Experimental study on thick rubber bearings of three-dimensional isolation of nuclear power plants

The application of vertical isolation technique to nuclear power plants could shift the main frequency of floor response spectra (FRS) to 2∼4 Hz, much lower than the operation frequency of the equipment and pipeline, thus reduce the damage to the inner equipment and pipeline due to the vertical earthquake. This paper provides an experimental study on the thick rubber bearings. Mechanical behaviors of two types of rubber-based bearings, normal bearings and thick rubber bearings were tested according to the code, including horizontal shear and vertical compress tests. The tests reveal that the thick rubber bearings possess a similar shear stiffness and smaller compressive stiffness nearly l/8 compared with the normal rubber bearings. Therefore, the thick rubber bearings are suitable for loading element of new type three-dimensional isolation equipment. (authors)