Owing to excellent energy-dissipating capability, buckling-restrained braced frames (BRBFs) are popular seismically resisting systems which can well meet the collapse prevention target under strong earthquakes. However, one major concern of BRBFs is the excessive residual displacements after earthquakes, which delays the post-event recovery process. To reduce the residual displacements within tolerant range, this study proposes supplementing SMA braces (SMABs) to address this issue. A design method toward increasing the post-yield stiffness of the global system is developed for this solution. The general trend is first observed through conducting nonlinear time-history analysis (NLTHA) on single-degree-of-freedom (SDOF) systems, based on the comparisons made between the original and retrofitted SDOF systems. And then NLTHA is carried out on two benchmark low-to-medium rise BRBFs. The performance indexes of interest include the maximum demand of drifts and accelerations, and the residual drift. Both the SDOF analysis and seismic performance evaluation on multi-story frames show that the designed SMABs could well reduce the residual displacements for the BRBFs, and meanwhile they nearly do not amplify the maximum accelerations. Finally, the efficacy of the design method is further confirmed by parametric analyses, in which the SMABs were sized based on different design parameters and changed hysteretic parameters of the SMAs and the designed frames were subjected to ground motions corresponding to several intensity levels.