Isolation from the ground during a seismic excitation has been one of the challenging subjects for researchers for many years. From the review of current approach to date, the general principles are for buildings or structures to be decoupled from the horizontal components of the earthquake ground motion by interposing a layer with low horizontal stiffness between the structure and the foundation. The harmonious movement of the structural basement will cause a significant reduction of fundamental frequency that is much lower than its fixed-base frequency and also much lower than the predominant frequencies of the ground motion.
In this paper the Base Isolation systems are investigated from the historical evidences up to now. The work presented herein is based on comparative perspective of different methods proposed to date based on their compatibility, efficiency, benefits and weaknesses of each system that are deliberated and analysed. Finally a five-storey building as a case study has been taken into consideration through simulated analysis for both, with and without base isolation systems. Numerical analyses are applied in order to observe dynamic behaviour of such structures under seismic loads. Brief review of the economy and practical effectiveness of base-isolation systems is reported for completeness.
Earthquake, Base-isolation history, Dynamic analysis
