ANSI SDPWS-2015 Special Design Provisions for Wind & Seismic.pdf

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1、SDPWS Special Design Provisions for Wind or wood strands or wafers; or a combination of veneer and wood strands or wafers; bonded together with waterproof synthetic resins or other suitable bonding systems. Examples of wood structural panels are plywood, oriented strand board (OSB), or composite pan

2、els. AMERICAN WOOD COUNCIL6 GENERAL DESIGN REQUIREMENTS2.3 Notation AMERICAN WOOD COUNCIL7MEMBERS AND CONNECTIONS3.1 Framing 83.2 Sheathing 83.3 Connections 10Table 3.1.1.1 Wall Stud Repetitive Member Factors 8Table 3.2.1 Nominal Uniform Load Capacities (psf) for Wall Sheathing Resisting Out-of-Plan

3、e Wind Loads 9Table 3.2.2 Nominal Uniform Load Capacities (psf) for Roof Sheathing Resisting Out-of-Plane Wind Loads 10SPECIAL DESIGN PROVISIONS FOR WIND AND SEISMIC3AMERICAN WOOD COUNCIL8 MEMBERS AND CONNECTIONS3.1 Framing 3.1.1 Wall Framing In addition to gravity loads, wall framing shall be desig

4、ned to resist induced wind and seismic forces. The framing shall be designed using the methods refer-enced in 2.1.2.1 for allowable stress design (ASD) and 2.1.2.2 for strength design (LRFD). 3.1.1.1 Wall Stud Bending Strength and Stiffness Design Value Increase: The reference bending design value,

5、Fb, for sawn lumber wood studs resisting out-of-plane wind loads shall be permitted to be multiplied by the repetitive member factors in Table 3.1.1.1, in lieu of the NDS repetitive member factor, Cr=1.15. The bend-ing stiffness, EI, for sawn lumber studs shall be permit-ted to be multiplied by the

6、repetitive member factors in Table 3.1.1.1 for the purposes of calculating out-of-plane deflection under wind load. The repetitive mem-ber factors in Table 3.1.1.1 apply when studs are de-signed for bending strength and stiffness, spaced no more than 24“ on center, covered on the inside with a minim

7、um of 1/2“ gypsum wallboard, attached in ac-cordance with minimum building code requirements and sheathed on the exterior with a minimum of 3/8“ (nominal) wood structural panel sheathing with all pan-el joints occurring over studs or blocking and attached using a minimum of 8d common nails spaced a

8、maxi-mum of 6“ on center at panel edges and 12“ on center at intermediate framing members. Table 3.1.1.1 Wall Stud Repetitive Member Factors Stud Size System Factor 2x4 2x6 2x8 2x10 2x12 1.50 1.35 1.25 1.20 1.15 3.1.2 Floor Framing In addition to gravity loads, floor framing shall be designed to res

9、ist induced wind and seismic forces. The framing shall be designed using the methods referenced in 2.1.2.1 for allowable stress design (ASD) and 2.1.2.2 for strength design (LRFD). 3.1.3 Roof Framing In addition to gravity loads, roof framing shall be designed to resist induced wind and seismic forc

10、es. The framing shall be designed using the methods referenced in 2.1.2.1 for allowable stress design (ASD) and 2.1.2.2 for strength design (LRFD). 3.2 Sheathing 3.2.1 Wall Sheathing Exterior wall sheathing and its fasteners shall be capable of resisting and transferring wind loads to the wall frami

11、ng. Maximum spans and nominal uniform load capacities for wall sheathing materials are given in Table 3.2.1. The ASD allowable uniform load capaci-ties to be used for wind design shall be determined by dividing the nominal uniform load capacities in Table 3.2.1 by an ASD reduction factor of 1.6. The

12、 LRFD factored uniform load capacities to be used for wind design shall be determined by multiplying the nominal uniform load capacities in Table 3.2.1 by a resistance factor, b, of 0.85. Sheathing used in shear wall assem-blies to resist lateral forces shall be designed in accord-ance with 4.3. Wal

