ASD-LRFD for Wood Construction (Provisions for Wind and Seismic)

MANUAL FOR ENGINEERED WOOD CONSTRUCTION

American Wood Council

AmericanForest &

PaperAssociation

2001 EDITIONSUPPLEMENTSpecial DesignProvisions forWind and Seismic

06-02 20M

American Forest & Paper AssociationAmerican Wood Council1111 19th Street, NWSuite 800Washington, DC [email protected]

America's Forest & Paper People ®

Improving Tomorrow's Environment Today ®

®

®

ASD/LRFDALLOWABLE STRESS

DESIGN

LOAD AND RESISTANCE

FACTOR DESIGN

Seismic 2001 Cover.pmd 6/9/02, 7:48 PM1

2001 EDITIONSUPPLEMENTSpecial DesignProvisions forWind and Seismic

MANUAL FOR ENGINEEREDWOOD CONSTRUCTION

ASD/LRFDALLOWABLE STRESS

DESIGN

Copyright © 2001

American Forest & Paper Association, Inc.

LOAD AND RESISTANCEFACTOR DESIGN

Seismic FM draft.pmd 5/3/02, 10:35 AM1

Table of ContentsChapter/Title Page

1 Designer Flowchart ..................................................11.1 Flowchart

2 General Design Requirements .. 32.1 General2.2 Terminology2.3 Notation

3 Members and Connections .................73.1 Framing3.2 Sheathing3.3 Connections

List of Tables

AMERICAN FOREST & PAPER ASSOCIATION

3.1.1.1 Wall Stud Bending Stress Increase Factors .......... 8

3.2A Nominal Uniform Load Capacities, psf,for Wall Sheathing Resisting Wind Loads ............. 9

3.2B Nominal Uniform Load Capacities, psf,for Roof Sheathing Resisting Wind Loads ........ 10

4.2.4 Maximum Diaphragm Aspect Ratios(Horizontal or Sloped Diaphragms) .......................... 13

4.2A Nominal Unit Shear Values for Wood-FrameDiaphragms (Blocked Wood Structural PanelDiaphragms) ............................................................................................ 16

4.2B Nominal Unit Shear Values for Wood-FrameDiaphragms (Unblocked Wood StructuralPanel Diaphragms) .......................................................................... 17

4.2C Nominal Unit Shear Values for Wood-FrameDiaphragms (Lumber Diaphragms) ........................... 18

4.3.3.4 Shear Capacity Adjustment Factor, Co ................... 20

4.3.4 Maximum Shear Wall Aspect Ratios ........................ 21

4.3A Nominal Unit Shear Values for Wood-FrameShear Walls (Wood-based Sheathing) ..................... 25

4.3B Nominal Unit Shear Values for Wood-FrameShear Walls (Gypsum and Cement Plaster) ..... 26

4.3C Nominal Unit Shear Values for Wood-FrameShear Walls (Lumber Shear Walls) ............................. 27

ASD/LRFD SUPPLEMENT – SPECIAL DESIGN PROVISIONS FOR WIND AND SEISMIC

Chapter/Title Page

4 Lateral Force-ResistingSystems .............................................................................................. 11

4.1 General4.2 Wood Diaphragms4.3 Wood Shear Walls

5 References .................................................................................29

Seismic FM draft.pmd 5/3/02, 10:35 AM2


1

DESIGNERFLOWCHART

1.1 Flowchart 2

1


Seismic C1 Draft.pmd 1/28/02, 4:58 PM1

AMERICAN WOOD COUNCIL

2 DESIGNER FLOWCHART

Special Design Provisions forWind and Seismic Supplement

Design Category = ASDAllowable Stress

(Sections 3.0 and 4.0)

Design Capacity ≥Applicable Load

Effect

Select a Trial Design

Design Method

Design Category = LRFDFactored Resistance

(Sections 3.0 and 4.0)

LRFDASD

Strength Criteria Satisfied

Yes

No

1.1 Flowchart



3

GENERALDESIGNREQUIREMENTS

2.1 General 4

2.2 Terminology 4

2.3 Notation 5


2



4 GENERAL DESIGN REQUIREMENTS

2.1 General

2.1.1 Scope

The provisions of this Supplement cover materials,design and construction of wood members, fasteners, andassemblies to resist wind and seismic forces.

2.1.2 Design Methods

Engineered design of wood structures to resist windor seismic forces shall be by one of the methods describedin Section 2.1.2.1 and 2.1.2.2.

Exception: Wood structures shall be permittedto be constructed in accordance with prescriptive

provisions permitted by the authority having ju-risdiction.

2.1.2.1 Allowable Stress Design: Allowable stress de-sign (ASD) shall be in accordance with the NationalDesign Specification® (NDS®)for Wood Construction(ANSI/AF&PA NDS-2001), its supplements, and provi-sions of this Supplement.

2.1.2.2 Strength Design: Load and resistance factordesign (LRFD) of wood structures shall be in accordancewith the Load and Resistance Factor Standard for Engi-neered Wood Construction (AF&PA/ASCE 16-95), itssupplements, and provisions of this Supplement.

2.2 Terminology

ALLOWABLE STRESS DESIGN A method of pro-portioning structural members such that elasticallycomputed stresses produced in the members by nominalloads does not exceed specific allowable stresses (alsocalled working stress design).

BOUNDARY ELEMENT Diaphragm and shear wallboundary members to which sheathing transfers forces.Boundary elements include chords and collectors at dia-phragm and shear wall perimeters, interior openings,discontinuities and re-entrant corners.

CHORD A boundary element perpendicular to the ap-plied load that is assumed to resist axial stresses due tothe induced moment.

COLLECTOR A diaphragm or shear wall element par-allel and in line with the applied force that collects andtransfers diaphragm shear forces to the vertical elementsof the lateral force-resisting system and/or distributesforces withing the diaphragm.

DIAPHRAGM A roof, floor or other membrane bracingsystem acting to transmit lateral forces to the vertical re-sisting elements. When the term “diaphragm” is used, itincludes horizontal bracing systems.

DIAPHRAGM, BLOCKED A diaphragm in which alladjacent sheathing edges are fastened to either commonframing or common blocking.

DIAPHRAGM, FLEXIBLE A diaphragm is flexible forthe purpose of distribution of story shear when the com-puted maximum in-plane deflection of the diaphragm itself

under lateral load is greater than two times the averagedeflection of adjoining vertical elements of the lateralforce-resisting system of the associated story under equiva-lent tributary lateral load.

DIAPHRAGM, RIGID A diaphragm is rigid for the pur-pose of distribution of story shear and torsional momentwhen the computed maximum in-plane deflection of thediaphragm itself under lateral load is less than or equal totwo times the average deflection of adjoining vertical el-ements of the lateral force-resisting system of theassociated story under equivalent tributary lateral load.For analysis purposes, it can be assumed that a rigid dia-phragm distributes story shear and torsional moment intolines of shear walls by the relative lateral stiffness of theshear walls.

[For the first iteration, an arbitrary load is ap-plied to each line of shear walls to determine therelative stiffness of the lines of walls. Once therelative stiffnesses of the wall lines have been de-termined, the applied lateral load is distributedproportionally. The shear walls are redesignedand the lateral stiffness is recalculated and theapplied load is re-apportioned. This is continueduntil convergence.]

DIAPHRAGM, UNBLOCKED A diaphragm that hasedge nailing at supporting members only. Blocking be-tween supporting structural members at panel edges is not



GENER

AL D

ES

IGN R

EQ

UIR

EM

ENTS

5ASD/LRFD SUPPLEMENT – SPECIAL DESIGN PROVISIONS FOR WIND AND SEISMIC

2

included. Diaphragm panels are field nailed to support-ing members.

DIAPHRAGM BOUNDARY A location where shear istransferred into or out of the diaphragm sheathing. Trans-fer is either to a boundary element or to anotherforce-resisting element.

FIBERBOARD A fibrous, homogeneous panel madefrom lignocellulosic fibers (usually wood or cane) andhaving a density of less than 31 pounds per cubic foot(497 kg/m3) but more than 10 pounds per cubic foot (160kg/m3).

HARDBOARD A fibrous-felted, homogeneous panelmade from lignocellulosic fibers consolidated under heatand pressure in a hot press to a density not less than 31pounds per cubic foot.

LATERAL STIFFNESS The inverse of the deforma-tion of shear walls under an applied unit load, or the forcerequired to deform a shear wall a unit distance.

NOMINAL STRENGTH Strength of a member, crosssection, or connection before application of any strengthreduction factors.

ORIENTED STRAND BOARD A mat-formed woodstructural panel product composed of thin rectangularwood strands or wafers arranged in oriented layers andbonded with waterproof adhesive.

PARTICLEBOARD A generic term for a panel prima-rily composed of cellulosic materials (usually wood),generally in the form of discrete pieces or particles, asdistinguished from fibers. The cellulosic material is com-bined with synthetic resin or other suitable bonding systemby a process in which the interparticle bond is created bythe bonding system under heat and pressure.

PERFORATED SHEAR WALL A sheathed wall withopenings, but which has not been specifically designedand detailed for force transfer around wall openings.

PERFORATED SHEAR WALL SEGMENT A sec-tion of a perforated shear wall with full height sheathingwhich meets the requirements for maximum aspect ratioin Section 4.3.4.

PLYWOOD A wood structural panel comprised of pliesof wood veneer arranged in cross-aligned layers. Theplies are bonded with an adhesive that cures on applica-tion of heat and pressure.

REQUIRED STRENGTH Strength of a member, crosssection, or connection required to resist factored loads orrelated internal moments and forces.

RESISTANCE FACTOR A factor that accounts forunavoidable deviations of the actual strength from thenominal value and the manner and consequences of fail-ure.

SEISMIC DESIGN CATEGORY A classification as-signed to a structure based on its Seismic Use Group andthe severity of the design earthquake ground motion atthe site.

SHEAR WALL A wall designed to resist lateral forcesparallel to the plane of a wall.

SHEAR WALL LINE A series of shear walls in a line ata given story level.

SUBDIAPHRAGM A portion of a larger wood dia-phragm designed to anchor and transfer local forces toprimary diaphragm struts and the main diaphragm.

TIE-DOWN (HOLD-DOWN) A device used to resistuplift of the chords of shear walls.

WOOD STRUCTURAL PANEL A panel manufacturedfrom veneers; or wood strands or wafers; or a combina-tion of veneer and wood strands or wafers; bondedtogether with waterproof synthetic resins or other suit-able bonding systems. Examples of wood structuralpanels are plywood, oriented strand board (OSB), or com-posite panels.

2.3 Notation

A = Area of chord cross-section, in.2

A = Area of end post cross-section, in.2

C = Compression chord force, lbs.

Co

= Shear capacity adjustment factor from Table

4.3.3.4.

E = Modulus of elasticity of end posts, psi

E = Modulus of elasticity of diaphragm chords, psi

G = Specific gravity

Ga

= Apparent shear wall shear stiffness from nail

slip and panel shear deformation, kips/in. (from

Column A, Table 4.3).



