11.43: Seismic performance of staggered steel plate shear wall systems in high rise buildings

Abstract

ABSTRACTUnstiffened Steel Plate Shear Walls (SPSWs) are used as the lateral load‐resisting systems in building structures. The energy dissipation mechanism of SPSWs is consisted of the tension yielding of web plates and the formation of plastic hinges at the ends of horizontal boundary elements (HBEs). High‐rise buildings experience the high overturning moments leading to the high axial demands in the vertical boundary elements (VBEs) of SPSWs. The presence of high axial forces in VBEs can cause a reduction in their flexural capacity resulting in the drift concentration or even soft‐story mechanisms in the lower storey levels during an earthquake event. Past studies have shown that a staggered arrangement of steel plates may help in reducing the force demand in VBEs. Two simple methods are investigated in this study to r b educe the VBE forces are (i) by increasing the width of the web plates and (ii) by staggering the web plates over the frame height. A 20‐story steel frame building has been considered as the study frame. Three types of systems are designed to study the effect of aspect ratio and staggering on the seismic behaviour of SPSW. Force‐displacement characteristic of SPSW used in the numerical model is validated with the test results. Both nonlinear static and dynamic analyses are carried out in this study. Axial and shear force demands in the VBEs are reduced for the study frame, while achieving the desired hinge mechanisms. Nonlinear dynamic analyses under twenty spectrum‐compatible design‐level ground motions exhibited that staggered steel plate shear wall systems reduced the inter‐story drift by about 50% with respect to their conventional counterpart.