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 soilstructure 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 soilstructure-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 interstory 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 (F S ), 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.

Seismic performance of rocking soil-structure systems subjected to near-fault pulses is investigated considering foundation uplifting and soil plasticity. An extensive parametric study is conducted including medium-to-high-rise buildings with different aspect ratios based on shallow raft foundation at stiff-to-rock sites. Mathematical directivity and fling pulses are used as input ground motion. The superstructure is assumed to have three different boundary conditions: (i) fixed-base, (ii) linear soil-structure interaction (SSI), and (iii) nonlinear SSI. Evidently, the prevailing pulse period T p is a key parameter governing nonlinear SSI effects. The normalized acceleration response spectra reveal that despite beneficial effects of foundation uplifting and soil yielding in most cases, there are some minor regions in which the response accelerations are amplified. In addition, more slender buildings significantly benefit from uplifting and soil yielding when subjected to short-and medium-period directivity pulses compared to squat structures. However, response amplifications with respect to fixed-base structures are Downloaded by [Gazi University] at 21:38 04 February 2015A c c e p t e d M a n u s c r i p t 2 considerable in case of slender structures subjected to medium-or long-period directivity pulses.So that neglecting the SSI effects on seismic performance of rocking structures with shallow foundations, as mostly assumed in common practice, may give rise to inaccurate estimations of force demands against near-fault pulselike ground motions. Furthermore, the envelope of residual foundation tilting θ r is limited to 0.015 rad. in case of directivity pulses.

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