In this study, multiple tuned mass dampers are optimally used for seismic vibration reduction of a multistory building. A five story building is modeled under lateral seismic vibration excitation as a lumped mass system. Modal analysis is then applied to the model and the natural frequencies are obtained. Noting the obtained natural frequencies, the displacements of the stories are obtained through a simulation under a chirp excitation covering all natural frequencies. The building is then modeled and simulated with five tuned mass dampers (TMDs) that are embedded in its five stories. The dynamical parameters of the TMDs such as mass, stiffness, and damping are obtained via the grey wolf optimization (GWO) method to minimize the maximum amplitude of stories displacements under the same chirp excitation which covers the new natural frequencies as well. The optimization method is also used to optimize a single large TMD at the top floor as it is customary. The building model is then simulated under excitation of a real recorded earthquake with and without the optimized TMDs. The effect of TMDs is then investigated showing the beneficial effects of the designed dampers in seismic vibration reduction of the building.
