Non-linear Analysis of the Effect of Cold-Formed Stain-Less-Steel Members’ Material Properties on the Portal Frames’ Ultimate Strengths

Cold-formed stainless-steel (CFSS) members are becoming popular in the design of steel structures because of their decent load-carrying capacity and corrosion resistance. The material properties of cold-formed stainless-steel sections ensure that they can be easily manufactured and designated for complex design purposes. For instance, they can be potentially used when designing structures, including floor joists, scaffolds, façade, and portal frames. Therefore, in the scope of this research, the performance of a cold-formed stainless-steel portal frame is investigated using Strand 7. Three material categories are considered for the portal frame, and they are Austenitic, Duplex, and Ferritic stainless steel. Since the material properties of the manufactured CFSS members have uncertainties in the real-life scenario, the uncertainties’ effect on the ultimate strength of the CFSS portal frame will be studied. In each material category, 40 sets of material properties for the CFSS members are randomly generated based on experimental data. Each set of material properties is used to define a stress-strain curve for the portal frame. The curve determines the frame’s flexural behaviour and ultimate strength. After that, Direct Design Method (DDM) is used to evaluate the model’s ultimate strength. During the non-linear analysis, loads over the frame gradually increase, and the frame will fail once its total fibre stress exceeds its ultimate stress. Stop the simulation once the frame fails and record the ultimate load of the frame. Repeat the simulations for the rest of the property sets and plot the obtained ultimate loads in a histogram for each material category.