6 GENERAL DESIGN REQUIREMENTS

2. The maximum clear height from top of

diaphragm to bottom of diaphragm framing

above.

t = Uniform uplift force, lbs./ft.

ν = Induced unit shear, lbs./ft.

νs

= Nominal unit shear capacity for seismic design,

lbs./ft.

νmax

= Maximum induced unit shear force, lbs./ft.

νsc

= Combined nominal unit shear capacity of two-

sided shear wall for seismic design, lbs./ft.

νs1

= Nominal unit shear capacity for side 1, lbs./ft.

(from Column A, Table 4.3).

νs2


(from Column A, Table 4.3).

νw

= Nominal unit shear capacity for wind design,

lbs./ft

νwc


sided shear wall for wind design, lbs./ft.

x = Distance from chord splice to nearest support,

in.

∆c

= Diaphragm chord splice slip at the induced unit

shear in diaphragm, in.

∆a

= Total vertical elongation of wall anchorage

system (including fastener slip, device

elongation, rod elongation, etc) at the induced

unit shear in the shear wall, in.

δdia

= Maximum diaphragm deflection determined by

elastic analysis, in.

δsw

= Maximum shear wall deflection determined by


φb

= Sheathing resistance factor for out of plane

bending

φD

= Sheathing resistance factor for in-plane shear

of shearwalls and diaphragms

Ω0

= System overstrength factor

Ga

= Apparent diaphragm shear stiffness from nail


Column A, Table 4.2).

Gac

= Combined apparent shear wall shear stiffness

of two-sided shear wall, kips/in.

Ga1

= Apparent shear wall shear stiffness for side 1,

kips/in. (from Column A, Table 4.3).

Ga2


kips/in. (from Column A, Table 4.3).

Kmin

= Minimum ratio of v1/G

a1 or v

2/G

a2

L = The dimension of a diaphragm perpendicular to

the direction of application of force. For open-

front structures, L is the length from the edge of

the diaphragm at the open front to the vertical

resisting elements parallel to the direction of

the applied force.

Lc

= The length of the cantilever for a cantilever

diaphragm, ft. (see figure 4.2.5.2)

ΣLi

= Sum of perforated shear wall segment lengths,

ft.

R = Response modification coefficient

T = Tension chord force, lbs.

V = Induced shear force in perforated shear wall,

lbs.

W = Diaphragm width, ft.

W = The width of a diaphragm in the direction of

application of force measured as the sheathed

dimension of the diaphragm.

b = The length of a shear wall or shearwall segment

measured as the sheathed dimension of the

shear wall.

bs

= Shear wall length for determining apect ratio.

For perforated shearwalls, use the minimum

shearwall segment length included in the Li , ft.

h = The height of a shear wall or shearwall segment

measured as:

1. The maximum clear height from top of

foundation to bottom of diaphragm framing

above or



7

MEMBERS ANDCONNECTIONS

3.1 Framing 8

3.2 Sheathing 8

3.3 Connections 10

Table 3.1.1.1 Wall Stud Bending Stress Increase Factors ..... 8

Table 3.2A Nominal Uniform Load Capacities, psf, forWall Sheathing Resisting Wind Loads .............. 9

Table 3.2B Nominal Uniform Load Capacities, psf, forRoof Sheathing Resisting Wind Loads ........... 10


3



8 MEMBERS AND CONNECTIONS

3.1 Framing

3.1.1 Wall Framing

In addition to gravity loads, wall framing shall bedesigned to resist induced wind and seismic forces. Theframing shall be designed using methods referenced in2.1.2.1 for allowable stress design (ASD) and 2.1.2.2 forstrength design (LRFD).

3.1.1.1 Wall Stud Bending Stress Increase: The bend-ing stress for sawn lumber wood studs resisting out ofplane wind loads shall be permitted to be increased by thefactors in Table 3.1.1.1, in lieu of the 1.15 repetitive mem-ber factor, to take into consideration the load sharing andcomposite action provided by wood structural panelsheathing. The factor applies when studs are designed forbending, spaced no more than 16 inches on center, cov-ered on the inside with a minimum of ½-inch gypsumwallboard, and sheathed on the exterior with a minimumof 3/8-inch wood structural panel sheathing that is attachedto the studs using a minimum of 8d common nails spaced amaximum of 6 inches o.c. at panel edges and 12 inches o.c.at intermediate framing members.

Table 3.1.1.1 Wall Stud BendingStress Increase Factors

Stud Size System Factor2x4 1.52x6 1.42x8 1.32x10 1.22x12 1.15

3.1.2 Floor Framing

In addition to gravity loads, floor framing shall bedesigned to resist induced wind and seismic forces. Theframing shall be designed using methods referenced in2.1.2.1 for allowable stress design (ASD) and 2.1.2.2 forstrength design (LRFD).

3.1.3 Roof Framing

In addition to gravity loads, roof framing shall be de-signed to resist induced wind and seismic forces. Theframing shall be designed using methods referenced in2.1.2.1 for allowable stress design (ASD) and 2.1.2.2 forstrength design (LRFD).

3.2 Sheathing

blies to resist lateral forces shall be designed in accor-dance with 4.3.

3.2.2 Floor Sheathing

Floor sheathing shall be capable of resisting and trans-ferring gravity loads to the floor framing. Sheathing usedin diaphragm assemblies to resist lateral forces shall bedesigned in accordance with 4.2.

3.2.1 Wall Sheathing

Exterior wall sheathing and its fasteners shall be ca-pable of resisting and transferring out of plane wind loadsto the wall framing. Maximum spans and nominal uni-form load capacities for wall sheathing materials are givenin Table 3.2A. The ASD allowable uniform load capaci-ties to be used for wind design shall be determined bydividing the nominal uniform load capacities by a safetyfactor of 1.6. The LRFD factored uniform load capacitiesto be used for wind design shall be determined by multi-plying the nominal uniform load capacities by a resistancefactor, φb, of 0.85. Sheathing used in shear wall assem-



MEM

BER

S A

ND

CO

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TIO

NS


3

Table 3.2A Nominal Uniform Load Capacities, psf, for Wall Sheathing ResistingWind Loads1

1. Nominal capacities shall be adjusted in accordance with Section 3.2.1 to determine ASD uniform load capacity and LRFD uniform resistances.2. Sheathing shall be OSB or plywood with 4 or more plies.3. Wood structural panels shall conform to the requirements for its type in DOC PS 1 or PS2. Particleboard sheathing shall conform to ANSI A208.1.

Hardboard panel and siding shall conform to the requirements of AHA A135.5 or AHA A135.4 as applicable. Cellulosic fiberboard sheathing shallconform to AHA A194.1 or ASTM C208.

4. Tabulated values are for maximum bending loads from wind. Loads are limited by bending or shear stress assuming a 2-span continuous condition.For more information, see the ASD Wood Structural Panels Supplement.

December 15, 2001

Sheathing Type3 Span Rating or Grade MinimumThickness

(in.)Sheathing Long Dimension Orientation:

Perpendicular to Supports Parallel to Supports

Maximum Stud Spacing

(in.)

Actual StudSpacing (in.)

Maximum Stud Spacing

(in.)

Actual StudSpacing (in.)

12 16 24 12 16 24

Nominal UniformLoads (psf)

Nominal UniformLoads (psf)

Wood Structural Panels4

(Sheathing Grades, C-C, C-D, C-C Plugged, OSB)

24/024/1632/1640/2048/24

3/87/1615/3219/3223/32

2424242424

425 540 625950

1160

240 305 355 595805

105135155265360

2424242424

90110155255380

50 6090145215

– 252

402

652

902

Particleboard Sheathing(M-S Exterior Glue)

3/81/2

1616

(contactmanufacturer)

1616


Particleboard PanelSiding(M-S Exterior Glue)

5/83/4

1624


1624


Hardboard Siding(Direct to Studs)

Lap SidingShiplap Edge Panel SidingSquare Edge Panel Siding

7/167/167/16

162424

460460460

260260260

-115115

-2424

-460460

-260260

-115115

Cellulosic FiberboardSheathing

RegularStructuralStructural

1/21/2

25/32

---

---

---

---

161616

90135 165

50 7590

---



10 MEMBERS AND CONNECTIONS

3.3 Connections

3.3.1 Connections

Connections resisting induced wind and seismic forcesshall be designed in accordance with methods referencedin 2.1.2.1 for allowable stress design (ASD) and 2.1.2.2for strength design (LRFD).

3.2.3 Roof Sheathing

Roof sheathing and its fasteners shall be capable ofresisting and transferring out of plane wind and gravityloads to the roof framing. Maximum spans and nominaluniform load capacities for roof sheathing materials aregiven in Table 3.2B. The ASD allowable uniform loadcapacities to be used for out of plane wind design shall be

determined by dividing the nominal uniform load capaci-ties by a safety factor of 1.6. The LRFD factored uniformload capacities to be used for wind design shall be deter-mined by multiplying the nominal uniform load capacitiesby a resistance factor, φb, of 0.85. Sheathing used in dia-phragm assemblies to resist lateral forces shall be designedin accordance with 4.2.

December 15, 2001

Sheathing Type Span Rating or Grade MinimumThickness

(in.)

Sheathing Long Dimension Applied Perpendicular to Supports

Rafter/Truss Spacing (in.)

12 16 19.2 24

Nominal Uniform Loads (psf)

Wood Structural Panels2,3

(Sheathing Grades, C-C, C-D, C-C Plugged, OSB)

24/024/1632/1640/2048/24

3/87/1615/3219/3223/32

425 540 625950

1160

240 305 355 595805

165210245415560

105135155265360

Wood Structural Panels2,3

(Single Floor Grades,Underlayment, C-CPlugged)

16 o.c.20 o.c.24 o.c.32 o.c.48 o.c.

19/3219/3223/327/8

1-3/32

705815

108513901790

395 455 610830

1295

275 320 425 5751060

175205270370680

Table 3.2B Nominal Uniform Load Capacities, psf, for Roof Sheathing ResistingWind Loads1

1. Nominal capacities shall be adjusted in accordance with Section 3.2.3 to determine ASD uniform load capacity andLRFD uniform resistances.

2. Wood structural panels shall conform to the requirements for its type in DOC PS 1 or PS2.3. Tabulated values are for maximum bending loads from wind. Loads are limited by bending or shear stress assuming a 2-

span continuous condition. For more information, see the ASD Wood Structural Panels Supplement.



11

LATERALFORCE-RESISTINGSYSTEMS

4.1 General 12

4.2 Wood Diaphragms 13

4.3 Wood Shear Walls 19

Table 4.2.4 Maximum Diaphragm Aspect Ratios(Horizontal or Sloped Diaphragms) ............ 13

Table 4.2A-C Nominal Unit Shear Values for Wood-Frame Diaphragms:

A = Blocked Diaphragms ........................... 16B = Unblocked Diaphragms ...................... 17C = Lumber Diaphragms .......................... 18

Table 4.3.3.4 Shear Capacity Adjustment Factor, Co ....... 20

Table 4.3.4 Maximum Shear Wall Aspect Ratios ........... 21

Table 4.3A-C Nominal Unit Shear Values for Wood-Frame Shear Walls:

A = Wood-based Sheathing........................ 25B = Gypsum and Cement Plaster ............. 26C = Lumber Shear Walls ........................... 27


4



12 LATERAL FORCE-RESISTING SYSTEMS

4.1 General

4.1.5 Wood Systems ResistingHorizontal Seismic ForcesContributed by Masonry andConcrete

Wood shear walls, diaphragms, trusses and other woodassemblies shall not be used to resist horizontal seismicforces contributed by masonry or concrete construction instructures over one story in height.

