Behaviour and design of cold-formed lean duplex stainless steel lipped channel columns

This paper presents a numerical investigation on the behaviour and design of lean duplex stainless steel (LDSS) lipped channel columns subjected to axial compression. Numerical models were developed using general purpose finite element (FE) package ABAQUS, and have been verified using experimental data available in the literature. Developed FE models included material nonlinearities as well as initial geometric imperfections. A comprehensive parametric study has been carried out covering a wide range of slenderness with different cross section geometries for the considered lipped channel columns. Column resistances obtained from the numerical study were used to assess the performance of the current Direct Strength Method (DSM) guidelines when applied for cold-formed LDSS columns; obtained comparisons showed considerable conservatism. A modified design method for LDSS lipped channels is proposed herein following DSM techniques, which provides considerably more accurate predictions for the considered cold-formed columns. Reliability of the proposed design equations is also presented showing a good agreement with both experimentally and numerically obtained results.