Performance-based design of sheathed CFS buildings in seismic area

The widely recognized structural performance provided by cold-formed steel (CFS) systems together with high levels of prefabrication, safety, durability and sustainability are spreading the CFS construction systems all over the world. At the same time, the actual lack in European seismic design codes requires the development of specific design procedures for the application in seismic area. The seismic behaviour of CFS structures is characterized by the lateral response of shear walls. In particular, when the sheathing-design methodology is adopted, then the seismic behaviour is strongly influenced by the nonlinear response of sheathing-to-frame connections. In this paper a performance-based design methodology for the seismic design of sheathed CFS walls is proposed. The presented methodology is based on the results of an extensive parametric nonlinear dynamic study carried out on one story buildings by means of incremental dynamic analysis. Moreover, a multistep design procedure that allows all the main structural components to be defined in three steps is developed. In particular, a nonlinear dynamic (ND) nomograph for the assessment of the external screw spacing is presented in this work in order provide a new tool that upgrade the design procedure under investigation by the Authors in the last years. Finally the application of the proposed design methodology is verified through a case study.