Exceptions:1. Wood floor and roof assemblies shall be per-

mitted to be used in diaphragms and horizontaltrusses to resist horizontal seismic forces (in-cluding those due to masonry veneer, fireplaces,and chimneys) provided such forces do not re-sult in torsional force distribution through thetruss or diaphragm.

2. Vertical wood structural panel sheathed shearwalls shall be permitted to be used to provideresistance to seismic forces in two-story struc-tures of masonry or concrete construction,provided the following requirements are met:a. Story-to-story wall heights shall not ex-

ceed 12 feet.b. Diaphragms shall not be considered to

transmit lateral forces by torsional force dis-tribution or cantilever past the outermostsupporting shear wall.

c. Combined deflections of diaphragms andshear walls shall not permit story drift ofsupported masonry or concrete walls to ex-ceed 0.7% of the story height.

d. Wood structural panel sheathing in dia-phragms shall have all unsupported edgesblocked. Wood structural panel sheathingfor both stories of shear walls shall haveall unsupported edges blocked and, for thelower story, shall have a minimum thick-ness of 15/32 inch.

e. There shall be no out-of-plane horizontaloffsets between the first and second sto-ries of wood structural panel shear walls.

4.1.1 Design Requirements

The proportioning, design, and detailing of engineeredwood systems, members, and connections in lateral force-resisting systems shall be in accordance with methodsreferenced in 2.1.2 and provisions in this Chapter.

A continuous load path, or paths, with adequatestrength and stiffness shall be provided to transfer all forcesfrom the point of application to the final point of resis-tance.

4.1.2 Shear Capacity

Nominal shear capacities of diaphragms and shearwalls are provided for reference assemblies in Tables 4.2and 4.3, respectively. Alternatively, shear capacity of dia-phragms and shear walls shall be permitted to be calculatedby principles of mechanics using values of fastenerstrength and sheathing shear capacity.

4.1.3 Deformation Requirements

Deformation of connections within and between struc-tural elements shall be considered in design such that thedeformation of each element and connection comprisingthe lateral force-resisting system is compatible with thedeformations of the other lateral force-resisting elementsand connections and with the overall system.

4.1.4 Boundary Elements

Shear wall and diaphragm boundary elements shallbe provided to transfer the design tension and compres-sion forces. Diaphragm and shear wall sheathing shall notbe used to splice boundary elements. Diaphragm chordsand collectors shall be placed in, or in contact with, theplane of the diaphragm framing unless it can be demon-strated that the moments, shears, and deflections,considering eccentricities resulting from other configura-tions, can be tolerated without exceeding the framingcapacity and drift limits.

4.1.6 Toenails

In seismic categories D, E, and F, toenails shall not beused to transfer lateral forces greater than 150 pounds perlineal foot from diaphragms to shearwalls, drag struts toother elements, or from shear walls to other elements.



LATER

AL FO

RC

E-R

ES

ISTIN

G S

YS

TEM

S

4


4.2 Wood Diaphragms

Alternatively, for wood structural panel diaphragms,deflection is permitted to be calculated using a rationalanalysis where apparent shear stiffness accounts for panelshear deformation and non-linear nail slip in the sheath-ing to framing connection.

4.2.3 Shear Capacities

The nominal unit shear capacities for seismic designare provided in Column A of Tables 4.2A, B, and C andfor wind design in Column B of Tables 4.2A, B, and C.The ASD allowable unit shear capacity shall be deter-mined by dividing the nominal unit shear capacity by asafety factor of 2.0. No further increases shall be permit-ted. The LRFD factored unit resistance shall bedetermined by multiplying the nominal unit shear capac-ity by a resistance factor, φD, of 0.65.

4.2.4 Diaphragm Aspect Ratios

Size and shape of diaphragms shall be limited to theaspect ratios in Table 4.2.4.

Table 4.2.4 Maximum DiaphragmAspect Ratios(Horizontal or Sloped Diaphragms)

Diaphragm MaximumSheathing Type L/W RatioWood structural panel, unblocked 3:1Wood structural panel, blocked 4:1Single-layer straight lumber sheathing 2:1Single-layer diagonal lumber sheathing 3:1Double-layer diagonal lumber sheathing 4:1

4.2.5 Horizontal Distribution ofShear

Diaphragms shall be defined as rigid or flexible forthe purposes of distributing shear loads and designing fortorsional moments. When a diaphragm is defined as flex-ible, the diaphragm shear forces shall be distributed to thevertical resisting elements based on tributary area. Whena diaphragm is defined as rigid, the diaphragm shear forcesshall be distributed based on the relative lateral stiffnessesof the vertical resisting elements for the story below.

4.2.5.1 Torsional Irregularity: Structures with rigidwood diaphragms shall be considered as torsionally ir-

4.2.1 Application Requirements

Wood diaphragms are permitted to be used to resisthorizontal forces provided the deflection in the plane ofthe diaphragm, as determined by calculations, tests, oranalogies drawn therefrom, does not exceed the permis-sible deflection of attached load distributing or resistingelements. Connections and blocking shall extend into thediaphragm a sufficient distance to develop the force trans-ferred into the diaphragm.

4.2.2 Deflection

Permissible deflection shall be that deflection up towhich the diaphragm and any attached load distributingor resisting element will maintain its structural integrityunder design load conditions, such that the resisting ele-ment will continue to support design loads without dangerto occupants of the structure.

Calculations of diaphragm deflection shall accountfor bending and shear deflections, fastener deformation,chord splice slip, and other contributing sources of de-flection.

The midspan diaphragm deflection, δdia , is permittedto be calculated by use of the following equation:

( )35 0.25

8 1000 2c

diaa

xL L

EAW G W

∆ν νδ = + + ∑(4.2-1)

where:

E = Modulus of elasticity of diaphragm chords, psi

A = Area of chord cross-section, in.2

Ga

= Apparent diaphragm shear stiffness from nail


Column A, Table 4.2)

L = Diaphragm length, ft.

ν = Induced unit shear in diaphragm, lbs./ft.

W = Diaphragm width, ft.

x = Distance from chord splice to nearest support,

in.

∆c

= Diaphragm chord splice slip at the induced unit

shear in diaphragm, in.

δdia

= Maximum diaphragm deflection determined by





regular when the maximum story drift, computed includ-ing accidental torsion, at one end of the structure is morethan 1.2 times the average of the story drifts at the twoends of the structure. Where torsional irregularity exists,diaphragms shall meet the following requirements:

1. The diaphragm conforms to 4.2.7.1 - 4.2.7.3.2. The L/W ratio of the diaphragm is less than

1:1 for one-story structures or 1:1½ for struc-tures over one story in height.

Exception: Where calculations show that diap-hragm deflections can be tolerated, the length, L,shall be permitted to be increased to an L/W rationot greater than 1½:1 when sheathed in conform-ance with 4.2.7.1 or to 1:1 when sheathed inconformance with 4.2.7.2 or 4.2.7.3.

4.2.5.1.1 Open Front Structures: Open front struc-tures utilizing rigid wood diaphragms to distribute shearforces through torsion shall be permitted provided:

1. The diaphragm length, L, (normal to the openside) does not exceed 25 feet.

2. The L/W ratio (as shown in Figure 4.2.5.1)of the diaphragm is less than 1:1 for one-storystructures or 1:1½ for structures over one storyin height.

Exception: Where calculations show that diap-hragm deflections can be tolerated, the length, L,(normal to the open side) shall be permitted to beincreased to an L/W ratio not greater than 1½:1when sheathed in conformance with 4.2.7.1 or4.2.7.3 or to 1:1 when sheathed in conformancewith 4.2.7.2.

Figure 4.2.5.1 Open Front Building

Figure 4.2.5.2 Cantilevered Diaphragm

Shear Walls

WL

Force

Open Fronton Building

Plan View

Shear Walls

Force

CantileveredDiaphragm

L

W

c

Plan View

4.2.5.2 Cantilevered Diaphragms: Rigid wood dia-phragms shall be permitted to cantilever past the outermostsupporting shear wall (or other vertical resisting element)a distance, Lc, of not more than 25 feet or two thirds of thediaphragm width, W, whichever is smaller. Figure 4.2.5.2illustrates the dimensions of Lc and W for a cantilevereddiaphragm.

4.2.6 Construction Requirements

4.2.6.1 Framing Requirements: Diaphragm boundaryelements shall be provided to transmit the design tension,compression and shear forces. Diaphragm sheathing shallnot be used to splice boundary elements. Diaphragmchords and collectors shall be placed in, or in contact with,the plane of the diaphragm framing unless it can be dem-onstrated that the moments, shears, and deflections,considering eccentricities resulting from other configura-tions, can be tolerated without exceeding the framingcapacity and drift limits.

4.2.6.2 Sheathing: Diaphragms shall be sheathed withapproved materials. Details on sheathing types and thick-nesses for commonly used floor, roof and ceilingdiaphragm assemblies are provided in 4.2.7 and Tables4.2A, B, and C.

4.2.6.3 Fasteners: Sheathing shall be attached to fram-ing using approved fasteners and/or adhesives. Nails orother approved sheathing connectors shall be driven flushwith the surface of the sheathing. Details on type, size,and spacing of mechanical fasteners for typical floor, roof,and ceiling diaphragm assemblies are provided in 4.2.7and Tables 4.2A, B, and C.

4.2.7 Diaphragm Assemblies

4.2.7.1 Wood Structural Panel Diaphragms: Dia-phragms sheathed with wood structural panel sheathingshall be permitted to be used to resist seismic and windforces. Wood structural panel sheathing used for dia-phragms that are part of the lateral force-resisting systemshall be applied directly to the framing members.

Exception: Wood structural panel sheathing in adiaphragm is permitted to be fastened over solidlumber planking or laminated decking providedthe panel joints and lumber planking or laminated

Seismic C4 Draft.pmd 6/28/02, 5:12 AM14


LATER

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TEM

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4


decking joints do not coincide. In addition, adja-cent panel 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 intermedi-ate supports 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 fram-ing of more than 1-1/2 in. are spaced 3inches o.c. or less

4. 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 dia-phragms shall be constructed of minimum 1-inch thick

nominal 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 seis-mic and 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 di-agonally sheathed 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 lum-ber laid 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.




Tab

le 4

.2A

N

om

ina

l U

nit

Sh

ea

r V

alu

es

fo

r W

oo

d-F

ram

e D

iap

hra

gm

s

a.N

omin

al u

nit s

hear

val

ues

shal

l be

adju

sted

in a

ccor

danc

e w

ith 4

.2.3

to d

eter

-m

ine

ASD

allo

wab

le u

nit s

hear

cap

acity

and

LR

FD fa

ctor

ed u

nit r

esis

tanc

e. F

orge

nera

l con

stru

ctio

n re

quire

men

ts se

e 4.2

.6. F

or sp

ecifi

c req

uire

men

ts, s

ee 4

.2.7

.1fo

r woo

d st

ruct

ural

pan

el d

iaph

ragm

s.b.

