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PLF ON FOUNDATION <br />Calculate moment and shear strength in wall to get max spacing, Condition All <br />Enter load per linear foot (calculated elsewhere): <br />w-totalplf 1,243 plf <br />Calculate Strength of Unreinforced Section <br />Foundation dimensions (Note: For thickened slab, enter thickening as footer and slab as wall) <br />T = 8 in (thickness of wall) <br />H = 24 in (ht of wall) <br />S = 8 in (ht of footer) <br />B = 16 in (width of footer) <br />D = 32 in (total ht of foundation) <br />Centroid, c = sum (AiYi)/ sum(Ai) <br />d-(dA2 * t + sA2 8 (b-t))/(2 * (b * s + h * t)) <br />= 18.40 in <br />Moment of Inertia (1) <br />I stem = <br />9,216 InA4 <br />parallel axis <br />7,864 InA4 <br />1footer = <br />683 InA4 <br />parallel axis <br />11,796 InA4 <br />1 = <br />29,559 InA4 <br />S = <br />1,606 inA3 - I/c <br />f'c = 2,500 psi — (assume 2,500 for conc) <br />Mn = 33,469 ft lb - 5 x sgrt(f'c) x S <br />Mu = 21,755 ft lb - 0.65 x Mn <br />Calculate Strength of Reinforced Section <br />Note: This analysis neglects the "ears" of the footer, using wall thickness as "b" and assumes 3" clear to the steel. <br />fy: 40,000 psi <br />k1: 0.85 <br />As: 0 inA2, assume none <br />phi: 0.9 <br />gmax= 0.371=0.6375*k1*(87,000/(87,000+fy) <br />q = 0.000 = [As/b*dJ*fy/f'c <br />Mu = 0 ft lb, phi*As*fy*d(1-0.59q) <br />Ma = 0 ft lb allowable, Mux0.65 <br />Mx = 21,755 ft lb, Max of unreinforced and reinforced <br />Calculate maximum span to achieve Moment strength <br />Mx = (wIA2)/8 <br />1,243 <br />Page 4 of 6 <br />