Design of Light Gauge Steel Structural Members
This Standard for The Design of Light Gauge Steel Structural Members is the first specification of its kind published by the Canadian Standards Association.
The American Iron and Steel Institute first published their specification Design of Light Gage Cold-Formed Steel Structural Members in the year 1946, and have revised it several times. The latest revision is dated 1962. The data used in compiling this Standard were obtained chiefly from the results of large testing programs, directed by Dr. George Winter of Cornell University.
It has long been customary in structural design to relate working stresses and load carrying capacity to the properties of the material as determined from standardized tests of small specimens. It is now known that the mechanical properties of sheet and strip steel may be significantly altered by the cold work that is exerted on it by forming it into structural sections. Utilization of the increased strength of a cold-formed structural member that results from the forming process is a recent development that is assuming importance in some structural applications of sheet and strip steel.
The strengthening effect of forming operations will vary widely, depending on the composition and prior treatment of the material, the extent to which it is cold worked in forming, the nature of the forming operation and the proportions of the sections. A compact section that is formed from narrow strip in roll forming machines may experience a considerable increase in strength relative to the strength of the unformed materia1. A relatively wide, thin section may experience such an increase only at the corners, and since in such a section the corners constitute a small percentage of the total the net effect is slight.
The provisions of the Design Specification and the data contained in this Standard give accurate results for carbon and low-alloy steels. They do not apply to non—ferrous metals whose modulus of elasticity is substantially different from that of steel.
The flexibility 0f the forming processes facilitates the production of a great variety of shapes, resulting in substantial economies. Designers should consult the manufacturers when specifying special sections.
The Committee wishes to acknowledge their indebtedness to the many individuals, Organizations, and Universities for their assistance in preparing this Standard, and wish to especially thank the following for their generous contributions:
W. G. KIRKLAND.....American Iron & Steel Institute, New York
DR. GEORGE WINTER.....Cornell University—Ithaca, N.Y.
DR. R. E. JAMIESON.....McGill University—Montreal
DR. A. H. CHILVER.....University College, London, England
PROF. M. R. HORNE.....University of Manchester, England
This Standard was prepared by the Committee on Design of Light Gauge Steel Structural Members under the jurisdiction of the Sectional Committee on Steel Construction and was approved by these Committees and the CSA Technical Council.
This Standard shall apply to the design of structural members fabricated by cold-forming sheet strip and plate, and will apply also to the design of any structural member fabricated by welding, riveting, and other methods, in which the width: thickness ratio (w/t) of any component may exceed that normally allowed in other Canadian Standards Association Standards for the design of steel structural members. It is intended to supplement and not to conflict with such standards, if used in conjunction with same.
Properties of sections, for design purposes, are established within practical limits. Design procedures utilizing suitable working stresses, and based on the elastic theory, are presented. No attempt is made to specify load requirements for the several categories into which structures and structural members may be divided. Loads shall be those stipulated in the local By-laws under which the structure is being designed or as determined by the authority having jurisdiction.