Stability of cold-formed steel stud walls subjected to vertical compression

Cold-formed steel (CFS) stud walls are the primary vertical load-bearing units in CFS residential systems. These walls need to meet both strength requirements and good stability. In this study, a CFS stud wall was simplified into a mechanical model of an orthotropic plate rib system using the orthotropic plate (OP) method. A formula for calculating the equivalent stiffness of the stud wall was obtained, and the correctness of the simplified calculation model and equivalent stiffness calculation formula was verified by finite element analysis. Various factors that affected the equivalent stiffness of the wall were investigated. Additionally, the stability of the stud walls under a vertical load was derived by considering the stability theory of the plate. The results indicated that the stability of the stud walls was mainly related to the height-thickness ratio of the walls. Finally, the correction factor of the allowable height-thickness ratio of the walls was obtained by analyzing the parameters of the wall thickness, stud spacing, sheathing materials, and wall opening, and a case study was used to illustrate the procedure of this simplified method.