2001 ASD/LRFD Wind/Seismic Supplement - American Wood Council

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ASD/LRFD SUPPLEMENT – SPECIAL DESIGN PROVISIONS FOR WIND AND SEISMIC15decking joints do not coincide. In addition, adjacentpanel edges shall be fastened to a commonmember and fasteners shall not be spaced less than3/8 inches from the edges of panels or joints inthe substrate.Where diaphragms are designated as blocked, all jointsin sheathing shall occur over and be fastened to commonframing members. The size and spacing of fasteners atwood diaphragm boundaries, panel edges, and intermediatesupports shall be as prescribed in Tables 4.2A and B.The diaphragm shall be constructed as follows:1. Panels not less than 4 ft. x 8 ft. except at endswhere reduced widths are permitted.2. Nails spaced not less than 3/8 inches from edgesand ends of panels and framing. Maximum nailspacing of 6 inches along intermediate framingmembers when supports are spaced 48 incheso.c. Maximum nail spacing along intermediateframing of 12 inches for other conditions.3. 2x nominal or wider framing at adjoiningpanel edges except that 3x nominal or widerframing and staggered nailing are requiredwhere:a) nails are spaced 2 inches o.c. or 2 ½inches o.c., orb) 10d nails having penetration into framingof more than 1-1/2 in. are spaced 3inches o.c. or less4. Wood structural panels shall conform to therequirements for its type in DOC PS1 or PS2.4.2.7.2 Diaphragms Diagonally Sheathed with Single-Layer of Lumber: Single diagonally sheathed lumberdiaphragms are permitted to be used to resist seismic andwind forces. Single diagonally sheathed lumber diaphragmsshall be constructed of minimum 1-inch thicknominal sheathing boards or 2-inch thick nominal lumberlaid at an angle of approximately 45° to the supports. Endjoints in adjacent boards shall be separated by at least onejoist space and there shall be at least two boards betweenjoints on the same support. Nailing of diagonally sheathedlumber diaphragms shall be in accordance with Table 4.2C.Single diagonally sheathed lumber diaphragms shall bepermitted to consist of 2x nominal lumber (1½ inchesthick) where the supports are not less than 3x nominal(2½ inches thick) in width or 4x nominal (3½ inches deep)in depth.4.2.7.3 Diaphragms Diagonally Sheathed withDouble-Layer of Lumber: Double diagonally sheathedlumber diaphragms are permitted to be used to resist seismicand wind forces. Double diagonally sheathed lumberdiaphragms shall be constructed of two layers of diagonalsheathing boards laid perpendicular to each other on thesame face of the supporting members. Each chord shallbe considered as a beam with uniform load per foot equalto 50% of the unit shear due to diaphragm action. Theload shall be assumed as acting normal to the chord in theplane of the diaphragm in either direction. Nailing of diagonallysheathed lumber diaphragms shall be inaccordance with Table 4.2C.4.2.7.4 Diaphragms Horizontally Sheathed withSingle-Layer of Lumber: Horizontally sheathed lumberdiaphragms are permitted to be used to resist seismic andwind forces. Horizontally sheathed lumber diaphragmsshall be constructed of minimum 1-inch thick nominalsheathing boards or minimum 2-inch thick nominal lumberlaid perpendicular to the supports. End joints inadjacent boards shall be separated by at least one joistspace and there shall be at least two boards between jointson the same support. Nailing of horizontally sheathedlumber diaphragms shall be in accordance with Table 4.2C.4LATERAL FORCE-RESISTING SYSTEMSAMERICAN FOREST & PAPER ASSOCIATION
