Fatigue Life of a Comb Plate Expansion Joint

Abstract

Comb-plate expansion joints are widely used in bridge construction, and their failures are mainly static strength and fatigue. This paper used a new type of comb-plate expansion joint as the research object. Firstly, the finite element models (FEM) of the comb-plate expansion joint with minimum and maximum openings were established by Ansys software. Then, the equivalent stress, vertical deformation, and shear stress of the expansion joint under these two working conditions were checked with code. The results showed that the static strength of the expansion joints met the code requirements under both working conditions. Secondly, to investigate the service span of the comb-plate expansion joint, the fatigue life of the expansion joint was predicted using nCode DesignLife software, and the results showed that the minimum fatigue life of the expansion joint was 2.012 × 106 times, which is higher than the 2 × 106 times specified in the code. Finally, a fatigue test of 2 million times was carried out on the full-size expansion joint. Failure modes such as deformation, fracture, or breakage hardly appeared after the fatigue test, demonstrating the reliability of this new type of comb-plate expansion joint.