Crack Resistance Behavior Of Long-span Box Girder Bridges

Box girder is widely used in long-span continuous beam bridges and continuous rigid-frame bridges due to its good monolithic performance. The traditional plane calculational methods are unable to truly simulate the spatial behavior of prestessed concrete bridges. In order to analyse the performance of PC box-girdered bridges under usual actions and overcome the limitation caused by simplification and assumption of plane analysis methods, a series of finite element models were introduced.In this dissertation, both 3-D solid and 2-D beam finite element models were introduced, which is baced on the secondary bridge of Sutong Yangtze River Bridge, a continuous rigid-frame bridge (140m+268m+140m). The box girder's stress state were analysed under the actions of creep and shrinkage, uniform temperature, temperature gradient of the deck, internal-external temperature difference, and live loads. The crack resistance of box girder were analysed under the worse combination for action effects to research the spacial effects on monolithic crack resistance of box girder.According to the results, differences are compared between 3-D solid model and 2-D beam model results. It is quite necessary for long-span PC box girder bridges to analyse crack resistance for the spacial stress.