Yangpu Bridge Steel - Composition Section Pilot Study

The main bridge of Yangpu bridge in Hainan is the hybrid girder cable-stayed bridge with two towers and space two-cable-sides. The span arrangement is (58.5+63+58.5+460+58.5+63+58.5)m. The girder of the side span is prestress concrete beam with ribbed plate type section, and the girder of middle span is the steel beam and the concrete bridge deck composite beam. The prestress concrete beam is deep into the girder of middle span 10m with the total length of 190m. The steel-concrete joint has the length of 2.6m with the steel beam bottom flange deep into the concrete beam 3.5m and the steel-concrete joint surface is located at 10m away from the center of cable tower in middle span. Mechanical behavior of the steel-concrete joint was studied systematically in this thesis by means of FEM analysis and model test. The major work is summarized as follows:1. Based on the results of the space finite element analysis(FEA) of the actual bridge and the steel-concrete joint, the extent of testing section and the model test conditions were determined.2. The simulation method of the internal force behaviour of the steel-concrete joint was studied. The axial compression was simulated by external prestressing, the vertical bending moment was simulated by vertical force and the eccentric external prestressing and the vertical shear force was simulated by the vertical loaded by jacks.3. Designed and produced an experiment model of the steel-concrete joint by a ratio of 1:3.2. The testing scheme was determined and the space finite element analysis of five kinds of load conditions of the model was completed. Conpared the finite element analysis results of the actual steel-concrete joint with the finite element analysis results of the model and adjusted the loading project until the stress distribution of the model agreed well with the actual steel-concrete joint.4. Four kinds of load conditions and one kind of overloading test were achieved. The experimental results revealed that the theoretical analysis results were agreeable to the experimental results. The structure of steel-concrete joint is reasonable, the force transmission is smooth and the level of stress is reasonable. The testing model was in linear elasticity under five load conditions, the stress of the steel-concrete joint is less than designed value; the steel-concrete joint has sufficient carrying capacity, and there is a large surplus left.The research results of this thesis not only provide the basis for design of The Yangpu Bridge in Hainan, but also provide references for study of other similar bridge structures.