Mechanisms of plasticity development and energy dissipation on concrete-encased steel plate shear wall with boundary steel frame under cyclic loading

Steel frame infilled with composite plate shear wall (SF-CPSW) is an efficient lateral load resisting structure with significant ductility and energy dissipation capacity. In this paper, CPSW comprises the infill steel plate, encased concrete panel and headed studs. The steel frames (SFs) are expected to sustain the vertical load, while as the boundary members of the CPSW, they also influence the lateral behaviors of structure. However, the research on the interactions or plasticity development of SF-CPSW is limited. Thus, its energy dissipation mechanism is unclear to date. This paper conducts finite element analyses on the hysteresis performance and energy dissipation mechanism of SF-CPSW structure under cyclic loading. The hysteresis and skeleton of lateral load-drift ratio responses, distributions and developments of internal forces, stresses and strains and the energy assignments are studied to reveal the mechanisms of lateral load-resisting and plasticity development of SF-CPSW. The effects of steel plate thickness, beam cross-section, column cross-section and concrete panel thickness on the hysteresis performance and energy assignment are investigated to propose the energy dissipation mechanism and associated design methods. The results indicate that the energy dissipation of SF-CPSW is governed by the plastic shearing of infill steel plate and beam web due to the shear force transfers and bending restraints from CPSW to the steel frame. Besides, the columns resist portions of lateral load under such interactions. The structural energy dissipation should develop successively by the shear yielding of steel plate, the shear yielding of beam and column, the flexural yielding of beam, the plastic buckling of steel plate and the flexural yielding of column. As the major members for energy dissipation, the yield shear strength of beam should be higher than 27.5% yield shear strength of infill steel plate.