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10080055 Geo Report\1 WAYNE ASSOCIATES, INC. GEOTECHNICAL CONSULTANTS Project No. 2882 5 August 2010 Mr. and Mrs. Baxter 10160 Lockwood Drive Cupertino, California Subject: PROPOSED TWO-STORY BAXTER ADDITIONS 10160 Lockwood Drive Cupertino, California Dear Mx. and Mrs. Baxter: In accordance with your authorization, Wayne Ting & Associates, Inc. (WTAI) has completed a geoi:echnical investigation for the proposed additions at the subject site. The purpose of this study was to investigate the site conditions and to obtain geotechnical data for use in the design and construction of the proposed development. The scope of this investigation included the following: a. Site and area reconnaissance by the Project Engineer. b. Excavation, logging and sampling of one exploratory boring. C. Laboratory testing of selected soil samples. d. Analysis of soil samples and information obtained. e. Preparation and writing of this report which presents our findings, conclusions, and recommendations. SITE LOCATION AND DESCRIPTION The subject lot is relatively flat and located at 10160 Lockwood Drive, Cupertino, California. It is bounded to the west by Lockwood Drive, and the other sides by single family residential structures. During our site visit, an existing residential structure, swimming pool, deck, and trees are presence at the site. PLANNED DEVELOPMENT The proposed additions will be constructed onto the east, south and west parts of the existing structures. We anticipate that the proposed structure will utilize wood frame construction with a raised wood floor. Light to moderate building loads are typic - h, ssociated with this type of construction. �.. 4LEA ', Umc. OCT 2 2 2010 - 42329 Osgood Road, Unit A • Fremont, CA 94539 • Tel; (510) 623-7768 a Fax: (510) 62 @sbcglobal.net Project No. 2882 5 August 2010 MOISTURE -DENSITY The natural moisture contents and/or dry weights were determined for selected samples obtained during our field investigation. These data are presented in the aforementioned Boring Log. SUBSURFACE SOIL CONDITIONS The following soil descriptions were derived from our site reconnaissance and the information obtained from our exploratory boring sample. Detailed description of the materials encountered in the exploratory borings and the results of laboratory testing are presented in the Boring Log. The subsurface soils in the upper 6.5 feet encountered. in our drill boring 1 consisted of brown sandy silt with clay, firm to stiff, moist, followed by brown silty sand with gravel, medium dense and very moist, to 10.0 feet, followed by light brown sandy clay with gravel, stiff and moist, to 12.5 feet, followed by brown silty sand with gravel, dense and moist, to the maximum depth explored of 13.5 feet. No groundwater was encountered at the time of the field study. It is noted that fluctuations in the groundwater table are anticipated to vary with respect to seasonal rainfall. LIQUEFACTION EVALUATION Liquefaction. is a phenomenon in which saturated (submerged) cohesionless soil subject to a temporary loss of strength due to the buildup of pore water pressures, especially as a result of cyclic loadings induced by earthquakes. In the process, the soil acquires a mobility sufficient to permit both horizontal and vertical deformations, if not confined. Soils that are most susceptible to liquefaction are clean, loose, saturated, uniformly graded, fine sands. Based on our boring log data, soils susceptible to liquefaction within the depth of boring were not encountered at the site. Therefore, it is our opinion that the probability of liquefaction at the site is low. CALIFORNIA BUILDING CODE SITE CHARACTERIZATION According to the published maps by International Conference of Building Officials (I.C.B.O.), in February 1998, the controlling nearest active fault to the subject site is the Mont Vista- Shannon Fault which is located approximately 1.3 kilometers northeast. The San Andreas Fault is located approximately 6.5 kilometers northeast. Therefore, the potential for surface fault trace rupture is considered to be negligible. WAYNE TING & ASSOCIATES, INC. Project No. 2882 5 August 2010 The following design values are base on the geologic information, longitude and latitude of the site and the USGS computer program (2007). Furthermore, in according with Chapter 16 of the 2007 California Building Code (CBC), the site seismic design values are provided as follow: CBC Category/Coefficient Design Value Figure 1613.5.(3), Short -Period MCE at 0.2s, Site Class B, Ss 2.409 Figure .1613.5.