大跨度钢管混凝土拱桥施工阶段稳定性分析

以新龙门大桥为工程依托,考虑钢管和混凝土的三向受力本构关系,利用ANSYS建立了空间有限元模型,从特征值屈曲、几何非线性失稳、几何材料双重非线性失稳3个方面分析了该桥整个施工阶段的稳定问题。结果表明:钢管混凝土拱桥在整个施工过程中受稳定性影响较大,稳定系数有不断下降的趋势,考虑双重非线性的稳定系数与特征值屈曲分析相比差别较大,最大可达30%。

Stability Analysis on Large-Span CFST Arch Bridge at Construction Stage

The stability of concrete filled steel tubular(CFST) arch bridge at construction stage is concerned by engineers.Based on the Xinlongmen Bridge,considering the constitutive relationship between steel tube and concrete,spatial finite element model is established by ANSYS.The stability of Xinlongmen Bridge at construction phase is analyzed from three aspects of eigenvalue buckling,geometric nonlinear instability,geometric and material double nonlinear instability.The results show that CFST arch bridge is greatly influenced by the stability during construction stage,and there is a downward trend of stability coefficients;meanwhile,a large difference exists between double nonlinear stability coefficients and eigenvalue buckling coefficients,which can get up to 30% at maximum.