Seismic Response Reduction of Structures using Base Isolation

Response of structuresand its components to earthquake vibrations is the major cause of damages and loss to lives. The intensity of loss of lives and damages can be reduced if the responses are controlled to a tolerable limit. The adverse effect of earthquakes led to the development earthquake protection devices. Among the three major types of protective systems namely passive, active and semi active, passive systems are simpler and easily adoptive.The base isolation system is one such passive control system that decouples the structure from the horizontal components of the ground motion by imposing flexible isolation elements with low horizontal stiffness between the superstructure and substructure. The isolation reduces the fundamental frequency of the structure that is much lower than the fixed base frequency and the predominant frequencies of the ground motion. In this paper the effect of base isolation on a structure has been studied by comparing the responses of the base isolated structure and fixed base structure. The influence of isolation characteristics on the seismic response of the structure has been investigated. The effect of using bilinear hysteretic isolation model on the response of the structure has been studied and compared with the linear models.