Fatigue Life Analysis of Comb Plate Type Bridge Expansion Joints

Bridge expansion joints are susceptible to fatigue damage under cyclic vehicle loading, and the cost of repair and replacement is high, so there is little research on the fatigue of comb-plate expansion joints. This paper takes a kind of comb-plate expansion joint as the research object, applies the structural dynamics analysis method and finite element analysis software for dynamic response analysis, and combines with miner fatigue cumulative damage theory for fatigue life estimation of the weak position of the expansion joint. Based on this, the results show that the panel and the welded seam are the vulnerable positions of the comb-plate expansion joint, and the welded seam is the most unfavorable position and suffers the most stress. The parts of the expansion joint show a linear growth trend with the increase in vehicle speed. The fatigue life at the panel is 24 million times, the life at the weld is 5.42 million times, and the weld is the earliest part to be damaged. The comb-plate expansion joint meets the fatigue load test requirement of not less than 2 million times and returns to the initial state after unloading, and the maximum strain appears at the weld.