16 LATERAL FORCE-RESISTING SYSTEMSTable 4.2A Nominal Unit Shear Values for Wood-Frame DiaphragmsBlocked Wood Structural Panel Diaphragms a,b64 2.5 26 4 2.5 2Minimum Minimum MinimumFastener Nominal NominalNail Spacing (in.) at Other Panel EdgesCommonSheathing GradePenetration in Panel FramingNail Spacing (in.) at Other Panel Edges (Cases 1, 2, 3, & 4)(Cases 1, 2, 3, & 4)Nail SizeFraming Thickness Width6 64 36 6 4 3(inches) (inches) (inches)6d 1 1/45/16Structural I c 8d 1 3/83/810d6dSheathing and Single-Floor c 8d10d1 1/21 1/41 3/81 1/215/325/163/83/87/1615/3215/3219/32ASEISMICNail Spacing (in.) at Diaphragm Boundries (All Cases), at Continuous Panel EdgesParallel to Load (Cases 3 & 4), and at All Panel Edges (Cases 5 & 6)v_s G_a v_s G_a v_s G_a v_s G_a v_w v_w v_w v_w(plf) (kips/in) (plf) (kips/in) (plf) (kips/in) (plf) (kips/in) (plf) (plf) (plf) (plf)2 370 15.0 500 8.5 750 12.0 840 20.0 520 700 1050 11753 420 12.0 560 7.0 840 9.5 950 17.0 590 785 1175 13302 540 14.0 720 9.0 1060 13.0 1200 21.0 755 1010 1485 16803 600 12.0 800 7.5 1200 10.0 1350 18.0 840 1120 1680 18902 640 24.0 850 15.0 1280 20.0 1460 31.0 895 1190 1790 20453 720 20.0 960 12.0 1440 16.0 1640 26.0 1010 1345 2015 22952 340 15.0 450 9.0 670 13.0 760 21.0 475 630 940 10653 380 12.0 500 7.0 760 10.0 860 17.0 530 700 1065 12052 370 13.0 500 7.0 750 10.0 840 18.0 520 700 1050 11753 420 10.0 560 5.5 840 8.5 950 14.0 590 785 1175 13302 480 15.0 640 9.5 960 13.0 1090 21.0 670 895 1345 15253 540 12.0 720 7.5 1080 11.0 1220 18.0 755 1010 1510 17102 510 14.0 680 8.5 1010 12.0 1150 20.0 715 950 1415 16103 570 11.0 760 7.0 1140 10.0 1290 17.0 800 1065 1595 18052 540 13.0 720 7.5 1060 11.0 1200 19.0 755 1010 1485 16803 600 10.0 800 6.0 1200 9.0 1350 15.0 840 1120 1680 18902 580 25.0 770 15.0 1150 21.0 1310 33.0 810 1080 1610 18353 650 21.0 860 12.0 1300 17.0 1470 28.0 910 1205 1820 20602 640 21.0 850 13.0 1280 18.0 1460 28.0 895 1190 1790 20453 720 17.0 960 10.0 1440 14.0 1640 24.0 1010 1345 2015 2295BWINDNail Spacing (in.) at Diaphragm Boundries (All Cases), atContinuous Panel Edges Parallel to Load (Cases 3 & 4),and at All Panel Edges (Cases 5 & 6)a. Nominal unit shear values shall be adjusted in accordance with 4.2.3 to determineASD allowable unit shear capacity and LRFD factored unit resistance. Forgeneral construction requirements see 4.2.6. For specific requirements, see 4.2.7.1for wood structural panel diaphragms.b. For framing grades other than Douglas-Fir-Larch or Southern Pine, reduced nominalunit shear capacities shall be determined by multiplying the tabulated nominalunit shear capacity by the Specific Gravity Adjustment Factor = [1-(0.5-G)],where G = Specific Gravity of the framing lumber from the NDS. The SpecificGravity Adjustment Factor shall not be greater than 1.c. Apparent shear stiffness values, G_a, are based on nail slip and panel stiffnessvalues for diaphragms constructed with OSB panels. When plywood panels areused, diaphragm deflections should be calculated in accordance with the ASDWood Structural Panels Supplement.AMERICAN WOOD COUNCIL
Page 1 and 2: 2001 EDITIONSUPPLEMENTSpecial Desig
Page 3 and 4: ASD/LRFD SUPPLEMENT - SPECIAL DESIG
Page 9 and 10: 6 GENERAL DESIGN REQUIREMENTSG aG a
Page 11 and 12: 8 MEMBERS AND CONNECTIONS3.1 Framin
Page 13 and 14: 10 MEMBERS AND CONNECTIONS3.2.3 Roo
Page 20 and 21: Table 4.2B Nominal Unit Shear Value

2001 ASD/LRFD Wind/Seismic Supplement - American Wood Council

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