Behavior of cold-formed steel wall stud with sheathing subjected to compression

A detailed experimental investigation of the axial performance of sixteen full-scale cold-formed steel (CFS) walls is presented. The impact of various parameters, such as sheathing configuration, type and layer of wall panels, stud section and spacing, and joint details of wall panels, is discussed, and some important conclusions are formulated. Based on the design rules of AISI S100-12, the nominal axial bearing capacities of wall studs were predicted and compared with those identified in the experimental investigation. However, the failure modes of wall studs predicted by AISI were quite different from those found in the present experiments, implying the inadequacy of current design rules. In addition, a finite element model of CFS walls under axial compression was developed and is described in detail, including element type, applied load definition, material properties, screw connectors, and initial imperfections. The ratios of the axial loading capacities of the wall studs given by the finite element model to those of the present experimental results were between 0.91 and 1.18, and the failure mode from the numerical simulation was in accordance with the experimental phenomenon. Moreover, a simplified numerical model of CFS walls was built by ignoring the existence of wall panels and steel tracks and replacing the screw connectors with lateral restrainers at the corresponding positions of the wall studs. The results showed that the predicted loading capacity and the failure mode obtained from the simplified numerical model also compared well to the experimental results, with good efficiency and convergence in computation.