(4), 1.Os Period MCE, Site Class B, S 1 0.861 Table 1613 5.2, Soil Profile Type, Site Class D Table 1613.5.3(1), Site Coefficient, Fa 1.0 Table 1613.5.3(2), Site Coefficient, Fv 1.5 SMS = Fa x SS, Spectral Response Accelerations 2.409 SM 1 = Fv x S 1, Spectral Response Accelerations 1.292 SDS = 2/3 x SMS Design Spectral Response Accelerations 1.606 SD 1= 2/3 x SM 1 Design Spectral Response Accelerations 0.861 ** Latitude 37.32075, Longitude:-122.07185 DISCUSSIONS, CONCLUSIONS AND RECOMMENDATIONS 1. Based on the results of our investigation, WTAI concludes that the subject site is geotechnically suitable for the newly proposed additions. The structure can be constructed provided the recommendations presented in this report are incorporated into the project plans and specifications. 2. It is recommended that WTAI should review the foundation plans and specifications so that comments can be made regarding the interpretation and implementation of our geotechnical recommendations in the design and specifications. 3. It is further recommended that WTAI be retained for foundation construction phases to help determine that the design requirements are fulfilled. Our firm should be notified at least two working days prior to grading and/or foundation operations on the property. Any work related to the grading and/or foundation operations performed without the direct observation of WTAI will invalidate the recommendations of this report. 4. The recommendations given in this report are applicable only for the design of the previously described structure and only at the location indicated on the site plan. They should not be used for any other purpose. FOUNDATION RECOMMENDATIONS 5. Due to the on -site low plasticity soils, the proposed additions can be satisfactorily supported on a deep footing foundation. Footing should be designed for allowable bearing pressures of 1,800 WAYNE TING & ASSOCIATES, INC. Project No. 2882 5 August 2010 p.s.f. due to dead loads plus design live loads, and 2,400 p.s.f. due to all loads which include wind or seismic forces. The bottom of footings should be founded at least 2 feet below the lowest adjacent pad grade. However, the east addition located approximately 6 feet from the existing swimming. pool, the proposed footings should be founded at least 4 feet deep. The reinforcement should be determined by the Project Structural Engineer. 6. Resistance to lateral force may be provided by sliding resistance between the base of the footings and the underlying soils. Sliding resistance may be taken as a friction value of 0.30. 7. Movements under the anticipated building loads are expected to be within tolerable limits for the proposed structure. We estimate that the total movement will be less than 1.0 inch, and post -construction differential settlements across the building should not exceed approximately 1 /2 inch during the life of the building following construction. CONCRETE SLAB -ON -GRADE 8. To reduce the potential cracking of the concrete slab, the following recommendations are made: a. Concrete slabs should be supported on a minimum of 4 inches of 3/4-inch of crushed rock. , b. The concrete slab should not be doweled into the perimeter foundation and should be reinforced using at least No. 4 bars at 16-inch on centers to reduce cracking. Additional reinforcement should be as specified by the Structural Engineer. GENERAL CONSTRUCTION REQUIREMENTS 9. All finish grading during and after the construction of the proposed structure must be adjusted to provide positive drainage away from the building structure to prevent ponding of water in or near the building. 10. Roof drainage should be collected by a system of gutters and downspouts and discharged by adequate piping or splash blocks to discharge water away from the building structure. 11. The backfill of utility trenches extending under the building and landscaping area should be properly compacted to ensure against water migration underneath the structure. 5 WAYNE TING & ASSOCIATES, INC. Project No. 2882 5 August 2010 LIMITATIONS AND UNIFORMITY OF CONDITIONS 12. Our client should recognize that this report is prepared for the exclusive use of this project. Our professional services, findings, and recommendations were prepared in accordance with generally accepted engineering principles and practices. No other warranty, expressed or implied, is made. 13. The conclusions and recommendations contained in this report will not be considered valid after a period of two years unless the changes are reviewed, and the conclusions of this report are modified or verified in writing. In the event that a geotechnical consultant firm other than WTAI is engaged in providing geotechnical services, WTAI must receive a letter of indemnification releasing us of any responsibility on the subject project. 