Effect of earthquake frequency content on seismic-induced vibration control of structures equipped with tuned mass damper

The main goal of this paper is to investigate the influence of the earthquake frequency content on the optimization of tuned mass damper (TMD) for multi-story buildings. Earthquake frequency content is divided into three groups (i.e., low, intermediate and high frequency content) according to the ratio of peak ground acceleration to the peak ground velocities. Time-domain analyses are performed to obtain the dynamic responses of 10-story and 40-story shear buildings equipped with a TMD under twelve different earthquake records. Advanced firefly algorithm is used to obtain the optimum parameters of the TMD such as the frequency ratio and the damping ratio. The optimization criterion is selected as the minimization of the maximum top story displacement of the building with TMD. The optimum parameters of TMD designed by this paper and its control performance are compared with those of other previous works available in the literature. Compared to the other methods, the optimum TMD designed by this study especially performs better in reducing the maximum top story displacements. Furthermore, it is discussed why TMD is ineffective in reducing the maximum floor accelerations of 40-story building, and then the effect of different mass ratios and objective functions in reducing the maximum responses of both buildings under critical earthquake excitation is investigated in detail. The results also show that the frequency content of earthquake ground motions has a significant effect on the optimum parameters of TMD and its control performance.