Effectiveness of dynamic vibration absorbers implemented in tall buildings

Abstract

In recent decades, dynamic vibration absorbers (DVAs), such as tuned sloshing dampers (TSDs) and tuned mass dampers (TMDs) have been increasingly used to enhance the serviceability performance of tall buildings subjected to wind excitation. While the fundamental theory of ideal structure-DVA systems is well developed, there is a lack of available literature documenting the performance of DVA systems that have been installed in tall buildings. Moreover, it is challenging to directly quantify the effectiveness of DVAs installed in buildings due to the uncertainties associated with the applied wind loading. In particular, traditional methods are generally unable to directly calculate the effective damping that a DVA adds to the building.This study presents the results of full-scale structural monitoring conducted on two tall buildings that have been equipped with DVAs to reduce wind-induced motion. The responses of the building and the DVA were monitored during significant wind events. The performance of the DVAs is directly determined by using the building and DVA responses, and the structure-DVA mass ratio, to calculate the added effective damping. The theoretical added effective damping of an ideal structure-DVA system is compared to the measured value, revealing that nonlinear effects that are typically neglected, such as friction, can significantly alter the theoretical added effective damping from its measured value at low response amplitudes. The DVAs studied have significantly decreased the wind-induced motions of the tall buildings monitored.