaluated and classified in accordance with the Unified Soil Classification System. The logs of our borings and a summary of the soil classification system used on the logs(Figure A-1), are attached. Several tests were performed in the field during drilling. The standard penetration test resistance was determined by dropping a 140-pound hammer through a 30-inch free fall and recording the blows required to drive the 2-inch diameter sampler 18 inches. The standard penetration test (SPT) resistance is the number of blows required to drive the sampler the last 12 inches and is recorded on the boring logs at the appropriate depths. Soil samples were also collected using 2.5-inch and 3.0-inch O.D. drive samplers. The blow counts shown on the logs for these larger diameter samplers do not represent SPT values and have not been corrected in any way. The location of the borings were established by pacing using the site plan prepared by LPAS Design, dated October 26, 2015 and should be considered accurate only to the degree implied by the method used. The boring logs and related information depict our interpretation of subsurface conditions only at the specific location and time indicated. Subsurface conditions and ground water levels at other locations may differ from conditions at the locations where sampling was conducted. The passage of time may also result in changes in the subsurface conditions. ♦♦i ♦♦♦ ♦♦♦ ♦♦♦ ♦♦♦ ROMIG ENGINEERS, INC. USCS SOIL CLASSIFICATION SIL PRIMARY DIVISIONS TOPE SECONDARY DIVISIONS TOY PE CLEAN GRAVEL GW .pa_ Well graded gravel,gravel-sand mixtures,little or no fines. COARSE GRAVEL (< 5%Fines) GP pe Poorly graded gravel or gravel-sand mixtures,little or no fines. GRAINED GRAVEL with GM :' ; Silty gravels,gravel-sand-silt mixtures,non-plastic fines. SOILS FINES GC . Clayey gravels,gravel-sand-clay mixtures,plastic fines. _oo (<50%Fines) CLEAN SAND SW .e. Well graded sands,gravelly sands,little or no fines. SAND (< 5%Fines) SP :: Poorly graded sands or gravelly sands,little or no fines. SAND SM :"9`, Silty sands,sand-silt mixtures,non-plastic fines. WITH FINES SC Clayey sands,sand-clay mixtures,plastic fines. ML Inorganic silts and very fine sands,with slight plasticity. FINE SILT AND CLAY CL �� Inorganic clays of low to medium plasticity,lean clays. GRAINED Liquid limit<50% OL � ��,, Organic silts and organic clays of low plasticity. SOILS MH Inorganic silt,micaceous or diatomaceous fine sandy or silty soil. (>50%Fines) SILT AND CLAY CH Inorganic clays of high plasticity,fat clays. Liquid limit>50% OH = Organic clays of medium to high plasticity,organic silts. . HIGHLY ORGANIC SOILS Pt aPeat and other highly organic soils. BEDROCK BR Weathered bedrock. RELATIVE DENSITY CONSISTENCY SAND&GRAVEL BLOWS/FOOT* SILT&CLAY STRENGTH^ BLOWS/FOOT* VERY LOOSE 0 to 4 VERY SOFT 0 to 0.25 0 to 2 LOOSE 4 to 10 SOFT 0.25 to 0.5 2 to 4 MEDIUM DENSE 10 to 30 FIRM 0.5 to 1 4 to 8 DENSE 30 to 50 S 1'11'1F 1 to 2 8 to 16 VERY DENSE OVER 50 VERY STIFF 2 to 4 16 to 32 HARD OVER 4 OVER 32 GRAIN SIZES BOULDERS COBBLES GRAVEL SAND SILT&CLAY COARSE I FINE COARSE I MEDIUM I FINE 12" 3" 0.75" 4 10 40 200 SIEVE OPENINGS U.S.STANDARD SERIES SIEVE Classification is based on the Unified Soil Classification System;fines refer to soil passing a No.200 sieve. *Standard Penetration Test(SPT)resistance,using a 140 pound hammer falling 30 inches on a 2 inch