Patent ID: 8402702

Claim:
A magnetically controlled sliding isolation system for protecting buildings, bridges, and other structures against earthquake damage, comprising: (a) an electricity-conducting metallic plate of predetermined shape and dimensions to serve as a base plate and furnish a sliding surface, attached in a horizontal position by conventional means to a foundation of a structure at each location where said foundation supports a structural member; (b) a sliding bearing disposed at each of said locations between lower ends of said structural members and the upper surfaces of said base plates and set so as to be able to slide on said base plates, each comprising: (1) a steel tube with a predetermined cross section, height, and wall thickness; (2) a steel plate of predetermined shape, size, and thickness welded to the upper end of said tube to serve as a cap to said steel plate and the bearing's anchoring element; (3) a circular groove made into an underside surface of said tube; (4) a sealing elastomeric O-ring fitted into said circular groove, with part of it protruding beyond said underside surface; (5) a low-compressibility fluid hermetically contained in a fluid chamber formed by said steel tube, said steel cap plate, said elastomeric O-ring, and said base plate; and (6) a plurality of permanent magnets of predetermined shape, size, and type attached to and arranged symmetrically and equally spaced on an exterior lateral surface of said tube; (c) mounting steel plates of predetermined shape and dimensions connected by conventional means to said cap plates and underside surfaces of the structural members being supported by said bearings; and (d) a plurality of permanent magnets of predetermined shape, size, and type fastened to and arranged symmetrically and equally spaced at an edge of each of said base plates, oriented in such a way as to produce repulsive forces on the permanent magnets attached to said tubes; whereby a structure may slide laterally relative to its foundation with insignificant resistance in the event of an earthquake, but at the same time limiting to practical levels the relative lateral displacements said structure may experience during said earthquake and gene-rating forces that prevent the traveling of said structure beyond the boundaries of said base plates and re-center said structure after said earthquake stops, achieving all this in a simple, practical, and cost-effective way.