Torsion Design And Analysis Of Curved Prestressed Concrete Girder Bridges

With the construction of highways and overpasses in the cities, and the further development of urban construction, demands for facilities in transportation of our society are higher and higher. Curved girder bridges are built more and more. It is of great significance to accurately hold the stress and deformation characteristics of the curved girder bridges for its safe operation and further development. This article mainly aimed at analyzing and calculating some problems related to the torsion design of curved prestressed concrete girder bridges.The most remarkable features of curved girder bridge under the load are as follows. Due to the influence of curvature, the torsion will appear inevitably, which will also cause bending deformation. This phenomenon is called flexure-torsion coupling.Considering the own characteristics of curved prestressed concrete girder bridge structure, and the mutual coupling affect of moment of flexion and torsion under the load, this article aimed at the research on some major factors causing the torsion of main beam ,and the thorough discussion on the influence of prestressed reinforcement, supporting condition and supporting position on the torsion. I have mainly done the following jobs.Firstly, I have briefly introduced the form and mechanical characteristic of curved girder bridges, synthetically analyzed all sorts of calculational theories, and discussed respective Applicable scope, advantages and disadvantages of them.Secondly, I have researched the influence of prestressed reinforcement on the torsion of curved girder bridges. To balance the external torsion structurally, we often use prestressed concrete structure. It can effectively resist the cross-sectional moment of flexion, shear and torsion in the curved girder bridges, but also can enhance the structural rigidity, reduce the sectional dimension and increase the span. This article mainly analyzed theproblems related to the distribution of prestressed reinforcement. And make adjustments of the prestressed reinforcement on the specific conditions, thus enable the stress of curved girder bridges to tend to a more reasonable state.Thirdly, I have made a further research on the relative problems of torsion design of curved prestressed concrete girder bridges. It is the key to choose a correct calculational theory and establish a reasonable model when we analyze the structure.Fourthly, I have discussed the method to adjust torsion through presetting decentration of support abutment, and analyzed the influence on the superstructure of it. It can improve the stress of main beam, reduce the torsion of both sides, reduce the deformation of cross direction and consequent direction, and avoid the cross move or drop of the main beam.Finally, through a case study, I have analyzed the influence of some factors such as curvature, supporting conditions and supporting positions of curved girder bridges on the results, from which I have generalized some useful conclusions.