Research On Spatial Finite Element Analysis Of Joint Section Of The Composite Girder Cable-Stayed Bridge With Three Towers

Composite girder cable-stayed bridge is the use of composite beam, side span concrete beam with a main span and side cross-section connected by a combination of cable-stayed bridge. It beyond capacity, light weight, good seismic performance, low cost, the advantages of easy construction, construction of bridge at home and abroad has been widely applied. Joint section is to connect the main span cable-stayed bridge girder and the side span girder important concrete beam structure and function of the requirements can be smoothly passed the internal force produced by a variety of loads, but also composite girder cable-stayed bridge material and structure of the mutant department, its structure and stress are very complex, an important link for the bridge design.However, there is no clear calculation of Combined Sections theory and design guidance, the lack of design specifications as the basis for combining the components section of the stress state is not clear. Therefore, it is necessary to comprehensively grasp the true combination of the three-dimensional stress state and the section internal force transfer law in order to verify the design is reasonable, and similar to the bridge design and construction of some reference value.Wuhan Yangtze river bridge construction of erqi is the biggest span cable-stayed bridge with the three towers, adopt double beam combination choices-double beam rib concrete beam combination. By using ANSYS software, the spatial plate and shell and entity unit and combining with unit, establish the fine spatial finite element model for the process of operation, according to the combination of six kinds of loads for adverse conditions, analysis of the displacement change for combination, the stress distribution, force transfer laws and normal stress distribution. Specifically, this paper made the following several aspects:1 first established by finite element software ANSYS in wuhan Yangtze river bridge for combining erqi segmental model of spatial finite element by using the finite element software, secondly, Civil "Midas" establish wuhan Yangtze river bridge erqi overall bridge model is obtained by the bridge model for combined with surface of internal force influence lines, joints and determine the section model for combined load conditions, the size loading range and boundary conditions for accurately to combining spatial fem simulation model, section of combining process of operation for the adverse six load condition. 2 the displacement analysis combined with section. Combining section displacement variation in-7.9 mm～14 mm interval, combining segment to the majority of displacement, combined with the surface in the level of mm in smaller components deformation. Combining section steel and concrete beam bridge, three displacement change.With the analysis of the section 3 stress distribution. The main stress of concrete beams are-1.46 MPa～1.34 MPa interval, the principal stress variation in the steel 84.6 MPa～31.9 MPa-the main interval, bridge panel stress changes in-16.9% MPa-0.99 MPa interval. Combining section steel, concrete beams, the bridge in low stress state of stress distribution, can completely satisfy the design requirements.4 the internal transfer for combining analysis and normal stress distribution. Combined with longitudinal directions for transferring law:combining period, the main compression stress along the reverse, vertical bridge wangou reverse longitudinal directions is degressive tendency. Steel and concrete beam bridge, longitudinal directions, but in HL4 confined plate longitudinal directions in existing sharp change phenomenon. Combining the von Mises pressure plate for the stress variation scope for 0.87 MPa～42.4 MPa. Pressure plate overall stress level is low, the stress distribution is uniform.