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353 Main Street Apartments <br />Redwood City, California <br />May 1, 2018 <br />(Originol Report Doted November 18, 20L6) <br />Analvsis Parameters <br />The liquefaction analysis was carried out using an assumed historic high groundwater table of 5 <br />feet below ground surface. A liquefaction factor of safety of L.3 was selected for the SPT based <br />liquefaction analysis. ln addition, a predominant earthquake magnitude of 8.05 was used. The <br />liquefaction analysis was performed utilizingthe peak ground acceleration of 0.5959 (PGAm). <br />Analvsis Results <br />ln general, the fine grained clay soils present at the site are deemed too expansive and st¡ff to be <br />susceptible to liquefaction. Therefore, we assumed the fine grained soils to be non-liquefiable. <br />The coarser grained deposits found at the site were assumed to be potentially liquefiable and the <br />results of our SPT and CPT liquefaction analysis are presented below. <br />SPT based Liquefaction Analysis <br />Boring <br />Number <br />Boring <br />Depth <br />Analyzed <br />(feet) <br />Liquefaction <br />Settlement <br />(inches) <br />Total <br />Liquefied <br />Thickness <br />(feet) <br />General Range of <br />Liquefiable Zone <br />(feet) <br />B4 50 L.4 6.5 22.0-3s.0 <br />CPT based Liquefaction Analysis <br />CPT <br />Number <br />Sounding <br />Depth <br />Analyzed <br />(feet) <br />Liquefaction <br />Settlement <br />(inches) <br />General Range of <br />Liquefiable Zone <br />(feet) <br />cPT CL 70 0.44 27-33 <br />CPT C2 60 0.74 25.5-33 <br />CPT C3 60 1.95 22-32 <br />CPT C4 70 2.L2 L8-32 <br />Lateral spreading potential on the order of 5 to 48 inches was also calculated in the analyses. <br />The liquefaction analysis results are included in Appendix C. <br />Discussion <br />ln general, there is a high potential of the medium dense granular deposits to liquefy during a <br />seismic event. The results from our SPT liquefaction analysis are in line with our CPT analysis. <br />The potentially liquefiable sands at the site are generally found from L8 to 35 feet. Should <br />301842-00L 10 1610-038.SER.REV2 <br />7.B. - Page 68