Steel - Concrete Joint Force Performance And Power Transmission Mechanism

As one of the most important structural nodes of mixed arch bridge, the steel and concrete joints must connect steel arch rib and concrete arch abutment structure into a co-stressing organic whole, in order to pass the internal forces and deformation caused by the loads in construction and using stages smoothly. The rationality of its design and structure can directly influence the use and structural safety of bridges. From the design code point of view, the analytical calculation theory and method about the steel and concrete joints of arch structure are still weak. The Yongxiu Bridge of Changjiu intercity railway is the background project of this paper. This bridge is a frame tied-arch bridge with main spans arranged as (31.75+128+31.75) m, that is a structural system of consolidated arch and pier, separate girder and pier, and of which the arch is crucial bearing member while the girder can only bear the loads between joints and form the floor system. To ensure the rationality, economy and security of the design and structure of the steel-concrete joint structure, this paper analyses the steel-concrete joint structure with analytical method and numerical analysis method. The main tasks are as follows:1. To simplify the steel-concrete joint of the arch structure in the background project as exposed steel-concrete joints. On the basis of collecting and summarizing literatures, this article has analyzed the compression, flexural and shear behaviors of the anchor bolt, bearing plate and concrete in the joints of the project according to the traditional analytic theory for exposed steel-concrete joints, and has pointed out some problems in the analysis, proved that for the bridge which is similar to the background project, it is not appropriate to design the structure as the exposed steel-concrete joints.2. Combining analytical theory for exposed joints with finite element analysis results, a new analytical method for exposed steel-concrete joints is proposed, which is based on the reaction distribution mode of folding line which between pressure plates and concrete, and has also considered the local stress.3. The background project has been analyzed using the analysis method for embedded steel-concrete joints based on the triangular and rectangular distribution of reaction. And a new calculation method which has considered the influence of steel-concrete bond strength is proposed in the analysis of rectangular reaction distribution. After comprehensive comparison, it has been concluded that the design of the steel-concrete joint of arch structure which similar to the background project should use the embedded joints.4. According to the fact that the stresses in the steel-concrete joints of the background project are very complicated, this paper has established a local model for computing the steel-concrete joints of arch structure in the background project with space finite element method, and analyzed the stress results to carry out an evaluation of the rationality of the joints design, explored the force transferring rule of the joints.