CITY PROJECT - 1821 & 1823 E Chestnut Ave - Plan

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ASSOCIATED SOILS ENGINEERING, INC. Project No.: 7160.23 2860 Walnut Avenue, Signal Hill CA 90755 January 23, 2024 Tel: (562) 426 -7990 * Fax: (562) 426 -1842 Page 8 ASCE 7-16, Supplement 3 be applied, a 50% increase on the SM1 value derived from Equation 11.4-2 of ASCE 7-16 (or Equation 16-21 of 2022 CBC) is required. The increased SM1 value should then serve as the basis for the derivation of SD1 value for structural design. Please note that the SM1 and SD1 values listed in the table on the preceding page do not reflect such 50% increase. If the structural design of the Building cannot be supported by the invoked exceptions, the Geotechnical Consultant should be contacted for performing additional, site-specific seismic hazard analysis such that values of site-specific design parameters could be established. Please also note that conformance to the 2022 CBC seismic design criteria does not constitute any kind of guarantee or assurance that significant structural damage or ground failure will not take place during the occurrence of a MCER event. The primary goal of seismic design is to protect life and not to avoid all damage, since such design may be economically prohibitive. Following a major earthquake, a building may be damaged beyond repair, yet not collapse. The Structural Consultant should review the pertinent parameters to evaluate the seismic design. 4.0 GEOLOGIC HAZARDS 4.1 Surface Fault Rupture and Ground Shaking The Site is not located within an Alquist-Priolo Earthquake Fault Zone. No known active or potentially active faults are shown crossing the Site on published maps reviewed. No evidence for active faulting was encountered in the exploratory excavations performed during this evaluation. The risk of surface rupture at the Site is considered very low. However, being in close proximity to several known active and potentially active faults, severe ground shaking should be expected during the life of the proposed development. 4.2 Seismic Hazards 4.2.1 Liquefaction: As evidenced in Figure 3, Local Seismic Map, the Site is not within an area identified by CGS as having a potential for soil liquefaction when subject to an MPE event. The term "liquefaction" describes a phenomenon in which a saturated cohesionless soil loses strength and acquires a degree of mobility as a result of strong ground shaking during an earthquake. The factors known to influence liquefaction potential include soil type and depth, grain size, relative density, groundwater level, degree of saturation, and both the intensity and duration of ground shaking. The soils to the maximum explored depth of 26 feet primarily consist of dense to very dense granular, sandy soils. During ASE’s field exploration, groundwater was not encountered to the maximum explored depth of 26 feet. Per Reference 4, historic high groundwater contour in the vicinity of the Site is