Cold-formed steel columns under L-D-G interaction - Experimental investigation

The paper addresses an experimental programme that is part of an ongoing investigation on the behaviour, strength and design of cold-formed steel lipped channel columns undergoing mode interaction involving local, distortional and global buckling. The 16 column specimens tested were selected to exhibit either (i) close local, distortional and critical buckling loads (PcrL ≍ PcrD ≍ PcrG) or (ii) PcrL ≍ PcrD (condition ensured via the cross-sectional dimensions) and PcrG up to around 20 % below or above that value (difference controlled via the column length). The test set-up, procedure and results are presented and discussed, and the failure load data obtained are used to explore the possibility of developing a design approach based on the direct strength method (DSM).