DSM Design of Cold-Formed Steel Columns Failing in Distortional Modes at Elevated Temperatures

Abstract

This paper aims at investigating the structural behaviour, strength and Direct Strength Method (DSM) design of cold-formed steel columns failing in distortional modes at elevated temperatures. The results concern pin-ended and fixed-ended columns displaying four cross-section shapes, with various dimensions, subjected to 8 temperatures. It is shown that the current DSM distortional design is unable to handle adequately distortional failures at elevated temperatures. Then, a modified DSM design approach is proposed: it consists of incorporating a temperature-dependent reduction factor ratio, based on the EC3-1.2 model, in the existing strength curve—the modified design curves are shown to yield adequate failure load predictions for the set of columns under consideration. This finding provides motivation and encouragement to continue the ongoing search for an efficient DSM-based design approach for columns failing in distortional modes under elevated temperatures.