The effect of multiple tuned mass dampers on response control of base isolated multi-storey space frame structure

Dynamic response of base isolated multi-storey symmetrical and asymmetrical space frame structures with multiple tuned mass dampers (MTMD), subjected to bi-directional harmonic and Mexico earthquake ground motions are studied. A four-storey space frame structure 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. Each tuned mass damper (TMD) is modelled using a two-noded element having two translational degrees of freedom at each node. MTMD with uniformly distributed frequencies are considered for this purpose. The effectiveness of MTMD in suppressing the structural response is determined by comparing the response of corresponding structure without MTMD. It is found that the MTMD can be used effectively to suppress the responses of the symmetrical and asymmetrical base isolated space frame structures. The effect of important parameters on the effectiveness of the MTMD is also studied. The parameters include the fundamental characteristics of the MTMD such as damping, total number of MTMD, tuning frequency ratio and frequency spacing of the dampers. It is shown that these parameters have considerable influence on the effectiveness of the MTMD in reducing the dynamic response of the base isolated structure.