14. This report is issued with the understanding that it is the responsibility of the owner or his representative, to ensure the information and recommendations contained in this report are brought to the attention of the architect, engineer, and contractor. In all cases, the contractor shall retain responsibility for the quality of the work and for repairing defects regardless of when they are found. It is also the responsibility of the contractor for conforming to the project plans, specifications, and recommendations of this report. Should you have any questions relating to the contents of this report, please contact our office at your convenience. Very truly yours, WAYNE TING & ASSOCIATES, INC. Wayne L. Ting, C.E. Principal Engineer Copies: 3 to Mr. and Mrs. Baxter QUO PyNE L. 1j� �t�� 3 No. C 46276 Exp: I-Z44� Q, Z-'4> CIVIL WAYNE TING & ASSOCIATES, INC. '® 7 Project No. 2882 5 August 2010 APPENDIX A Site Plan, Figure 1 Boring Log, Figure 2 7 WAYNE TING & ASSOCIATES, INC. IUIUU LOCKWO061 Vrive, uupervmo, waiirornia rrojeGL NO. Z-00Z Lockwood Drive WAYNE TING & A550CIATE5, INC. Site Plan Figure No. 1 GEOTECHNICAL CONSULTANTS V = 20' Page No. 5 10160 Lockwood Drive, Cupertino, California Project No. 2882 5 August 2010 0 v Description ii i ° Remarks m LL m p ii q) u o E SN- Mown May 6117 wrM clay, firm aria moiof. ML LL =L3% 1 2 3 1-1 7 121.4 15.1 more gravels, Stiff 4 5 6 7Drown 5M si y San Withgravels, rr ium ense and very moist 8 1-2 23 101.9 14.5 9 10 Light rown sandy clay with gravel, s i an CL 11 moist 12 13 1-3 5M >50 120.8 15.0 rown oiity oarld with gravels, Jenoe. arO mci5 14 oring terminatM a ee No groundwaterencounted 15 16 17 18 19 20 21 22 23 24 25 WAYNE TING & A550CIATE5, INC. BORING LOG NO. 1 Figure No. 2 GEOTECHNICAL CONSULTANTS Date Drilled: 28 July 2010 By: T.N. Fage No. 9 WAYNE TING & ASSOCIATES, INC. 42329 Osgood Rand, UORA, Freownt, CA 94539 Phone (510) 623-7768 ♦ Fax (SIO) 623-7861 FAX TRANSMI ITAL SHEET DATE: 9/l /2010 lM COMPANY:, FAX NO.: 510-889-0103 NUMBER OF S130EETS TRANSMITTED INCLUDING THIS COVER PAGE: If you do not receive all of the pages, please call (510) 623-7768 INSTRUCTIONS / NOTES: Rudy: Please see my report pale 4. Site class is D. 4LEAF, ENC. OCT 2 2 2010 FROM: W nt ?is►o REMEWED 1 d 010Z Z d3S((1H1) 198L-EM-015 9NI1 3NANAI W083 Project No. 2882 5 August 2010 The following deign values are base on the geologic information, longitude and latitude of the site and the USGS computer program (2007). Furthermore, in wx ording with Chapter 16 ofthe 2007 California Building Code (CBC), the site seismic design values are provided as follow: CBC C4mga/Coe1ficien1 Desigg Value Figure 1613.5.(3), Short -Period MCE at 0.2s, Site Class B, Ss 2.409 Figure 1613.5.(4), LOs Period MCI, Site Class B, S1 0.861 Table 16135.2, Soil Profile Type, Site Class D Table 1613.5.3(1), Site Coefficient, Fa 1.0 Table 1613.5.3(2), Site Coefficient, ry 1.5 SMS = Fa x Ss, Spectral Response Accelerations 2.409 SM1= Fv x S 1, Spectral Response Accelerations 1.292 SDS = 2/3 x SMS Design Spectral Response Accelerations 1.606 SDI — 2/3 x SM 1 Design Spectral Response Accelerations 0.961 '* latitude 37.32075, Longitude:-122.07195 (DISCUSSIONS, CONCLUSIONS AND RECOMMENDATIONS 1, Based on the results of our investigation, WTAI concludes that the subject site is geotechnically suitable for the newly proposed additions. The structure can be constructed provided the recommendations presented in this report arc incorporated into the project plans and specifications. 2. It is recommended that WTAI should review the foundation plans and specifications so that comments can be trade regarding the interpretation and implementation of our geoteclutical recommendations in the design and specifications. 3. It is further recommended that WTAI be retained for foundation construction phases to help determine that the design requirements are fulfilled. Our firm should be notified at least two working days prior to grading and/or foundation operations on the property. Any work related to the grading and/or foundation operations performed without the direct observation of WTAI will invalidate the recommendations of this report. 4. The recommendations given in this report are applicable only for the design of the previously described structure and only at the location indicated on the site plan. They should not be used for any other purpose. 5. Due to the on -site low plasticity soils, the proposed additions can be satisfactorily supported on a deep footing foundation. Footing should be designed for allowable bearing pressures of 1,800 WAYNE TING A ASSOCIATES. INC. Z 010Z Z MOW ML-M-Ol5 DNU 3NKVM W08A