2015 National Design Specification

1 ANSI/AWC NDS-2015 Approval date September 30, 2014 NDS National Design Specification for Wood Construction2015 EDITIONU pdates and ErrataWhile every precaution has been taken toensure the accuracy of this document, errorsmay have occurred during or Errata are posted to the American Wood Council website at Technical inquiries may be addressed to 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 makes products that are essential to everyday life. AWC s 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 to assure the safe and efficient Design and use of wood structural American Wood Council.

2 Downloaded/printed pursuant to License Agreement. No reproduction or transfer 2014 American Wood Council NDS National Design Specification for Wood Construction2015 EDITIONANSI/AWC NDS-2015 Approval date September 30, 2014 AMERICAN WOOD COUNCILiiNATIONAL Design Specification FOR WOOD CONSTRUCTIONN ational Design Specification (NDS) for Wood Construction 2015 EditionFirst Web Version: November 2014978-1-940383-05-7 Copyright 2014 by American Wood Council All rights reserved. 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) without express written permission of the American Wood Council.

3 For information on permission to copy material, please contact: Copyright PermissionAmerican Wood Council222 Catoctin Circle, SE, Suite 201 Leesburg, VA American Wood Council. Downloaded/printed pursuant to License Agreement. No reproduction or transfer WOOD COUNCILNATIONAL Design Specification FOR WOOD CONSTRUCTION iiiiiiFOREWORD The National Design Specification for Wood Construction (NDS ) 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.

4 By 1971, the scope 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 rewritten to provide greater 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 National Standard designated ANSI/NFoPA NDS-1991 with an approval date of October 16, 1992.

5 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 September 30, 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 is intended that this Specification be used in conjunction with competent engineering Design , accurate fabrication, and adequate supervision of construction.

6 Particular attention is directed to Sec-tion , relating to the designer s responsibility to make adjustments for particular end uses of the first edition of the NDS in 1944, the Association s 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 edi-tion incorporates numerous changes considered by AWC s 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 is also made to the Forest Products Laboratory, 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 .

7 AWC invites and welcomes comments, inquiries, suggestions, and new data relative to the provisions of this 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 engineering 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 Wood CouncilNATIONAL Design Specification FOR WOOD CONSTRUCTIONC opyright American Wood Council.

8 Downloaded/printed pursuant to License Agreement. No reproduction or transfer WOOD COUNCILivNATIONAL Design Specification FOR WOOD CONSTRUCTIONC opyright American Wood Council. Downloaded/printed pursuant to License Agreement. No reproduction or transfer WOOD COUNCILNATIONAL Design Specification FOR WOOD CONSTRUCTIONvTABLE OF CONTENTSPart/Title PagePart/Title Page1 General Requirements for Structural Design .

9 Scope General Requirements Standard as a Whole Design Procedures Specifications and Plans Notation 32 Design Values for Structural Members .. General Reference Design Values Adjustment of Reference Design Values 103 Design Provisions and Equations .. General Bending Members General Bending Members Flexure Bending Members Shear Bending Members Deflection Compression Members General Solid Columns Tension Members Combined Bending and Axial Loading Design for Bearing 234 Sawn Lumber .. General Reference Design Values Adjustment of Reference Design Values Special Design Considerations 315 Structural Glued Laminated Timber.

10 General Reference Design Values Adjustment of Reference Design Values Special Design Considerations 396 Round Timber Poles and Piles .. General Reference Design Values Adjustment of Reference Design Values 447 Prefabricated Wood I-Joists .. General Reference Design Values Adjustment of Reference Design Values Special Design Considerations 508 Structural Composite Lumber .. General Reference Design Values Adjustment of Reference Design Values Special Design Considerations 549 Wood Structural Panels .. General Reference Design Values Adjustment of Reference Design Values Design Considerations 5810 Cross-Laminated Timber.