Seismic resistant cold-formed steel moment-resisting frames

This paper studies the behaviour of cold-formed steel (CFS) sections as moment resisting frames (MRFs) for seismic applications. A basic concept in seismic resistant MRFs is that beams dissipate seismic energy by producing large plasticity, whereas columns and joints are designed to remain elastic. Premature local buckling of typical CFS sections and lack of out-of-plane stiffness due to low element thickness, especially in CFS connections, result in low ductile capacity in current CFS structures such as shear/stud wall frames. New ideas for the development of CFS MRFs are introduced and examined both experimentally and analytically. A through plate type of connection is proposed which potentially limits out-of-plane actions in connection elements. In addition, CFS beam sections with curved flanges are introduced and their elastic and inelastic responses are compared with those of conventional sections. The results of this study show an improvement in the ductile behaviour of CFS frames in comparison with that of current CFS structures