新月型钢管混凝土拱桥极限承载能力分析

发布时间：2018-09-07 09:10

【摘要】：为了研究结构参数对新月型钢管混凝土拱桥极限承载力的影响,基于考虑约束效应的核心混凝土本构关系,对新月型拱桥的极值点稳定问题进行了分析.首先通过特征值分析,获取对结构承载能力最不利的荷载工况;其次在该工况下考虑结构的几何非线性和材料非线性,采用Riks法迭代求解,得到结构的极限承载力和稳定安全系数;最后以石棉大渡河桥为工程背景,研究了主副拱肋夹角、钢管材料强度、核心混凝土强度、含钢率等结构参数对极限承载能力的影响.研究结果表明:新月拱的失稳形式为拱肋整体的横向失稳,结构的稳定性主要取决于恒载大小;考虑几何非线性后,极限承载能力下降3%,当初始缺陷从1%增加至10%时,极限承载能力下降1%,考虑材料非线性后,承载能力下降55%;含钢率增加至1.5倍时,稳定安全系数提高19.0%;核心混凝土强度从C50提高至C60时,稳定安全系数提高12.0%;钢材强度从Q345提高至Q420时,稳定安全系数提高9.6%;随主副拱肋夹角从10°变化至25°时,稳定安全系数降低5.9%.
[Abstract]:In order to study the influence of structural parameters on ultimate bearing capacity of crescent concrete-filled steel tubular arch bridge, the problem of extreme point stability of crescent arch bridge is analyzed based on the constitutive relation of core concrete considering constraint effect. First of all, through eigenvalue analysis, the most unfavorable load condition is obtained to the bearing capacity of the structure. Secondly, the geometric nonlinearity and material nonlinearity of the structure are considered under this condition, and the Riks method is used to solve the problem iteratively. The ultimate bearing capacity and stability safety factor of the structure are obtained. Finally, taking the Dadu River Bridge of asbestos as the engineering background, the influence of the main and auxiliary arch rib angle, the strength of steel tube material, the strength of core concrete and the steel content on the ultimate bearing capacity is studied. The results show that the instability of the crescent arch is the transverse instability of the arch rib, and the stability of the structure mainly depends on the size of dead load, and the ultimate bearing capacity decreases by 3 parts when the initial defect increases from 1% to 10% when geometric nonlinearity is considered. The ultimate load-bearing capacity is reduced by 1 / 10. After considering the nonlinearity of the material, the bearing capacity decreases by 55%; when the steel content is increased to 1.5 times, the stability safety coefficient increases by 19.0; the strength of the core concrete increases from C50 to C60. When the strength of steel increased from Q345 to Q420, the coefficient of stability increased by 9.6, and with the change of the angle of arch rib from 10 掳to 25 掳, the factor of stability decreased by 5.9%.
【作者单位】：西南交通大学土木工程学院;
【基金】：国家自然科学基金资助项目(50978221)
【分类号】：U448.22

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