This edition of CSA Standard CAN3-S136, Cold Formed Steel Structural Members, is dedicated to the late Dr. George Winter (April 1, 1907—November 3, 1982) of Cornell University, who made invaluable contributions to the advancement of cold formed steel design.
CSA Standard S136 (now CAN3—S136) is based entirely on limit states design principles in contrast to the previous (1974) edition, which was based on Working stress design, with a limit states design option. In addition, this Standard has been prepared for use with SI (metric) units; however, the designer has the option to use any other consistent system of measurement by using the applicable expressions provided in brackets.
Considerable technical changes, reflecting the latest research developments, have been incorporated into this Standard. These changes are based on an increased understanding of the behaviour of cold formed steel structures, members, and elements and of cold formed steel as a structural material. In addition, a number of editorial clarifications have been made throughout the Standard in order to lessen ambiguity and make provisions less liable to misinterpretation.
Significant changes incorporated into this edition include:
(a) a common effective width approach is used for both stiffened and unstiffened compressive elements;
(b) a new method for the design of web bending has been introduced, based on the post-buckling capacity approach;
(c) changes in the calculation of web crippling of sections, particularly for multi-web deck sections, have been made;
(d) a new clause on the inelastic reserve capacity of members in bending has been added;
(e) a new and different design approach for load bearing wall studs has been introduced;
(f) a new clause has been added for combined axial load and bending of singly symmetric shapes; and
(g) the sections on bolted connections and welding have been completely revised.
This Standard was prepared by the Technical Committee on Cold Formed Steel Structural Members under the jurisdiction of the Standards Steering Committee on Structures (Design), and was formally approved by these Committees. It has been approved as a National Standard of Canada by the Standards Council of Canada.
Scope and Application
This Standard applies to the design, based on limit states, of structural members cold formed to shape from carbon or low alloy steel sheet, strip, or plate up to 25 mm in thickness and intended for load carrying purposes in buildings. For application of this Standard to the design of cold formed steel structural members in structures other than buildings, supplementary specifications shall be provided where necessary to account for differences in structural loads and effects, environment, and other service conditions.
When designing structural members to this Standard, the provisions of CSA Standard S136—1974 shall not apply.
Where a structure is comprised of cold formed steel structural members, provision shall be made to ensure adequate stability of the structure as a whole, and adequate lateral, torsional, and local stability of all structural parts. Where members designed in accordance with this Standard are intended for use in structures where other recognized standards apply, this Standard shall supplement such standards as applicable.
The resistance factors adopted in this Standard are correlated with the loads and load factors for buildings as specified in the National Building Code of Canada and Clause 4 of this Standard. For other cases, load factors shall be established such that, in conjunction with the resistance factors used in this Standard, the required level of reliability is maintained.
Where this Standard provides design expressions or dimensional limitations that are not applicable to a specific situation, a rational design may be used if based on appropriate theory, test, analysis, and engineering judgement.