Seismic behavior of self-centering concrete-filled square steel tubular frame with slit steel plate shear walls

A self-centering concrete-filled square steel tubular frame with slit steel plate shear walls (SC-SSPSW) adopting post-tensioned (PT) column base was proposed in this study. The slit steel plate shear walls (SSPSWs) with edge stiffeners were only connected to the beams. Cycle tests were conducted on three 1/3 scaled single-span twostory specimens to investigate their mechanical and seismic behavior, and the formulas for beam and column internal forces considering frame expansion effects were derived. Finite element (FE) models of SC-SSPSWs were established, and the FE results agreed well with the test results. The results indicate that the hysteretic curves of specimens exhibit a typical double flag shape, and the residual deformation of all specimens is approximately 0.20% when loading to 2.0% story drift. Damage is primarily concentrated in the SSPSWs while other structural members remain elastic, and favorable resilience and energy dissipation capacity are achieved. With an increase in the width-to-thickness ratio or aspect ratio of links while keeping the thickness of SSPSWs unchanged, the energy dissipation decreases, and the self-centering capacity improves. The column that expands in the same direction as the loading direction bears more lateral loads. The theoretical gap opening value, PT tendons force, as well as beam axial force agree well with the test and FE results.