Optimum Seismic Design of Structures with Hysteretic Damper Considering Soil Flexibility

The widespread use of energy dissipation systems has led researchers to investigate the optimal mechanical properties of these systems for improving the seismic performance of a structure with the installation of such devices. So far, considerable researches have been conducted on optimum seismic design of fixed-base systems with passive dampers. On the other hand, recent studies have shown that effect of soil-structure interaction (SSI) can have remarkable effects on optimum seismic loading patterns of structures in both elastic and inelastic states. In these investigations, several new optimization algorithms were proposed for optimum seismic design of buildings considering soil-structure interaction effects. However, very rarer optimization studies have performed on soil-structures systems with dampers. In this paper, a new optimization algorithm based on uniform damage distribution of equivalent shear building model considering soil-structure interaction effect is developed. To this end, shear buildings models with hysteretic dampers located on flexible base soil are optimized under 16 far-fault earthquake ground motions without pulse, and the effect of key soil-structure interaction parameters on optimum response is investigated. Results of this study indicate that using proposed optimization algorithm for soil-structure systems with hysteretic dampers to achieve optimum distribution of dampers will lead to significant improvement of the seismic performance of the primary structure. In addition, it was concluded that the soil-structure key parameters such as dimensionless frequency and structural slenderness ratio can significantly affect the optimum load patterns such that increasing SSI effect will lead to increasing seismic load on base and top of the structure compared to the fixed-base systems. This can be attributed to the flexibility and higher modes effect of soil-structure systems when compared to the corresponding fixed-base system.