ANSI NDS-2015 National Design Specification for Wood Construction (Incorporates Commentary).pdf

1、ANSI/AWC NDS-2015Approval date September 30, 2014NDSNational Design Specification for Wood Constructionwith Commentary2015 EDITIONUpdates and ErrataWhile every precaution has been taken toensure the accuracy of this document, errorsmay have occurred during development.Updates or Errata are posted to

2、 the American Wood Council website at www.awc.org. Technical inquiries may be addressed to infoawc.org.The American Wood Council (AWC) is the voice of North American traditional and engineered wood products. From a renewable resource that absorbs and sequesters carbon, the wood products industry mak

3、es products that are essential to everyday life. AWCs engineers, technologists, scientists, and building code experts develop state-of-the-art engineering data, technology, and standards on structural wood products for use by design professionals, building officials, and wood products manufacturers

4、to assure the safe and efficient design and use of wood structural components.Copyright 2014 American Wood CouncilNDSNational Design Specification for Wood Construction with Commentary2015 EDITIONANSI/AWC NDS-2015Approval date September 30, 2014AMERICAN WOOD COUNCILii NATIONAL DESIGN SPECIFICATION F

5、OR WOOD CONSTRUCTIONNational Design Specification (NDS) for Wood Construction with Commentary 2015 EditionFirst Electronic Version: November 2014 Second Electronic Version: November 2015 Third Electronic Version: December 2016978-1-940383-38-5Copyright 2015 by American Wood Council All rights reserv

6、ed. No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including, without limitation, electronic, optical, or mechanical means (by way of example and not limitation, photocopying, or recording by or in an information storage retrieval system) with

7、out express written permission of the American Wood Council. For information on permission to copy material, please contact:Copyright PermissionAmerican Wood Council222 Catoctin Circle, SE, Suite 201Leesburg, VA 20175infoawc.orgAMERICAN WOOD COUNCILNATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION

8、 iiiFOREWORDThe National Design Specificationnullfor WoodConstruction (NDSnull) was first issued by the Na-tional Lumber Manufacturers Association (now the American Wood Council) (AWC) in 1944, under the title National Design Specification for Stress-Grade Lumber and Its Fastenings. By 1971, the sco

9、pe of the Specification had broadened to include additional wood products. In 1977, the title was changed to reflect the new nature of the Specification, and the content was rearranged to simplify its use. The 1991 edition was reorganized in an easier to use “equation format”, and many sections were

10、 rewritten to provide greater clarity.In 1992, the American Forest & Paper Association (AF&PA) formerly the National Forest Products Association was accredited as a canvass sponsor by the American National Standards Institute (ANSI). The Specification subsequently gained approval as an American Nati

11、onal Standard designated ANSI/NFoPA NDS-1991 with an approval date of October 16, 1992. In 2010, AWC was separately incorporated, re-chartered, and accredited by ANSI as a standards developing organization. The current edition of the Standard is designated ANSI/AWC NDS-2015 with an approval date of

12、September 30, 2014.In developing the provisions of this Specification, the most reliable data available from laboratory tests and experience with structures in service have been carefully analyzed and evaluated for the purpose of providing, in convenient form, a national standard of practice.It is i

13、ntended that this Specification be used in conjunction with competent engineering design, accurate fabrication, and adequate supervision of construction. Particular attention is directed to Sec-tion 2.1.2, relating to the designers responsibility to make adjustments for particular end uses of struct

14、ures.Since the first edition of the NDS in 1944, the Associations Technical Advisory Committee has continued to study and evaluate new data and devel-opments in wood design. Subsequent editions of the Specification have included appropriate revisions to provide for use of such new information. This

15、edi-tion incorporates numerous changes considered by AWCs ANSI-accredited Wood Design Standards Committee. The contributions of members of this Committee to improvement of the Specification as a national design standard for wood construction are especially recognized.Acknowledgement is also made to

