Investigation of Subpanel Size Effect on Behavior Factor of Stiffened Steel Plate Shear Wall

Steel plate shear wall (SPSW) systems have been used in recent years in highly seismic areas to resist lateral loads. In general, a steel plate shear wall system consists of a steel plate wall, boundary columns, horizental floor beams and optional vertical and horizental stiffener plates. Utilizing stiffener plates causes changing of Steel Plate Shear Wall system behaviour, especially in nonlinear domain. In this paper subpanel size effects have been investigated on such nonlinear behavior. Five cases (one without stiffener and four with stiffener) were considered. A numerical analysis, based on finite element method was performed for each case. These analyses possess a pushover monotonic analysis. Then capacity curvature of system was derived and nonlinear behavior parameters such as “Behaviour Factor” and “Ductility Factor” were calculated by prevailing relationships. Studies show that by reducing of subpanel size, nonlinear characteristics of Steel Plate Shear Wall systems improve considerably. Also some relationships proposed for assessment of nonlinear characteristics of such system. Regarding the structures with high hardness (frequencies greater than about 2 Hz), increase in the behaviour coefficient in negligible, and in general, for this frequency range, it is recommended to use a fixed amount for the behaviour factor ranged from 11 to 13.