Development of the core-suspended isolation system

A new type of seismic isolation system-called the core-suspended isolation (CSI) system-has been developed and first building application recently completed. The CSI system consists of a reinforced concrete core on top of which a seismic isolation mechanism composed of a double layer of inclined rubber bearings is installed to create a pendulum isolation mechanism. A multi-level structure is then suspended from a hat-truss or an umbrella girder constructed on the seismic isolation mechanism. In this paper, the mechanics of the CSI system are described, followed by a discussion of results of shaking table tests and quasi-static loading tests of rubber bearings with rotated flanges, and a description of the first building constructed utilizing the CSI system, located in Tokyo, Japan. Copyright (C) 2010 John Wiley & Sons, Ltd.