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Geotecnnical Gngineering Report <br /> �I 17 23"� Ave W <br /> January 2, 2009 <br /> RMI File No. 50909 <br /> Pagc 7 <br /> Do also note as shown on Pigure 3: Schcmatic Cross-Section that the outside face of the footing of the <br /> wall MUST be at least .` feet from the surface of the slope to develop adequate bearing, This requirement <br /> takes precedence over the suggestion in thc previous paragraph in limiting the depth of the footing. <br /> Convcntional sprcad foundations shoald be placed on undisturbed medium dense or better native soils. <br /> W�ierc less than dense soils are encountered at footing bearinK elevation, the subgrade should be <br /> ovcrexcavated to cxpose suitable bcaring soil. Thc overexcavation could be filled with stnictural fill or <br /> rock spalls (sec subsec[ion on Stractural FiIY) or the footing may be extended down to the bearing native <br /> soils. If Footings are supported on struct�iral fill or rock spalis, the fi!I zone should extend outside the <br /> edges of the footing a distance equul to the dcpth of overexcavation below the footing. <br /> Pootings should extend at least ]8 inches bclow the lowest adjacent fini�hed ground surface for fros[ <br /> protection and!or bearing capacity consiJcrltions. Standing water should not be allowed to accumulate <br /> in footing trenches. .0.11 loose or disturbed soil should bc removed from the foundation excavation p�ior <br /> to pouring of the concrete. <br /> Por foundations constructed as ouNined above, wc recommend an allowable design �earing pressure of <br /> not more tha.0 2,000 pounds per square foot (psf) be used for the footing design. Current lnremational <br /> Rcsidential 9uilding Code (IRQC) guidelines should be used when considerin� increased allowable <br /> bcaring pressurc for short-term tr�nsitory wind or seismic ioads. Potential foundation settlement using <br /> thc rccommended allo"�ablc bearing pressurc is estimated to be Iess than 1 inch total and I/2-inch <br /> diffcrential betwcen adjacrnt footings or lcross a distance of about 25 f�et. <br /> Latcral loads may be resisteci by friction on the base of thc footing and passive resistance against the <br /> subsurface portions of dte founustiur. A cocfficient of friction of 035 may be used to calculate the base <br /> friction, and shoidd be applied to thc vertical dcad load only. Pnssive resistance may be calculated as a <br /> triangular equivalent fluid pressure distribution. An equivalent fluid density of 200 pounds per cubic <br /> foot (pc� should be used for passivc resistance design. These rccommended values incorporate safety <br /> fxtors of I.5 and 2.0 applied to the estimated ultimate values for frictional and passive resistance, <br /> respectivcly. To achirve this valuc of passivc resistance, the foundations should be placed "neaP' <br /> (without :onns) ngainst the native medium dense or better soils or compacted soil should be placed <br /> around thc footing. We recommend that tBc upper foot of soil be neglecred when calculating the passive <br /> RMI ASSOCIATES LLC q ��„ 1 <br /> C � ,� <br />