The seismic behaviour of base isolated buildings is herein analysed by using an innovative mathematical formulation in the state space, that allows us to describe the dynamic response of structures in the case of non-classical damping. Particularly, the seismic response of base isolation with linear–viscous behaviour is herein investigated by studying the mode shapes, the frequencies and the modal participation factors, that are obtained by the proposed formulation varying the main design parameters. In such a manner, the effect of these parameters on the isolated structure behaviour as a whole is evident.
Over the last two decades, world-wide attention has been directed toward the use of innovative passive and active structural response control systems to mitigate the dynamic effects of wind and seismic loads. Although passive systems provide a limited response control level compared to the active ones, they do not require an external power supply to operate and therefore are still considered as viable and cost effective solutions to control vibrations of buildings or other civil engineering structures. Examples of passive response control systems, also known as supplemental damping systems, include viscoelastic dampers, tuned mass dampers, tuned liquid dampers, viscous dampers and friction dampers. Supplemental damping systems have been in existence for well over forty years and have been thoroughly researched and tested. Furthermore, their performance has been also validated through full scale monitoring during wind storms or seismic events. A considerable number of supplemental damping system implementations are for wind-induced motion control of skyscrapers. Their implementation has gained much recognition as a workable and highly reliable solution to enhance the serviceability performance of tall buildings and other dynamically sensitive structures. In this paper, supplemental damping systems that have become increasingly popular will be discussed, with specific attention to their recent notable applications in actual wind-sensitive buildings.
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