The Tuned Mass Damper (TMD) is a classical engineering device consisting of a mass, a spring and a viscous damper attached to a vibrating main system in order to attenuate any undesirable vibrations. The vast area of major researches show the effects of TMD in elastic structures .This paper aims to evaluate the application of TMD as a passive controlling system for structures considering nonlinear behavior. Tow 4 & 8 story reinforced concrete buildings designed based on Iranian code are modeled for time history analysis using different intensities of Tabas records. Three kinds of TMDs specified according to some literature proposals, are installed on the roof floor. In the numerical simulation procedures, tuned mass damper contributes to dynamic equations as an interaction force calculated in each time step. Hysteretic energy absorption and a criterion introduced for floor local displacement during vibration (RMS) are studied to illustrate the seismic effectiveness of TMD compare to the case without using TMD for structural systems

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