A practical system for isolating structures from earthquake attack

The recent development of a range of hysteretic energy absorbers permits practical shock isolation systems to be incorporated in the bases of a wide range of structures. This isolation gives reduced earthquake loads which may be resisted by the normal lateral strength of the structure. Hence a plastic reserve of earthquake resistance is no longer essential. A wider choice of architectural and structural forms is available with such an isolation system. The structures may be designed to prevent structural and non-structural damage with a high degree of reliability. The special hysteretic dampers limit the lateral movement of the base of a structure to a few inches. With these small movements the lateral flexibility required for an isolating system can be conveniently provided, for many structures, by rubber bearings.