ABSTRACT
The segmental steel box girder is designed and the fatigue test is carried out. Through the analysis of the whole process of fatigue damage evolution of steel box girder, it can be seen that the damage development has experienced three stages: the first stage is crack initiation stage, that is, the rapid development of micro defects in the specimen and the formation of micro cracks, at this time, the damage of the specimen accumulates rapidly, which accounts for about 5% of the total life; the second stage is the stable crack growth stage, at this time, the damage develops steadily, which is the stage of stable crack growth The third stage is the stage of crack instability and propagation, in which the damage increases sharply and even the specimen is damaged, which accounts for about 5% of the total life. It can be seen from the test analysis that when the component enters the instability stage, the cycle ratio experienced by the test piece has reached about 0.95, and the damage value is about 0.5.
