Seismic optimization design of buckling-restrained braced frames for uniform damage criterion

This paper proposes a uniform damage design method for buckling-restrained braced frames (BRBFs). Through the optimization of buckling-restrained braces (BRBs), an improved design result could be achieved. This means a uniform degree of damage to each story, so that the weak story could be eliminated. The objective was to achieve an equal or similar damage index for each story by optimizing the initial stiffness of the BRBs. The uniform damage design of BRBFs was achieved using a combination of an intelligent algorithm and the finite element platform. Non-linear time history analysis and incremental dynamic analysis were conducted to verify the optimization results. These results indicated that the damage degree distribution could be effectively controlled by optimizing the BRBs' initial stiffness distribution using an intelligent algorithm. The optimal initial stiffness distribution of BRBs under different seismic waves was not identical. A design scheme that takes the average value of the optimal results under different seismic waves as the initial stiffness distribution of BRBs could improve structural seismic capacity.