初应力对大跨度钢管混凝土拱桥极限承载力的影响

Influence of initial stress on the ultimate bearing capacity of long-span CFST arch bridges

针对钢管混凝土拱桥施工中存在钢管初应力的现状,采用大型有限元软件ANSYS对某主跨368 m的钢管混凝土拱桥进行了施工过程模拟仿真,在考虑双重非线性和一致几何缺陷后,得到了无初应力与有初应力的极限承载力稳定系数。研究结果表明,钢管混凝土拱桥的钢管初应力度较大,且混凝土收缩徐变引起的初应力不容忽视;初应力不仅对大跨度钢管混凝土拱桥的面内极限承载力有一定的影响,而且对于面外极限承载力有着不可忽略的影响。

Initial stress of steel tube always exists during the construction of the CFST arch bridge. In this article, construction process of the CFST arch bridge with a main span of 368 m was simulated by the finite element software ANSYS, furthermore the coefficient of ultimate bearing capacity was calculated by taking into account both the double non -linearity and geometric defect. The results show that steel tube of the CFST arch bridge has a larger degree of initial stress, and the initial stress caused by the shrinkage and the creep of the concrete cannot be ignored. Initial stress not only has some influence on the in -plane ultimate strength of the long- span CFST arch bridge, but also has the influence that cannot be neglected on the out - of - plane ultimate bearing capacity.