Enhancing seismic isolation using the inertial amplification mechanism based damper

To improve the performance of the traditional base isolation structure, this paper introduces a vibration control system that combines the base isolation structure with the Inertial Amplification Mechanism enhanced Damper (IAM-D). First, the governing equations for a base-isolated multistory building equipped with the IAM-D under earthquake excitations are established. Based on the simplified analytical model, the analytical expressions for the equivalent damping ratio and the damping enhancement equation of the IAM-D are derived. Second, the IAM-D in the considered base isolation structure is optimized, and closed-form solutions for the optimal parameters of the IAM-D are derived based on the damping enhancement equation. Parametric analyzses explore the effects of geometric and physical parameters on the optimal parameters. Finally, the seismic isolation performance of an MDOF base isolation structure equipped with the IAM-D or a viscous damper (VD) with the same damping ratio is analyzed by performing time history analysis and energy dissipation analysis. Compared to the VD, the IAM-D suppresses the base floor displacement, the absolute acceleration of the roof, and the base shear force by about 35%, 26%, and 31%, respectively. With appropriate design, the IAM-D can improve the energy dissipation capability of the conventional VD and enhance the seismic isolation performance of the traditional base isolation system.