Seismic performance of a self-centering concrete frame with tuned viscous mass dampers based on mode tuning design

This study investigates the seismic performance of self-centering (SC) structures with tuned viscous mass dampers (TVMDs). Optimal TVMD parameters for a multi-degree-of-freedom SC structure were designed based on fixed-point theory and mode tuning. Numerical models of six-storey SC structures, one with a TVMD (SC-TVMD) and one with a viscous fluid damper (VFD (SC-VFD)) were established in the OpenSees software framework. The TVMD parameters for each storey of the SC-TVMD structure were designed using a mode-tuning design method. The parameters of the VFDs in the SC-VFD structure were consistent with those of the viscous elements in the TVMD. Seven ground motions were selected as the seismic inputs for dynamic analysis. The analysis results show that the TVMD can effectively control both the displacement and acceleration of each storey under strong intensive earthquake excitations. Under frequent earthquake actions, the acceleration response will be amplified slightly, but the displacement will still decrease significantly. The first-order equivalent modes of the SC-TVMD structure represent the characteristic inter-storey drift distribution patterns observed during fundamental vibration modes. After first-order mode tuning, each storey of the TVMD can increase the deformation of the damping element to improve energy dissipation. By comparing the dynamic analysis results of the SC-VFD and SC-TVMD structures, it was found that under the same seismic conditions, the TVMD provided better control of the effects of acceleration and displacement than the VFD and could dissipate energy more effectively.