Seismic Design of Bottom Boundary Columns in Steel Plate Shear Walls

Seismic Design of Bottom Boundary Columns in Steel Plate Shear Walls

Steel plate shear walls(SPSWs) can effectively resist earthquake forces by the development of tension field action after infill steel plates buckle in shear and dissipate energy through cyclic tensile yielding of the infill plates. The tension field forces of the infill plates can cause some plastic hinges to form within the beam span or column height. During the past decade, many researchers have aimed to develop design methods to ensure that the boundary beams or columns have adequate strength to prevent the occurrence of in-span plastic hinges. However, limiting plastic hinges to concentrate at the column bases usually requires heavy bottom columns. In addition, past tests show that the formation of a plastic hinge within the height of the bottom columns would not deteriorate the seismic performance of the SPSWs. In order to achieve an economical design, this study proposes a series of less-stringent capacity design methods to determine the flexural or shear demands for the bottom boundary column in a SPSW. The proposed design requirements allow a plastic zone to form within the lower part of the bottom column but prevent the column top end from yielding. In this study, a series of capacity design methods is developed to control he location of the in-span plastic zone on the bottom column and prevent yielding of the column top end under two large deformation levels: State-UY and State-HD, which respectively correspond to the onset of the plastic mechanism and the maximum considered earthquake(MCE) hazard level.