O.D. split spoon sampler; blow counts not corrected for larger diameter samplers. A Unconfined Compressive strength in tons/sq.ft.as estimated by SPT resistance,field and laboratory tests,and/or visual observation. KEY TO SAMPLERS Modified California Sampler(3-inch O.D.) Mid-size Sampler (2.5-inch O.D.) Standard Penetration Test Sampler(2-inch O.D.) KEY TO EXPLORATORY BORING LOGS FIGURE A-1 CRESLEIGH HOMES MIXED-USE BUILDING OCTOBER 2015 CAMPBELL, CALIFORNIA PROJECT NO. 3578-1 ROMIG ENGINEERS, INC. • DRILL TYPE:Minuteman with 3-1/4" tinuous Flight Auger LOGGED BY:CT DEPTH TO GROUND WATER: Not Encountered. SURFACE ELEVATION:NA DATE DRILLED: 10/13/2015 W z x a En CLASSIFICATION AND DESCRIPTION z oE. z z o ~ O � � p � 1 W � W w q q a rown, ean ay,moist, ow p asticity, me to coarse grain t L 0 sand,trace fine angular to rounded gravel,roots,gasoline odor. to Firm 10 15 5 6 16 I • 8 13 10 Brown,Clayey Gravel,slightly moist,fine to coarse grained Medium GC sand,fine sub-angular to rounded gravel,gas odor,some low Dense plasticity fines,gasoline odor in 12 to 13.5 foot sample. 20 10 • 41%Passing No. 200 Sieve. 5 15 • 15%Passing No.200 Sieve. 22 2 20 Continued on next page. EXPLORATORY BORING LOG EB-1 BORING EB-1 CRESLEIGH HOMES MIXED-USE BUILDING OCTOBER 2015 CAMPBELL, CALIFORNIA PROJECT NO. 3578-1 ROMIG ENGINEERS, INC. DRILL TYPE:Minuteman with 3-1/4" tinuous Flight Auger LOGGED BY:CT DEPTH TO GROUND WATER: Not Encountered. SURFACE ELEVATION:NA DATE DRILLED: 10/13/2015 N N 4L Z Q w - C~ > o Fv Ev fx W w W H a CLASSIFICATION AND DESCRIPTION o 0 `ii) O q a w v' p o rown, ayey rave ,s ig t y moist, me to coarse grained Very 20 sand,fine sub-angular to rounded gravel, some low Dense plasticity fines. 64 4 25 IMP ;0/4" 4 Bottom of Boring at 28 feet. 30 35 Note: The stratification lines represent the approximate boundary between soil and rock types,the actual *Measured using Torvane and Pocket Penetrometer devices. 40 EXPLORATORY BORING LOG EB-1 BORING EB-1 CRESLEIGH HOMES MIXED-USE BUILDING OCTOBER 2015 CAMPBELL, CALIFORNIA PROJECT NO. 3578-1 ROMIG ENGINEERS, INC. DRILL TYPE:Minuteman with 3-1/4" tinuous Flight Auger LOGGED BY:CT DEPTH TO GROUND WATER: Not Encountered. SURFACE ELEVATION:NA DATE DRILLED: 10/13/2015 c ',;)1 6, W W z x a W w CLASSIFICATION AND DESCRIPTION z ° oW z ° A 8 Brown,Lean Clay,moist,low plasticity,fine to medium grained Stiff CL \\ 0 sand. 10 11 5 Gasoline odor in 5 to 8 foot samples. 9 II At 8 feet high silt and fme sand content,some fine angular to rounded gravel. 12 7 10 Brown,Clayey Gravel,moist,fme to coarse grained sand,fine Medium GC angular to rounded gravel,low plasticity fines,no odor. Dense to Very Dense • 18%Passing No. 200 Sieve. 21 4 15 AI 42 ; 2(1 Continued on next page. EXPLORATORY BORING LOG EB-2 BORING EB-2 CRESLEIGH HOMES MIXED-USE BUILDING OCTOBER 2015 CAMPBELL, CALIFORNIA PROJECT NO. 3578-1 ROMIG ENGINEERS, INC. RILL TYPE:Minuteman with 3-1/4" tinuous Flight Auger LOGGED BY:CT DEPTH TO GROUND WATER: Not Encountered. SURFACE ELEVATION:NA DATE DRILLED: 10/13/2015 _ N u" k. v I✓ U Q W W O � E-� � � v) 8 w w CLASSIFICATION AND DESCRIPTION o " 4z o z a U w z O a CA wz O A 3 x _ Brown,Clayey Gravel,moist,fine to coarse grained sand,fine Very GC X 20 angular to rounded gravel,low plasticity fines,no odor. Dense 50/5" 4 25 47 3 Bottom of Boring at 25 feet. 30 35 Note: The stratification lines represent the approximate boundary between soil and rock types,the actual *Measured using Torvane and Pocket Penetrometer devices. 