Post-fire seismic performance of low-yielding-steel plate shear wall systems

In this study, the post-fire seismic behaviour of steel structures with a special low-yielding steel plate shear wall system was investigated. Three steel structures of 3, 6, and 9-storey with special moment-resisting steel frames and special low-yielding SPSW were designed according to AISC-360/16, AISC-341/16, and ASCE-07/16 using software CSI ETABS. One 2D frame of each structure was then modelled using the finite element package ABAQUS and analysed with the push-over method to determine their response modification factors R, an indicator of the nonlinear seismic performance of a structure. The models were validated against experimental testing on a steel plate shear wall system, which showed good agreement. The post-fire mechanical properties of steel were then implemented into the model and the post-fire response modification factors were determined. According to the results, the post-fire response modification factors of the 3, 6, and 9-storey models could respectively be reduced by 14.9%, 15.9%, and 9.0% compared to those before the fire, showing a considerable reduction in the nonlinear seismic performance of the structures. Furthermore, the results showed that higher temperature with more stories exposed to fire followed by air cooling leads to more reduction in seismic capacity, and overall water cooling tends to reduce the seismic capacity less than air cooling. Also, it was indicated that the code-specified value of R is rather over-conservative for post-fire calculations.