1228 GRAND AVE Geotech Report 2022-10-25

April 7,2008 Mr. Don Levin L&A Job No. 8A037 Page 11 If the above recommendations are followed, our recommended design criteria for footing foundations are as follows: • Allowable soil bearing pressure, including dead and live loads, should not be more than 3,000 psf for footings poured on or into dense silty sand and/or hard fine sandy silt soils, and not more than 2,500 psf for footings poured on structural fill constructed on these competent basal soils. The footing bearing soils should be verified on-site by a geotechnical engineer after the footing trenches have been excavated and before the footings are poured. • The minimum depth to bottom of perimeter footings below adjacent final exterior grade should be no less than 18 inches. The minimum depth to bottom of the interior footings below top of floor slab should be no less than 12 inches. • The minimum width should be no less than 16 inches for continuous footings, and no less than 24 inches for individual footings, except those footings supporting light-weight porches and wood deck. A one-third increase in the above recommended allowable soil bearing pressures may be used when considering short-term,transitory,wind or seismic loads. For footing foundations designed and constructed per recommendations above, we estimate that the maximum total post- construction settlement of the buildings should be 1/2 inch or less and the differential settlement across building width should be 3/8 inch or less. Lateral loads on the new residence can be resisted by the friction force between the foundations and the subgrade soils or the passive earth pressure acting on the below-grade portion of the foundations. For the latter, the foundations must be poured "neat" against undisturbed soils or backfilled with a clean, free-draining, compacted structural fill. We recommend that an equivalent fluid density (EFD) of 350 pcf(pounds per cubic foot) for the passive earth pressure LIU & ASSOCIATES, INC.