Study On0#Block Spatial Elastic-plastic Analysis And Parameter Design Of Prestressed Concrete Continuous Box Girder Bridge

Prestressed concrete continuous box girder bridge is more and more favorred inengineering practice because of its good structural behavior and crossing ability. Butin the construction and operation, there are often found cracks of prestressed concretecontinuous box girder bridge, they affect the bridge structure performance.This thesis bases on the engineering background of a highway bridge. Using0#block and adjacent1#blocks to establish the finite element model, considering theloss of prestress, reasonable applying boundary constraints, Focus on analysis for0#block spatial elastic stress distribution and elastic-plastic stress distribution. All thework by means of ANSYS.When with the spatial elastic stress analysis, the thesis analyses stressdistribution of0#block in the cases of each concrete section with right constructionconditions, has concluded some distribution law that diaphragm plate’s stress iscomplex, its upper often appear larger principal tensile stress,it is easy to producestress concentration in its around and some other positions with section ofmutation,such as inspection and maintenance opening.Generally speaking, the longerthe length of cantilever, the greater principal tensile stress in0#block.It is necessaryto strengthen rebars in diaphragm plate and other positions with section of mutation.The thesis also analyses stress distribution of0#block when one side of hangingbaskets lose balance as cantilever cast-in-place.When with the elastic-plastic stress analysis, using solid65element to simulateconcrete, considering ordinary reinforcement ratio by setting the real constant forsolid65element. The control parameters settings for convergence are discussed inreinforced concrete nonlinear solution. The thesis analyses the elastic-plastic stressdistribution and development under the maximum cantilever state and operationstages, simulates the cracking process, calculates the crack width. Elastic-plasticanalysis shows that considering ordinary reinforced effect can effectively improve thestructure stress distribution, especially for tensile stress. Can be appropriatelyincreased the reinforcement ratio to improve0#block security reserve for emergencies.Anchorage zone to tension longitudinal prestressed bar is compressed atlongitudinal and transverse near the anchor plate position, it is transverse tensile aftera certain distance away from the anchor plate tensile. The scope of impact aboutwithin the shortest side length of the structure. Concrete stress under anchor plate isaffected by pre-channel, fallopian tube, tensioning order, its value much bigger thanother area, so it is necessary to add indirect reinforcement to weaken stress.