The object of this proposal is to explore the feasibility of controlling various modes of a structure under seismic loading through the installation of various groups of tuned mass dampers with the frequency range of each group distributed around a different modal frequency. The proposed scheme is called multiple distributed tuned mass damper (MDTMD). A MDTMD could combine the robustness and efficiency already demonstrated for single mode distributed TMD (in general referred to as multiple TMD, or MTMD), with the efficacy of highly damped and high mass devices proposed for some single TMD. The exploratory study will proceed in stages. First, some analytical studies reported in the literature will be simulated experimentally, on a shake table. The aim is to better understand why different studies yielded inconclusive results. Second, one optimization criteria already developed in the literature for single TMD will be extended to the case of a single distributed TMD (controlling one mode), and then to the case of a MDTMD controlling several modes. One benchmark case study, available to the seismic engineering research community, will be retrofitted with the MDTMD. Simple analytical and laboratory tests will be carried out on the reduced scale model to verify the potential effectiveness of the dampers. The aim is to explore the feasibility of the MDTMD for controlling multi-modal response for earthquake excitation. Significance and impact of the project. This exploratory work should advance the understanding of an important passive control device, and indicate whether or not TMD have the potential to be used for multi-modal control. If the answer in the exploratory study is positive, a more in depth research effort will be proposed. The expected outcome of the research will be a versatile, robust, and efficient methodology for vibration control of structures. The research will also provide much needed experimental data regarding the behavior of TMD subjected to ground excitation.
