S136-12 - North American specification for the design of cold-formed steel structural members
The North American Specification for the Design of Cold-Formed Steel Structural Members, as its name implies, is intended for use throughout Canada, Mexico, and the United States. This Specification supersedes the 2007 and previous editions 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 S136, Cold Formed Steel Structural Members, published by CSA Group.
This Specification applies to the design of structural members cold-formed to shape from carbon or low-alloy steel sheet, strip, plate, or bar not more than 1 in. (25.4 mm) in thickness and used for load-carrying purposes in
(a) Buildings, and
(b) Structures other than buildings provided allowances are made for dynamic effects.
S136.1-12 - Commentary on North American specification for the design of cold-formed steel structural members
This document provides a commentary on the 2012 edition of the North American Specification for the Design of Cold-Formed Steel Structural Members. This Commentary should be used in combination with the 2013 edition of the AISI Cold-Formed Steel Design Manual.
The cross-sectional configurations, manufacturing processes and fabrication practices of cold-formed steel structural members differ in several respects from those of hot-rolled steel shapes. For cold-formed steel sections, the forming process is performed at, or near, room temperature by the use of bending brakes, press brakes, or roll-forming machines.
Some of the significant differences between cold-formed sections and hot-rolled shapes are:
(1) absence of the residual stresses caused by uneven cooling due to hot-rolling
(2) lack of corner fillets
(3) presence of increased yield stress with decreased proportional limit and ductility resulting from cold-forming
(4) presence of cold-reducing stresses when cold-rolled steel stock has not been finally annealed
(5) prevalence of elements having large width-to-thickness ratios
(6) rounded corners, and
(7) different characteristics of stress-strain curves, that can be either the sharp-yielding type or gradual-yielding type.
The Specification is applicable only to cold-formed sections not more than 1 inch (25.4 mm) in thickness. Research conducted at the University of Missouri-Rolla (Yu, Liu, and McKinney 1973b and 1974) has verified the applicability of the Specification's provisions for such cases.
In view of the fact that most of the design provisions have been developed on the basis of the experimental work subject to static loading, the Specification is intended for the design of cold-formed steel structural members to be used for load-carrying purposes in buildings. For structures other than buildings, appropriate allowances should be made for dynamic effects.