Post-Yielding Behavior of Hinge-Supported Wall with Buckling-Restrained Braces in Base

Abstract

A novel structural wall with hinge support and buckling restrained braces (BRBs) set in the base (HWBB) is studied. HWBB can be applied to precast manufacturing due to its considerable ductility and the separate loading mechanism in HWBB–frame structure. In elastic stage, BRBs play a brace role to make the hinged wall resist horizontal forces like a shear wall. BRBs dissipate seismic energy through plastic and hysteresis effects after yielding and the damage is only concentrated in BRBs. The performance of an HWBB is equivalent to a shear wall structure with excellent ductility and stable energy dissipation capacity. Numerical analysis indicates that the hinged wall body in the HWBB well controls the deformation mode of the structure, avoiding the concentration of story drifts, thereby protecting the remaining parts of the structure. It is revealed that the moments of the wall body will generate significant increments after BRBs yielding, and the Seismic Intensity Superposition Method is proposed to calculate the moments. In this method, nonlinear response of an HWBB can be regarded as the sum of the responses of two elastic corresponding structures excited with two parts of the seismic intensity, respectively. Modes and moments equations of the hinged wall with uniform distribution of stiffness and mass are derived, and calculation results coincide with that of the nonlinear time history analysis (NHA). For a more general case, the white noise scan method is proposed to solve the structure’s natural characteristics and to further calculate the response. Finally, the post-yielding moment calculation method and the process based on design response spectrum are proposed. It is proved that the moments from proposed Seismic Intensity Superposition Method can envelop most of the moments from NHA, and it is a good estimate of the response of HWBB in nonlinear stage.