ABSTRACT
To study the fatigue problem of diaphragm-U-rib welding joint and diaphragm arc gap in steel box girder of Yangtze River Bridge, analysis of stress range and service life were carried out on fatigue details mentioned above based on the strain data collected from sensors in real bridge. Meanwhile, in order to improve fatigue behavior of the diaphragm, two new types of diaphragm structure were proposed, including transverse stiffener between major diaphragms and stiffener set on the arc gap. The finite element model of the steel bridge deck was established to analyze influence of the new structure on the fatigue stress. The result shows that the fatigue lives of diaphragm-U-rib weld ending and diaphragm arc web gap are, respectively, 3 years and 10.5 years. The optimized structures proposed in this study can effectively reduce stress range and the possibility of fatigue cracking in these two fatigue details.
