Effect of dominant ground frequency and soil on multiple tuned mass dampers

Using the proposed model of earthquake ground motions, the parametric study is performed to examine the effects of the DGF and SC on the performance of the MTMD with identical stiffness and damping coefficient but unequal mass. Examination on the optimum parameters of the MTMD is conducted through minimization of the minimum values of the maximum displacement dynamic magnification factors of the structure with the MTMD. The optimum parameters of the MTMD include the optimum frequency spacing measuring the robustness, average damping ratio and tuning frequency ratio. Minimizing the minimum values of the maximum displacement dynamic magnification factors, non‐dimensionalized by the maximum displacement dynamic magnification factors of the structure without the MTMD, is used to measure the effectiveness of the MTMD. Likewise, an evaluation is made on the stroke displacement of the MTMD through assessing the maximum displacement dynamic magnification factors of each TMD in the MTMD. The results indicate that DGF and SC, in particular, the former, have significant effects on the optimum parameters, effectiveness and stroke displacement of the MTMD. Nonetheless, the MTMD may be used to reduce the seismic response of the structure with controlled natural frequency less than DGF. Copyright © 2009 John Wiley & Sons, Ltd.