16、the Forest Products Laboratory, U.S. Department of Agriculture, for data and publications generously made avail-able, and to the engineers, scientists, and other users who have suggested changes in the content of the Specification. AWC invites and welcomes comments, inquiries, suggestions, and new d

17、ata relative to the provisions of this document.It is intended that this document be used in con-junction with competent engineering design, accurate fabrication, and adequate supervision of construction. AWC does not assume any responsibility for errors or omissions in the document, nor for enginee

18、ring designs, plans, or construction prepared from it. Those using this standard assume all liability aris-ing from its use. The design of engineered structures is within the scope of expertise of licensed engineers, architects, or other licensed professionals for applica-tions to a particular struc

19、ture.American Wood CouncilAMERICAN WOOD COUNCILiv NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTIONAMERICAN WOOD COUNCILNATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION vTABLE OF CONTENTS FOR THE NDSPart/Title Page Part/Title Page1 General Requirements for Structural Design 11.1 Scope 21.2 Gene

20、ral Requirements 21.3 Standard as a Whole 21.4 Design Procedures 21.5 Specifications and Plans 31.6 Notation 32 Design Values for Structural Members .92.1 General 102.2 Reference Design Values 102.3 Adjustment of Reference Design Values 103 Design Provisions and Equations . 133.1 General 143.2 Bendi

21、ng Members General 153.3 Bending Members Flexure 153.4 Bending Members Shear 173.5 Bending Members Deflection 193.6 Compression Members General 203.7 Solid Columns 213.8 Tension Members 223.9 Combined Bending and Axial Loading 223.10 Design for Bearing 234 Sawn Lumber 254.1 General 264.2 Reference D

22、esign Values 274.3 Adjustment of Reference Design Values 284.4 Special Design Considerations 315 Structural Glued Laminated Timber . 335.1 General 345.2 Reference Design Values 355.3 Adjustment of Reference Design Values 365.4 Special Design Considerations 396 Round Timber Poles and Piles . 436.1 Ge

23、neral 446.2 Reference Design Values 446.3 Adjustment of Reference Design Values 447 Prefabricated Wood I-Joists 477.1 General 487.2 Reference Design Values 487.3 Adjustment of Reference Design Values 487.4 Special Design Considerations 508 Structural Composite Lumber .518.1 General 528.2 Reference D

24、esign Values 528.3 Adjustment of Reference Design Values 528.4 Special Design Considerations 549 Wood Structural Panels 559.1 General 569.2 Reference Design Values 569.3 Adjustment of Reference Design Values 579.4 Design Considerations 5810 Cross-Laminated Timber 5910.1 General 6010.2 Reference Desi

25、gn Values 6010.3 Adjustment of Reference Design Values 6010.4 Special Design Considerations 6211 Mechanical Connections 6311.1 General 6411.2 Reference Design Values 6511.3 Adjustment of Reference Design Values 6512 Dowel-Type Fasteners . 7312.1 General 7412.2 Reference Withdrawal Design Values 7612

26、.3 Reference Lateral Design Values 8012.4 Combined Lateral and Withdrawal Loads 8612.5 Adjustment of Reference Design Values 8612.6 Multiple Fasteners 9013 Split Ring and Shear Plate Connectors .11713.1 General 11813.2 Reference Design Values 11913.3 Placement of Split Ring and Shear Plate Connector

27、s 12514 Timber Rivets .13114.1 General 13214.2 Reference Design Values 13214.3 Placement of Timber Rivets 134AMERICAN WOOD COUNCILviPart/Title Pag Part/Title PageTABLE OF CONTENTS15 Special Loading Conditions 14315.1 Lateral Distribution of a Concentrated Load 14415.2 Spaced Columns 14415.3 Built-Up

28、 Columns 14615.4 Wood Columns with Side Loads and Eccentricity 14916 Fire Design of Wood Members 15116.1 General 15216.2 Design Procedures for Exposed Wood Members 15216.3 Wood Connections 154Appendix .155Appendix A (Non-mandatory) Construction and Design Practices 156Appendix B (Non-mandatory) Load

