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AF&PA/ASCE 16-95

American Forest & Paper AssociationAmerican Society of Civil Engineers

Standard for Load and ResistanceFactor Design (LRFD) for

Engineered Wood Construction

Published by the American Society of Civil Engineers345 East 47th Street

New York, NY 10017-2398



ABSTRACT:

This first Standard for Load and Resistance Factor Design (LRFD) for EngineeredWood Construction was prepared as a joint activity between the American Society ofCivil Engineers and the American Forest & Paper Association (AF & PA) to providedesign provisions based on reliability theory. This standard was the result of deliber-ations of a team of structural engineers and wood material scientists with wide expe-rience and high professional standing. The team included professionals from privatepractice, industry, government, and universities. By reflecting this current state ofknowledge, the LRFD Standard offers uniform practice in the design of engineeredwood structures. It specifically covers such topics as: 1) Design requirements; 2) ten-sion members; 3) compression members and bearing; 4) flexura! members; 5} mem-bers with combined bending and axial loads; 6) mechanical connections; 7) struc-tural-use panels; 8) shear walls and diaphragms; and 9) serviceability. In addition,the Appendices address issues such as: 1) Resistance of spaced columns; 2) gluedlaminated timber; 3) ponding; 4} qualification of fasteners and connectors; 5) resis-tance of shear plates; and 6} design of panel-based assemblies. Finally, a Glossaryand a Commentary that provides additional background information are included.

Library of Congress Cataloging-in-Publication Data

American Society of Civil Engineers.Standard for load and resistance factor design (LRFD) for engineered wood construction:AF&PA/ASCE-16-95 /American Society of Civil Engineers.

p. cm.ISBN 0-7844-0041-51. Building, Wooden—Standards—United States. 2. Load and resistance factordesign—Standards—United States. I. Title.TA666.A52 1996 95-51202624.1'84—dc20 CiP

Photocopies. Authorization to photocopy material for internal or personal use undercircumstances not falling within the fair use provisions of the Copyright Act is grant-ed by ASCE to libraries and other users registered with the Copyright ClearanceCenter (CCC) Transactional Reporting Service, provided that the base fee of $4.00per article plus $.50 per page is paid directly to CCC, 222 Rosewood Drive, Danvers,MA 01923. The identification for ASCE Books is 0-7844-0041-5/96 $4.00 + $.50 perpage. Requests for special permission or bulk copying should be addressed toPermissions & Copyright Dept., ASCE.

Copyright © 1996 by the American Society of Civil Engineers,All Rights Reserved.Library of Congress Catalog Card No: 95-51202ISBN 0-7844-0041-5Manufactured in the United States of America.



PREFACEThe design of wood structures has previously

been governed by the general design provisionsand recommended practice of the National DesignSpecification® for Wood Construction (NDS®).This specification was first adopted in 1944 andhas been updated periodically to reflect new knowl-edge under the auspices of the American Forest &Paper Association (AF&PA) and its predecessor or-ganizations, the National Lumber ManufacturersAssociation and the National Forest Products Asso-ciation. In recognition of a new generation of stand-ards based on reliability theory, this first Load andResistance Factor Design (LRFD) Standard for En-gineered Wood Construction was prepared as ajoint activity between AF&PA and ASCE to pro-vide alternate design provisions reflecting the cur-rent state of knowledge. The LRFD Standard wasdeveloped to provide uniform practice in the de-sign of engineered wood structures.

Design criteria provide recommended practicefor most applications but may not cover infre-quently encountered designs for which additionaljudgment in applying data or recommendationsmust be exercised. It is intended that the LRFDStandard be used in conjunction with competentengineering design, accurate fabrication, and ade-quate supervision of construction. Particular atten-tion is directed to the designer's responsibility tomake adjustments for particular end use conditions.

The Appendices to this Standard are consid-ered an integral part of the LRFD Standard. ACommentary has been prepared to provide addi-

tional background information. Users desiringfurther details leading to LRFD Standard provi-sions are requested to consult the Commentaryand cited references.