For f

ram

ing

grad

es o

ther

than

Dou

glas

-Fir-

Larc

h or

Sou

ther

n Pi

ne, r

educ

ed n

omi-

nal u

nit s

hear

capa

citie

s sha

ll be

det

erm

ined

by

mul

tiply

ing

the t

abul

ated

nom

inal

unit

shea

r ca

paci

ty b

y th

e Sp

ecifi

c G

ravi

ty A

djus

tmen

t Fa

ctor

= [

1-(0

.5-G

)],

whe

re G

= S

peci

fic G

ravi

ty o

f the

fram

ing

lum

ber f

rom

the

ND

S. T

he S

peci

ficG

ravi

ty A

djus

tmen

t Fac

tor s

hall

not b

e gr

eate

r tha

n 1.

c.A

ppar

ent s

hear

stif

fnes

s va

lues

, G_a

, are

bas

ed o

n na

il sl

ip a

nd p

anel

stif

fnes

sva

lues

for d

iaph

ragm

s con

stru

cted

with

OSB

pan

els.

Whe

n pl

ywoo

d pa

nels

are

used

, dia

phra

gm d

efle

ctio

ns s

houl

d be

cal

cula

ted

in a

ccor

danc

e w

ith th

e A

SDW

ood

Stru

ctur

al P

anel

s Su

pple

men

t.

64

2.5

2

66

43

v_

sG

_a

v_

sG

_a

v_

sG

_a

v_

sG

_a

v_w

v_

wv

_w

v_

w

(plf

)(k

ips

/in

)(p

lf)

(kip

s/i

n)

(plf

)(k

ips

/in

)(p

lf)

(kip

s/i

n)

(plf

)(p

lf)

(plf

)(p

lf)

23

70

15

.05

00

8.5

75

01

2.0

84

02

0.0

52

07

00

10

50

11

75

34

20

12

.05

60

7.0

84

09

.59

50

17

.05

90

78

51

17

51

33

0

25

40

14

.07

20

9.0

10

60

13

.01

20

02

1.0

75

51

01

01

48

51

68

0

36

00

12

.08

00

7.5

12

00

10

.01

35

01

8.0

84

01

12

01

68

01

89

0

26

40

24

.08

50

15

.01

28

02

0.0

14

60

31

.08

95

11

90

17

90

20

45

37

20

20

.09

60

12

.01

44

01

6.0

16

40

26

.01

01

01

34

52

01

52

29

5

23

40

15

.04

50

9.0

67

01

3.0

76

02

1.0

47

56

30

94

01

06

5

33

80

12

.05

00

7.0

76

01

0.0

86

01

7.0

53

07

00

10

65

12

05

23

70

13

.05

00

7.0

75

01

0.0

84

01

8.0

52

07

00

10

50

11

75

34

20

10

.05

60

5.5

84

08

.59

50

14

.05

90

78

51

17

51

33

0

24

80

15

.06

40

9.5

96

01

3.0

10

90

21

.06

70

89

51

34

51

52

5

35

40

12

.07

20

7.5

10

80

11

.01

22

01

8.0

75

51

01

01

51

01

71

0

25

10

14

.06

80

8.5

10

10

12

.01

15

02

0.0

71

59

50

14

15

16

10

35

70

11

.07

60

7.0

11

40

10

.01

29

01

7.0

80

01

06

51

59

51

80

5

25

40

13

.07

20

7.5

10

60

11

.01

20

01

9.0

75

51

01

01

48

51

68

0

36

00

10

.08

00

6.0

12

00

9.0

13

50

15

.08

40

11

20

16

80

18

90

25

80

25

.07

70

15

.01

15

02

1.0

13

10

33

.08

10

10

80

16

10

18

35

36

50

21

.08

60

12

.01

30

01

7.0

14

70

28

.09

10

12

05

18

20

20

60

26

40

21

.08

50

13

.01

28

01

8.0

14

60

28

.08

95

11

90

17

90

20

45

37

20

17

.09

60

10

.01

44

01

4.0

16

40

24

.01

01

01

34

52

01

52

29

5

1

1/4

1

3/8

1

1/2

Min

imu

m

Fa

ste

ne

r

Pe

ne

tra

tio

n i

n

Fra

min

g

(in

ch

es

)

1

1/4

1

3/8

1

1/2

A

SE

ISM

IC

15

/32

7/1

6

15

/32

Sh

ea

thin

g a

nd

Sin

gle

-

Flo

orc

10

d

19

/32

8d

3/8

8d

3/8

Na

il S

pa

cin

g (

in.)

at

Oth

er

Pa

ne

l E

dg

es

(C

as

es

1,

2,

3,

& 4

)

66

B

Co

mm

on

Na

il S

ize

Sh

ea

thin

g G

rad

e4

3

Blo

ck

ed

Wo

od

Str

uc

tura

l P

an

el

Dia

ph

rag

ms

a,b

Na

il S

pa

cin

g (

in.)

at

Dia

ph

rag

m B

ou

nd

rie

s (

All

Ca

se

s),

at

Co

nti

nu

ou

s P

an

el

Ed

ge

s

Pa

rall

el

to L

oa

d (

Ca

se

s 3

& 4

), a

nd

at

All

Pa

ne

l E

dg

es

(C

as

es

5 &

6)

6

Na

il S

pa

cin

g (

in.)

at

Dia

ph

rag

m B

ou

nd

rie

s (

All

Ca

se

s),

at

Co

nti

nu

ou

s P

an

el

Ed

ge

s P

ara

lle

l to

Lo

ad

(C

as

es

3 &

4),

an

d a

t A

ll P

an

el

Ed

ge

s (

Ca

se

s 5

& 6

)

WIN

D

42

.52

Str

uctu

ral Ic

Na

il S

pa

cin

g (

in.)

at

Oth

er

Pa

ne

l E

dg

es

(Ca

se

s 1

, 2

, 3

, &

4)

6d

5/1

6

Min

imu

m

No

min

al

Pa

ne

l

Th

ick

ne

ss

(in

ch

es

)

Min

imu

m

No

min

al

Fra

min

g

Wid

th

(in

ch

es

)

15

/32

6d

5/1

6

3/8

10

d


LATER

AL FO

RC

E-R

ES

ISTIN

G S

YS

TEM

S

4


Tab

le 4

.2B

N

om

ina

l U

nit

Sh

ea

r V

alu

es

fo

r W

oo

d-F

ram

e D

iap

hra

gm

s

a.N

omin

al u

nit s

hear

val

ues s

hall

be a

djus

ted

in a

ccor

danc

e w

ith 4

.2.3

to d

eter

min

e ASD

allo

wab

le u

nit s

hear

cap

acity

and

LR

FD fa

ctor

ed u

nit r

esis

tanc

e. F

or g

ener

al c

onst

ruct

ion

requ

irem

ents

see

4.2.

6. F

orsp

ecifi

c re

quire

men

ts, s

ee 4

.2.7

.1 fo

r woo

d st

ruct

ural

pan

el d

iaph

ragm

s.b.

For f

ram

ing

grad

es o

ther

than

Dou

glas

-Fir-

Larc

h or

Sou

ther

n Pi

ne, r

educ

ed n

omin

al u

nit s

hear

cap

aciti

es sh

all b

e de

term

ined

by

mul

tiply

ing

the

tabu

late

d no

min

al u

nit s

hear

cap

acity

by

the

Spec

ific

Gra

vity

Adj

ustm

ent F

acto

r = [1

-(0.

5-G

)], w

here

G =

Spe

cific

Gra

vity

of t

he fr

amin

g lu

mbe

r fro

m th

e N

DS.

The

Spe

cific

Gra

vity

Adj

ustm

ent F

acto

r sha

ll no

t be

grea

ter t

han

1.c.

App

aren

t she

ar st

iffne

ss v

alue

s, G

_a, a

re b

ased

on

nail

slip

and

pan

el st

iffne

ss v

alue

s for

dia

phra

gms c

onst

ruct

ed w

ith O

SB p

anel

s. W

hen

plyw

ood

pane

ls a

re u

sed,

dia

phra

gm d

efle

ctio

ns sh

ould

be

calc

ulat

edin

acc

orda

nce

with

the

ASD

Woo

d St

ruct

ural

Pan

els

Supp

lem

ent.

v_

sG

_a

v_

sG

_a

v_

wv_

w

(plf)

(kip

s/in

)(p

lf)

(kip

s/in

)(p

lf)

(plf)

Ed

ge

Na

il S

pa

cin

g :

6 in

ch

es

Un

blo

cke

d W

oo

d S

tru

ctu

ral P

an

el D

iap

hra

gm

sa,b

Ed

ge

Na

il S

pa

cin

g:

6 in

ch

es

Co

mm

on

Na

il S

ize

B

WIN

D

Sh

ea

thin

g G

rad

e

A

SE

ISM

IC

Table

4.2

(continued)

Nom

inal U

nit S

hear

Valu

es for

Wood-F

ram

e D

iaphra

gm

s

Min

imu

m

No

min

al

Pa

ne

l

Th

ickn

ess

(in

ch

es)

Min

imu

m

No

min

al

Fra

min

g

Wid

th

Ca

se

s 2

,3,4

,5,6

Ca

se

1C

ase

1C

ase

s 2

,3,4

,5,6

Min

imu

m

Fa

ste

ne

r

Pe

ne

tra

tio

n in

Fra

min

g

(in

ch

es)

v_

sG

_a

v_

sG

_a

v_

wv_

w

(plf)

(kip

s/in

)(p

lf)

(kip

s/in

)(p

lf)

(plf)

23

30

6.5

25

04

.54

60

35

0

33

70

7.0

28

04

.55

20

39

0

24

80

8.5

36

06

.06

70

50

5

35

30

7.5

40

05

.07

40

56

0

25

70

14

.04

30

9.5

80

06

00

36

40

12

.04

80

8.0

89

56

70

23

00

9.0

22

06

.04

20

31

0

33

40

7.0

25

05

.04

75

35

0

23

30

7.5

25

05

.04

60

35

0

33

70

6.0

28

04

.05

20

39

0

24

30

9.0

32

06

.06

00

45

0

34

80

7.5

36

05

.06

70

50

5

24

60

8.5

34

05

.56

45

47

5

35

10

7.0

38

04

.57

15

53

0

24

80

7.5

36

05

.06

70

50

5

35

30

6.5

40

04

.07

40

56

0

25

10

15

.03

80

10

.07

15

53

0

35

80

12

.04

30

8.0

81

06

00

25

70

13

.04

30

8.5

80

06

00

36

40

10

.04

80

7.0

89

56

70

Ed

ge

Na

il S

pa

cin

g :

6 in

ch

es

Un

blo

cke

d W

oo

d S

tru

ctu

ral P

an

el D

iap

hra

gm

sa

,b

Ed

ge

Na

il S

pa

cin

g:

