Analysis and Optimization Design of Arch Foot Force of Large-Span Continuous Beam-Arch Composite Bridge

To study the influence of the force conditions of the arch-beam connection segment on the arch foot of a large-span continuous beam-arch composite bridge under different working conditions, taking the Yuehu Extra-large Bridge in Yingtan City as the engineering background, to understand the stress distribution law at the arch foot and make a reasonable evaluation of the construction at this location. The direct modeling method was used to select the GJa segment of the bridge for direct modeling. According to Saint-Venant’s principle, Midas Civil was used to extract the internal forces of the arch rib segments from the overall bar system calculation model and apply them to the local model established by Abaqus through rigid surfaces to analyze the mechanical properties of the arch foot nodes, and analyze the changes in the mise stress cloud diagrams of each plate in the beam-arch connection segment under different working conditions. The results show that the absolute value of the stress inside the arch foot fixed nodes is small, and the maximum value appears in the web and diaphragm of the main beam above the bearing. The beam-arch connection segment can ensure the stable operation of the bridge structure under the ultimate bearing capacity state load conditions, and reveals the force characteristics, deformation laws, stress transfer paths, and most unfavorable points of the beam-arch connection segment. Based on the finite element calculation results, using the method of optimizing the web thickness can effectively reduce the maximum stress and avoid stress concentration. At the same time, during the construction process, attention should be paid to the accurate positioning of the members and ensuring that the weld strength meets the standards.