Seismic response control of asymmetric buildings using tuned mass dampers

The aim of the present study is to investigate the efficiency of the torsional tuned mass dampers (T-TMDs) in response control of asymmetric buildings under bidirectional earthquake ground excitations. The efficiency of the T-TMDs is compared with bidirectional tuned mass dampers (BTMDs). The T-TMDs are oriented to the rotation of the structures about vertical axis with a single torsional mass attached to spring–dashpot elements, whereas the BTMD connects a single mass to two orthogonal sets of spring–dashpot elements oriented to principal axes of the building. The buildings are idealized three-dimensional models with two translational and one torsional degrees of freedom for each floor. Three different configurations (cruciform-shaped, L-shaped, and T-shaped) of multistory buildings are considered. The 5-, 15-, and 20-story buildings with and without the tuned mass damper schemes are subjected to bidirectional earthquake ground excitation. In order to evaluate the effectiveness of the T-TMDs and BTMD, the rotation, displacement, acceleration, and base shear force responses are computed. Parametric studies are conducted for all the configurations installed with the T-TMDs and BTMD by varying their mass ratio, damping ratio, and ground motions. It is concluded that the T-TMDs are more effective in mitigating the torsional response of asymmetric buildings as compared with the BTMD.