Buckling, Post-Buckling, Collapse and Design of Three Span Cold-Formed Steel Beams

Abstract

This paper reports the available results of an ongoing numerical investigation on the buckling, post- buckling, collapse and design of two-span cold-formed steel lipped channel beams subjected to uniformly distributed loads. The results presented and discussed are obtained through analyses based on Generalised Beam Theory (elastic buckling analyses) and shell finite element models (elastic and elastic-plastic post-buckling analyses up to collapse). Moreover, the ultimate loads obtained are used to establish preliminary guidelines concerning the design of continuous (multi-span) cold-formed steel beams failing in modes that combine local, distortional and global features. An approach based on the existing Direct Strength Method (DSM) expressions is followed and the comparison between the numerical and predicted ultimate loads makes it possible to draw some conclusions concerning the issues that must be addressed by a DSM design procedure for cold-formed continuous beams.