Optimum design for more effective tuned mass damper system and its application to base-isolated buildings

Base-isolated structures are vulnerable to long-period ground motions due to resonances. The hybrid control strategy combining traditional tuned mass dampers (TMDs) with base-isolation systems has been proved by some researchers to be effective in preventing the resonant behaviors. However, large space for TMDs is required because of large stroke lengths of TMDs, which may be difficult to realize in practical applications. In this paper, a non-traditional TMD that is directly connected to the ground by a dashpot is adopted to mitigate the resonant behavior of a structure. It is found that the conventional design method of traditional TMDs based on the quasi-fixed points theory cannot provide the global minimum value of the objective function for non-traditional TMD systems. An optimum design method for obtaining a wide suppression bandwidth is proposed. Seismic-induced vibration control for a three degree-of-freedom base-isolated structural system with a non-traditional TMD is studied. The control effect of the optimally designed non-traditional TMD is significantly improved, and the stroke length of the non-traditional TMD is greatly reduced, compared with the traditional TMD during near-field long-period earthquakes. In these regards, non-traditional TMDs may provide a better solution for retrofitting or constructing base-isolated structures.