Seismic design procedure for cold-formed steel sheathed shear wall frames: Proposal and evaluation

A seismic design procedure for CFS structures employing sheathed shear wall panels (SWP), compatible with the framework of the Eurocodes, is proposed in this paper. In order to assess the structural behaviour and generate the required data for the appraisal of the seismic design procedure, the OpenSees finite element environment was used to simulate the nonlinear behaviour of CFS-SWP adopting a novel deteriorating hysteresis model. Nonlinear static (pushover) and incremental dynamic analyses (IDA) have been carried out on 54 CFS-SWP frames having 2-, 4- and 5-storeys designed with varying seismic intensity levels. Fragility curves based on buildings collapse probability have been developed following the FEMA P695 methodology. Based on the defined design requirements, the CFS structural system evaluated in this study is shown to meet the acceptance criteria for a behaviour factor (q) equal to 2 for low- and moderate-seismicity. Furthermore, the results reveal that the lateral overstrength has a relevant influence on the probability of collapse and that an improved performance could be achieved if continuity of the CFS-SWP chord studs along the height is enforced.