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353 Main Street Apartments <br />Redwood City, California <br />May 1, 2018 <br />(Original Report Dated November L8,20L6) <br />liquefaction occur, liquefaction related settlements on the order of 0.4 to 2.t inches are <br />expected. Approximately L.7 inches of seismically induced differential settlement is possible at <br />the site over a distance of approximately 75 feet. <br />The boundary curve for discriminating between occurrence and non-occurrence of surface <br />effects of liquefaction, after lshihara 1985 (Youd and Garris, L995), is presented at the end of <br />Appendix C. The point representative of CPT C3 and C4 plot above the curve, while the point <br />representative of Boring 84, CPT C1 and C2 plot below the curve, indicating high and low <br />likelihood of surface manifestation potential, respectively. <br />The site is relatively flat but located adjacent to Redwood Creek. Our site review of the Redwood <br />Creek indicates that it is about L5 feet deep. The liquefiable sand layers are located from 18 to <br />33 feet. We calculated lateral spreading in the range of 5 to 48 inches. <br />Static Settlement <br />During our subsurface exploration, a relatively soft upper fill was encountered underlain by a <br />very soft Bay Mud from the approximate depths of 6 to 15 feet below the surface., Below the f¡ll <br />and Bay mud, a medium stiff to stiff clay soils were encountered below the Bay Mud to <br />approximately 25 feet below the ground surface. These layers are relatively uniform throughout <br />the site and will undergo long-term, post-construction settlement under high loads. Therefore, <br />a preliminary settlement analysis was performed to estimate the magnitude of static, post- <br />construction settlement that is likely to occur under the anticipated structural loads <br />Detailed loadings, foundation elevations, foundation types were not known at the time this <br />analysis was conducted. For preliminary analysis we have assumed that the bottom foundation <br />elevation will be 2 feet below the finish surface. Additionally, we have assumed column loads of <br />400, 500, and 600 kips and a bearing pressure of 2,500 psf. <br />A summary of our settlement analysis for the unmitigated condition is presented below <br />Summary of Static Settlement <br />Condition Settlement (inl <br />400 kips, 12.5 foot square footing LL.9 <br />500 kips, 14 foot square footing L2.6 <br />600 kips, 15.5 foot square footing L3.L <br />301842-001 11 1610-038.SER.REV2 <br />7.B. - Page 69