6 in

ch

es

Co

mm

on

Na

il S

ize

B

WIN

D

1

1/2

Sh

ea

thin

g G

rad

e

1

1/4

1

3/8

1

1/2

1

1/4

1

3/8

7/1

6

15

/32

15

/32

19

/32

3/8

Sh

ea

thin

g a

nd

Sin

gle

-

Flo

orc

6d

8d

Str

uctu

ral Ic

6d

10

d

8d

10

d

A

SE

ISM

IC

5/1

6

3/8

5/1

6

3/8

15

/32

Ta

ble

4.2

(co

ntin

ue

d)

No

min

al U

nit S

he

ar

Va

lue

s f

or

Wo

od

-Fra

me

Dia

ph

rag

ms

Min

imu

m

No

min

al

Pa

ne

l

Th

ickn

ess

(in

ch

es)

Min

imu

m

No

min

al

Fra

min

g

Wid

th

Ca

se

s 2

,3,4

,5,6

Ca

se

1C

ase

1C

ase

s 2

,3,4

,5,6

Min

imu

m

Fa

ste

ne

r

Pe

ne

tra

tio

n in

Fra

min

g

(in

ch

es)




Tab

le 4

.2C

N

om

ina

l U

nit

Sh

ea

r V

alu

es

fo

r W

oo

d-F

ram

e D

iap

hra

gm

s

a.N

omin

al u

nit

shea

r va

lues

sha

ll be

adj

uste

d in

acc

orda

nce

with

4.2

.3 t

o de

term

ine

ASD

allo

wab

le u

nit

shea

r ca

paci

ty a

nd L

RFD

fac

tore

d un

it re

sist

ance

. Fo

r ge

nera

l co

nstr

uctio

n re

quir

e-m

ents

see

4.2

.6.

For

spec

ific

req

uire

men

ts, s

ee 4

.2.7

.2 f

or d

iaph

ragm

s di

agon

ally

she

athe

d w

ith a

sin

gle

laye

r of

lum

ber,

see

4.2.

7.3

for

diap

hrag

ms

diag

onal

ly s

heat

hed

with

a d

oubl

e la

yer

of l

umbe

r, an

d se

e 4.

2.7.

4 fo

r di

aphr

agm

s ho

rizo

ntal

ly s

heat

hed

with

a s

ingl

e la

yer

of l

umbe

r.

BW

IND

v_s

G_a

v_w

(plf

)(k

ips/

in)

(plf

)1x

61x

82x

62x

81x

61x

82x

62x

81x

61x

82x

62x

8

Lu

mb

er D

iap

hra

gm

sa

AS

EIS

MIC

600

6.0

100

1.5

Sh

eath

ing

Mat

eria

lS

hea

thin

g

No

min

al

Dim

ensi

on

s

Typ

e, S

ize

and

Nu

mb

er o

f N

ails

per

Bo

ard

Nai

ling

at

Inte

rmed

iate

an

d E

nd

Bea

rin

g S

up

po

rts

Nai

ling

at

Bo

un

dar

y M

emb

ers

(Nai

ls/b

oar

d/s

up

po

rt)

(Nai

ls/b

oar

d/e

nd

)

140

840

1200

9.5

1680

3-16

d co

mm

on n

ails

(4-

16d

box

nails

)

Hor

izon

tal L

umbe

r S

heat

hin g

2-8d

com

mon

nai

ls (

3-8d

box

nai

ls)

3-8d

com

mon

nai

ls (

5-8d

box

nai

ls)

3-8d

com

mon

nai

ls (

4-8d

box

nai

ls)

4-8d

com

mon

nai

ls (

6-8d

box

nai

ls)

2-16

d co

mm

on n

ails

(3-

16d

box

nails

)3-

16d

com

mon

nai

ls (

5-16

d bo

x na

ils)

4-16

d co

mm

on n

ails

(6-

16d

box

nails

)

3-16

d co

mm

on n

ails

(4-

16d

box

nails

)4-

16d

com

mon

nai

ls (

6-16

d bo

x na

ils)

Dia

gona

l Lu

mbe

r S

heat

hin g

2-8d

com

mon

nai

ls (

3-8d

box

nai

ls)

3-8d

com

mon

nai

ls (

5-8d

box

nai

ls)

3-8d

com

mon

nai

ls (

4-8d

box

nai

ls)

4-8d

com

mon

nai

ls (

6-8d

box

nai

ls)

2-16

d co

mm

on n

ails

(3-

16d

box

nails

)3-

16d

com

mon

nai

ls (

5-16

d bo

x na

ils)

4-16

d co

mm

on n

ails

(6-

16d

box

nails

)

Dou

ble

Dia

gona

l Lu

mbe

r S

heat

hin g

2-8d

com

mon

nai

ls (

3-8d

box

nai

ls)

3-8d

com

mon

nai

ls (

5-8d

box

nai

ls)

3-8d

com

mon

nai

ls (

4-8d

box

nai

ls)

4-8d

com

mon

nai

ls (

6-8d

box

nai

ls)

2-16

d co

mm

on n

ails

(3-

16d

box

nails

)3-

16d

com

mon

nai

ls (

5-16

d bo

x na

ils)

3-16

d co

mm

on n

ails

(4-

16d

box

nails

)



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4.3 Wood Shear Walls

4.3.1 Application Requirements

Wood shear walls are permitted to resist horizontalforces provided the deflection of the shear wall, as deter-mined by calculations, tests, or analogies drawn therefrom,does not exceed the permissible deflection.

4.3.2 Deflection

Permissible deflection shall be that deflection up towhich the shear wall and any attached distributing or re-sisting element will maintain its structural integrity underdesign load conditions and continue to support design loadswithout danger to occupants of the structure.

Calculations of shear wall deflection shall account forbending and shear deflections, fastener deformation, an-chorage slip, and other contributing sources of deflection.

The shear wall deflection, δsw, is permitted to be cal-culated by use of the following equation:

38

1000a

sw

a

hh h

EAb G b

∆ν νδ = + + (4.3-1)

where:

b = Shear wall length, ft.

∆a

= Total vertical elongation of wall anchorage

system (including fastener slip, device

elongation, rod elongation, etc.), at the induced

unit shear in the shear wall, in.

E = Modulus of elasticity of end posts, psi

A = Area of end post cross-section, in.2

Ga

= Apparent shear wall shear stiffness from nail

slip and panel shear deformation, (from Column

A, Table 4.3), kips/in.

h = Shear wall height, ft.


δsw

= Maximum shear wall deflection determined by


Alternatively, for wood structural panel shear walls,deflection is permitted to be calculated using a rationalanalysis where apparent shear stiffness accounts for panelshear deformation and non-linear nail slip in the sheath-ing to framing connection.

4.3.2.1 Deflection of Perforated Shear Walls: The de-flection of a perforated shear wall shall be calculated inaccordance with Section 4.3.2, where ν is equal to νmax inEquation 4.3-1 and b is taken as the sum of the perforatedshear wall segments ∑Li.

4.3.3 Shear Capacities

The ASD allowable unit shear capacity shall be de-termined by dividing the nominal unit shear capacity by asafety factor of 2.0. No further increases shall be permit-ted. The LRFD factored unit resistance shall be determinedby multiplying the nominal unit shear capacity by a resis-tance factor, φD, of 0.65.

4.3.3.1 Tabulated Nominal Unit Shear Capacities:Tabulated nominal unit shear capacities for seismic designare provided in Column A of Tables 4.3A, B, and C and forwind design in Column B of Tables 4.3A, B, and C.

4.3.3.2 Summing Shear Capacities: For shear wallssheathed with the same construction and materials on op-posite sides of the same wall, the combined nominal unitshear capacity, νsc or νwc, shall be permitted to be taken astwice the nominal unit shear capacity for an equivalentshear wall sheathed on one side.

For seismic design of shear walls sheathed with thesame construction and materials on opposite sides of ashear wall, the shear wall deflection shall be calculatedusing the combined apparent shear wall shear stiffness,Gac and the combined nominal unit shear capacity, νsc,shall be calculated using the following equations:

1 2ac a aG G G= + (4.3-2)

V K Gsc ac= min (4.3-3)

where:

Gac

= Combined apparent shear wall shear stiffness

of two-sided shear wall, kips/in.

Ga1


kips/in. (from Column A, Table 4.3)

Ga2


kips/in. (from Column A, Table 4.3)

Kmin

= Minimum ratio of νs1

/Ga1

or νs2

/Ga2

νs1


(from Column A, Table 4.3)




νs2


(from Column A, Table 4.3)

νsc


sided shear wall for seismic design, lbs./ft.

Nominal unit shear capacities for shear walls sheathedwith dissimilar materials on the same side of the wall arenot cumulative. For shear walls sheathed with dissimilarmaterials on opposite sides, the combined nominal unitshear capacity, νsc or νwc, shall be either two times thesmaller nominal unit shear capacity or the larger nominalunit shear capacity, whichever is greater.

Exception: For wind design, the combined nomi-nal unit shear capacity νwc, of shear walls sheathedwith a combination of wood structural panels andgypsum wall-board on opposite sides shall equalthe sum of the sheathing capacities of each sideseparately.

4.3.3.3 Summing Shear Wall Lines: The nominalshear capacity for shear walls in a line utilizing shear wallssheathed with the same construction and materials, shallbe permitted to be combined.

4.3.3.4 Shear Capacity of Perforated Shear Walls: Thenominal shear capacity of a perforated shear wall shall betaken as the nominal unit shear capacity multiplied by thesum of the shear wall segment lengths, ∑Li, and the ap-propriate shear capacity adjustment factor, Co, from Table4.3.3.4.

1 The maximum opening height shall be taken as the maximum opening clear height in a perforated shear wall. Where areas above and belowan opening remain unsheathed, the height of the opening shall be defined as the height of the wall.

2 The sum of the lengths of the perforated shear wall segments divided by the total length of the perforated shear wall.

o

WALL HEIGHT, h

MAXIMUM OPENING HEIGHT 1

h/3 h/2 2h/3 5h/6 h

8' Wall 2'-8" 4'-0" 5'-4" 6'-8" 8'-0"10' Wall 3'-4" 5'-0" 6'-8" 8'-4" 10'-0"

Percent Full-Height Sheathing 2 Effective Shear Capacity Ratio

10%20%30%40%50%60%70%80%90%

100%

1.001.001.001.001.001.001.001.001.001.00

0.690.710.740.770.800.830.870.910.951.00

0.530.560.590.630.670.710.770.830.911.00

0.430.450.490.530.570.630.690.770.871.00

0.360.380.420.450.500.560.630.710.831.00

Table 4.3.3.4 Shear Capacity Adjustment Factor, Co



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4.3.4 Shear Wall Aspect Ratios

Size and shape of shear walls shall be limited to theaspect ratios in Table 4.3.4.

Table 4.3.4 Maximum Shear WallAspect Ratios

Shear Wall MaximumSheathing Type h/bs RatioWood structural panels, all edges nailed 3½:11

Particleboard, all edges nailed 2:1Diagonal Sheathing, conventional 2:1Gypsum wallboard2 2:1Portland Cement Plaster2 2:1Fiberboard 1½:1

1 For design to resist seismic forces, the shear wall aspect ratio shall notexceed 2:1 unless the nominal unit shear capacity is multiplied by 2bs/h. Inno case shall the aspect ratio exceed 3½:1.

