中文摘要：

为了提高大跨度钢管混凝土拱桥主拱受力性能,提出了钢管初应力释放转移的新思路：在混凝土灌注前对钢管采取脱粘措施,混凝土灌注完成达到强度后,将钢管“切断”,使钢管初应力转移至核心混凝土,然后将钢管重连,使钢管与混凝土共同承担后续荷载。采用有限元方法按以上思路对1座单圆管钢管混凝土拱桥和1座桁架式钢管混凝土拱桥进行了桥例分析。研究结果表明,如果不计钢管与混凝土之间的摩擦,钢管“切断”后,钢管初应力能够有效地释放转移至核心混凝土;钢管初应力释放转移后,与原设计相比,在成桥状态下拱肋钢管应力大幅降低,对于本桁架式桥例最大应力降低幅度为14.5%;管内混凝土应力大幅提升,但并未超过考虑套箍效应后的混凝土抗压强度。证明该方法能够显著提高大跨度钢管混凝土拱桥拱肋截面的组合效率,改善主拱的受力性能。

英文摘要：

In order to improve the performance of the main arch of the large-span CFST arch bridge, a new idea on the initial stress release and transfer of the steel tube was presented. Take debonding measures for steel tube before pouring concrete,after the concrete is poured and the strength is reached,cutting off the steel tube to allow the initial stress of the steel tube to be transferred to the core concrete, and then reconnected the steel tube so that it together with the concrete bears the follow-up load. According to the above ideas , the finite element method was used to analyze the case of a single pipe rib CFST arch bridge and a truss rib CFST arch bridge. The analysis shows that without friction the initial stress of the steel tube can be effectively released and transferred to the core concrete after the steel tube is cut off. Compared with the original design, after the initial stress release and transfer, the stress on the steel tube of the arch rib is significantly reduced under the completion state.For the truss CFST arch bridge,the maximum stress can be reduced by 14.5% .Considering the confining effect, the stress of concrete filled steel tube is greatly increased, but still under the compressive strength of concrete. It proves that this method can significantly improve the combination efficiency of arch rib section of the large-span CFST arch bridge, and improve the performance of the main arch rib.