Semi-active hybrid control systems for nonlinear buildings against near-field earthquakes

Abstract

Because of the high peak acceleration and high velocity pulse with long period, near-field earthquakes, such as Northridge, Kobe and Chi-Chi earthquakes, are responsible for the destruction and severe damage to civil infrastructures. Under this circumstance, the low-damping passive base isolation system alone cannot ensure the safety of building structures. The purpose of this paper is to present the safety performances of various types of hybrid control systems for nonlinear buildings against near-field earthquakes. Hybrid control systems considered consist of mainly the base isolation system and either the passive control devices or the semi-active dampers or the combination thereof. Passive control systems studied involve viscous dampers and friction dampers, whereas two newly proposed semi-active control systems are investigated including the resetting semi-active stiffness damper and the semi-active electromagnetic friction damper. The elasto-plastic behaviors of both the base-isolation system and the building have been considered in the analysis. Extensive simulation studies have been conducted for control of base-isolated buildings subject to various near-field earthquakes. Simulation results demonstrate that the newly proposed resetting semi-active stiffness damper and semi-active electromagnetic friction dampers are quite effective in protecting the safety of building structures against near-filed earthquakes.