Development of the LRFD Standard was a resultof deliberations of a team of structural engineers andwood material scientists with wide experience andhigh professional standing. The team included pro-fessionals from private practice, industry, govern-ment, and universities. Review and trial use by prac-ticing consulting engineers preceded publication.

The information contained herein is not in-tended as a representation or warranty, on the partof AF&PA or ASCE or any other person involvedin its development, that this Standard is suitablefor any general or particular use.

While every effort has been made to insure theaccuracy of the data and information containedherein, neither AF&PA nor ASCE assumes respon-sibility for errors or omissions, nor for plans, de-signs, or construction prepared from this LRFDStandard.

Those using this LRFD Standard assume allliability arising from its use. The design of engi-neered structures is within the scope of exper-tise of licensed engineers, architects, or other li-censed professionals for applications to aparticular structure.

This Standard is not intended to preclude theuse of any other materials, assemblies, or designsthat can satisfactorily demonstrate adequate per-formance.

in



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STANDARDSIn April 1980, the Board of Direction approved

ASCE Rules for Standards Committees to governthe writing and maintenance of standards devel-oped by the Society. All such standards are devel-oped by a consensus standards process managedby the Management Goup F (MGF), Codes andStandards. The consensus process includes ballot-ing by the balanced standards committee made upof Society members and non-members, ballotingby the membership of ASCE as a whole and ballot-ing by the public. All standards are updated or reaf-firmed by the same process at intervals not exceed-ing five years.

The following standards have been issued:

ANSI/ASCE 1-82 N-725 Guidelines for Designand Analysis of Nuclear Safety Related EarthStructures

ANSI/ASCE 2-91 Measurement of Oxygen Trans-fer in Clean Water

ANSI/ASCE 3-91 Standard for the Structural De-sign of Composite Slabs and ANSI/ASCE 9-91 Standard Practice for the Construction andInspection of Composite Slabs

ASCE 4-86 Seismic Analysis of Safety-RelatedNuclear Structures

Building Code Requirements for Masonry Struc-

tures (ACI530-95/ASCE5-95/TMS402-95)and Specifications for Masonry Structures(ACI530.1-95/ASCE6-95/TMS602-95)

Specifications for Masonry Structures (ACI530-95/ASCE6-95/TMS602-95)

ANSI/ASCE 7-93 Minimum Design Loads forBuilding and Other Structures

ANSI/ASCE 8-90 Standard Specification for theDesign of Cold-Formed Stainless Steel Struc-tural Members

ANSI/ASCE 9-91 listed with ASCE 3-91ANSI/ASCE 10-90 Design of Latticed Steel Trans-

mission StructuresANSI/ASCE 11-90 Guideline for Structural Condi-

tion Assessment of Existing BuildingsANSI/ASCE 12-91 Guideline for the Design of Ur-

ban Subsurface DrainageASCE 13-93 Standard Guidelines for Installation

of Urban Subsurface DrainageASCE 14-93 Standard Guidelines for Operation

and Maintenance of Urban SubsurfaceDrainage

ASCE 15-93 Standard Practice for Direct Designof Buried Precast Concrete Pipe Using Stand-ard Installations (SIDD)

ASCE 16-95 Standard for Load and ResistanceFactor Design (LRFD) of Engineered WoodConstruction

v



ACKNOWLEDGMENTSThis standard was developed in two phases.

The initial draft was funded by the wood prod-ucts industry and was developed by EngineeringData Management, Inc., under the direction ofDr. James R. Goodman, RE. The second phaseof development was under the auspices of theASCE Standards Committee for Design of Engi-neered Wood Construction, chaired by Mr.Thomas G. Williamson, RE. Both phases werecoordinated by the American Forest & Paper As-sociation.

In addition to the participants listed below, theleadership of a Wood Industry Technical Commit-tee, chaired by Dr. Kevin C.K. Cheung, WesternWood Products Association, and the Wood Indus-try Management Committee, chaired by Jeffrey M.Van Cott, and the vision of the funding organiza-tions is acknowledged.