29、 Duration (ASD Only) 158Appendix C (Non-mandatory) Temperature Effects 160Appendix D (Non-mandatory) Lateral Stability of Beams 161Appendix E (Non-mandatory) Local Stresses in Fastener Groups 162Appendix F (Non-mandatory) Design for Creep and Critical Deflection Applications 167Appendix G (Non-manda

30、tory) Effective Column Length 169Appendix H (Non-mandatory) Lateral Stability of Columns 170Appendix I (Non-mandatory) Yield Limit Equations for Connections 171Appendix J (Non-mandatory) Solution of Hankinson Formula 174Appendix K (Non-mandatory) Typical Dimensions for Split Ring and Shear Plate Con

31、nectors 177Appendix L (Non-mandatory) Typical Dimensions for Dowel-Type Fasteners and Washers 178Appendix M (Non-mandatory) Manufacturing Tolerances for Rivets and Steel Side Plates for Timber Rivet Connections 182Appendix N (Mandatory) Load and Resistance Factor Design (LRFD) 183References .185Fore

32、word to the NDS Commentary .189C1 General Requirements for Structural Design .190C1.1 Scope 190C1.2 General Requirements 190C1.3 Standard as a Whole 191C1.4 Design Procedures 191C1.5 Specifications and Plans 192C1.6 Notation 192C2 Design Values for Structural Members .193C2.1 General 193C2.2 Referen

33、ce Design Values 193C2.3 Adjustment of Reference Design Values 193TABLE OF CONTENTS FOR THE NDS COMMENTARYPart/Title Page Part/Title PageC3 Design Provisions and Equations 197C3.1 General 197C3.2 Bending Members - General 197C3.3 Bending Members - Flexure 198C3.4 Bending Members - Shear 199C3.5 Bend

34、ing Members - Deflection 200C3.6 Compression Members - General 201C3.7 Solid Columns 202C3.8 Tension Members 204C3.9 Combined Bending and Axial Loading 204C3.10 Design for Bearing 206C4 Sawn Lumber .207C4.1 General 207C4.2 Reference Design Values 209C4.3 Adjustment of Reference Design Values 211C4.4

35、 Special Design Considerations 213AMERICAN WOOD COUNCILNATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION viiC5 Structural Glued Laminated Timber 215C5.1 General 215C5.2 Reference Design Values 217C5.3 Adjustment of Reference Design Values 219C5.4 Special Design Considerations 221C6 Round Timber Po

36、les and Piles 223C6.1 General 223C6.2 Reference Design Values 224C6.3 Adjustment of Reference Design Values 225C7 Prefabricated Wood I-Joists 227C7.1 General 227C7.2 Reference Design Values 227C7.3 Adjustment of Reference Design Values 228C7.4 Special Design Considerations 229C8 Structural Composite

37、 Lumber .231C8.1 General 231C8.2 Reference Design Values 231C8.3 Adjustment of Reference Design Values 231C8.4 Special Design Considerations 232C9 Wood Structural Panels .233C9.1 General 233C9.2 Reference Design Values 234C9.3 Adjustment of Reference Design Values 236C9.4 Design Considerations 237C1

38、0 Cross-Laminated Timber .239C10.1 General 239C10.2 Reference Design Values 239C10.3 Adjustment of Reference Design Values 240C10.4 Special Design Considerations 241C11 Mechanical Connections .243C11.1 General 243C11.2 Reference Design Values 244C11.3 Adjustment of Reference Design Values 245C12 Dow

39、el-Type Fasteners 247C12.1 General 247C12.2 Reference Withdrawal Design Values 249C12.3 Reference Lateral Design Values 252C12.4 Combined Lateral and Withdrawal Loads 255C12.5 Adjustment of Reference Design Values 256C12.6 Multiple Fasteners 259C13 Split Ring and Shear Plate Connectors .260C13.1 Gen

40、eral 260C13.2 Reference Design Values 261C13.3 Placement of Split Ring and Shear Plate Connectors 262C14 Timber Rivets 265C14.1 General 265C14.2 Reference Design Values 266C14.3 Placement of Timber Rivets 268C15 Special Loading Conditions .269C15.1 Lateral Distribution of a Concentrated Load 269C15.