13、ls sheathed with wood structural panel sheathing or siding that are designed to resist up-lift from wind, or combined shear and uplift from wind shall be in accordance with 4.4. AMERICAN WOOD COUNCILMEMBERS AND CONNECTIONS 39SPECIAL DESIGN PROVISIONS FOR WIND AND SEISMICTable 3.2.1 Nominal Uniform L

14、oad Capacities (psf) for Wall Sheathing Resisting Out-of-Plane Wind Loads1Sheathing Type4Span Rating or Grade Minimum Thickness (in.) Strength Axis6Perpendicular to Supports Parallel to Supports Maximum Stud Spacing (in.) Actual Stud Spacing (in.) Maximum Stud Spacing (in.) Actual Stud Spacing (in.)

15、 12 16 24 12 16 24 Nominal Uniform Loads (psf) Nominal Uniform Loads (psf) Wood Structural Panels (Sheathing Grades, C-C, C-D, C-C Plugged, OSB)2,524/0 3/8 24 425 240 105 24 90 50 30324/16 7/16 24 540 305 135 24 110 60 35332/16 15/32 24 625 355 155 24 155 90 45340/20 19/32 24 955 595 265 24 255 145

16、75348/24 23/32 24 116038403395324 455325531153Particleboard Sheathing (M-S Exterior Glue) 3/8 16 (contact manufacturer) 16 (contact manufacturer) 1/2 16 16 Particleboard Panel Sid-ing (M-S Exterior Glue) 5/8 16 (contact manufacturer) 16 (contact manufacturer) 3/4 24 24 Hardboard Siding (Direct to St

17、uds) Lap Siding 7/16 16 460 260 - - - - - Shiplap Edge Panel Siding 7/16 24 460 260 115 24 460 260 115 Square Edge Panel Siding 7/16 24 460 260 115 24 460 260 115 Cellulosic Fiberboard Sheathing Regular 1/2 16 90 50 - 16 90 50 - Structural 1/2 16 135 75 - 16 135 75 - Structural 25/32 16 165 90 - 16

18、165 90 - 1. Nominal capacities shall be adjusted in accordance with Section 3.2.1 to determine ASD uniform load capacity and LRFD uniform resistances.2. Unless otherwise noted, tabulated values are based on the lesser of nominal values for either OSB or plywood with 3 or more plies.3. Tabulated valu

19、es are based on the lesser of nominal values for either OSB or plywood with 4 or more plies.4. Wood structural panels shall conform to the requirements for its type in DOC PS 1 or PS 2. Particleboard sheathing shall conform to ANSI A208.1. Hardboardpanel and siding shall conform to the requirements

20、of ANSI/CPA A135.6. Cellulosic fiberboard sheathing shall conform to ASTM C 208.5. Tabulated values are for maximum bending loads from wind. Loads are limited by bending or shear stress assuming a 2-span continuous condition. Wherepanels are continuous over 3 or more spans the tabulated values shall

21、 be permitted to be increased in accordance with the ASD/LRFD Manual for EngineeredWood Construction. 6. Strength axis is defined as the axis parallel to the face and back orientation of the flakes or the grain (veneer), which is generally the long panel direction, unless otherwise marked.3.2.2 Floo

22、r Sheathing Floor sheathing shall be capable of resisting and transferring gravity loads to the floor framing. Sheath-ing used in diaphragm assemblies to resist lateral forces shall be designed in accordance with 4.2. 3.2.3 Roof Sheathing Roof sheathing and its fasteners shall be capable of resistin

23、g and transferring wind and gravity loads to the roof framing. Maximum spans and nominal uniform load capacities for roof sheathing materials are given in Table 3.2.2. The ASD allowable uniform load capaci-ties to be used for wind design shall be determined by dividing the nominal uniform load capac

24、ities in Table 3.2.2 by an ASD reduction factor of 1.6. The LRFD factored uniform load capacities to be used for wind design shall be determined by multiplying the nominal uniform load capacities in Table 3.2.2 by a resistance factor, b, of 0.85. Sheathing used in diaphragm as-semblies to resist lat

