Ultimate behavior of large-scale base isolated structure model using E-defense shaking table

For the next generation Fast Breeder Reactor (FBR), application of seismic isolation technology to the reactor building is planned to reduce seismic loadings to both internal equipments and structures. And it is required to obtain data on the ultimate behavior of base isolated structures for earthquake ground motions exceeding design ground motion. Large scale shaking table tests of a horizontal base isolation system were conducted using world largest shaking table 'E-defense' of National Research Institute for Earth Science and Disaster Prevention. Large scale test models of 600t weight supported by 6 lead plug rubber bearings of diameter 505mm, which is one third of the real scale, were used for the shaking table test. Shaking was given to the test model to grasp ultimate state of the base isolation system, until shear crack appears on shear walls and finally the rubber bearing breaks. Experimental data on the ultimate behavior and the capacity of the base isolated structure were obtained which can be used to evaluate seismic margins and seismic risks of the base isolated structures. Numerical simulations were conducted for the shaking table tests and the simulation method for the ultimate state of the base isolated structure was demonstrated. (author)