Design of Hybrid Base Isolation Systems with Passive Friction Dampers

摘要

Using base isolation systems for seismic protection of structures became one of the most popular ways in the past few decades. Usually such systems yield improvement in structural seismic response, but the displacements at the base isolators' level are rather big. Addition of friction dampers as well as other energy dissipating devices to base isolators is a known way for reduction of base displacements. Using additional active or semi-active dampers aimed to achieve optimal structural behavior is also good reported. This paper presents a design method for selection of passive friction dampers' properties based on optimal active control algorithms. The aim of the design is to select the properties of passive friction dampers so that the seismic response of a base isolated structure with these dampers would be as close as possible to that of a structure with optimally controlled active damping devices. According to the proposed method, such behavior is achieved if the energy, dissipated in passive friction dampers, will be equal to that in active controlled in a numerical example. Behavior of a base isolated structure with supplemental passive friction dampers, designed according to various strategies is compared and a most effective one is selected. It is shown that the proposed method yields a structural seismic response that is more similar to that an active control system.