Interactive Behaviour of Structures Equipped with Combined Seismic Dampers and Unbounded Foundations

Abstract

The use of supplemental damping to dissipate seismic energy is one of the most economical and effective ways to mitigate the effects of earthquakes on structures. Both displacement-dependent and velocity-dependent devices dissipate earthquake-induced energy effectively. Combining displacement-dependent and velocity-dependent devices for seismic mitigation of structures minimizes the shortcomings of individual dampers, and is the most economical solution. Previous studies have focused on reducing seismic responses of a damped structure without considering the consequence of the unbounded foundation. To better understand the seismic response of structures, it is necessary to anticipate the interaction of damped structures and the unbounded foundations during earthquakes. This paper focuses on the flexibility and radiation effects on a time-domain procedure based on the finite element method for damped structures. The infinitesimal finite-element cell method for unbounded media addresses the interactive behaviour of a damped structure and the foundation with an unbounded far field. In this study, significant differences between the system with and without the radiation damping are observed. To obtain better accuracy, the radiation damping needs to be properly taken into account. Quantitative results also reveal that interaction effects between damped structures and unbounded media are important.