Effects of seismic action and material properties variations on seismic responses of base-isolated nuclear containment structure

The mechanical properties of rubber bearing continuously change with the aging and environmental conditions. To evaluate the effects of deteriorating factors during the lifecycle of the base-isolated nuclear containment structure, a series of nonlinear time history analyses was performed. Computations were performed for three representative periods (2, 2.5, and 3 s), four types of deteriorating factors (aging, scragging, ambient temperature and multi-factor coupling), and actual ground motion. The influences of the deteriorating factors on acceleration and displacement of the superstructure have been discussed, as well as the shear force and deformation of the rubber bearing, and their response ratio. The results show that the changes in the mechanical properties of the rubber bearing had a significantly influence on the seismic responses of the base-isolated nuclear containment structure.