Design of Cold-Formed Lean Duplex Stainless Steel Members in Combined Compression and Bending

Abstract

The structural performance and design of cold-formed lean duplex stainless steel members in combined compression and bending are investigated. A wide range of square and rectangular hollow sections has been performed by finite-element analysis. A finite-element model has been developed and verified against the available test data for lean duplex stainless steel members subjected to axial compression and minor axis bending. An extensive parametric study was conducted using the verified finite-element model, and 150 finite-element analysis results were obtained. A total of 233 data, including the numerical results obtained in this study as well as the experimental and numerical data from the literature, are compared with design predictions from the current American, Australian/New Zealand, and European specifications for stainless steel structures. Reliability analysis was carried out to assess the reliability of these design rules for the lean duplex stainless steel beam-column members. It is shown that the American Specification is capable of providing accurate prediction for the compression and bending capacities, whereas the Australian/New Zealand Standard (AS/NZS) and European Code provide quite conservative predictions. However, the calculation procedure in the American Specification involves tedious iterative processes. Therefore, two modified design methods are proposed for lean duplex stainless steel beam-columns in this study. The two modified design methods in the AS/NZS and direct strength method generally provide better predictions for the cold-formed lean duplex stainless steel beam-columns compared to the current design rules.