Assessment of the Seismic Performance of Large Mass Ratio Tuned Mass Dampers in a Soil-Structure System

The use of Tuned Mass Dampers with a large mass ratio (LM-TMD) can represent an efficient means for seismic retrofitting of existing structures, intended as a superelevation of the pre-existing layout having a mass up to 20– 30% of the structural mass. The mechanical properties of the LM-TMD should be designed to reproduce a proper dynamic coupling with the remaining structural system but there is still a limited knowledge about its effectiveness. Hence, this study presents a coupled numerical modelling of a soil-structure system equipped with a LM-TMD, implemented in OpenSees, as a benchmark to test the effectiveness of the non-conventional device. The full model simulates the nonlinear response of the soil-structure-TMD system and the multi-directionality of the seismic motion. The soil-structure interaction effects are quantified by comparing the results of the full model with those obtained in the case of structure with fixed-base. The results highlight the significant improvement of the structural performance when the LM-TMD is used, and the influence of soil-structure interaction on its effectiveness, as an additional source of energy dissipation not affected by the presence of the anti-seismic device.