SHAKING TABLE TESTS ON BASE-ISOLATED NUCLEAR POWER PLANT

Base isolation technique is able to standardize the seismic design of nuclear power plants, shorten design and construction period and improve economic benefits. Moreover, it provides nuclear power plants a larger seismic margin to protect structures and facilities from potential huge earthquakes. Two types of rubber-based isolators, namely traditional horizontal isolators and three-dimensional isolators, were employed to design and construct shaking table models of base-isolated nuclear power plants, together with oil dampers installed in the base isolation layer. Through the shaking table tests and numerical simulations, the response comparison in both time-domain and frequency-domain reveals that the peak of horizontal acceleration is suppressed by 50% for both isolated models than the one without isolation; the dominated frequency of three-dimensionally base-isolated model shifts to lower frequency of 2Hz~3Hz, thus avoiding the resonant of facilities and pipes with dominant frequencies ranging from 10 to 20Hz. Meanwhile, both experiment and calculation verify that 15% additional horizontal damping to the isolation layer is able to effectively suppress the structural response, and reduce the peak of horizontal floor spectrum by about 50%.