Base isolation or seismic isolation is a collection of special units in a building resting on its foundation to provide separation of the building from the shaking ground thus improving its seismic performance .
Basic parts of base isolation system 
Base isolation system consists of isolation units with or without isolation components, where:
1. Isolation units are the basic elements of base isolation system which provide the mentioned separation effect to a building structure.
2. Isolation components are the connections between isolation units and other parts of the building having no separation effect of their own.
Famous base-isolated buildings 
From the very beginning, the theory of base isolation rested on two pillars: heavy damping and frequency separation. Unfortunately, nobody paid any attention that the heavy damping was a sort of a strong connection between a substructure and superstructure, and that the idea of decoupling them with the help of such connections was of no good . Anyway, to virtually test-drive any design concept of base isolation, some online help is available now .
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