Study on Corrosion Fatigue Degradation Performance of Welded Top Plate-U Rib of Cross-Sea Steel Box Girder

Abstract

With the development of the economy and transportation, more and more cross-sea bridges are appearing in people’s view. However, cross-sea bridges are not only subjected to repeated traffic loads but also to corrosion from the marine environment. In addition, the steel box girder deck plate is directly subjected to repeated vehicle loads, and its welded details are highly susceptible to fatigue damage and destruction, resulting in fatigue or corrosion damage to the welded top plate-U rib of the cross-sea steel box girder. This paper is based on fracture mechanics analysis methods and finite element simulation analysis, in order to establish the numerical analysis method of the welded top plate-U rib of the steel box girder deck plate fatigue, which is to take into account the coupling of the marine corrosive environment and fatigue cyclic loading, explore the welded top plate-U rib of the stress intensity factor, crack expansion, crack expansion life and total fatigue life of the welded details. Furthermore, the establishment of the welded top plate-U rib corrosion fatigue life assessment model is to explore the fatigue life of different top plate thicknesses. The results show that: the stress intensity factor along the crack front is symmetrically distributed, and with the increase in the crack expansion step, the corresponding stress intensity factor amplitude is also increasing; in addition, with the increase in the top plate thickness, fatigue crack expansion rate significantly reduced.