大跨径中承式钢箱系杆拱桥施工阶段稳定性分析

为明确大跨径中承式钢箱系杆拱桥施工阶段稳定性，以西双版纳澜沧江黎明大桥为研究对象，建立全桥空间有限元模型对该桥进行施工阶段全过程稳定性分析，研究考虑初始缺陷的几何非线性、材料非线性、风撑、临时风撑、吊杆非保向力和抗风缆索对结构施工阶段稳定的影响。结果表明:施工全过程中结构的稳定系数满足相应规范要求，考虑初始缺陷的几何非线性分析，结构的稳定系数降低7%~8%；考虑几何与材料双重非线性时，结构的稳定系数降低49.67%~52.05%，故材料非线性对结构稳定性有显著影响。增加永久风撑数量能有效提高缆索吊装最不利施工阶段及拱肋合拢后施工阶段的稳定性，布设临时风撑能显著提升结构缆索吊装最不利施工阶段的稳定性，非保向力效应对中承式钢箱系杆拱桥稳定性有较大的影响，布设抗风缆索显著提升拱肋合拢后施工阶段稳定性。由此可见，施工阶段稳定性的影响因素较多，本研究可为同类型桥梁的施工与设计提供参考。

Stability analysis of long-span half-through steel box tied arch bridge

In order to clarify the stability of the long-span half-through steel box tied arch bridge during the construction phase, the Xishuangbanna Lancang River Liming Bridge was taken as the research object, and a full-bridge space finite element model was established to analyze the stability of the bridge during the whole construction phase, and the initial defects were considered. The influence of geometric nonlinearity, material nonlinearity, wind bracing, temporary wind bracing, non-directional force of suspender and wind-resistant cable on the stability of the structure during construction. The results show that the stability coefficient of the structure during the whole construction process meets the requirements of the corresponding specifications. Considering the geometric nonlinear analysis of initial defects, the stability coefficient of the structure is reduced by 7% to 8%; when the double nonlinearity of geometry and material is considered, the stability coefficient of the structure is reduced 49.67%~52.05%, so the material nonlinearity has a significant influence on the structural stability. Increasing the number of permanent wind braces can effectively improve the stability of the most unfavorable construction stage of cable hoisting and the construction stage after the arch ribs are closed. The placement of temporary wind bracing can significantly improve the stability of the most unfavorable construction stage of structural cable hoisting, and the non-directional force effect is centered. The stability of the through-type steel box tied arch bridge has a greater impact, and the installation of wind-resistant cables significantly improves the stability of the construction stage after the arch ribs are closed. It can be seen that there are many factors affecting the stability of the construction stage, and this study can provide a reference for the construction and design of the same type of bridge.