Seismic design of boundary frame members of steel plate shear walls

Steel Plate Shear Walls (SPSWs), which consist of infill steel panels surrounded by columns, called Vertical Boundary Elements (VBEs), and beams, called Horizontal Boundary Elements (HBEs), are rapidly becoming an appealing alternative lateral force resisting system for building structures in the United States, Canada, Mexico, Japan, Taiwan and other countries. This paper presents results of some recent research to expand the range of applicability of SPSWs with emphasis on improving the understanding of seismic performance of the boundary frame members. Following a brief review of the observed failure of the intermediate HBE from the MCEER/NCREE testing program, the models developed to investigate the behavior of HBEs are presented, followed by design recommendations. Then, analytical models to prevent the in-plane shear yielding and to estimate the out-of-plane buckling strength of VBEs are developed, followed by a review of past experimental data to investigate if the previously observed VBE failures were due to excessive VBE flexibilities or other causes. It is shown that the existing VBE flexibility requirement specified in the current design codes is uncorrelated to satisfactory VBE performance. The proposed analytical models predict the performance of previously tested SPSWs that correlates well with the experimental observations.