2 Walls having aspect ratios exceeding 1½:1 shall be blocked.

4.3.4.1 Aspect Ratio of Perforated Shear Wall Seg-ments: The aspect ratio limitations of 4.3.4 shall apply toperforated shear wall segments within a perforated shearwall. For design to resist seismic forces, the nominal shearcapacity of the perforated shear wall shall be multipliedby 2bs/h when the aspect ratio of any perforated shearwall segment included in the sum of shear wall segmentlengths, ∑Li, is greater than 2:1, but does not exceed 3½:1.Portions of walls with aspect ratios in excess of 3½:1 shallnot be counted in the sum of shear wall segments.

4.3.5 Shear Walls With Openings

The provisions of this section shall apply to the de-sign of shear walls with openings. Where framing andconnections around the openings are designed for forcetransfer around the openings the provisions of 4.3.5.1 shallapply. Where framing and connections around the open-ing are not designed for force transfer around the openingsthe provisions of 4.3.5.2 shall apply.

4.3.5.1 Force Transfer Around Openings: Whereshear walls with openings are designed for force transferaround the openings, the aspect ratio limitations of 4.3.4shall apply to the overall shear wall including openingsand to each wall pier at the sides of an opening. The heightof a wall pier shall be defined as the clear height of thepier at the side of an opening. The length of a wall piershall be defined as the sheathed length of the pier. Designfor force transfer shall be based on a rational analysis.The length of a wall pier shall not be less than 2 feet.

4.3.5.2 Perforated Shear Walls: Where wood struc-tural panel shear walls with openings are not designed forforce transfer around the opening, they shall be designedas perforated shear walls. The following limitations shallapply:

a. A perforated shear wall segment shall be lo-cated at each end of a perforated shear wall.Openings shall be permitted to occur beyondthe ends of the perforated shear wall, how-ever the length of such openings shall not beincluded in the length of the perforated shearwall.

b. The nominal unit shear capacity shall not ex-ceed 2,000 plf.

c. Where out of plane offsets occur, portions ofthe wall on each side of the offset shall beconsidered as separate perforated shear walls.

d. Collectors for shear transfer shall be providedthrough the full length of the perforated shearwall.

e. A perforated shear wall shall have uniformtop of wall and bottom of wall elevations.Perforated shear walls not having uniformelevations shall be designed by other meth-ods.

f. Perforated shear wall height, h, shall not ex-ceed 20 feet.

4.3.6 Construction Requirements

4.3.6.1 Framing Requirements: All framing used forshear wall construction shall be 2x nominal or larger mem-bers. Shear wall boundary elements, such as end posts,shall be provided to transmit the design tension and com-pression forces. Shear wall sheathing shall not be used tosplice boundary elements. End posts (studs or columns)shall be framed to provide full end bearing.

a. Tension and Compression Chords: Tensionforce, T, and a compression force, C, result-ing from shear wall overturning forces at eachstory level shall be calculated in accordancewith the following:

T C h= = ν (4.3-4)

where:

C = Compression chord force, lbs.

h = Shear wall height, ft.

T = Tension chord force, lbs.





Each end of each perforated shear wall shall be de-signed for a tension force, T, and a compression force, C.Each end of each perforated shear wall segment shall bedesigned for a compression force, C, in each segment.For perforated shear walls, the values for T and C result-ing from shear wall overturning forces at each story levelshall be calculated in accordance with the following:

T CVh

C Lo i

= =∑ (4.3-5)

where:

Co

= Shear capacity adjustment factor from Table

4.3.3.4

V = Induced shear force in perforated shear wall, lbs.

∑Li

= Sum of perforated shear wall segment lengths,

ft.

4.3.6.2 Sheathing: Shear walls shall be sheathed withapproved materials. Sheathing nails or other approvedsheathing connectors shall be driven flush with the sur-face of the sheathing. Details on sheathing types andthicknesses for commonly used shear wall assemblies areprovided in 4.3.7 and Tables 4.3A, B, and C.

4.3.6.3 Fasteners: Sheathing shall be attached to fram-ing using approved fasteners. Details on type, size, andspacing of mechanical fasteners in commonly used shearwall assemblies are provided in 4.3.7 and Tables 4.3A, B,and C.

a. Adhesives: Adhesive attachment of shear wallsheathing is not permitted as a substitute formechanical fasteners. Approved adhesive at-tachment systems shall be permitted in SeismicDesign Categories A and B where R = 1.5 andΩ0 = 2.5 unless other values are approved. InSeismic Design Categories C-F, adhesive at-tachment of shear wall sheathing is notpermitted.

4.3.6.4 Shear Wall Anchorage and Load Path: De-sign of shear wall anchorage and load path shall conformto the requirements of this section, or shall be calculatedusing principles of mechanics.

a. Anchorage for In-plane Shear: Connectionsshall be provided to transfer the induced unitshear force, ν, into and out of each shear wall.(1) In-plane Shear Anchorage for Perforated

Shear Walls: The maximum induced unitshear force, νmax, transmitted into the topof a perforated shear wall, out of the baseof the perforated shear wall at full heightsheathing, and into collectors (drag struts)

connecting shear wall segments, shall becalculated in accordance with the follow-ing:

νmax =∑V

C Lo i(4.3-6)

b. Uplift Anchorage at Shear Wall Ends: Wherethe dead load stabilizing moment is not suffi-cient to prevent uplift due to overturningmoments on the wall (from 4.3.6.1a), an an-choring device shall be provided at the endof each shear wall.(1) Uplift Anchorage for Perforated Shear

Walls: In addition to the requirements of4.3.6.4.b, perforated shear wall bottomplates at full height sheathing shall be an-chored for a uniform uplift force, t, equalto the unit shear force, ν, determined inSection 4.3.6.4.a.(1) or calculated by ra-tional analysis.

c. Anchor Bolts: Foundation anchor bolts shallhave a steel plate washer under each nut notless than 2½" x 2½" x ¼". The plate washershall extend to within ½" of the edge of thebottom plate on the sheathed side.

d. Load Path: A load path to the foundation shallbe provided for uplift, shear, and compres-sion forces. Elements resisting shear wallforces contributed by multiple stories shallbe designed for the sum of forces contributedby each story.

4.3.7 Shear Wall Systems

4.3.7.1 Wood Structural Panel Shear Walls: Shearwalls sheathed with wood structural panel sheathing shallbe permitted to be used to resist seismic and wind forces.The size and spacing of fasteners at shear wall bound-aries, panel edges, and intermediate supports shall be asprovided in Table 4.3A. The shear wall shall be constructedas follows:

a. Panels installed either horizontally or verti-cally with panel joints occurring overcommon studs or blocking. Panels not lessthan 4 ft. x 8 ft. except that a single panelwith a minimum dimension of 1 foot is per-mitted if it is fully blocked and nailed.

b. Nails spaced not less than 3/8 inch from edgesand ends of panels, studs, blocking, and topand bottom plates. Maximum nail spacing



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of 6 inches along intermediate framing mem-bers for 3/8-inch and 7/16-inch panelsinstalled on studs spaced 24 inches o.c. Maxi-mum nail spacing along intermediate framingof 12 inches for other conditions.

c. 2x or wider framing at adjoining panel edgesexcept that 3x or wider framing and staggerednailing are required where:(1) nails are spaced 2 inches o.c., or(2) 10d nails having penetration into framing

of more than 1-1/2 inches are spaced 3inches o.c., or less, or

(3) nominal unit shear capacity exceeds 700plf in seismic Design Category D, E, or F.

d. Maximum stud spacing of 24 inches.e. Wood structural panels shall conform to the

requirements for its type in DOC PS1 or PS2.4.3.7.2 Particleboard Shear Walls: Shear walls

sheathed with particleboard sheathing shall be permittedto be used to resist wind forces and seismic forces in Seis-mic Design Categories A, B, and C. The size and spacingof fasteners at shear wall boundaries, panel edges, andintermediate supports shall be as provided in Table 4.3A.The shear wall shall be constructed as follows:

a. Panels installed either horizontally or verti-cally with panel joints occurring overcommon studs or blocking. Panels not lessthan 4 feet x 8 feet except that a single panelwith a minimum dimension of 1 foot is per-mitted if it is fully blocked and nailed.

b. Nails spaced not less than 3/8 inch from edgesand ends of panels, studs, blocking, and topand bottom plates. Maximum nail spacingof 6 inches along intermediate framing mem-bers for 3/8-inch panels installed on studsspaced 24 inches o.c. Maximum nail spac-ing along intermediate framing of 12 inchesfor other conditions.

c. 2x or wider framing at adjoining panel edges.d. Maximum stud spacing of 24 inches.e. Particleboard shall conform to ANSI A208.1.4.3.7.3 Fiberboard Shear Walls: Shear walls sheathed

with fiberboard sheathing shall be permitted to be used toresist wind forces and seismic forces in Seismic DesignCategories A, B, and C. The size and spacing of fastenersat shear wall boundaries, panel edges, and intermediatesupports shall be as provided in Table 4.3A. The shearwall shall be constructed as follows:

a. 4 feet x 8 feet fiberboard sheathing shall beapplied vertically (long dimension parallel to

studs) with panel joints occurring over com-mon studs or blocking.

b. Nails spaced not less than 3/8 inch from edgesand ends of panels, studs, blocking, and topand bottom plates. Maximum nail spacing 6inches along intermediate framing members.

c. 2x or wider framing at adjoining panel edges.d. Maximum stud spacing of 16 inches.e. Minimum length of galvanized roofing nails

is 1½" for ½ inch thick sheathing and 1¾"for 25/32 inch thick sheathing.

f. Fiberboard sheathing shall conform to eitherAHA 194.1 or ASTM C208.

4.3.7.4 Gypsum Wallboard, Gypsum Veneer Base,Water-Resistant Backing Board, Gypsum Sheathing, Gyp-sum Lath and Plaster, or Portland Cement Plaster ShearWalls: Shear walls sheathed with gypsum wallboard, gyp-sum veneer base, water-resistant backing board, gypsumsheathing, gypsum lath and plaster, or portland cementplaster shall be permitted to be used to resist wind forcesand seismic forces in Seismic Design Categories A-D. Endjoints of adjacent courses of gypsum wallboard or sheath-ing shall not occur over the same stud. The size and spacingof fasteners at shear wall boundaries, panel edges, andintermediate supports shall be as provided in Table 4.3B.Nails shall be spaced not less than 3/8 inch from edgesand ends of panels, studs, blocking, and top and bottomplates. Wood framing shall be 2x or wider.

a. Gypsum Wallboard, Gypsum Veneer Base,Water-Resistant Backing Board: Gypsumwallboard, gypsum veneer base, or water-resistant backing board shall be appliedparallel or perpendicular to studs. Gypsumwallboard shall conform to ASTM C36 andshall be installed in accordance with ASTMC 840. Gypsum veneer base shall conformto ASTM C 588 and shall be installed in ac-cordance with ASTM C 844. Water-resistantbacking board shall conform to ASTM C630and shall be installed in accordance withASTM C 840.

b. Gypsum Sheathing: Four-foot-wide pieces ofgypsum sheathing shall be applied parallel orperpendicular to studs. Two-foot-wide piecesof gypsum sheathing shall be applied perpen-dicular to the studs. Gypsum sheathing shallconform to ASTM C79 and shall be installedin accordance with ASTM C 1280.

c. Gypsum Lath and Plaster: Gypsum lath shallbe applied perpendicular to the studs. Gyp-sum lath shall conform to ASTM C37 and




shall be installed in accordance with ASTMC 841. Gypsum plaster shall conform to therequirements of ASTM C 28.

d. Expanded Metal or Woven Wire Lath andPortland Cement: Expanded metal or wovenwire lath and portland cement shall conformto ASTM C847, ASTM 1032, and ASTM C150 and shall be installed in accordance withASTM C 926 and ASTM C 1063. Metal lathand lath attachments shall be of corrosion-resistant material.

