Numerical Study of Seismic Behavior of Light-Gauge Cold-Formed Steel Stud Walls

Abstract

Light-gauge structures framed with cold-formed steel (CFS) are considered a suitable alternative to the traditional hot-rolled or built-up steel framing as a primary structural system. Recently, CFS has been used as a lateral load resisting system in low- to mid-rise buildings. In this study, the seismic behavior of light-gauge CFS stud walls was evaluated through numerical modeling to investigate the failure modes, load capacities, initial stiffness, ductility ratio, and seismic response modification factor. Studies on different structural components of the light-gauge CFS stud wall were conducted. For framing members, different numbers of mid-field studs were considered. Moreover, the effects of adding blocking and the blocking locations were investigated by increasing their numbers along the wall height. As for the sheathing boards, different types of sheathing materials were investigated, including steel sheets, cement boards, and ferro-cement boards. Furthermore, sheathing openings with different configurations were studied. The numerical model results were verified against the results obtained from an experimental study conducted by the authors and reported in an associated paper. The results revealed that using steel sheathing could significantly increase the loading capacity, as well as the initial stiffness, whereas using cement board and ferro-cement board sheathing had adverse effects on the model behavior. However, models with cement board and ferro-cement board sheathing exhibited lesser instability in their framing members at the ultimate load in comparison with models with steel sheathing. Meanwhile, the presence of an opening in the sheathing resulted in significant reductions in the loading capacity and initial stiffness in comparison with their counterparts without sheathing openings.