Phase 1 funding organizationsAlpine Engineered ProductsAlpine StructuresAmerican Forest & Paper AssociationAmerican Institute of Timber ConstructionAPA—The Engineered Wood AssociationBoise CascadeCalifornia Lumber Inspection ServiceCalifornia Redwood Association/Redwood

Inspection ServiceCanadian Wood CouncilFabricated Wood ComponentsFibreboard TechnologyGeorgia-PacificJager IndustriesLouisiana PacificMacMillan BloedelMcCausey LumberMitekMSR Lumber Producers CouncilNational Timber Piling CouncilNordelNortheast Lumber Manufacturers AssociationPacific Lumber Inspection BureauSoutheast Lumber Manufacturers AssociationSouthern Forest Products AssociationSouthern Pine Inspection BureauStandard StructuresSuperior Wood ProductsTecton LaminatesTimber Products InspectionTrus Joist MacMillan

Truss Plate InstituteTruswalUnit StructuresWest Coast Lumber Inspection BureauWestern Wood Preservers InstituteWestern Wood Products AssociationWeyerhaeuserWillamette Industries

Phase 2 Committee MembersAlbert H. AlexanianDonald E. BreyerJames R. BrownLinda S. BrownR. Michael Caldwell, Vice ChairKevin C. CheungKelly E. CobeenMarvin E. CriswellThomas R CunninghamNancy H. DevineSusan DowtyBruce R. EllingwoodKenneth J. FridleyCharles B. GoehringAllan H. GoldJames R. GoodmanJames S. GrahamDavid S. Gromala, SecretaryKirk H. GrundahlDominique R JanssensStuart L. LewisJohn D. LowoodCatherine M. MarxThomas McLainJoseph F. MurphyMichael O'HalloranMichael P. O'ReardonMarcia Paton-MalloryClarkson W PinkhamRobert M. PowellChandrasekhar PutchaDon T PyleJulie RuthDouglas L. SarkkinenDonald J. SharpBradley E. ShelleyJohn H. Showalter, Jr.Judith J. StalnakerNader TomasbiMichael H. TricheThomas G. Williamson, Chair

vn



Contents PAGE

Preface

Acknowledgments

Table Of Contents

Notation

1 General Provisions1 1 Scope

1 1 1 Units1 2 Applicable Documents1 3 Loads and Load Combinations

1 3 1 Nominal loads1 3 2 Load combinations1 3 3 Other loads1 3 4 Counteracting loads

1 4 Design Basis1 4 1 Limit states design1 4 2 Structural analysis

1 4 2 1 Modulus of elasticity1.4.2.2 End restraints1 4 2 3 Long-term loading

1 4 3 Strength limit states1.4.3.1 Force due to factored loads1 4 3 2 Design resistance

144 Serviceability limit states145 Existing structures

2 Design Requirements2 1 Scope2 2 Gross And Net Areas

2 2 1 Gross area2.2.2 Net area

2 3 Stability2 4 Lateral Support2 5 Reference Conditions2 6 Adjusted Resistance and Adjusted Strength

2 6 1 General2 6 2 Adjustment factors for end-use2 6 3 Adjustment factors for member configuration2.6.4 Additional adjustments for structural lumber and glued laminated timber2.6.5 Additional adjustments for structural panels2 6 6 Additional adjustments for timber poles and piles2 6 7 Additional adjustments for structural connections

3 Tension Members3 1 General

3 1 1 Scope3 1 2 Member design

iii

vii

ix

xvii

11112222222233333344

4444444455555777

7777

ix



LRFD FOR ENGINEERED WOOD CONSTRUCTION

3 1 3 Special considerations3 2 Tension Resistance Parallel to Grain

3 2 1 Tension resistance3 2 2 Special considerations for unsymmetrical net areas

3 3 Tension Resistance Perpendicular to Grain34 Resistance of Built-up and Composite Members

3 4 1 Built-up members with components of similar materials3 4 2 Composite members with components of dissimilar materials

