上承式钢管混凝土拱桥拱肋混凝土非对称灌注结构安全性研究

为掌握拱肋钢管内混凝土不对称灌注对结构安全性的影响规律，利用有限元方法对南浦溪特大桥拱肋钢管内混凝土左右幅非对称顶升灌注过程中结构的变形、应力及稳定性进行了分析。计算结果表明：非对称灌注过程中，先灌注侧拱肋下挠量大，两侧拱肋挠度差值随完成灌注的拱肋数量增多而逐渐减小，灌注完成后，横截面对称位置处拱肋竖向挠度对称；整个施工阶段拱肋应力大于横撑应力，尤其是首灌混凝土过程中拱肋应力较大，应重点关注；首灌混凝土完成时结构的稳定安全系数最低，随着混凝土逐步完成灌注，结构的稳定安全系数逐渐增大；结构初始几何缺陷对结构的稳定性不利，应以考虑结构初始几何缺陷的稳定系数来评价结构的安全性。

Study on Structure Safety of Arch Rib Concrete Asymmetric Pouring Construction of Deck-type Concrete Filled Steel Tube Arch Bridge

In order to obtain the influence rule of asymmetric pouring of concrete in arch rib steel tube on structural safety, the deformation, stress and stability of the structure during the asymmetric jacking pouring of concrete in arch rib steel tube of Nanpuxi Bridge are analyzed by finite element method. The calculation results show that in the process of asymmetric pouring, the deflection of arch rib on the first pouring side is large, and the deflection difference of arch rib on both sides decreases gradually with the increase of the number of arch ribs completed pouring. After pouring, the vertical deflection of arch rib at the symmetrical position of cross section is symmetrical. The stress of arch rib is greater than that of transverse brace in the whole construction stage, especially in the first concrete pouring process, which should be paid more attention to. When the first pouring concrete is completed, the stability safety factor of the structure is the lowest. As the concrete is gradually completed, the stability safety factor of the structure gradually increases. The initial geometric defects of the structure are unfavorable to the stability of the structure. The stability coefficient considering the initial geometric defects of the structure should be used to evaluate the safety of the structure.