Influence of uneven aging on mechanical property of natural rubber bearing for offshore bridge and simplified aging prediction method

The natural rubber bearing, rubber block and rubber sheet with the same rubber material were put forward together on the same experimental condition to test, and the changing rule formula of the rubber hardness over the distance from the surface distance was established. Based on the above research, the finite element analysis model of the rubber bearing was set up by use of ABAQUS software. After comparing the testing data and the finite element analysis results, the effectiveness of the finite element model was verified. And then, the uneven aging model of the natural rubber bearing was established; hardness was changed in distance from the surface; the uneven aging influence analysis on mechanical property of the rubber bearing was carried out. The stiffness calculation formula of the rubber bearing considering uneven aging was put forward, and a simplified method to estimate aging performance of the rubber bearing was given. The results show that uneven aging will result in the uneven vertical strain of bearing surface, and the rubber bearing will be damaged under long-term load and aging; the horizontal stiffness of the rubber bearing is related with aging area, but is irrelevant to the loading direction.