4 Compression Members And Bearing4 1 General

4 1 1 Scope4 1 2 Member design

4.2 Slenderness and Effective Length Considerations4.2.1 Effective column length4 2 2 Column slenderness ratio

4 3 Resistance of Solid Columns Concentrically Loaded in Compression4 3 1 Design material values and design factors4.3.2 Resistance of prismatic columns4 3 3 Resistance of notched or bored prismatic columns

4.33.1 Notch in critical location4.3.3.2 Notch in noncritical location

4 3 4 Resistance of tapered columns4.34.1 Tapered circular members4.3.4.2 Tapered rectangular columns

4,4 Resistance of Spaced, Built-up, and Composite Columns4.4.1 Spaced columns4.4.2 Built-up columns4.4.3 Composite columns

4.5 Resistance in Bearing4.5.1 Resistance in end bearing4.5.2 Resistance in side bearing4.5.3 Bearing at an angle to grain

4.6 Radial Compression in Curved Members

5 Flexural Members, Bending, And Shear5.1 General

5.1.1 Scope5.1.2 Member design5.1.3 Design span5.1.4 Notching of flexural members5.1.5 Member orientation and support conditions5.L6 Partial composite action of parallel member assemblies5.1.7 Moment resistance of square and circular prismatic members5.1.8 Moment resistance of box beams and I-beams5.1.9 Moment resistance of nonprismatic members5.1.10 Tapering of members5.1.11 Stress interaction at a cut face of a member5.1.12 Moment resistance of composite members5.1.13 Moment resistance of built-up members

5.2 Conditions of Lateral Support5.2.1 General

5.2.1.1 Consideration of lateral support conditions5.2.1.2 General requirements for lateral bracing

77777888

888888899999999

10101010101010111111

11111112121212121213131313131313131313

x



5.3

5.4

5.55.6

5.7

LRFD FOR ENGINEERED WOOD

5.2.1.3 Effective laterally unsupported length5.2.2 Moment resistance of laterally supported beams5.2.3 Moment resistance of members without full lateral support

5.2.3.1 Strength and stiffness5.2.3.2 Prismatic beams5.2.3.3 Nonrectangular members5.2.3.4 Wood I-joists

Moment Resistance of Assemblies5.3.1 Scope5.3.2 Adjustment factors for uniformly-loaded assemblies5.3.3 Composite action factor5.3.4 Load-sharing factor

Resistance of Members in Shear5.4.1 Calculation of design shear force5.4.2 Flexural shear resistance5.4.3 Shear resistance in the vicinity of notches5.4.4 Shear resistance in the vicinity of connections

Resistance of Members in TorsionCurved or Pitched/Tapered Curved Glued Laminated Beams

5.6.1 Adjustment of flexural resistance for curvature5.6.2 Radial tension and compression in curved members

5.6.2.1 Curved members of constant cross section5.6.2.2 Pitched and tapered glued laminated beams

Ponding

6 Members With Combined Bending And Axial Loads6.1

6.26.3

6.46.56.6

General6.1.1 Scope6.1.2 Member Design

Resistance in Combined Bending and Axial TensionMember Resistance in Biaxial Bending and in Combined Bending and Axial

Compression6.3.1 Beams, columns, and frame members6.3.2 Truss members

Columns Loaded on Side BracketsArchesTrusses

6.6.1 Sheathed truss compression chords

7 Mechanical Connections7.1

7.2

7.3

General7.1.1 Scope7.1.2 Connection Design7.1.3 Adjustment factor issues for connections7.1.4 Time effect factor for connections

Material Property Basis7.2.1 Fasteners, connectors, and connecting elements7.2.2 Specific gravity7.2.3 Dowel bearing strength

Connection configuration basis7.3.1 Simple connections7.3.2 Bearing7.3.3 Member stress at connection7.3.4 Mixed fastener connections

