Compression Tests of Cold-Formed Steel C- and Z-Sections with Different Stiffeners

© 2019 American Society of Civil Engineers.This paper describes an experimental investigation of stub column tests of cold-formed steel C- and Z-sections with different stiffeners. The experimental program consisted of 30 fixed-ended column tests of 6 series of C-sections and 4 series of Z-sections. The configurations of stiffeners comprised simple edge stiffeners, simple lips with inward or outward return lips, and intermediate web stiffeners. The specimens were brake-pressed from high-strength zinc-coated grades G450 and G550 structural steel sheets. The material properties were measured through tensile coupon tests. The load-carrying capacities, load-end shortening responses, and failure modes of stub column specimens are presented and discussed in this paper. The test strengths and observed failure modes were compared with the design strengths and failure modes predicted by the Direct Strength Method. The comparison showed that the Direct Strength Method provides accurate and reliable design strength predictions for C- and Z-sections with different edge stiffeners but provides less accurate design strength predictions for C-sections with intermediate web stiffeners.