25、eral forces shall be designed in ac-cordance with 4.2. AMERICAN WOOD COUNCIL10 MEMBERS AND CONNECTIONSTable 3.2.2 Nominal Uniform Load Capacities (psf) for Roof Sheathing Resisting Out-of-Plane Wind Loads1,2,6Sheathing Type5Span Rating or Grade Minimum Thickness (in.) Strength Axis7Applied Perpendic

26、ular to Supports Strength Axis7Applied Parallel to Supports Rafter/Truss Spacing (in.) Rafter/Truss Spacing (in.) 12 16 19.2 24 32 48 12 16 24 Nominal Uniform Loads (psf) Nominal Uniform Loads (psf) Wood Structural Panels (Sheathing Grades, C-C, C-D, C-C Plugged, OSB) 24/0 24/16 32/16 40/20 48/24 3/

27、8 7/16 15/32 19/32 23/32 425 540 625 955 11603240 305 355 595 8403165 210 245 415 6153105 135 155 265 3953- - 90 150 2203- - - - 100390 110 155 255 455350 60 90 145 25533033534537531153Wood Structural Panels (Single Floor Grades, Underlayment, C-C Plugged) 16 o.c. 20 o.c. 24 o.c. 32 o.c. 48 o.c. 19/

28、32 19/32 23/32 7/8 1-1/8 705 815 116031395417904395 455 67031000412954275 320 4653695410604175 205 300344548054100 115 170325044554- - - 11042004170 235 4403116041790495 135 25036554114545037031103290451041. Nominal capacities shall be adjusted in accordance with Section 3.2.3 to determine ASD unifo

29、rm load capacity and LRFD uniform resistances.2. Unless otherwise noted, tabulated values are based on the lesser of nominal values for either OSB or plywood with 3 or more plies. 3. Tabulated values are based on the lesser of nominal values for either OSB or plywood with 4 or more plies.4. Tabulate

30、d values are based on the lesser of nominal values for either OSB or plywood with 5 or more plies.5. Wood structural panels shall conform to the requirements for its type in DOC PS 1 or PS 2.6. Tabulated values are for maximum bending loads from wind. Loads are limited by bending or shear stress ass

31、uming a 2-span continuous condition. Wherepanels are continuous over 3 or more spans, the tabulated values shall be permitted to be increased in accordance with the ASD/LRFD Manual for EngineeredWood Construction. 7. Strength axis is defined as the axis parallel to the face and back orientation of t

32、he flakes or the grain (veneer), which is generally the long panel direction, unless otherwise marked.3.3 Connections Connections resisting induced wind and seismic forces shall be designed in accordance with the meth-ods referenced in 2.1.2.1 for allowable stress design (ASD) and 2.1.2.2 for streng

33、th design (LRFD). AMERICAN WOOD COUNCILMEMBERS AND CONNECTIONS 311SPECIAL DESIGN PROVISIONS FOR WIND AND SEISMIC3.4 Uplift Force Resisting Systems 3.4.1. General The proportioning, design, and detailing of engi-neered wood systems, members, and connections resist-ing wind uplift shall be in accordan

34、ce with the refer-ence documents in 2.1.2 and the provisions of 3.4.2. A continuous load path, or paths, with adequate strength and stiffness shall be provided to transfer all forces from the point of application to the final point of re-sistance. 3.4.2 Design Requirements Uplift force resisting sys

35、tems shall comply with the following: 1. Metal connectors, continuous tie rods, or oth-er similar connection devices used in the winduplift load path shall be of adequate strengthand stiffness to transfer induced forces tosupporting elements.2. The design strength and stiffness of woodmembers and co

36、nnections used in combina-tion with metal connectors, continuous tierods, or other similar connection devices shallbe determined in accordance with 3.3.3. Where wind uplift load path connections arenot aligned from point of load application topoint of resistance, additional forces and de-flections r

37、esulting from such eccentricitiesshall be accounted for in the design of sup-porting load path elements.Exception: Walls sheathed with wood structural panel sheathing or siding that are designed to resist uplift from wind, or combined shear and uplift from wind shall be in accordance with 4.4. AMERI