CONSTRUCTION

141515151515161616161616161617171718181818181818

1919191919

19192121212121

222222222222222223232323232323

xi




7.3.5 Placement of fasteners7.3.6 Multiple fasteners

7.4 Nails, Spikes, and Wood Screws7.4.1 General

7.4.1.1 Scope7.4.1.2 Fastener properties and dimensions7.4.1.3 Installation

7.4.2 Spacing of fasteners7.4.3 Resistance to lateral forces

7.4.3.1 Reference lateral resistance: single shear7.4.3.2 Reference lateral resistance: double shear7.4.3.3 Adjusted lateral resistance

7.4.4 Resistance to Axial Forces7.4.4.1 General provisions7.4.4.2 Fastener tensile resistance7.4.4.3 Reference Shank withdrawal resistance7.4.4.4 Adjusted Shank withdrawal Resistance

7.4.5 Combined axial and lateral forces7.5 Bolts, Lag Screws, Drift Pins, and Dowels

7.5.1 General7.5.1.1 Scope7.5.1.2 Fastener properties and dimensions

7.5.2 Installation7.5.2.1 Lead holes7.5.2.2 Washers

7.5.3 Spacing of fasteners7.5.4 Resistance to lateral forces

7.5.4.1 Reference lateral resistance7.5.4.2 Adjusted lateral resistance

7.5.5 Resistance to axial forces7.5.5.1 General7.5.5.2 Fastener tensile resistance7.5.5.3 Reference shank withdrawal resistance7.5.5.4 Adjusted shank withdrawal resistance7.5.5.5 Bearing under washers

7.5.6 Resistance to combined axial and lateral forces7.6 Shear Plates and Split Rings

7.6.1 General7.6.1.1 Scope7.6.1.2 Connector unit7.6.1.3 Connector properties and installation

7.6.2 Spacing of connectors7.6.3 Resistance to lateral forces

7.6.3.1 Reference lateral resistance in side grain7.6.3.2 Adjusted lateral resistance in side grain 7.6.3.3 Reference strength in end grain

8 Structural-Use Panels8.1 Scope8.2 Design Requirements

8.2.1 Reference conditions8.2.2 Specification of structural-use panels

8.3 Reference Resistance8.3.1 Panel stiffness and factored reference resistance

xii

23242525252525262626272728282828282828282828292929293030313232323232323232323233333333333336

36363636363636



LRFD FOR ENGINEERED

8.3.2 Reference strength and elastic properties8.4 Design Section Properties

8.4.1 Design thickness8.4.2 Design section properties

8.5 Design8.5,1 Applicable procedures8.5.2 Flatwise bending8.5.3 Tension in the plane of the panel8.5.4 Compression in the plane of the panel8.5.5 Panel shear

9 Shear Walls And Diaphragms9.1 General

9.1.1 Scope9.2 Shear Wall and Diaphragm Design

9.2.1 Design principles9.2.1.19.2.1.2

9.3 Required Resistance9.4 Reference Resistance

9.4.1 In-plane shear resistance9.4.1.1 Adjusted in-plane shear resistance

9.4.2 Boundary element resistance9.4.3 Shear transfer at shear wall and diaphragm boundaries

9.5 Other Design Considerations

10 Serviceability Considerations10.1 General Considerations10.2 Material and Member Stiffness

Appendix Al Resistance Of Spaced ColumnsAl.l Geometry and Geometry LimitsA 1.2 Spaced Column Fixity ConditionsA1.3 Resistance of Spaced ColumnsA 1.4 Requirements for Connectors in End Blocks

Appendix A2 Glued Laminated Timber (Glulam)A2.1 GeneralA2.2 Pitched and Tapered Curved Beams

A2.2.1 Moment resistance limited by radial stressA2.2.2 Moment resistance limited by bending stressA2.2.3 Deflection of pitched and tapered curved beamsA2.2.4 Radial reinforcementA2.2.5 Adjustment factorsA2.2.6 Stress interaction factor

