AISI Cold-Formed Design Manual (2008 Edition), The 2007 Edition of the North American Specification for the Design of Cold-Formed Steel Structural Members and The Commentary to the 2007 Edition of the North American Specification Design of Cold-Formed Steel Structural Members Manual Set

PREFACE
The 2008 edition of the Cold-Formed Steel Design Manual consists of six Parts. This information is supplemental to the 2007 edition of the North American Specification for the Design of Cold-Formed Steel Structural Members. Each part in the Design Manual should be used in conjuction with the Specification, Commentary and the other parts, where appropriate.

Part I, Dimensions and Properties contains (a) information regarding the availability and properties of steels referenced in the Specification, (b) tables of section properties, and (c) formulas and examples of calculations of section properties.

Part II, Beam Design contains (a) tables and charts to aid in beam design, and (b) beam design example problems.

Part III, Column Design contains (a) tables to aid in column design, and column design example problems.

Part IV, Connections contains (a) tables to aid in connection design, and (b) connection example problems.

Part V, Supplementary Information contains (a) a table of Specification cross-references to the examples provided in this manual (b) design procedures of specification nature which are not included in the Specification itself, either because they are infrequently used or are regarded as too complex for routine design, and (c) other information intended to assist users of cold-formed steel.

Part VI, Test Standards contains (a) test methods for cold-formed steel, (b) a bibliography of other pertinent test methods, and (c) an example problem.
In addition to updating the Design Manual for conformance with the 2007 edition of the North American Specification, the following improvements or additions have been made:

• A series of brief discussions is provided in Parts I-IV, which summarize the intent of the Specification provisions and provide guideline for users
• Standard studs and tracks produced by members of the Steel Stud Manufacturers Association (SSMA) are included in Parts I and IV.
• Formulas for calculating section properties used in distortional buckling analysis are added, along with distortional buckling tables for C-, Z- and SSMA stud sections.
• Tables for screw shear, pull-out and pull-over are provided specifically for SSMA sections
• A table is added to arc spot welds for the case of shear of a sheet welded to an identical sheet.
• The following new design examples have been added to illustrate new design provisions in the Specification:
  1. Round and rectangular tubular section member design in Parts II and III,
  2. C-section member subjected to combined bending and torsional loading in Part II,
  3. Distortional buckling of C-Section members in Parts II and III,
  4. Sigma-shaped flexural and compression member design by the Direct Strength Method in Parts II and III,
  5. Web crippling strength of beam webs with bearing stiffeners in Part II, and
     1. Frame Design with consideration of second order analysis in Part III.
• The Direct Strength Method is introduced for designing members subject to local, distortional and/or global buckling.
• A table of cross-references between the new and previous Test Standard designations is provided in Part IV.
• Editorial changes have been made to all the test standards. Technical guidance and commentary. The following six standards are included in Part IV:
  1. AISI S900-08, Standard Test Method for Determining the Web Crippling Strength of Cold-Formed Steel Beams
  2. AISI S910-08, Testing Method for Distortional Buckling of Cold-Formed Steel Hat Shaped Compressed Members,
  3. AISI S911-08, Method for Flexural Testing Cold-Formed Steel Hat Shaped Beams
  4. AISI S912-08, Test Procedure for Determining a Strength Value for a Roof Panel-To-Purlin-To-Anchorage Device Connection,
  5. AISI S913-08, Test Standard for Hold-Downs Attached to Cold-Formed Steel Structural, and
  6. AISI S914-08, Test Standard For Joist Connectors Attached to Cold-Formed Steel Structural Framing.

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.