09-8944 - Laserfiche WebLink

Browse Search

• . ,. • • • 1. Pull force can be expressed as,fQlloVs: r , Pf.- S'x L Where: �� • . Pf is the pull out force. S is the strength, or retention force of the lag in lbs. per inch (from above). a :''' L is the length of thread that is imbedded in wood. • • Our 11 panel system•above will have 38 bolts, 1/4 " 4" securing -the panel frames to the roof system and into wood joists. The bolts will ruh through the retaining clips, having three inches of bolt 1eggth imbedded in the wood. The pull out force is calculated as ' follows: 260 x 3 = 780 x 38 bolts 29,640 lb. of retention force with wood at 0.55 specific • 1 F I 7 : { gravity. This pull out force is greater than the uplift force determined for our 11pn� anel J „4 r 4 , , . array. ' Fe than 11 panels may be used per collector array, since the anchorage is ffl . 1 •;' '• ' ' proportional to the number of panels in the array. Do not exceed 11 anels per arra as I � ', " 474' ' I '" I ' 1 this will degrade p • , b • =Pilot holes should always be drilled for lag bolts, to improve holding power. The pull pull out force of the thrust washer is .5 x 3.14159 x .125 x 60,000 = 11,775 lb. This pull out force exceeds the retaining clip bolt strength of 2209 Ib. You must use thrust ' I .asliers to prevent the bolt head from pulling through the clips. a w Where roofing materials require the use of roof jacks to allow the array to clear the • shingles or tiles, roof jacks should be made and spaced according to sheet 3 of the drawing. ng • set, and talled per the framed series installation instructions. With blocks spaced at 24 f ins . ;intervals, the. pull out of the stiinger arrangement can be expressed as above. Applying the same formula, each block has a retentipn capability of 3901b. x 3, or 1170 lb. The array . : will have an arrangement of stringers and roof jacks equal to the number of panels + 1, f~ • multiplied by the number o'stringers called for in the table located on sheet 3 of I drawing set for framed. series• collectors. • • . • , I have included a series of wofksheets that calculate the uplift forces and retention forces for an array' consisting of two to 11 panels, at a design pressure of 61.5 psf. This is the 0 } • design pressure for coastal communities to meet the 2003 code revision. Using the recommended number of attachment points in the charts for the number of collectors in a ° • given array will assure a wind.— safe•installation. • • • i . • S • I . . • r • 1 • • • i ■ • - . • a • • i