A2.3 Glued Laminated Timber ArchesA2.3.1 Types of archesA2.3.2 Three-hinged archesA23.3 Two-hinged archesA2.3.4 Axial compressive resistanceA2.3.5 Radial stresses in archesA2.3.6 Nominal moment resistanceA2.3.7 Interaction of moment and axial forces in archesA2.3.8 Deflection of arches

Appendix A3 Ponding

WOOD CONSTRUCTION

36363636363636373737

3737373737373737383838383838

383838

3939394040

404041414242424242434343434343434344

44

xiii




A3.1 ScopeA3.2 One-Way Roof Systems

A3.2.1 Minimum slope to drainA3 .2.2 Increased Moment Caused by Ponding

A3.3 Two-Way Roof Systems

Appendix A4 Qualification Of Fasteners And ConnectorsA4.1 GeneralA4.2 Nails and SpikesA4.3 Wood ScrewsA4.4 Bolts, Lag Screws, Drift Pins, and DowelsA4.5 Split RingsA4.6 Shear PlatesA4.7 Metal Connector Plates

Appendix A5 Resistance Of Shear Plates Or Split Rings In End GrainA5.1 Definitions and NotationsA5.2 Design BasisA5.3 Connectors Installed in Square-Cut or Sloping SurfacesA5.4 Spacings

Appendix A6 Design Of Panel-Based AssembliesA6.1 ScopeA6.2 ComponentsA6.3 FabricationA6.4 End JointsA6.5 Design ProcedureA6.6 Deflection LimitationsA6.7 I-BeamsA6.8 Stressed-Skin PanelsA6.9 Sandwich PanelsA6.10 Curved Panels

Glossary

CommentaryCommentary is numbered according to Chapter/Section numbering.

Index

4445454545

4646464646464647

4747474747

4949494949494949494949

51

57

121

xiv



FOREWORDThe material presented in this publication has

been prepared in accordance with recognized engi-neering principles. This Standard and Commentaryshould not be used without first securing compe-tent advice with respect to their suitability for anygiven application. The publication of the materialcontained herein is not intended as a representation

or warranty on the part of the American Society ofCivil Engineers, or of any other person namedherein, that this information is suitable for any gen-eral or particular use or promises freedom from in-fringement of any patent or patents. Anyone mak-ing use of this information assumes all liabilityfrom such use.

xv



Notation

Gross areaNet area, net bearing areaMinimum spacing permitted for shear plates and split rings, parallel and perpendicular tograin, respectivelyRequired spacing of shear plates and split rings to achieve reference connection resistance,parallel and perpendicular to grain, respectivelyMoment magnification factor for loads that result in no appreciable sidesway (strong andweak axes, respectively)Moment magnification factor for loads that result in sidesway (strong and weak axes, respec-tively)Composite action factorSize factorGrade/construction factor for structural panelsShear stress factorStress interaction factorBeam stability factorWet service factorColumn stability factorBuckling stiffness factor for dimension lumberVolume effect factor for structural glued laminated timberBearing area factorBending coefficient dependent on moment gradientCurvature factor for structural glued laminated timberCritical section factor for round timber pilesPenetration depth factor for connectionsDiaphragm factorEnd-grain factor for connectionsForm factorFlat-use factorGroup action factor for connectionsMoment shape factor for biaxial bending (general, strong, and weak axes, respectively)Preservative treatment factorLoad-sharing factorFire-retardant treatment factorSingle pile factorMetal side plate factor for 4 in. shear plate connectionsTemperature factorToe-nail factor for nailed connectionsUntreated factor for round timber pilesWidth factor for structural panelsGeometry factor for connectionsDiameterDead loadReference and adjusted diaphragm shear resistance per unit lengthDiaphragm shear force per unit length due to factored loadsMinimum and maximum diameters in round tapered membersEarthquake loadReference and adjusted mean modulus of elasticity

xvii

AAn

Amin, Bmin

Aopt, Bopt

Bbx, Bby

Bsx, Bsy

CECFCGCHCiCLCMCPCTCvCbCbCc

CcsCdCdiCegCf

Cfu

CgCm, Cmx, Cmy

Cpt

Cr

Crt

Csp

CstCtCtn

Cu

Cw

CADDD,D'DuDi,D2EE,E'




