Seismic Performance of TMDs in Improving the Response of MRF Buildings

Abstract

In this paper, the e ectiveness of Tuned Mass Dampers (TMDs) in controlling building structures under earthquake excitations is studied through investigating the practical considerations and vibration control e ciency 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 e ect of detuning, on some TMD parameters, on the seismic performance is studied through time-history 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 e ectiveness. Under earthquake excitation, the performance of structures having TMDs greatly depends on the characteristics of the ground motion. When the rst mode of a MDOF structure dominates the structural response, a seismic response reduction can be easily achieved. While the rst 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 e ective 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.