The Research On Shear Lag Effect Of Box Girder With Wide Flange In Cable-stayed Bridge With Short Tower

The box girder has been used widely in bridge engineering due to its strongtorsional rigidity and excellent structural stability. However, because of the structuralfeatures of the box girder with wide flange, shear lag phenomenon exists in wideflange. Shear lag will cause stress concentration in wide flange, if this effect isignored in the design and construction process, it is bound to reduce the reserves ofthe structural safety and even lead to structural damage. So this thesis studys the shearlag effect of box girder with triple-cell used in xijiang bridge. And I think this studywill have important engineering value and theoretic significance.The work this thesis has done is as follows:(1) This paper refers to a large number of references, and reviews and analysesby contrast existing shear lag theories and methods, and pointed out the limitationsand applicable occasions of the methods refered by this paper, and propose someplace where existing shear lag theory needs to be improved. At last, the significanceand necessity of this thesis are made clear.(2)This paper establish finite element model of Xijiang bridge by ANSYSsoftware. It shows the shear lag result of ordinary cross-section (cross-section withoutdiaphragm and stiffener) in comparison with special cross-section (cross-section withdiaphragm and stiffener) in cantilever state and finished state.(3) This paper establishes a number of parameterized finite element model byANSYS. Influencing factors to shear lag effect such as pre-stressed reinforcement,web thickness etc are analysed. By longitudinal normal stress and shear lagcoefficient curve illustration in the main typical cross section, some usefulconclusions are drawn.(4) Combined with the strain data collected during the construction control, testresearch in Xijiang bridge is done in order to studying shear lag effect. And the resultis compared with the date got from spatial finite element method.