2001 ASD Supplements - unprotected PDF - American Wood Council

SW-10DIAPHRAGMSTable 3.1A Recommended Shear (pounds per foot) For Horizontal WoodStructural Panel Diaphragms with Framing of Douglas fir-Larch orSouthern Pine a for Wind Loading OnlyPanelGradeStructural IgradesSheathing,Single-Floorsand otherstructuralusepanelgradesCommonNail SizeaFor framing of other species: (1) Find specific gravity for species offraming lumber in the NDS. (2) Find shear value from table above for nailsize of actual grade. (3) Multiply value by the following adjustment factor= [1 - (0.5 - G)], where G = specific gravity of the framing lumber. Thisadjustment factor shall not be greater than 1.bSpace nails maximum 12 in. oc along intermediate framing members (6in. oc when supports are spaced 48 in. oc).cFraming at adjoining panel edges shall be 3 in. nominal or wider, andnails shall be staggered where nails are spaced 2 in. o.c. or 2-1/2 in. ocdFraming at adjoining panel edges shall be 3-in. nominal or wider, andnails shall be staggered where 10d nails having penetration into framingof more than 1-5/8 in. are spaced 3 in. oc.LoadMinimumNailPenetrationin Framing(in.)Case 1MinimumNominalPanelThickness(in.)6d e 1-1/4 5/168d 1-3/8 3/810d d 1-1/2 15/326d e 1-1/4 5/168d 1-3/83/83/87/1615/3210d d 1-1/2 15/3219/32FramingWIND LOADING ONLYBlocked DiaphragmsNail Spacing (in.) atdiaphragm boundaries (all cases),at continuous panel edges parallelto load (Cases 3 & 4), and atall panel edges (Cases 5 & 6) b6 4 2-1/2 c 2 cMinimumNominal Width Nail Spacing (in.) atof Framingother panel edgesMember(Cases 1, 2, 3 & 4) b(in.) 6 6 4 32260 350 525 5903295 390 590 6652380 505 740 8403420 560 840 9452450 595 895 10203505 670 1010 11502240 315 470 5303265 350 530 6002260 350 525 5903295 390 590 6652335 450 670 7653380 505 755 8552355 475 705 8053400 530 800 9052380 505 740 8403420 560 840 9452405 540 805 9153455 600 910 10302450 595 895 10203505 670 1010 1150LoadeCase 28d is recommended minimum for roofs due to negative pressures of highwinds.Notes: Design for diaphragm stresses depends on direction of continuouspanel joints with reference to load, not on direction of long dimension ofsheet. Continuous framing may be in either direction for blockeddiaphragms.The recommended shears presented in Table 3.1A are based on thehistorically used design stresses for diaphragms which are listed in Table3.1B multiplied by 1.4. Some building codes, including the 2000International Building Code, have provided for this increase due to thebetter understanding of wind loading. The designer should confirm thatthe increase is applicable under the local code.Blocking,if usedLoadCase 3Unblocked DiaphragmsNails Spaced 6 in. max. atSupported Edges bCase 1 (NoUnblocked edgesor continuousjoints parallelto load)230260335370400450210240230260300335322375335370355405400450All otherconfigurations(Cases 2, 3,4, 5 & 6)175195250280300335155175175195225250240265250280265300300335Continuous panel jointCase 4LoadBlocking,if usedDiaphragm boundaryCase 5LoadBlocking,if usedLoadCase 6FramingContinuous panel jointAPA – The Engineered Wood AssociationContinuous panel joint