Abstract: The stability of concrete filled steel tubular (CFST) arch bridge at construction stage is concerned by engineers. Based on the Xinlongmen Bridge, considering the constititive relationship between steel tube and concrete, spatial finite el- ement model is established by ANSYS. The stability of Xinlongmen Bridge at construction phase is analyzed from three as- pects of eigenvalue buckling, geometric nonlinear instability, geometric and material double nonlinear instability.The re- sults show that CFST arch bridge is greatly influenced by the stability during consruction stage, and there is a downward trend of stability coefficient; meanwhile, a large difference exists between double nonlinear srability coefficients and eigen- value buckling coefficients which can get up to 30% at maximun.

Key words: CFST arch bridge;conshuction stage, stability, constitutive relationship, buckling, nonlinear instability

摘要： 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%。

关键词: 钢管混凝土拱桥, 施工阶段, 稳定性, 本构关系, 屈曲, 非线性失稳