Seismic Performance of TMDs in Improving the Response of MRF Buildings


Department of Civil Engineering,University of Tehran


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 eciency 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.