Study on ultimate behavior of base-isolated building: Effect of random rupture of isolation device

This paper describes the results of the numerical analysis on the ultimate behavior of the base-isolated Fast Breeder Reactor (FBR) building with 272 isolation devices from the viewpoint of the Cascade Failure phenomenon so that the rupture of an arbitrary isolator might induce that of others. Three-dimensional seismic response analyses are carried out, in which the rupture of isolators are considered, and the influence on the ultimate behavior of the isolation layer due to the torsional response which is attributable to partial rupture of isolators is investigated. Further, fragility of the seismic isolation layer is evaluated by employing the Monte Carlo Simulation technique, where randomness of strength of the isolation device is considered