【摘要】 钢管混凝土拱桥有许多优点 ,在我国发展很快 ,有许多成功的经验。因为目前尚无钢管混凝土拱桥的设计及施工规范 ,因此 ,必须注意总结经验 ,防止在工程中发生事故。本文就某钢管混凝土拱桥施工中钢管开裂事故进行结构分析 ,提出一些看法 ,以供参考。更多还原

【Abstract】 Why some great cracks are occurred in steel tubes of a concrete-filled-steel-tube arch bridge during construction?It is discussed from the structural viewpoint and some suggestions are proposed in the paper It is shown that the inner stress of a web member can not be allowed to exceed 0 229 MPa in the design However,the inner stress is 0 9 MPa during construction Therefore a very high concentrated stress is occurred at the joint of upper chord tube and web tube The concentrated stress is much more than the yield stress or the strength limit This is an external cause of cracks A hardened area is formed in the heat influence zone due to welding The brittleness is increased as the plasticity and the ductility are decreased That is an internal cause It can be found that the Mises stress of a tube due to partial loading may be many times as much as that of the whole loading at same magnitude更多还原