Robust optimum design of tuned mass dampers for high-rise buildings under moderate earthquakes

In the present study the optimum design of tuned-mass-damper (TMD) devices used for the vibration control of high-rise buildings subject to moderate earthquakes is developed. For these structures a large acceleration demand can produce damage in equipment and contents: therefore, the performance of TMD will be based on the capacity of reducing this structural response. In order to maximize the performance and the efficiency of the TMD strategy, the ratio between the absolute accelerations of the protected and of the unprotected systems is assumed as objective function in the optimum design. The method is carried out in a stochastic way and a stationary-filtered stochastic process is assumed to model the seismic action. Since the main disadvantage of using a single TMD is the mistuning related to errors in the evaluation of the natural frequency of the main structure, an uncertainty is introduced for this structural parameter, which is modelled as a random variable. Uncertainties in other structural mechanical properties and in TMD are neglected.