38、CAN WOOD COUNCILMEMBERS AND CONNECTIONS12This page left blank intentionally.AMERICAN WOOD COUNCIL13LATERAL FORCE-RESISTING SYSTEMS4.1 General 144.2 Wood-Frame Diaphragms 154.3 Wood-Frame Shear Walls 254.4 Wood Structural Panels Designed to Resist Combined Shear and Uplift from Wind 39Table 4.2.4 Max

39、imum Diaphragm Aspect Ratios .16Tables 4.2A-D Nominal Unit Shear Capacities for Wood- Frame Diaphragms .21 24Table 4.3.3.2 Unblocked Shear Wall Adjustment Factor, Cub26Table 4.3.3.5 Shear Capacity Adjustment Factor, Co28Table 4.3.4 Maximum Shear Wall Aspect Ratios 28Tables 4.3A-D Nominal Unit Shear

40、Capacities for Wood- Frame Shear Walls .35 38Table 4.4.1 Nominal Uplift Capacity of 7/16“ Wood Structural Panel Sheathing or SidingCombined Shear and Uplift .43Table 4.4.1.6 Maximum Shear Wall Aspect Ratios 43Table 4.4.2 Nominal Uplift Capacity of 3/8“ Wood Structural Panel Sheathing or SidingUplift

41、 Only 444SPECIAL DESIGN PROVISIONS FOR WIND AND SEISMICAMERICAN WOOD COUNCIL14 LATERAL FORCE-RESISTING SYSTEMS4.1 General 4.1.1 Design Requirements The proportioning, design, and detailing of engi-neered wood systems, members, and connections in lateral force-resisting systems shall be in accordance

42、 with the reference documents in 2.1.2 and provisions in this chapter. A continuous load path, or paths, with ad-equate strength and stiffness shall be provided to trans-fer all forces from the point of application to the final point of resistance. 4.1.2 Shear Capacity Nominal shear capacities of di

43、aphragms and shear walls are provided for reference assemblies in Tables 4.2A, 4.2B, 4.2C, and 4.2D and Tables 4.3A, 4.3B, 4.3C, and 4.3D, respectively. Alternatively, shear ca-pacity of diaphragms and shear walls shall be permitted to be calculated by principles of mechanics using val-ues of fasten

44、er strength and sheathing shear capacity. 4.1.3 Deformation Requirements Deformation of connections within and between structural elements shall be considered in design such that the deformation of each element and connection comprising the lateral force-resisting system is compat-ible with the defo

45、rmations of the other lateral force-resisting elements and connections and with the overall system. 4.1.4 Boundary Elements Shear wall and diaphragm boundary elements shall be provided to transfer the design tension and compres-sion forces. Diaphragm and shear wall sheathing shall not be used to spl

46、ice boundary elements. Diaphragm chords and collectors shall be placed in, or in contact with, the plane of the diaphragm framing unless it can be demonstrated that the moments, shears, and deflec-tions, considering eccentricities resulting from other configurations, can be tolerated without exceedi

47、ng the framing capacity and drift limits. 4.1.5 Wood Members and Systems Resisting Seismic Forces Contributed by Masonry and Concrete Walls Wood-frame shear walls, wood-frame diaphragms, trusses, and other wood members and systems shall not be used to resist seismic forces contributed by masonry or

48、concrete walls in structures over one story in height. Exceptions: 1. Wood floor and roof members shall be permit-ted to be used in diaphragms and horizontaltrusses to resist horizontal seismic forces con-tributed by masonry or concrete walls providedsuch forces do not result in torsional force dis-

49、tribution through the diaphragm or truss.2. Vertical wood structural panel sheathed shearwalls shall be permitted to be used to provideresistance to seismic forces contributed by ma-sonry or concrete walls in two-story structures,provided the following requirements are met:a. Story-to-story wall heights shall not exceed12.b. Diaphragms shall not be considered totransmit lateral forces by torsional forcedistribution or cantilever past the outermostsupporting shear wall.c. Combined deflections of diaphragms andshear walls shall not permit design story dri