Effect of soil-structure interaction on seismic performance of tuned mass dampers in buildings

Tuned Mass Dampers (TMDs) are aimed at mitigating vibrations of a structure under seismic or wind excitation by tuning the characteristics of the device to control specific resonance frequencies of the structure. However, the vibration modes of a structure can be considerably altered by the interaction with soil, leading to a loss of efficiency of the device. This paper shows the preliminary results of a study aimed at formulating a methodology for the design of TMDs accounting for soil-structure interaction. Taking as a reference an illustrative case study of a timber building equipped with a TMD, the results of a parametric study on the effects of soil-structure interaction are presented. This is accomplished through finite element simulations in which soil-structure interaction is described by dynamic impedance functions, in order to have computationally efficient models to study the properties of the soil-structure system. The results are expressed in terms of non-dimensional performance curves of the TMD accounting for soil-structure interaction. The performance curve describes the progressive decay of the TMD efficiency as a function of the structure-to-soil relative stiffness, highlighting the main features of the response of the soil-structure system. This also allowed a clear quantification of the relative contributions of soil stiffness and TMD to the attenuation of the structural displacements.