| The Tied-arch bridge has reasonable structure, great span ability and beautiful shape. Because the tie bar bear the horizontal thrust at spring of arch, it breaks the restrictions on the foundation, Pier, abutment of traditional arch bridges, thus widely used in the currently rapidly developped railway. In this paper, SYL, the railway prestressed concrete tied-arch bridge, works as the background, the deformation and mechanical behavior of the whole bridge, the mechanical behavior of the local bridge and the stability of the whole bridge were studied. Main work and achievements are listed below:1.3D finite element model of the whole bridge was established. Analysis and calculation of the force condition in the construction process of the whole bridge proves that the bridge has a good force condition and meets the specifications.2. The deformation and mechanical characteristics of the bridge under the combined impact of dead load, worst-case of living load, additional forces and loads were studied. The results show that the stiffness and strength of the bridge meet the requirements, the working condition being generally reasonable.3. Considering all details of structure, the refined finite element model of the spring of arch was established. The mechanical behaviors of the spring of arch under various working conditions were studied. The results show that the phenomenon of stress centralization exists, and we make some recommdendations on design.4. The refined finite element model of the lower structure and the horizontal ring box was established. The results show that it has a good force condition, meeting the specifications.5. The global stability of the bridge in the completion state with or without train were studied. The results show that the train load has great influence on the global stability of the bridge, while across-wind load has only a little influence. The first order buckling mode was controlled by the out-plane instability of longitudinal bracing rods, while the global instability didn’t happen unless in higher order buckling mode. The stability safety coefficient of the whole bridge is larger than 9, and the whole bridge has a good stability characteristic.The results of this article provide design basis for SYL Bridge, and also provide references for other similar bridges. |
