Orthotropic steel bridge deck is the main deck system of steel girder in long-span bridges with the advantage of light deadweight,high carrying capacity,and quick construction speed.With the increase of service life and traffic flow,fatigue cracks appeared in bridge decks of some bridges in China.The trough to deck plate welded joint at the crossbeam section is one location where fatigue cracks often appear.This kind of crack is difficult to be detected and repaired.The cracks affect the durability and operation safety of bridge deck.It is appropriate to conduct fatigue evaluation using reasonable fatigue evaluation methods in anti-fatigue design stage to reduce the occurrence of this fatigue damage.