Seismic performance of steel plate shear walls considering two different design philosophies of infill plates. I: Deterioration model development

Research was conducted to investigate the seismic performance of steel plate shear walls (SPSWs) having infill plates designed to resist different percentages of the applied lateral loads. The FEMA P695 methodology, which defines the performance in terms of collapse potential under maximum considered earthquake (MCE) ground motions, was used to compare the performance of the SPSWs under consideration. This paper describes the development of component strength deterioration models that are needed to perform the collapse assessment of SPSWs, focusing on stress-strain or force-deformation relationships for infill plates and boundary elements. The approach began with identifying the deterioration and failures modes of SPSW from 36 tested specimens. Cyclic deformation capacities of these SPSWs when reaching their ultimate strength, failure points, and rates of degradation were statistically quantified. Based on these statistical results, initial deterioration models for SPSW components were developed in a format compatible for use with the FEMA P695 procedures. The chosen deteriorated material models for infill plates and boundary elements were calibrated to four selected SPSW specimens varying from one to four stories. A companion paper presents the steps and results of the seismic performance assessments.