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<br />Where: <br /> <br />W'u = Uplift wind load per vertical member (Ib) <br /> <br />W = manufactured home width (ft) <br /> <br />Wu = Uplift wind load (psI) <br /> <br />s = Vertical member spacing lengthwise (ft) <br /> <br />The pullout capacity (Cs) of 1/2 in. lag screws with wood having a specific gravity of 0.42 is 291 Ib, <br />per inch of shank diameter. To determine the required penetration length (Ib) per screw, the following <br />calculation is used. " <br /> <br />Lp <br /> <br />= W'f + W'u <br />(4) (291) <br /> <br />In calculating the required penetration length the following values were used. <br />h = 9.75 ft. <br />Wi = 15 and 25 psf. <br /> <br />s = 5, 6, 7, 8, 9, and 10 ft. <br />a = 751/2 in. <br />W = 14 ft. <br />Wu = 9 and 15 psf. <br /> <br />Cross and End Bracing <br />To determine the number and diameter of bolts needed for cross and end bracing, the lateral wind <br />load, which acts horizontally, must be adjusted to act parallel with the load bearing the bracing member <br />as follows: <br />W' f = (h)(Wf) <br />sin -t <br /> <br />Where: <br />W'f = Adjusted load (Ib.lft. home) <br />h = Manufactured home height (ft) <br />Wf = Lateral wind load (psf) <br />sin -t = sine of the angle between horizontal and bracing member <br />In this calculation the following values were used. <br />h = 9.75 ft. <br />Wf = 15 and 25 psf <br />sin e = Based on geometry of 12 ft. wide horizontal dimension and height of vertical <br />member at 3, 4, 5, 6, 7, 8, and 10 ft. (corrected by subtracting 1 ft. to allow <br />for horizontal beam depth) <br />Bolt capacity Table 4.25 was developed based on the type of wood previously described for vertical <br />members and corrected for interpolation between capacity parallel and perpendicular to grain as follows: <br />Q = [ (Qol) (QII) I <br />[(QII)(Cos2 e)) + [(Qol )(sin2 e)J X '12 <br /> <br />Where: <br />Q = Bolt capacity as loaded (Ib) <br />Qol = Capacity perpendicular to grain (Ib) <br /> <br />96 <br />