Vertical Flexibility in Isolation Systems

Abstract

This paper will review the history of three-dimensional (3-D) seismic isolation, its implementation and its drawbacks. It will cover the theoretical analysis of the rigid block on springs and the circumstances under which the various motions are and are not uncoupled. We will also review the records from a building with a 3-D isolation system that was impacted by fairly severe earthquake action. This review suggests that the search for full 3-D isolation is unlikely to be successful.