Torsion effects on the seismic performance of adjacent mass-irregular buildings connected by viscous dampers

Many numerical studies have proved that connecting adjacent buildings by passive dampers can effectively improve the seismic performance of both connected regular buildings, however, its effect on irregular buildings is unknown. The torsion effect on the seismic performance of two three-dimensional adjacent buildings, including 8- and 12-story RC special moment-resisting frame buildings connected by viscous dampers was investigated in this paper, considering a mass eccentricity variable from 0-20% of the buildings’ plan dimension. The torsion effect on the control system was evaluated by comparing the maximum top-floor displacement and fragility curves of the connected and corresponding unconnected buildings. The results were derived by nonlinear time history analysis and incremental dynamic analysis under 22 far-field ground motions using the OpenSees software. According to the results obtained, the suggested control system enhances the seismic performance of both connected irregular buildings by reducing the maximum top-floor displacement and enabling the buildings to withstand higher values of ground motion intensity.