This study proposes the development of a magnetorheological self-centering brace (MR–SCB) that can improve the energy dissipation capability of SCBs. The proposed brace reduces residual deformation and enhances the seismic performances of the structure. The disc springs enable recentering capability, while the magnetorheological fluid dissipates energy. The mechanics of the MR–SCB are presented, and a restoring force model to describe its hysteretic responses is established. Cyclic tests were conducted on the magnetorheological damping components of the brace and the entire large-scale MR–SCB specimens under sinusoidal excitations. Results confirm that the MR–SCB exhibits full flag-shaped responses, high ultimate bearing capacity, special superior energy dissipation capability, and stable restoring force. In addition, the proposed MR–SCB eliminates 96% of residual deformation. The superior energy dissipation capability of the MR–SCB can dissipate more energy and achieve greater control of seismic responses. The predicted and experimental results agree well. Thus, the Bouc–Wen restoring force model can be used to accurately describe the force–displacement behavior of the MR–SCB.

In this paper, the seismic performance and resilience of a 15-story variable-damping self-centering braced frame (VD–SCBF) were analyzed. The interstory drift ratios (IDRs) of the VD–SCBF are similar to those of the buckling-restrained braced frame, but are lower than the prepressed self-centering braced frame (PS–SCBF). The residual deformation ratios (RDRs) of the VD–SCBF are reduced, and its story acceleration ratios are smaller than the PS–SCBF. Under near-fault earthquakes, the higher-order mode has a greater impact, which increases the inelastic response and ductility demand. The effects of the brace design parameters on structural performance were also investigated. The optimal design parameters are as follows: the activation displacement is appropriately small; the variable-damping region corresponds to the axial displacement of 1% IDR; the ratio of the prepressed force to initial Coulomb damping force is 1.0–1.1; and the viscous damping coefficient increases. Combining the damage development process of different components, the VD–SCBF can be designed based on its four seismic performance levels to ensure a reliable resilience.