4.3.7.5 Shear Walls Diagonally Sheathed with Single-Layer of Lumber: Single diagonally sheathed lumber shearwalls are permitted to be used to resist wind forces andseismic forces in Seismic Design Catergories A, B, C, andD. Single diagonally sheathed lumber shear walls shall beconstructed of minimum 1-inch thick nominal sheathingboards laid at an angle of approximately 45° to the sup-ports. End joints in adjacent boards shall be separated byat least one stud space and there shall be at least two boardsbetween joints on the same support. Nailing of diagonallysheathed lumber shear walls shall be in accordance withTable 4.3C.

4.3.7.6 Shear Walls Diagonally Sheathed with Double-Layer of Lumber: Double diagonally sheathed lumbershear walls are permitted to be used to resist wind forcesand seismic forces in Seismic Design Categories A, B, C,and D. Double diagonally sheathed lumber shear wallsshall be constructed of two layers of 1-inch thick nominaldiagonal sheathing boards laid perpendicular to each other

on the same face of the supporting members. Nailing ofdiagonally sheathed lumber shear walls shall be in accor-dance with Table 4.3C.

4.3.7.7 Shear Walls Horizontally Sheathed withSingle-Layer of Lumber: Horizontally sheathed lumbershear walls are permitted to be used to resist wind forcesand seismic forces in Seismic Design Categories A, B,and C. Horizontally sheathed lumber shear walls shall beconstructed of minimum 1-inch thick nominal sheathingboards applied perpendicular to the supports. End jointsin adjacent boards shall be separated by at least one studspace and there shall be at least two boards between jointson the same support. Nailing of horizontally sheathedlumber shear walls shall be in accordance with Table 4.3C.

4.3.7.8 Shear Walls Sheathed with Vertical Board Sid-ing: Vertical board siding shear walls are permitted to beused to resist wind forces and seismic forces in SeismicDesign Categories A, B, and C. Vertical board siding shearwalls shall be constructed of minimum 1-inch thick nomi-nal sheathing boards applied directly to studs and blocking.Nailing of vertical board siding shear walls shall be inaccordance with Table 4.3C.



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Tab

le 4

.3A

N

om

ina

l U

nit

Sh

ea

r V

alu

es

fo

r W

oo

d-F

ram

e S

he

ar

Wa

lls

a,c

a.N

omin

al u

nit s

hear

val

ues

shal

l be

adju

sted

in a

ccor

danc

e w

ith 4

.3.3

to d

eter

min

e ASD

allo

wab

le u

nit s

hear

cap

acity

and

LR

FD fa

ctor

ed u

nit r

esis

tanc

e. F

or g

ener

al c

onst

ruct

ion

requ

irem

ents

see

4.3

.6.

For

spec

ific

requ

irem

ents

, see

4.3

.7.1

for w

ood

stru

ctur

al p

anel

she

ar w

alls

, 4.3

.7.2

for p

artic

lebo

ard

shea

r wal

ls, a

nd 4

.3.7

.3 fo

r fib

erbo

ard

shea

r wal

ls.

b.Sh

ears

are

per

mitt

ed to

be

incr

ease

d to

val

ues

show

n fo

r 15/

32 in

ch s

heat

hing

with

sam

e na

iling

pro

vide

d (a

) stu

ds a

re s

pace

d a

max

imum

of 1

6 in

ches

o.c

., or

(b) i

f pan

els

are

appl

ied

with

long

dim

ensi

onac

ross

stu

ds.

c.Fo

r fra

min

g gr

ades

oth

er th

an D

ougl

as-F

ir-La

rch

or S

outh

ern

Pine

, red

uced

nom

inal

uni

t she

ar c

apac

ities

sha

ll be

det

erm

ined

by

mul

tiply

ing

the

tabu

late

d no

min

al u

nit s

hear

cap

acity

by

the

Spec

ific

Gra

vity

Adj

ustm

ent F

acto

r = [1

-(0.

5-G

)], w

here

G =

Spe

cific

Gra

vity

of t

he fr

amin

g lu

mbe

r fro

m th

e N

DS.

The

Spe

cific

Gra

vity

Adj

ustm

ent F

acto

r sha

ll no

t be

grea

ter t

han

1.d.

App

aren

t she

ar st

iffne

ss v

alue

s, G

_a, a

re b

ased

on

nail

slip

and

pan

el st

iffne

ss v

alue

s for

shea

r wal

ls c

onst

ruct

ed w

ith O

SB p

anel

s. W

hen

plyw

ood

pane

ls a

re u

sed,

shea

r wal

l def

lect

ions

shou

ld b

e ca

lcul

ated

in a

ccor

danc

e w

ith th

e AS

D W

ood

Stru

ctur

al P

anel

s Su

pple

men

t.

Woo

d-ba

sed

She

athi

ng

64

32

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)

(kip

s/in)

(plf)

(kip

s/in)

(plf)

(kip

s/in)

(plf)

(kip

s/in)

(plf)

(plf)

(plf)

(plf)

Nail

(com

mon o

r

galv

aniz

ed b

ox)

5/1

61-1

/46d

400

13.0

600

18.0

780

23.0

1020

35.0

560

840

1090

1430

3/8

b460

19.0

720

24.0

920

30.0

1220

43.0

645

1010

1290

1710

7/1

6b

510

16.0

790

21.0

1010

27.0

1340

40.0

715

1105

1415

1875

15/3

2560

14.0

860

18.0

1100

24.0

1460

37.0

785

1205

1540

2045

15/3

21-1

/210d

680

22.0

1020

29.0

1330

36.0

1740

50.0

950

1430

1860

2435

5/1

6360

13.0

540

18.0

700

24.0

900

37.0

505

755

980

1260

3/8

400

11.0

600

15.0

780

20.0

1020

32.0

560

840

1090

1430

3/8

b440

17.0

640

25.0

820

31.0

1060

45.0

615

895

1150

1485

7/1

6b

480

15.0

700

22.0

900

28.0

1170

42.0

670

980

1260

1640

15/3

2520

13.0

760

19.0

980

25.0

1280

39.0

730

1065

1370

1790

15/3

2620

22.0

920

30.0

1200

37.0

1540

52.0

870

1290

1680

2155

19/3

2680

19.0

1020

26.0

1330

33.0

1740

48.0

950

1430

1860

2435

Nail

(galv

aniz

ed c

asin

g)

5/1

61-1

/46d

280

13.0

420

16.0

550

17.0

720

21.0

392

588

770

1008

3/8

1-1

/28d

320

16.0

480

18.0

620

20.0

820

22.0

448

672

868

1148

Nail

(com

mon o

r

galv

aniz

ed b

ox)

3/8

6d

240

15.0

360

17.0

460

19.0

600

22.0

335

505

645

840

3/8

8d

260

18.0

380

20.0

480

21.0

630

23.0

365

530

670

880

1/2

280

18.0

420

20.0

540

22.0

700

24.0

390

590

755

980

1/2

10d

370

21.0

550

23.0

720

24.0

920

25.0

520

770

1010

1290

5/8

400

21.0

610

23.0

790

24.0

1040

26.0

560

855

1105

1455

1/2

8d

co

mm

on

or

11

ga

. g

alv

.

roo

fin

g n

ail

(0.1

20

" x 1

1/2

"

lon

g x

7/1

6"

he

ad

)

340

4.0

460

5.0

520

5.5

475

645

730

25/3

28

d c

om

mo

n o

r 1

1 g

a.

ga

lv.

roo

fin

g n

ail

(0.1

20

" x 1

3/4

"

lon

g x

7/1

6"

he

ad

)

360

4.0

480

5.0

540

5.5

505

670

755

Wood S

tructu

ral

Panels

- S

heath

ing

d

Ply

wood S

idin

g

Nail

(com

mon o

r

galv

aniz

ed r

oofing)

1-1

/4

Wood S

tructu

ral

Panels

- S

tructu

ral Id

Fib

erb

oard

Sheath

ing -

Str

uctu

ral

Panel E

dge F

aste

ner

Spacin

g (

inches)

AS

EIS

MIC

64

32

Part

icle

board

Sheath

ing -

(M-S

"E

xte

rior

Glu

e"

and M

-2 "

Exte

rior

Glu

e")

WIN

D

F

aste

ner

Type &

Siz

e

Min

imum

Nom

inal

Panel

Thic

kness

(inches)

Sheath

ing M

ate

rial

B

Panel E

dge F

aste

ner

Spacin

g (

inches)

Min

imum

Faste

ner

Penetr

ation in

Fra

min

g

(inches)

1-3

/8

1-3

/8

1-1

/2

8d

10d

6d

8d




Tab

le 4

.3B

N

om

ina

l U

nit

Sh

ea

r V

alu

es

fo

r W

oo

d-F

ram

e S

he

ar

Wa

lls

a

a.N

omin

al u

nit s

hear

val

ues

shal

l be

adju

sted

in a

ccor

danc

e w

ith 4

.3.3

to d

eter

min

e A

SD a

llow

able

uni

t she

ar c

apac

ity a

nd L

RFD

fac

tore

d un

it re

sist

ance

. Fo

r ge

nera

l con

stru

ctio

n re

quir

emen

ts s

ee 4

.3.6

. Fo

rsp

ecif

ic r

equi

rem

ents

, se

e 4.

3.7.

4.b.

Type

S o

r W

dry

wal

l scr

ews

shal

l con

form

to r

equi

rem

ents

of A

STM

C 1

002.

c.W

here

tw

o nu

mbe

rs a

re g

iven

for

max

imum

fas

tene

r ed

ge s

paci

ng, t

he f

irst

num

ber

deno

tes

fast

ener

spa

cing

at

the

edge

s an

d th

e se

cond

num

ber

deno

tes

fast

ener

spa

cing

in

the

fiel

d.

BW

IND

v_s

G_a

v_w

(plf

)(k

ips/

in)

(plf

)7"

24"

unbl

ocke

d15

04.

015

04"

24"

unbl

ocke

d22

06.

522

07"

16"

unbl

ocke

d20

05.

520

04"

16"

unbl

ocke

d25

07.

