High Mass Ratio Tuned Mass Dampers Obtained Through Building Superelevations for Seismic Retrofit

Tuned Mass Dampers (TMDs) are widely adopted passive vibration control devices used to mitigate structural oscillations induced by wind and seismic actions. Conventional TMD systems typically involve relatively small auxiliary masses installed near the top of tall buildings. This paper investigates an alternative strategy for seismic retrofitting of existing structures based on large mass ratio TMDs obtained through building superelevations. In this approach, one or more additional storeys supported by seismic isolation devices behave as large tuned masses capable of reducing structural response during earthquake excitation. A comprehensive parametric numerical investigation is carried out in order to evaluate the influence of the mass ratio, structural period and damping characteristics on the effectiveness of the system. The results are summarized in a set of design charts that allow engineers to determine optimal tuning parameters. In particular, by using the obtained design abaci they can find a solution which minimizes both displacement and acceleration.