高速铁路(110+208+110)m连续梁-钢管混凝土拱屈曲分析

以高速铁路桥梁比较方案(110+208+110) m连续梁-钢管混凝土拱组合结构桥为背景,探求几何非线性及几何-材料双重非线性对大跨度钢管混凝土拱屈曲失稳的影响程度,研究考虑上述非线性因素后钢管混凝土拱弹塑性屈曲因子的衰减系数。结合相关规范和文献,采用空间有限元软件CSIBridge,以钢管混凝土统一理论为材料本构模型建立全桥空间模型,对结构按实际作用荷载工况进行弹性及弹塑性屈曲分析。结果表明:材料非线性对钢管混凝土拱屈曲失稳的影响比几何非线性的影响大得多,考虑几何-材料双重非线性后钢管混凝土拱弹塑性屈曲因子衰减系数约为0.55。桥式方案中钢管混凝土拱弹性及弹塑性稳定系数均满足国家标准及行业标准要求。

Buckling Analysis of (110+208+110) m Continuous Beam Concrete-filled Steel Tubular Arch of High Speed Railway

The influence of geometric nonlinearity and geometric material double nonlinearity on the buckling of large span concrete filled steel tube arch is investigated.The attenuation coefficient of elastoplastic buckling factor of concrete filled steel tube arch is studied with the above nonlinear factors with reference to the bridge of(110+208+110) m continuous beam concrete-filled steel tubular arch.Based on the relevant norms and documents,the space finite element software CSIBridge is used to establish the full bridge space model with the unified theory of concrete filled steel tube as the material constitutive model,and the elastic and elastoplastic buckling analysis of the structure is carried out according to the actual loading conditions.The results show that the effect of material nonlinearity on the buckling of concrete filled steel tube arch is much greater than that of geometric nonlinearity.The attenuation coefficient of the elastoplastic buckling factor of concrete-filled steel tube arch is about 0.55 in consideration of the dual nonlinearity of geometry and material.The elastic and elastoplastic stability coefficients of CFST arch bridge meet the requirements of national and industry standards.