Capacity Fragility of Screw Connections installed in Cold-Formed Steel Partition Walls

The cold-formed steel partition walls (CFSPWs) consisting of steel framing and gypsum boards are usually damaged at shake intensities much lower than those required to initiate structural damages. In order to reduce earthquake-induced-loss on buildings, a better understanding of the seismic performance of CFSPWs is still required. The main purpose of this study is to quantitatively evaluate the capacity fragility of screw connections installed in cold-formed steel partition walls and to find out the effects of construction details on the seismic performance of CFSPWs. Based on the component tests for screw connections, physical responses and damage mechanisms of screw connections consisting of CFSPWs are investigated including the effects of screw spacing, edge distance, and layers of gypsum boards. A series of nonlinear analysis model is proposed to properly capture hysteretic behaviors of screw connection installed in CFSPWs and calibrated using component test results. The analytical data are then utilized to develop capacity fragility curves for CFSPWs in terms of drift as the representative engineering demand parameter.