Reference and adjusted fifth percentile modulus of elasticityAxial stiffnessFlexural stiffnessReference and adjusted bending strengthBending strength for strong (x-x) axis bending multiplied by all applicable adjustment fac-tors except Cfu, Cv, and CLReference and adjusted compression strength parallel to grainCompression strength parallel to grain multiplied by all applicable adjustment factors exceptCPReference and adjusted compression strength perpendicular to grainDowel bearing strengthDowel bearing strength of main and side members, respectivelyDowel bearing strength parallel, perpendicular^ and at an angle to the grain, respectivelyReference and adjusted bearing strength parallel to grainAdjusted radial strength (general, compression, and tension, respectively)Reference and adjusted rolling shear strength for structural panelsReference and adjusted tensile strength parallel to grainAdjusted torsional shear strengthReference and adjusted shear strength parallel to grain (horizontal shear)Reference and adjusted through-thickness shear strength for structural panelsBending yield strength of fastenerSpecific gravityReference and adjusted shear modulusReference and adjusted shear modulus for structural panelsMoment of inertiaTorsional constant for a sectionMoisture content coefficient for sawn lumber truss compression chordsTruss compression chord coefficient for sawn lumberEffective length factor for compression membersDesign span of bending member or compression memberLive load caused by storage, occupancy, or impactRoof live loadReference and adjusted moment resistanceSmaller and larger end moment in a beam or segmentFactored moment from loads that result in no appreciable sidesway (strong and weak axes,respectively)Elastic lateral buckling momentFactored moment, including magnification for second-order effects (strong and weak axes,respectively)Adjusted moment resistance computed with CL = 1.0Factored moment from loads that result in sidesway (strong and weak axes, respectively)Reference and adjusted torsion resistanceTorsion due to factored loadsMoment due to factored loads (general, strong and weak axes, respectively)Adjusted moment resistance (strong and weak axes, respectively)Moment resistance for strong (x-x) axis bending multiplied by all applicable adjustment fac-tors except Cfu, Cv, and CLReference and adjusted compression resistance parallel to grainAdjusted member axial parallel to grain resistance of a zero length column (i.e., the limit ob-tained as length approaches zero)Assumed axial load acting on a side bracketEuler buckling resistanceReference and adjusted bearing resistance

Eos, Eos'EAElFb, Fb'Fbx*

Fc, Fc'Fc*

FC±, FcJ.'Fe

Fern, FesFe||, Pel, FeO

Fg, pg'Fr', Frc', Frt'Fs, Fs'F«, Ft'Fw'Fv, Fv'Fv, Fv'Fyb

GG, G'Gv> Gv'IJKMKTKeLLLrM, M'Mi, M2Mbx, Mby

Me

Mmx, Mmy

Ms'Msx, MsyM,, Mt'MmMu, Mux, MuyMX', My'MX*

p, P'Po'

Pa

Pe

Pg> Pg'

xviii




Reference and adjusted compression resistance perpendicular to grainReference and adjusted compression resistance in bearing at angle 0Assumed horizontal side load placed at center of height of columnCompressive or bearing force due to factored loadsStatical moment of an area about the neutral axisLoad caused by initial rain water and/or iceReference and adjusted resistanceSlenderness ratio of bending memberRatio of minimum to maximum member axial stiffness in a connectionRatio of main to side member embedment strength in a connectionRatio of main to side member thickness in a connectionRadius of curvature at the inside face and at mid-depth, respectivelyForce due to factored loadsSection modulusSnow loadReference and adjusted tension resistance parallel to grainTensile force due to factored loadsReference and adjusted shear resistanceShear force due to factored loadsWind loadReference and adjusted connection lateral resistanceConnection force due to factored loadsReference and adjusted connection withdrawal resistanceAdjusted resistance of a fastener loaded at an angle to the surface of the wood memberAdjusted resistance of a fastener loaded parallel, perpendicular, and at an angle to the grain,respectivelyEnd distance for a connectionEffective number of fasteners for row iMinimum end distance permitted for connectionsRequired end distance to achieve reference connection resistanceMember widthEdge distance for connectionMinimum edge distance permitted for connectionsRequired edge distance to achieve reference connection resistanceCoefficient in column stability factor equationCoefficient in beam stability factor equationMember depthMinimum and maximum depth for a uniform width, linearly tapered memberEffective depth of member at a connectionDepth of member remaining at a notchEccentricityHeightDesign span of bending member or compression memberDistance between points of lateral support of a compression memberSpan length, clear span of arch between hingesBearing lengthDistance from the bottom of the column or column segment to the top of the columnbracket, in.Clear spanEffective lengthLength of dowel-type fastener in main memberDistance measured vertically from point of application of load on bracket to farther end ofcolumn

