Effects of Cold-Forming on Light-Gage Steel Members

Cold-forming causes significant changes in the mechanical properties of certain light-gage steel members. The average yield strength in a cold-formed section may be as much as 70% larger than that of the original, as-rolled sheet steel. These changes in properties are not distributed uniformly in the cross sections, being considerably larger in the corners than in the flats of light-gage members. However, the quantitative information obtained in this investigation permits more rational and economical design of many such members. Both the tensile and compressive properties of corners, flats, and full sections were determined in an extensive experimental investigation. A method is devised for determining the stress-strain characteristics of full sections from simple tensile coupon tests. These stress-strain properties are related analytically to the inelastic buckling of compact cold-formed columns, using a generalized form of Shanley's tangent modulus equation.