40 EXPLORATORY BORING LOG EB-2 BORING EB-2 CRESLEIGH HOMES MIXED-USE BUILDING OCTOBER 2015 CAMPBELL, CALIFORNIA PROJECT NO. 3578-1 ROMIG ENGINEERS, INC. TRILL TYPE:Minuteman with 3-1/4" tinuous Flight Auger LOGGED BY: CT • DEPTH TO GROUND WATER: Not Encountered. SURFACE ELEVATION:NA DATE DRILLED: 10/13/2015 44 N • W W F CLASSIFICATION AND DESCRIPTION v� c o v �a z z `n El A � � � O x _ 2 inch asphalt-concreteyarking lot. 0 Brown,Lean Clay,moist,low plasticity,fme to medium grained Finn CL sand. to Stiff • Liquid Limit=29,Plasticity Index=9. 7 17 5 7 17 Gasoline odor in 8 foot sample. 10 15 10 9 18 I0 15 Brown,Clayey Gravel,moist,fme to coarse grained sand,fine Medium GC rounded to angular gravel,no odor. Dense • 14%Passing No. 200 Sieve. 20 Continued on next page. EXPLORATORY BORING LOG EB-3 BORING EB-3 CRESLEIGH HOMES MIXED-USE BUILDING OCTOBER 2015 CAMPBELL, CALIFORNIA PROJECT NO. 3578-1 ROMIG ENGINEERS, INC. BRILL TYPE:Minuteman with 3-1/4" tinuous Flight Auger LOGGED BY:CT DEPTH TO GROUND WATER: Not Encountered. SURFACE ELEVATION:NA DATE DRILLED: 10/13/2015 uz x Q 3 e W W W c.) � o a CLASSIFICATION AND DESCRIPTION �o. rp z z� Z O v' o acn E- 0 Brown, Clayey Gravel,moist,fine to coarse grained sand, fine Medium GC :, 20 rounded to angular gravel,no odor. Dense S 50/2" Auger refusal at 22.3 feet. 25 30 35 Note: The stratification lines represent the approximate boundary between soil and rock types,the actual *Measured using Torvane and Pocket Penetrometer devices. 40 EXPLORATORY BORING LOG EB-3 BORING EB-3 CRESLEIGH HOMES MIXED-USE BUILDING OCTOBER 2015 CAMPBELL, CALIFORNIA PROJECT NO. 3578-1 ROMIG ENGINEERS, INC. Y APPENDIX B LABORATORY TESTS Samples from subsurface exploration were selected for tests to help evaluate the physical and engineering properties of the soils encountered at the site. The tests that were performed are briefly described below. The natural moisture content was determined in accordance with ASTM D2216 on nearly all of the soil samples recovered from the borings. This test determines the moisture content, representative of field conditions at the time the samples were collected. The results are presented on the boring logs at the appropriate sample depths. The Atterberg Limits were determined on one sample in accordance with ASTM D4318. The Atterberg Limits are the moisture content within which the soil is workable or plastic. The result of this test is presented in Figure B-1 and on the log of Boring EB-3 at the appropriate sample depth. The amount of silt and clay-sized material present was determined on four samples of soil in accordance with ASTM D422. The results of these tests are presented on the boring logs at the appropriate sample depths. ♦♦♦ •♦♦♦ •♦♦♦ •♦♦♦ •♦♦♦ ♦♦♦♦ ♦ ROMIG ENGINEERS, INC. a 60 50 CH v��� 40 AP X CI CL >- 30 4- v MH 20 or OH 10 • 4 CL or ML ////// ML or OL ML 0 0 10 20 30 40 50 60 '70 80 90 100 LIQUID LIMIT (%) Passing USCS Chart Boring Sample Water Liquid Plasticity Liquidity No. 200 Soil Symbol Number Depth Content Limit Index Index Sieve Classification (feet) (percent) (percent) (percent) (percent) (percent) • EB-3 1-2.5 17 29 9 -33 CL PLASTICITY CHART FIGURE B-1 CRESLEIGH HOMES MIXED-USE BUILDING OCTOBER 2015 CAMPBELL, CALIFORNIA PROJECT NO. 3578-1 ROMIG ENGINEERS, INC.