Numerical investigation of cold‐formed stainless steel elliptical hollow section beam‐column members

Abstract This paper presents an investigation of the structural behavior of cold‐formed stainless steel (CFSS) elliptical hollow section (EHS) beam‐column members. By using a validated numerical model for cold‐formed tubular beam‐column members, a parametric study was carried out for CFSS EHS beam‐column members. Finite element predicted ultimate loads were compared with the design strengths predicted from the current design codes. The Direct Strength Method (DSM) was recently proposed to predict the compression and bending resistances of CF normal grade steel EHS beam‐column members. Thus, the design expressions associated with the DSM end points were also evaluated. As the existing Continuous Strength Method (CSM) was only suitable for CFSS tubular members subjected to axial load plus uniaxial bending. Therefore, in this study, a modified CSM was proposed for CFSS EHS beamcolumn members subjected to combined axial load and biaxial bending. The comparisons revealed that the existing codified interaction design curves provided conservative and scattered predictions. After adopting the DSM end points, the accuracy of the design formulae can be highly improved. Nevertheless, the proposed new CSM can achieve the most accurate and reliable design predictions for CFSS EHS beam‐column members.