Research on the Effect of the Sequence of Exterior Concrete Placement on the Stability of Reinforced Concrete Arches with Rigid Skeleton

In the process of casting concrete in the outer package of reinforced concrete arch bridge with strong skeleton, the force state of the main arch ring will be constantly changed with the advancement of concrete casting, and this dynamic load distribution makes the mechanical properties of the main arch ring extremely complicated. It is a key issue in the construction of reinforced concrete arch bridges with strong skeleton to study the influence of different pouring sequences on the linearity and stability of the arch ring. This paper takes a reinforced concrete arch bridge with strong skeleton on the Sichuan-Tibet line as the engineering background, and simulates the influence of different pouring sequences of exterior concrete on the stability of the strong skeleton concrete arch ring. Based on the optimal working surface (eight working surfaces) and the optimal pouring method (ring-segmented pouring), 24 first pouring schemes are numerically simulated, and the optimal location of the first pouring section is determined through the analysis and comparison of stability and deflection analyses. The study shows that the first-order flexural modal coefficient of Scheme 4 (simultaneous casting of 1-1, 3-1, 5-1 and 7-1 bottom slabs) reaches 22.51, which is the highest value of all the schemes, indicating that its ability to resist instability is significantly enhanced. In addition, the deflections of scheme 4 in all critical sections are at the lowest level, and the maximum deflection is 86.9% lower than the worst scheme, and the distribution shows a gradual growth characteristic, which avoids the risk of local abrupt changes in the high deflection scheme.