1130 RAINIER AVE WHOLE SITE DOCUMENTS 2016-01-01 MF Import

C� Evereft Housing Acrthoiity P,1 ay t G, 2012 C� JN 120Q0 Page 5 Depending on the final site yrades, overexcavation may be required below lhe fcotings to expose competent native soil. Unless lean concrete is used to fill an ovarexcavated hole, the overe:ccavation must be at least as wide at the bottom as the sum of the depth of the overexcavation and Ihe footing width. For example, an overexcavation exlending 2(eel below ihe bottom o( a 2-foot-wide footing musl be at least 4 feet wide at the base of the excavafion. If lean concrete is used, the overexcavation need only extend 6 inches beyond the edges of lhe footing. .4n alio�.vable bearing pressure oi 3,000 pounds per square fool (psf) is appropriale for fooCinys supported on competen' soil anC/or structural fill as noted above. A one-third increase in Ihis design bearing pressure may be used �vhen considering short-term wind or seismic loads. Fcr the abo•.e design criteria, it is anticipated that the total posl-construction selllement of footings founded on competent native soil, or on structural fill up to 5 feet �n thickness, will be about one inch, with differenlial settlemenls on the order of one-half inch in 2 distance of 50 feet along a conLnuous footing caith a uniform load. Lateral loads di�e to �vind or seismic forces may be resisted by friction between !he foundation and the bearing soil, or by passive earth pressure acting on the vertical, emhedded portions of the foundation. For the latter ccndition, the foundation must be eilher poured direclly against relatively level, undisturbed soil or be surrounded by levei, compacl f�ll. If the ground in iront of a foundation i> loose or sloping, the oassive earth pressure given above will not be appropriate. We recommend using the follo�.vine, ultimate values for the `ounda:ion's resistance to laleral loading: - ----- - —� I I CoeHi� cier�t o( Friction 0.50 �i �I Passive Earth Pressure 300 pcf � Where: (I) pcf Is pountls per cu61e tool, antl (II) passlve e, rth pressure Is computed using Ihe equlvalent Ould densily. We recommend maintaining a sa(ety factor of at least 1.5 for the foundation's resistance to lateral loading, �vhen using the above ultimale values. P/PE PILES Three-, 4- or G-inch-diameter pipe piles driven wilh a 800- or 1,100-pound hydraulic jackhammer lo the following (inal penetration rales may be assigned the following compressive capacities. 3 inches 10 sec!inch 6 sechnch nla I 6 tans 4 inches 15 seclinch 10 seGinch 5 sec/inch � 10 ton: 6 inches n/a —� 20 seclinch __L 10 sec/inch ___20 ton: Note: The refusal crileria indicated in lhe above table are valid only (or pipe piles that are installed using a hydraulic impacl hammer carried on Ieads lhat allow lhe hammer to sit on GGOTECH CONSULTANTS.INC.