Seismic response control in base isolated structure using tuned mass dampers

The response of a base isolated multi-storey space frame structure with tuned mass dampers (TMD's), subjected to bi-directional harmonic and Mexico earthquake ground motions are studied. A four-storey space frame structure with consistent mass system having six degrees of freedom (three translations along x, y, z-axes and three rotations about these axes) at each node is considered for study. The effect of superstructure damping, isolation damping, TMD damping, mass ratio, tuning frequency ratio, superstructure time period and isolation period on the response of base isolated structure with tuned mass dampers is investigated. The response of base isolated structure with tuned mass dampers is found to be less in comparison to the corresponding response without tuned mass dampers, implying that the TMD is effective in reducing acceleration, forces and displacement in the system. It is also found that the superstructure damping, isolation damping, TMD damping, mass ratio, tuning frequency ratio, superstructure time period and isolation period have considerable influence on the response of a base isolated structure with tuned mass dampers.