025

07"

16"

bloc

ked

250

6.5

250

4"16

"bl

ocke

d30

09.

030

08/

12"

16"

unbl

ocke

d12

03.

012

04/

16"

16"

bloc

ked

320

8.5

320

4/12

"24

"bl

ocke

d31

09.

531

08/

12"

16"

bloc

ked

140

4.0

140

6/12

"16

"bl

ocke

d18

05.

018

07"

24"

unbl

ocke

d23

06.

023

04"

24"

unbl

ocke

d29

08.

029

07"

16"

bloc

ked

290

7.5

290

4"16

"bl

ocke

d35

010

.035

08/

12"

16"

unbl

ocke

d14

04.

014

08/

12"

16"

bloc

ked

180

4.0

180

5/8"

Bas

e: 9

"

(Tw

o-P

ly)

Fac

e: 7

"

4"24

"bl

ocke

d35

010

.035

07"

16"

unbl

ocke

d20

05.

020

04/

7"

5.0

17.0

150

Gyp

sum

wal

lboa

rd,

gyps

um v

enee

r ba

se, o

r w

ater

-res

ista

nt g

ypsu

m

back

ing

boar

d

AS

EIS

MIC

500

1/2"

x 2

' x 8

'

500

150

16"

5/8"

Mat

eria

l T

hic

knes

s

No.

6 T

ype

S o

r W

dry

wal

l scr

ews

1-1/

4" lo

ng

Bas

e pl

y--6

d co

oler

(0.

092"

x 1

-7/8

" lo

ng, 1

/4"

head

) or

wal

lboa

rd n

ail (

0.09

15"

x

1-7/

8"

long

, 19/

64"

head

) or

0.1

20"n

ail x

1-3

/4"

long

, min

3/8

" he

adF

ace

ply-

-8d

cool

er (

0.11

3" x

2-3

8" lo

ng, 0

.281

" he

ad)

or

wal

lboa

rd n

ail (

0.11

3" x

2-3

/8"

long

, 3/8

" he

ad)

or 0

.120

" na

il x

2-3/

8" lo

ng, m

in 3

/8"

head

16"

0.12

0" n

ail x

1½

” lo

ng, 7

/16"

hea

d

Sh

eath

ing

Mat

eria

l

360

12.0

400

400

13.0

Exp

ande

d m

etal

or

wov

en

wire

lath

and

por

tland

ce

men

t pla

ster

16"

7/8"

6"

No.

6 T

ype

S o

r W

dry

wal

l scr

ews

1-1/

4" lo

ng

No.

6 T

ype

S o

r W

dry

wal

l scr

ews

1-1/

4" lo

ng

4"

Fas

ten

er T

ype

& S

izeb

6d c

oole

r (0

.092

" x

1-7/

8" lo

ng, 1

/4"

head

) or

wal

lboa

rd n

ail (

0.09

15"

x 1-

7/8"

long

, 19/

64"

head

) or

0.1

20"

nail

x 1-

3/4"

long

, min

3/8

" he

ad

No.

6 T

ype

S o

r W

dry

wal

l scr

ews

1-1/

4" lo

ng

Max

. Fas

ten

er

Ed

ge

Sp

acin

g c

0.1

20"

nail

x 1

3/4"

long

, 7/

16"

head

, dia

mon

d-po

int,

galv

aniz

ed

1/2"

Max

. Stu

d

Sp

acin

g

Gyp

sum

lath

, pla

in o

r pe

rfor

ated

3/8"

lath

and

1/

2" p

last

er

5/8"

x 4

'6d

gal

vani

zed

cool

er (

0.09

2" x

1-7

/8"

long

, 1/4

" he

ad)

or w

allb

oard

nai

l (0.

0915

" x

1-7/

8"

long

, 19/

64"

head

) or

0.1

20"

nail

x 1-

3/4"

long

, min

3/8

" he

ad

0.09

2"x

1-1/

8" lo

ng, 1

9/64

" he

ad, g

ypsu

m w

allb

oard

blu

ed n

ail o

r 0.

120"

nai

l x1

1/4"

long

, m

in 3

/8"

head

1/2"

x 4

'G

ypsu

m s

heat

hing

5d c

oole

r (0

.086

" x

1-5/

8" lo

ng, 1

5/64

" he

ad)

or w

allb

oard

nai

l (0.

086"

x 1

-5/8

" lo

ng, 9

/32"

he

ad)

or 0

.120

" na

il x

1-1/

2" lo

ng, m

in 3

/8"

head

200

360

unbl

ocke

d

unbl

ocke

d20

06.

5

bloc

ked

unbl

ocke

d

5"16

"

bloc

ked

16"

Gyp

sum

and

Cem

ent

Pla

ster



LATER

AL FO

RC

E-R

ES

ISTIN

G S

YS

TEM

S

4


Tab

le 4

.3C

N

om

ina

l U

nit

Sh

ea

r V

alu

es

fo

r W

oo

d-F

ram

e S

he

ar

Wa

lls

a

a.N

omin

al u

nit s

hear

val

ues

shal

l be

adju

sted

in a

ccor

danc

e w

ith 4

.3.3

to d

eter

min

e A

SD a

llow

able

uni

t she

ar c

apac

ity a

nd L

RFD

fac

tore

d un

it re

sist

ance

. Fo

r ge

nera

l con

stru

ctio

n re

quir

emen

ts s

ee 4

.3.6

. Fo

rsp

ecif

ic r

equi

rem

ents

, see

4.3

.7.5

- 4

.3.7

.8.

Lum

ber

She

ar W

alls

BW

IND

v_s

G_a

v_w

(plf

)(k

ips/

in)

(plf

)1x

6 &

sm

alle

r1x

8 &

larg

er1x

6 &

sm

alle

r1x

8 &

larg

er1x

6 &

sm

alle

r1x

8 &

larg

er1x

6 &

sm

alle

r1x

8 &

larg

er

Dia

gona

l Lu

mbe

r S

heat

hing

Hor

izon

tal L

umbe

r S

heat

hing

Sh

eath

ing

N

om

inal

D

imen

sio

ns

Ver

tical

Lum

ber

Sid

ing

3-8d

com

mon

nai

ls (

5-8d

box

nai

ls)

Nai

ling

at

Inte

rmed

iate

Stu

ds

Nai

ling

at

Sh

ear

Wal

l Bo

un

dar

y M

emb

ers

(nai

ls/b

oar

d/s

up

po

rt)

(nai

ls/b

oar

d/e

nd

)

Dou

ble

Dia

gona

l Lum

ber

She

athi

ng

Sh

eath

ing

Mat

eria

l

A

3-8d

com

mon

nai

ls (

4-8d

box

nai

ls)

4-8d

com

mon

nai

ls (

6-8d

box

nai

ls)

Typ

e, S

ize

and

Nu

mb

er o

f N

ails

per

Bo

ard

2-8d

com

mon

nai

ls (

3-8d

box

nai

ls)

SE

ISM

IC

1200

10.0

140

100

1.5

840

6.0

3-8d

com

mon

nai

ls (

5-8d

box

nai

ls)

2-8d

com

mon

nai

ls (

3-8d

box

nai

ls)

3-8d

com

mon

nai

ls (

5-8d

box

nai

ls)

600

3-8d

com

mon

nai

ls (

4-8d

box

nai

ls)

4-8d

com

mon

nai

ls (

6-8d

box

nai

ls)

2-8d

com

mon

nai

ls (

3-8d

box

nai

ls)

3-8d

com

mon

nai

ls (

5-8d

box

nai

ls)

3-8d

com

mon

nai

ls (

4-8d

box

nai

ls)

4-8d

com

mon

nai

ls (

6-8d

box

nai

ls)

1680

3-8d

com

mon

nai

ls (

4-8d

box

nai

ls)

4-8d

com

mon

nai

ls (

6-8d

box

nai

ls)

125

901.

02-

8d c

omm

on n

ails

(3-

8d b

ox n

ails

)



LATERAL FORCE-RESISTING SYSTEMS28



29

REFERENCES


5



30 REFERENCES

References

13. ASTM C840-01, Standard Specification for Appli-cation and Finishing of Gypsum Board, ASTM, WestConshocken, PA, 2001.

14. ASTM C841-99, Standard Specification for Instal-lation of Interior Lathing and Furring, ASTM, WestConshocken, PA, 1999.

15. ASTM C844-99, Standard Specification for Appli-cation of Gypsum Base to Receive Gypsum VeneerPlaster, ASTM, West Conshocken, PA, 1999.

16. ASTM C847-95(2000), Standard Specification forMetal Lath, ASTM, West Conshocken, PA, 2000.

17. ASTM C926-98a, Standard Specification for Appli-cation of Portland Cement Based Plaster, ASTM,West Conshocken, PA, 1998.

18. ASTM C1032-96, Standard Specification for WovenWire Plaster Base, ASTM, West Conshocken, PA,1996.

19. ASTM C1063-99, Standard Specification for Instal-lation of Lathing and Furring to Receive Interior andExterior Portland Cement-Based Plaster, ASTM,West Conshocken, PA, 1999.

20. ASTM C1280-99, Standard Specification for Appli-cation of Gypsum Sheathing, ASTM, WestConshocken, PA, 1999.

21. PS1-95 Construction and Industrial Plywood, UnitedStates Department of Commerce, National Instituteof Standards and Technology, Gaithersburg, MD,1995.

22. PS2-92 Performance Standard for Wood-BasedStructural Use Panels, United States Department ofCommerce, National Institute of Standards and Tech-nology, Gaithersburg, MD, 1992.

1. AHA A194.1-85, Cellulosic Fiber Board, AmericanHardboard Association, Palatine, IL, 1985.

2. ANSI/AHA A135.4-95, Basic Hardboard, AmericanHardboard Association, Palatine, IL, 1995.

3. ANSI/AHA A135.5-95, Prefinished Hardboard Pan-eling, American Hardboard Association, Palatine, IL,1995.

4. ANSI A208.1-93, Particleboard, ANSI, New York,NY, 1993

5. ASTM C28/C28M-01, Standard Specification forGypsum Plasters, ASTM, West Conshocken, PA,2001.

6. ASTM C36/C36M-01, Standard Specification forGypsum Wallboard, ASTM, West Conshocken, PA,2001.

7. ASTM C37/C37M-01, Standard Specification forGypsum Lath, ASTM, West Conshocken, PA, 2001.

8. ASTM C79/C79M-01, Standard Specification forTreated Core and Non-treated Core Gypsum Sheath-ing Board, ASTM, West Conshocken, PA, 2001.

9. ASTM C150-00, Standard Specification for PortlandCement, ASTM, West Conshocken, PA, 2000.

10. ASTM C208-95(2001), Standard Specification forCellulosic Fiber Insulation Board, ASTM, WestConshocken, PA, 2001.

11. ASTM C588/C588M-01, Standard Specification forGypsum Base for Veneer Plasters, ASTM, WestConshocken, PA, 2001.

12. ASTM C630/C630M-01, Standard Specification forWater-Resistant Gypsum Backing Board, ASTM,West Conshocken, PA, 2001.


Documents

ASD-LRFD for Wood Construction (Provisions for Wind and Seismic)