Optimal Design of Viscoelastic Dampers in Frame Structures considering Soil-Structure Interaction Effect

The seismic response control of multistory frame structures using optimally placed viscoelastic dampers (VEDs) within consideration of soil-structure interaction (SSI) effect is investigated in this paper. The system is assumed to be elastic and responses of the system are obtained in frequency domain for stationary random seismic excitations. The optimal designs of VEDs in structures are achieved through genetic algorithm (GA) by minimizing the maximum response quantities of the system for a determined total amount of viscoelastic material. Two typical elastic multistory frame structures with different soil types and foundation embedment ratios are considered to demonstrate the optimization process. It is shown that the VEDs have the best control of the structural response for fixed base condition and the control efficiency decreases as the soil becomes softer. The optimal placement types of VEDs for different soil types differ from each other. With the decrease of soil stiffness, the optimal locations of VEDs have a tendency to shift to top floors.