Case study on the impact of horizontal boundary elements design on seismic behavior of steel plate shear walls

A case study was conducted to investigate the seismic behavior of steel plate shear walls having boundary elements designed by two different philosophies. The first design approach does not guarantee that formation of in-span plastic hinges on horizontal boundary elements (HBEs) will be prevented, whereas the second approach guarantees that plastic hinges can only occur at the ends of HBEs. Pushover and nonlinear time-history analyses were conducted to investigate behavior. Results show that the development of in-span plastic hinges has significant consequences on the behavior of the structure through inducing (1)significant accumulation of plastic incremental deformations on the HBEs; (2)partial yielding of the infill plates; (3)lower global plastic strength compared with values predicted by code equations; and (4)total (elastic and plastic) HBE rotations greater than 0.03radians after the structure was pushed cyclically up to a maximum lateral drift of 3%. Nonlinear time-history analyses also demonstrated that increasing the severity of the ground excitations [i.e., from design basis earthquake (DBE) to maximum considered earthquake (MCE)] acting on the structure with in-span plastic hinge accentuated the accumulation of plastic incremental deformations on the HBEs.