xix

P^, Pi'Pe, Pe'PsPu

QRR, R'RBREARe

RtRf, RmRussT,rTuv,vVu

wZ,Z'ZuZw, Zw'Z 'Z| | ' ,Z_L' ,Ze '

aai3min

3opt

bbDmin

bopt

C

Cb

ddi, d2de

dneh€€€4€br

€c€e

£m€P




Laterally unsupported span length of bending or compression memberTotal number of fasteners in a connectionNumber of equally spaced fasteners in row iNumber of serial rows of fasteners in a connectionDepth of fastener penetration into wood memberRadius of gyrationSpacing of fasteners in a connection (also called pitch spacing)Minimum spacing for adjusted connection resistanceRequired spacing for reference connection resistanceThicknessThickness of main and side members, respectively, in a connectionUniform loadAngle between applied force vector and the surface of the wood memberAngle of connector axis with respect to member longitudinal axisFactor in design of flexural membersFactor in design of columnsLoad/slip constant for a single fastenerDeflectionTime-effect factorResistance factorResistance factor for flexureResistance factor for compressionResistance factor for stabilityResistance factor for tensionResistance factor for shear/torsionResistance factor for connectionsAngle of cut taper or cut notch from the grain directionAngle of force vector with respect to a direction parallel to grainAngle between bearing force and the direction of grain

xx

€unfninrPrsSmin

Soptt

tm> ts

W



CHAPTER 1

General Provisions

1.1 ScopeThis standard provides design criteria for

structures constructed of structurally graded lum-ber, structural glued laminated timber, panelproducts, poles, piles, and other structural woodcomponents, and their connections. This standardis for the design of buildings and similar struc-tures. Wherever in this standard reference ismade to the appendices, the provisions of the ap-pendices shall apply. The derivation of designstrengths and resistances is outside the scope ofthis standard.

Design strengths and resistances established foruse with this standard shall be determined in ac-cordance with ASTM Specification D5457-93.

1.1.1 Units. Where units are required in theprovisions of this standard, they are providedboth in metric (SI) and in U.S. customary units.Many of the checking equations do not requireexplicit statement of units; in these equationsthe designer shall use units for all quantities thatare consistent.

1.2 Applicable DocumentsAmerican Forest & Paper Association. 1991. Na-

tional Design Specification for Wood Construction.AF&PA. Washington, DC.

American Society of Civil Engineers. 1993,Minimum Design Loads for Buildings and OtherStructures. ASCE 7-93. New York, NY.

American National Standards Institute. 1981.American National Standards for Wood Screws(inch series). ANSIB18.6.1-198L New York, NY.

American National Standards Institute. 1981.American National Standard for Square and HexBolts and Screws (inch series). ANSI BIS. 2.1-1981. New York, NY.

American National Standards Institute. 1992.Specifications and Dimensions for Wood Poles.ANSI OS.1-1992. New York, NY

American Society for Testing and Materials.1986. Standard Method for Determining the Me-chanical Properties of Externally and InternallyThreaded Fasteners, Washers and Rivets. ASTMF606-86. Philadelphia, PA.

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