Seismic performance of multiple tuned mass dampers for soil–irregular building interaction systems

This paper deals with the applicability of multiple tuned mass dampers (MTMD) on the vibration control of irregular buildings modelled as torsionally coupled structures due to base motions considering the soil–structure interaction (SSI) effect. An efficient modal analysis methodology is used to systematically assess the combined soil–structure interaction and torsional coupling effects on asymmetric buildings. This method is implemented in the frequency domain to accurately incorporate the frequency-dependent foundation impedance functions. The performance index of MTMD is established based on the foundation-induced building floor motions with and without the installation of MTMDs. Unlike the traditional MTMD design criteria, the frequency ratio of each MTMD substructure to the controlled structural frequency is independent, in this paper, so that the MTMD with the optimal parameters can actually flatten the transfer functions of building responses. Numerical verifications show that the increase of height–base ratio of an irregular building and the decrease of relative stiffness of soil to structure generally amplify both SSI and MTMD detuning effect, especially for a building with highly torsionally coupled effect. With appropriately enlarging the frequency spacing of the optimal MTMDs, the detuning effect can be reduced. Moreover, the results of numerical investigations also show that the MTMD is more effective than single TMD as the SSI effect is significant.