| Although the traditional buckling restrained brace（BRB）structure system can ensure the safety of the structure under earthquake through reasonable design,their energy consumption mainly depends on the elastic-plastic deformation of BRB.Due to the low post yield stiffness of buckling restrained braces,there will be large residual displacement after large earthquake,which will lead to the weak ability of the structure to resist aftershocks,and the structure is difficult to repair after the earthquake.In order to solve this problem,the concept of self-centering buckling restrained brace（SMA-BRB）is proposed,hoping that the structure can be restored to its original position after the earthquake.Compared with buckling restrained braces,the influence of self-centering buckling restrained brace on seismic performance is more complex,and the main contents are as follows:（1）Based on ANSYS,a refined model which can truly reflect the performance of SMABRB model is established.The influences of the strength of BRB core steel,the crosssectional area of SMA bar and the pretension on the performance of SMA-BRB model are discussed.The results show that the energy dissipation capacity of SMA-BRB brace can be improved by increasing the steel strength of BRB core or the area of BRB core,but the selfcentering capacity of self-centering system needs to be improved accordingly.Under the condition of economy,the larger the cross-sectional area of SMA,the better the effect.In a certain range,increasing the pretension of SMA bar can improve the seismic performance and self-centering ability of SMA-BRB brace.（2）The seismic performance of SMA-BRB frame,BRB frame and steel frame is studied by OPENSEES software,and the seismic response and residual deformation are compared and analyzed.It can be seen that SMA-BRB frame has better energy dissipation capacity than BRB braced frame,and the residual deformation of the structure is greatly reduced.（3）Based on the endurance time method（ETM）and incremental dynamic analysis method（IDA）,the structural response analysis and vulnerability analysis are carried out on the benchmark framework.Through comparison,the efficiency and accuracy of ETM are verified.Through the ETM method,the vulnerability of SMA-BRB braced steel frame and BRB braced steel frame is analyzed.Because of the better bearing capacity,energy dissipation capacity and ductility of SMA-BRB frame,the exceeding probability of SMABRB frame is much lower than that of BRB frame under the same damage measure. |
