Investigation for crack on base-isolated rubber bearing subjected to environmental degradation factors and external loads

For investigating the effect of environmental degradation factors and external loads on the crack occurrence on the surface of rubber bearing and to develop a countermeasure, a series of accelerated exposure experiments was carried out. The accelerated exposure experiment was performed on large size rubber bearing specimens under the condition that the temperature was 40 degrees Celsius and the ozone density was 100 pphm. The crack was observed on the surface of rubber bearing by 384 hours, especially in the large tensile strain region. The crack simulated the actual one observed in the real base-isolated rubber bearing. After the experiments, the load carrying capacity and the stiffness of damaged rubber bearing were examined. However, the performance of damaged rubber bearing was not deteriorated compared with those of virgin state.