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353 Main Street Apartments <br />Redwood City, California <br />May 1, 2018 <br />(Originol Report Dated November L8,20L6) <br />Factor Variable Term Correction <br />Overburden Pressure C¡r (P"/o'uo)o's ; 0.4<Crrr<2 <br />Energy Ratio Safety Hammer <br />Donut Hammer <br />Automatic Tríp Hammer <br />Ce <br />0.60 to 1.17 <br />0.45 to 1.00 <br />0.9 to L.6 <br />Borehole Diameter 65 mm to 115 mm <br />150 mm <br />200mm <br />Ce <br />1.0 <br />1.05 <br />L.15 <br />Rod Length 3m to 4m <br />4m to 6m <br />6m to 10m <br />10m to 30m <br />>30 m <br />Cn <br />0.75 <br />0.85 <br />0.9s <br />1.0 <br /><1.0 <br />Sampling Method Standard Sampler <br />Sampler without liners <br />Cs <br />1".0 <br />1.2 <br />The other steps involve obta¡n¡ng two variables: the seismic demand on a soil layer, expressed in <br />terms of CSR (cyclic stress ratio), and the capac¡ty of a soil layer to resist liquefaction, expressed <br />in terms of CRR (cyclic resistance ratio). <br />CSR can be calculated using the following equation: <br />CSR = (t.u/o'uo) = 0.65(â'r*/g)(ouo/o'uo)ru <br />where: <br />âmax = peak hor¡zontal acceleration at the ground surface generated by the <br />earthquake <br />g = acceleration of gravity <br />ovo = total vertical overburden stress <br />o'vo = effective vertical overburden stress <br />rd = stress reduct¡on coefficient <br />CRR can be obtained from the Simplified Base Curve graphical representation recommended for <br />determination of CRR from SPT for Magnitude 7.5 along with Empirical Liquefaction Data (after <br />Youd and ldriss 1977). A factor of safety (FS) against liquefaction is then calculated using the <br />following equat¡on: <br />¡5 = (CRRz.s/CSR) MSF <br />8301842-00L 1610-038.SER.REV2 <br />7.B. - Page 66