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March 7. 2011 <br />Mr. Paul Iltompson/Kolhcar. Inc. <br />L&A lob No. 11-001 <br />Page 11 <br />cemented, fresh till soils. Thc footing bearing soils should be verified onsite by a <br />gcotechpical engineer after the footing trenches are excavated and before the footings <br />poured. <br />• 'llte minimum depth to bottom of perimeter footings below adjacent final exterior grade <br />should be no less than 18 inches. The minimum depth to bottom of the interior footings <br />below top of floor slab should be no less than 12 inches. <br />• The minimum width should be no less than 16 inches for continuous footings, and no less <br />than 24 inches for individual footings, except those footings supporting light -weight <br />decks or porches. <br />A one-third increase in the above recommended allowable soil bearing pressure may be used <br />when considering short-term. transitory, wind or seismic loads. For footing foundations designed <br />and constructed per recommendations above, we estimate that the maximum to'al post - <br />construction setuement of the buildings should be 1 /2 inch or less and the differential settlement <br />across building width should be 3/8 inch or less. <br />Lateral loads on the proposed residence may be resisted by the friction force between the <br />foundations and the subgrade soils or the passive earth pressure acting on the below -grade <br />portion of the foundations. For the latter, the foundations must be poured "neat" against <br />undisturbed soils or backfilled with a clean, free -draining, compacted structural fill. We <br />recommend that an equivalent fluid density (EFD) of 300 pcf (pounds per cubic foot) for the <br />passive earth pressure be used for lateral resistance. The above passive pressure assumes that the <br />backfill is level or inclines upward away from the foundations for a horizontal distance at least <br />1.5 times the depth of the foundations below the final grade. A coefficient of friction of 0.55 <br />between the foundations and the subgrade soils may be used. The above recommended soil <br />LIU & ASSOCIATES, INC. <br />