Last month, the 2016 edition of the North American Specification for the Design of Cold-formed Steel Structural Members was published. This specification was the result of work by both the American Iron and Steel Institute (AISI) Committee on Specifications for the Design of Cold-formed Steel Structural Members and the CSA Group Technical Committee on Cold-formed Steel Members.
Supplanting previous editions, this version of the specification has been updated to incorporate information from research advances, and reorganized to be a more user-friendly reference. It is intended to enhance consistency in cold-formed steel (CFS) design technology across the United States, Canada, and Mexico, so as to eliminate barriers to collaboration and facilitate technological innovation.
In the new edition:
- the Direct Strength Method appears in the document’s main body (parallel to the traditional Effective Width Method), with design provisions incorporated into Chapter E (compression member design), Chapter F (flexural member design), and Chapter G (shear design);
- there is a primary document to be used by all three countries, comprising Chapters A through M and Appendices 1 and 2;
- a new appendix relates to “Elastic Buckling Analysis of Members;”
- two country-specific appendices are introduced—one for the United States and Mexico, and the other for Canada;
- integrated treatment of Allowable Strength Design (ASD), Load and Resistance Factor Design (LRFD), and Limit States Design (LSD) is provided;
- interaction check equations for each of the above three design methods are combined into a single format;
- design provisions for applications of other steels, which were previously country-specific, are consolidated;
- system stability analysis, including second-order analysis, is revised to be consistent with the method in American Institute of Steel Construction (AISC) 360, Specification for Structural Steel Buildings;
- AISI S240, North American Standard for Cold-formed Steel Structural Framing, and AISI S400, North American Standard for Seismic Design of Cold-formed Steel Structural Systems, are referenced for CFS light-frame construction applications;
- AISI S310, North American Standard for the Design of Profiled Steel Diaphragm Panels, is referenced for diaphragm design applications;
- a total of 16 AISI test standards from the AISI S900 series are referenced;
- new provisions are added for power-actuated fastener embedment in concrete, as related to track connections in cold-formed steel framing applications; and
- statistical data for determining resistance factors is reorganized and simplified.