Effects of nonlinear soil–structure interaction on the seismic response of structure-TMD systems subjected to near-field earthquakes

Abstract

The present investigation illustrates the performance of structure-Tuned Mass Damper (TMD) system to suppress the excessive vibration of structure buildings subjected to near-field ground motions involving the nonlinear effects of three dimensional soil–structure interaction (SSI). Accordingly, three medium-to-high-rise controlled structures based on a shallow mat foundation located on soft to very dense soil are examined. The ground motion database compiled for nonlinear time history (NTH) analyses of the soil–structure-TMD systems consists of an ensemble of 52 near-field ground motions. Comparisons are made in terms of maximum inter-story drift ratio as well as maximum inter-story acceleration ratio for the three possible conditions of the foundation: fixed-base structure, linear SSI (LSSI) and nonlinear SSI (NLSSI). The seismic responses of building structures are studied under the variation of key parameters such as peak ground velocity, factor of safety against vertical load bearing of the foundation (FS), non-dimensional frequency (a 0), ground motion characteristic and number of stories. On the one hand, the results indicate that the nonlinear effects of SSI significantly modify the structural responses in comparison with the LSSI counterpart. On the other hand, soil failure decreases the effectiveness of TMD. In a more precise view, it can be demonstrated that installing TMD can suppress the response of structures with linear SSI and without SSI (fixed-base structure) more significantly than that of structures considering NLSSI. Consequently, the responses would generally be underestimated if a linear behavior of the soil is assumed.