既有双曲拱桥拱上填料更换方案设计与计算分析

Design and Calculation Analysis of Arch Fill Replacement Scheme for Existing Double-Curved Arch Bridge

摘要: 桥面恒载是否均衡对双曲拱桥受力性能影响较大。为探究既有双曲拱桥拱上填料更换过程的安全性，本文基于某三跨空腹式双曲拱桥，首先具体分析了该桥梁病害情况以及主拱圈计算结果，并提出相应的加固维修措施，其次对由于长期过载而严重破损的拱上填料进行拆除换填。针对主拱圈段的拱上填料，使用四组不同的加卸载方案，采用有限元仿真软件Midas Civil 2021对各加卸载顺序方案进行模拟计算。通过对比加卸载时各方案M_max和M_min包络图，选择对称、均衡拆除(换填)第1、8分块→第3、6分块→第2、7分块→第4、5分块填料作为最优设计加卸载方案。又通过与活载效应对比、施工时挠度值和上下缘应力的变化，进一步验证了该方案的施工质量与安全性，并为同类型桥梁拱上填料加固换填施工提供了理论与实际依据。

Abstract: The balance of deck dead load significantly influences the mechanical performance of two-way curved arch bridges. This study investigates the safety of spandrel fill replacement in existing two-way curved arch bridges, based on a three-span open-spandrel arch bridge. The bridge’s disease conditions and the calculation results of the main arch ring are first analyzed in detail, and corresponding strengthening and maintenance measures are proposed. Subsequently, the spandrel fill, severely damaged due to long-term overloading, is removed and replaced. Four distinct loading-unloading schemes were employed, and finite element simulation software Midas Civil 2021 was used to simulate the construction process of the spandrel fill within the main arch ring segment under each scheme. The symmetrical and balanced removal (replacement) sequence of filler blocks—specifically, Block 1 and 8 → Block 3 and 6 → Block 2 and 7 → Block 4 and 5—was selected as the optimal design scheme by comparing the envelope diagrams of M_max and M_min during the loading and unloading processes across different schemes. Furthermore, by comparing with live load effects and analyzing variations in deflection values and stresses at the upper and lower edges during construction, the construction quality and safety of this scheme were further verified, providing both theoretical and practical foundations for the reinforcement and replacement of spandrel fill in similar bridge types.