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DESIGN MANUAL& KEYWALL OPERATING GUIDEAINFINITE SLOPE SURCHARGE NCMA 2ND EDITION - COULOMB METHODOLOGY6) SlidingSliding Resistance (at interface or through pad)F v = 0.92R v = 0.92(3' x 120pcf) = 331 lbs/ft (from shear curves)F v = R v Tan 40˚ = (3' x 1' x 120pcf) (Tan40) = 302 lbs/ft (through pad)= 302 lbs/lf (lower of two)FS sl = F v ⁄ P ah = 302/156 = 1.94 > 1.5 OK7) Bearing Pressure (under crushed stone leveling pad)Equation (3i) e= B/2 - (M r - M o )/R v= 1'/2 - (256 - 156)/(3'x1'x120pcf)= 0.222'tB-2eB12Applied Bearing Pressure (under 6" pad)B-2e + tEquation (3j) σ v(modified)= R v / ((B-2e)+0.5')+0.5'γ= (3x120pcf)/((1'-2x0.222')+0.5) +0.5'(130pcf)= 406 lbs/sf8) Bearing Capacity (under crushed stone leveling pad)Equation (3k) Q ult =cNc + γDN q + 0.5γ(B-2e)Nγwhere:N c = 30.14, N q = 18.4, Nγ = 22.40B = (B-2e) + 0.5 = (1'-2 x 0.222) + .5 = 1.06'D = .5 + .5 = 1.0' (to bottom of pad)c = 0Q ult = 0 + (120) (1) (18.4) + (0.5) (120) (1.06) (22.40)= 3633 psfFS br = 3633/406 = 8.95 > 2.0 OKNote:Factor of safety inbearing without 6"crushed stone base isonly 3.3.A.3