The Study Of The Continuous Skew Box Girder Bridge’s Spatial Behavior And Crack Origin

Abstract:In some special conditions, compared to the straight bridge, the continuous skew girder bridge can better adapt to the terrain features, conform to the linear change, improve road conditions, and shorten the span so as to reduce the project cost. As the result, continuous skew girder bridges are widely used in practical engineering. But because of the complex structural characteristics of the skew box girder, the study of their spatial behavior and crack resistance is very necessary. Taking the MA’AN Bridge as the background, this paper has mainly dealt with the following aspects:Chapter1and Chapter2summarize the research situation of skew girder bridge and crack resistance of box girder. And it also elaborates some theory of the skew continuous box girder bridge and several main factors which affect box girder crack resistance.Chapter3respectively uses MIDAS/CIVIL and MIDAS/FEA to establish the Ma’An Bridge finite element model based on grillage and the spatial entity unit model, and analyzes of whole bridge structure. Based on the Ma’An Bridge, it establishes the grillage model with different skew angles, and studies the effect of skew angle on support reaction, vertical moment, and inner forces of transverse beams. Through summarizing the rules, this paper tries to provide some suggestions for design of continuous skew girder bridges.In the fourth chapter, it respectively analyzes the influence on several kinds of box girder crack resistance effect, and concludes that various effects on the principal tensile stress distribution in the structure and the most unfavorable structure crack combination in the normal use combined with the influence of the specification. Through the nonlinear analysis of the structure, distribution of cracks in the skew continuous box girder bridge, and reinforcement improvement measures are put forward.