Seismic Performance of TMDs in Improving the Response of MRF Buildings

In this paper, the effectiveness of tuned mass dampers (tmds) in controlling building structures under earthquake excitations is studied through investigating the practical considerations and vibration control efficiency of tuned mass dampers for 5-, 8-, 10- and 15-story buildings utilizing a structural system with special moment-resisting frames (mrfs) in both directions. assuming its frequency to be near the 1st natural frequency of buildings, it is designed to control the largest response of the buildings. the effect of detuning, on some tmd parameters, on the seismic performance is studied through time~hist6ry analysis using the el centro and tabas earthquake records. in addition, the results of time-history analysis are compared with those of a response spectrum analysis for the structures with and without tmd, in order to judge its effectiveness. under earthquake excitation, the performance of structures having tmds greatly depends on the characteristics of the ground motion. when the first mode of a mdof structure dominates the structural response, a seismic response reduction can be easily achieved. while the first mode response of a structure with tmd is proved to be substantially reduced, the higher mode response, in fact, increases as the number of stories increases. it is observed that tmd is effective in reducing maximum displacement in mrf buildings by as much as 32.2% in the tabas earthquake and 45.3% in the el centro earthquake. the maximum displacement results of a response spectrum analysis for the uncontrolled and controlled case in the el centro earthquake, in an 8-story structure, are 25.70 cm and 14.59 cm, respectively, whereas the maximum displacement using time-history analysis, in the uncontrolled and controlled cases, are 27.54 cm and 15.14 cm, respectively.