Cold-formed stainless steel SHS and RHS columns subjected to local-flexural interactive buckling

Abstract

Design of cold-formed stainless steel tubular columns undergoing local-overall flexural interactive buckling is investigated in this paper. A numerical study has been carried out to study the interactive buckling behavior of square hollow section (SHS) and rectangular hollow section (RHS) columns of various stainless steel grades that are employed in structural applications. A finite element model was developed and verified against available experimental cold-formed stainless steel SHS/RHS column data. Extensive parametric studies, with cross-section aspect ratio, plate slenderness, overall slenderness and stainless steel grade selected as key variable parameters, were carried out thereafter to generate further numerical data featuring the tubular columns undergoing local-flexural interactive buckling. The obtained interactive buckling strengths were used to assess the design provisions in current European, American, Australian/New Zealand and Chinese design standards for stainless steel structures as well as available Direct Strength Method (DSM) design rules in the literature. It is shown that better predictions can be achieved when material nonlinearities of different material grades are accounted for. A modified DSM, which relies on simple hand calculations, is developed in this paper. It is demonstrated that the modified DSM is a suitable and efficient design alternative for cold-formed stainless steel SHS/RHS columns subjected to local-flexural interactive buckling.