41、2 Spaced Columns 269C15.3 Built-Up Columns 272C15.4 Wood Columns with Side Loads and Eccentricity 273C16 Fire Design of Wood Members .275C16.1 General 275C16.2 Design Procedures for Exposed Wood Members 277References 281AMERICAN WOOD COUNCILviiiLIST OF TABLES FOR THE NDSLIST OF TABLES2.3.2 Frequentl

42、y Used Load Duration Factors, CD. 112.3.3 Temperature Factor, Ct. 112.3.5 Format Conversion Factor, KF(LRFD Only) 122.3.6 Resistance Factor, (LRFD Only) . 123.3.3 Effective Length, e, for Bending Members . 163.10.4 Bearing Area Factors, Cb. 244.3.1 Applicability of Adjustment Factors for Sawn Lumber

43、 294.3.8 Incising Factors, Ci305.1.3 Net Finished Widths of Structural Glued Laminated Timbers . 345.2.8 Radial Tension Design Factors, Frt, for Curved Members 365.3.1 Applicability of Adjustment Factors for Structural Glued Laminated Timber . 376.3.1 Applicability of Adjustment Factors for Round Ti

44、mber Poles and Piles 456.3.5 Condition Treatment Factor, Cct. 456.3.11 Load Sharing Factor, Cls,per ASTM D 2899 467.3.1 Applicability of Adjustment Factors for Prefabricated Wood I-Joists 498.3.1 Applicability of Adjustment Factors for Structural Composite Lumber 539.3.1 Applicability of Adjustment

45、Factors for Wood Structural Panels 579.3.4 Panel Size Factor, Cs5810.3.1 Applicability of Adjustment Factors for Cross-Laminated Timber 6110.4.1.1 Shear Deformation Adjustment Factors, Ks. 6211.3.1 Applicability of Adjustment Factors for Connections 6611.3.3 Wet Service Factors, CM, for Connections

46、. 6711.3.4 Temperature Factors, Ct, for Connections 6711.3.6A Group Action Factors, Cg, for Bolt or Lag Screw Connections with Wood Side Members . 7011.3.6B Group Action Factors, Cg, for 4“ Split Ring or Shear Plate Connectors with Wood Side Members 7011.3.6C Group Action Factors, Cg, for Bolt or La

47、g Screw Connections with Steel Side Plates 7111.3.6D Group Action Factors, Cg, for 4“ Shear Plate Connectors with Steel Side Plates . 7212.2A Lag Screw Reference Withdrawal Design Values, W 7712.2B Cut Thread or Rolled Thread Wood Screw Reference Withdrawal Design Values, W . 7812.2C Nail and Spike

48、Reference Withdrawal Design Values, W 7912.2D Post-Frame Ring Shank Nail Reference Withdrawal Design Values, W 8012.3.1A Yield Limit Equations. 8112.3.1B Reduction Term, Rd8112.3.3 Dowel Bearing Strengths, Fe, for Dowel- Type Fasteners in Wood Members . 8312.3.3A Assigned Specific Gravities 8412.3.3

49、B Dowel Bearing Strengths for Wood Structural Panels . 8512.5.1A End Distance Requirements . 8712.5.1B Spacing Requirements for Fasteners in a Row 8712.5.1C Edge Distance Requirements 8812.5.1D Spacing Requirements Between Rows . 8812.5.1E Edge and End Distance and Spacing Requirements for Lag Screws Loaded in Withdrawal and Not Loaded Laterally . 8812.5.1F Perpendicular to Grain Distance Requirements for Outermost Fasteners in Structural Glued Laminated Timber Members . 8812.5.1G End Distance, Edge Distance and Fastener Spacing Requirements in Narrow Edge