A Study On The Prestress Design Of The Continuous Girder Bridge

The prestress design is the important part in the design of concrete continuous girder bridges. By using the finite element software to analyse the construction process of a prestressed concrete continuous girder bridge, this paper calculates the influence for the stress state of the box girder if the web strand bends adown or not, and the diagonal tension stress of web is contrasted according to three different cases which the vertical prestressing force is not considered, thirty percent of the vertical prestressing force is considered or fifty percent of the vertical prestressing force is considered. As to the study of vertical prestress design, combining concrete bi-shear strength criterion with three parameters, this paper introduces reasonable calculation method of the number of vertical prestessing force in consideration of enhancing concrete strength, and discusses the methods how to improve the construction technics. This paper introduces two predigested calculation methods of transverse internal force: the frame method with elastic support and the frame method with rigid support. The internal force of the two predigested calculation methods are contrasted in symmetrical load and unsymmetrical load. And the temperature effect in transverse internal force is analysed. By the top discussions, some advices are provided for the reasonable design of large-span three-dimension stress prestressed concrete continuous girder bridges in theory.