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Fastener Loads for Plywood - Screws <br />CITY OF SANTA ANA <br />Planning and Building Agency <br />a shear specimen and joint <br />behavior is dependent upon <br />the shear strength of the <br />fastener. Shear failure of the <br />screw shank occurs at the <br />wood -metal interface. <br />0 The metal -critical joint may <br />fail in one of two ways. Failure <br />occurs when the resistance of <br />the screw head to embedment <br />is greater than the resistance <br />of the metal to lateral and/ <br />or withdrawal load, and the <br />screw tears through or away <br />from the metal. Failure also <br />occurs when thin metal in a <br />metal -to -panel joint crushes or <br />tears away from the screw. <br />The following test data are pre- <br />sented for plywood only. <br />Tables 1 and 2 present average <br />ultimate lateral loads for wood - <br />and sheet -metal -screw connec- <br />tions in plywood -and -metal <br />joints. The end distance of the <br />loaded -edge in these tests was <br />one inch. Plywood face grain <br />was parallel to the load since this <br />direction yields the lowest lat- <br />eral loads when the joint is ply- <br />wood -critical. All wood -screw <br />specimens were tested with a <br />3/16-inch-thick steel side plate, <br />and values should be modified if <br />thinner steel is used4F <br />Approved <br />FOR PERMIT ISSUANCE <br />TABLE 1 <br />SCREWS: METAL -TO -PLYWOOD CONNECTIONS(-) M <br />Depth of Average Ultimate Lateral Load ( b'f ester ID. <br />Threaded <br />Penetration Wood Screws Sheet a dAcr <br />inch #8 #10 dew_ __,golll�#8 gin All <br />1/2 415 (500) 590 465 (565) 670 <br />5/8 — — 500 (600) 705 <br />3/4 — — — 590 (655) 715 <br />(a) Plywood was C-D grade with exterior glue (all plies Group 1), face grain parallel to load. Side <br />plate was 3/16"-thick steel. <br />(b) Values are not design values. Values in parentheses are estimates based on other tests. <br />PLYWOOD -TO -METAL CONNECTIONSW <br />Average Ultimate Lateral Load (Ibf)1b1 <br />Plywood <br />Performance <br />Screw Size <br />1/4"-20 Self <br />Framing <br />Category <br />#8 <br />#10 <br />#12 <br />#14 <br />Tapping Screw <br />1/4 <br />330 <br />360 <br />390 <br />410 <br />590 <br />0.080-incl#r <br />Aluminum <br />1/2 <br />630 <br />850* <br />860 <br />920 <br />970 <br />3/4 <br />910* <br />930* <br />1250 <br />1330 <br />1440 <br />0.078-inch <br />1/4 <br />360 <br />380 <br />400 <br />410 <br />650 <br />Galvanized <br />1/2 <br />700* <br />890* <br />900 <br />920 <br />970 <br />Steel (14 gage) <br />3/4 <br />700* <br />950* <br />1300* <br />1390* <br />1500 <br />(a) Plywood was A-C EXT (all plies Group 1), face grain parallel to load. <br />(b) Values are not design values. Loads denoted by an asterisk(*) were limited by screw-to-from- <br />ing strength; others were limited by plywood strength. <br />BE <br />Form No. E830E ■ © 2011 APA— The Engineered Wood Association 0 www.apawood.org <br />