SEISMIC DESIGN OPTIMIZATION OF FRAME STRUCTURE WITH SELF-CENTERING SMA FRICTION DAMPER

The goal of seismic design optimization of buildings is to meet the requirements on loading capacity and deformation under different levels of earthquake by adjusting the location and number of energy-dissipation devices. An innovative self-centering damper is proposed in this paper which consists of shape memory alloy (SMA) and friction material, and can be installed in frame structures to reduce the seismic response. Taking the inter-story drift ratio (IDR) under the four-level seismic fortification targets as the constraint condition, a two-step design optimization method is proposed based on cyclic iterative method and backtracking search optimization algorithm (BSA). Firstly, cyclic iterations are carried out by increasing the number of dampers in the structure one by one to find the total number of dampers. Then the BSA based on global search mechanism is used to conduct the re-optimization. Seismic design optimization is conducted for a nine-story benchmark building by the aforementioned method. Results show that the proposed method can generate a reasonable placement scheme of dampers. The IDR of the optimal structure is more evenly distributed along the floor, which satisfies the preset IDR limit under seismic loading with the minimum number of dampers.