Base isolated/damping platforms for seismic protection of essential equipment - Lead rubber bearing platform

Half of a lead-rubber isolated platform, consisting of two rubber bearings supporting one steel beam that in turn supports a mass that simulates the self-weight of a piece of equipment, is tested to study the ability of the isolated platform to control earthquake accelerations and displacements of the equipment. To simulate the equipment weight, steel plates totaling 5,700 lbs are supported by the steel beam (8 feet long), the beam is supported on two lead-core rubber bearings and a shaped-lead brick. The platform is subjected to ground and floor accelerations. The floor accelerations intend to replicate floor accelerations recorded in multi-story buildings under historic earthquake shaking.