Full-scaled model fatigue test of orthotropic steel deck

In order to study the fatigue failure behavior and fatigue strength of orthotropic steel deck of urban rail transit steel bridge, a full-scale test model of orthotropic steel deck was established based on the main span beam of a cable-stayed bridge of urban rail transit. During the test, the stress values and the cracking condition of the structure was observed to evaluate the fatigue strength. The results show that there is no crack during 2 million external load cycles, the main tensile stress values of each key test point before and after each cycle have little difference. It shows that there is no obvious redistribution of stress, and the fatigue performance of the model under 2 million external load cycles meets the requirements, and has a certain safety reserve. The load amplitude was increased and another 1.5 million cycles were carried out. When the external load cycles to 3.25 million times, cracks appear at the joint of the plate and U-rib. When the external load cycles to 3.5 million times, cracks are found at the symmetrical position of the first crack, and the test is terminated. The paper provides theoretical and experimental basis for the same type of bridge.