PREFACE 2007 The North American Specification for the Design of Cold-Formed Steel Structural Members, as it’s name implies, is intended for use throughout Canada, Mexico and the United States. This Specification supersedes the 2001 edition of the North American Cold-Formed Steel Specification, the previous editions of the Specification for the Design of Cold-Formed Steel Structural members published by the American Iron and Steel Institute, and the previous editions of CSA Standard S136, Cold-Formed Steel Structural members, published by the Canadian Standard Association. The Specification was developed by a joint effort of the American Iron and Steel Institute’s Committee on Specifications, the Canadian Standards Association’s Technical Committee on Cold Formed Steel Structural Members (S136), and Camara Nacional de la Industria del Hierro y del Acero (CANACERO) in Mexico. This effort was coordinated through the North American Specification Committee, which was made up of members from the AISI Committee on Specifications and CSA’s S136 Committee. Since the Specification is intended for use in Canada, Mexico and the United States, it was necessary to develop a format that would allow for requirements particular to each country. This resulted in a main document, Chapters A through G and Appendix 1 and 2, that is intended for use in all three countries, and two country-specific appendices (A and B). In this edition of the Specification, what was previously Appendix C has been combined with Appendix A. The new Appendix A is for use in both the United State and Mexico, and Appendix B is for use in Canada. A symbol (A,B) is used in the main document to point out that additional provisions are provided in the corresponding appendices indicated by the letters. This Specification provides an integrated treatment of Allowable Strength Design (ASD), Load and Resistance Factor Design (LRFD), and Limit States Design (LSD). This is accomplished by including the appropriate resistance factors(o) for use with LRFD and LSD and the appropriate safety factors () for use with ASD. It should be noted that the use of LSD is limited to Canada and the use of LRFD and ASD is limited to the United States and Mexico. The Specification also contains some terminology that is defined differently in Canada, the United States, and Mexico. These differences are set out in Section A1.3, “Definitions”. The Specification provides well-defined procedures for the design of load-carrying cold-formed steel members in buildings, as well as other applications, provided that proper allowances are made for dynamic effects. The provisions reflect the results of continuing research to develop new and improved information on the structural behavior of cold-formed steel members. The success of these efforts is evident in the wide acceptance of the previous editions of the Specification developed by AISI and CSA. The AISI and CSA consensus committees responsible for developing these provisions provide a balance forum, with representatives of steel producers, fabricators, users, educators, researchers, and building code regulators. They are composed of engineers with a wide range of experience and high professional standing from throughout Canada and the United States. AISI, CSA, and CANACERO acknowledge the continuing dedication of the members of the specifications committees and their subcommittees. The membership of these committees follows this Preface. PREFACE This document provides a commentary on the 2007 edition of the North American Specification for the Design of Cold-Formed Steel Structural Members. This Commentary should be used in combination with the 2008 edition of the AISI Cold-Formed Steel Design Manual. The purpose of the Commentary includes: (a) to provide a record of the reasoning behind, and justification for the various provisions of the North American Specification by cross-referencing the published supporting research data and to discuss the changes make in the current Specification; (b) to offer a brief but coherent presentation of the characteristics and performance of cold-formed steel structures to structural engineers and other interested individuals; (c) to furnish the background material for a study of cold-formed steel design methods to educators and students; and (d) to provide the needed information to those will be responsible for future revisions of the Specification. The readers who wish to have more complete information, or who may have questions which are not answered by the abbreviated presentation of this Commentary, should refer to the original research publications. Consistent with the Specification, the Commentary contains a main document, Chapters A through G, and Appendices 1 and 2, and Appendices A and B. A Symbol A,B is used in the main document to point out that additional discussions are provided in the corresponding country specific provisions in Appendices A and/or B.
The Assistance and close cooperation of the North American Specification Committee under the Chairmanship of Professor Reinhold M. Schuster and the AISI Committee on Specifications under the Chairmanship of Mr. Roger L. Brockenbrough and the Vice Chairmanship of Mr. Jay W. Larson are gratefully acknowledge. Special thanks are extended to Professor Wei-Wen Yu for revising the draft of this Commentary. The Institute is very grateful to members of the editorial Subcommittee and all members of the AISI Committee on Specifications for their careful review of the document and thei valuable comments and suggestions. The background materials provided by various subcommittees are appreciated. |