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Veco Design Studio <br />June 3, 2024 <br />Project 10112-04 <br />Page 11 <br /> <br />5.5 Seismic Coefficients <br /> <br />The seismic coefficients in accordance with ASCE 7-16 Standards are as follows: <br /> <br />ITEM VALUE <br />Site Latitude (Decimal-degrees) 33.73309 <br />Site Longitude (Decimal-degrees) -117.90058 <br />Site Class D (Default) <br />Seismic Design Category D <br />Site Modified Peak Ground Acceleration, PGAM 0.666 <br />Mapped Spectral Response Acceleration-Short Period (0.2 Sec) - SS 1.301 <br />Mapped Spectral Response Acceleration-1 Second Period – S1 0.464 <br />Short Period Site Coefficient-Fa 1.2 <br />Long Period Site Coefficient Fv 1.836 <br />Adjusted Spectral Response Acceleration @ 0.2 Sec. Period (Sms) 1.561 <br />Adjusted Spectral Response Acceleration @ 1Sec.Period (Sm1) 0.852 <br />Design Spectral Response Acceleration @ 0.2 Sec. Period (SDs) 1.041 <br />Design Spectral Response Acceleration @ 1-Sec. Period (SD1) 0.568 <br /> <br />5.6 Liquefaction <br /> <br />a) Even though the residences up to 2 stories in height are exempt from a <br />liquefaction analysis and the historic ground water was at 5 feet below <br />grade, the site is anticipated to experience some effects of the liquefaction <br />during a seismic event. The effects mostly will be in the form of <br />settlement. However, as the new ADU footprint is relatively small, 767 ft2, <br />the settlement is anticipated be uniform. <br /> <br />b) Mitigating measures such as deeper footings (2 feet instead of the code <br />required 1 foot), thicker slab (6 inches instead of the conventional 4 <br />inches) and additional reinforcement (#4 bars on 12-inch center instead of <br />the conventional wire mesh or #3 bars on 18 inches center) have been <br />recommend to reduce the effects of the liquefaction. <br /> <br />c) Even with these measures the homeowner is advised that there may be a <br />structural damage due to liquefaction. <br /> <br /> <br /> <br /> <br /> <br /> <br />