Investigation on the axial behavior of cold-formed thick-walled steel columns

An experimental study on the stub columns of cold-formed thick-walled square, rectangular and circular steel tubes under axial compression was presented in this paper. Obvious cold-forming effect was observed from the tensile coupon test for RHS and SHS, in terms of the yield strength and elongation. It was shown that the widthto-thickness ratio had a significant influence on the failure modes and load-displacement curves of the stub columns. Performance of current design methods, including effective width methods in design codes, direct strength method (DSM) and continuous strength method (CSM), in predicting the ultimate capacity of stub columns was assessed by comparing the predicted capacities with the experimental capacities in this study and existing literature. It is shown that the CSM can provide more accurate and consistent strength predictions than the methods in current design codes.