12728 19TH AVE SE BASE FILE Geotech Report 2025-07-29

tMay 28,2007 Proposed Office Building L&A Job No. 7A053 Page 13 • Disturbed soils in footing trenches should be completely removed or thoroughly re-compacted prior to pouring concrete for the footings. 1 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 be no greater than 3,500 psf for footings poured on or into the very-dense, fresh till soils, and no more than 3,000• psf on structural fill constructed over 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 footing supporting light-weight decks and porches. U A one-third increase in the above recommended allowable soil bearing pressure may be used Iwhen considering short-term,transitory,wind or seismic loads. Forr 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 buildings 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 LIU & ASSOCIATES, INC.