Abstract: A seismic isolation bearing including a top load plate (11A) for securing the bearing to a structure to be supported, a lower load plate (11B) for securing the bearing assembly to the foundation, and a steel reinforced rubber bearing body (13) sandwiched therebetween. The rubber bearing body (13) performs the bearing and restorative functions of the seismic isolation bearing. A steel midplate (14) extends radially from the middle of the bearing body laminated stack, and includes a plurality of holes (35) proximate the outer circumaference of the midplate. A first series of yield pins (12T) are anchored to the top load plate and extended downwardly toward the bottom load plate, and a second series of yield pins (12B) are anchored to the bottom load plate and extend upwarlly towards to the top load plate. The yield pins (12T, 12B) are received within the oversized holes (35) disposed about the periphery of the midplate.

Abstract: A seismic isolation bearing for structures consisting a steel ball sandwiched between two horizontal, steel load plates. The load plates have a shallow, concave, conical recess of vertical, collinear axis. The cone axis passes through the ball centerline at rest. The load plates are bolted the structure under and above. Gravity restores the bearing's displacement in the lack of external forces. Lateral bearing forces are independent of displacements.

Abstract: A seismic brake assembly comprises an annular pipe journaled through a gripping block which frictionally engages the pipe about the pipe's outer diameter. The force with which the gripping block frictionally engages the pipe is controlled by a Belleville or spring-loaded washer. By securing the gripping block to one point in a structure and by securing one end of the pipe to another point in or associated with the same building or structure to be supported, the seismic brake functions as a rigid member of applied lateral stresses less than a design threshold. When the applied lateral force exceeds the design threshold, controlled sliding friction between the rod and gripping block is experienced, whereupon the building or structural framing returns the seismic brake to its nominal position when the seismic activity ceases. By controlling various factors including the diameter of the pipe and the tension with which the block engages the pipe, virtually any desired hysteresis loop may be achieved.