中文摘要：

为进一步增大拱桥的跨越能力,结合劲性骨架钢筋混凝土拱桥的结构和施工特点,提出钢腹杆-劲性骨架混凝土（SRC）弦杆组合桁式拱圈结构,利用钢腹杆替代混凝土腹板,省去混凝土腹板的浇筑工作,并减轻拱圈自重以达到增大拱桥跨径的目的。为了解这种组合拱连接节点的受力特点,在钢腹杆-SRC弦杆组合拱桥试设计研究基础上,以弦杆外包混凝土厚度为主要参数,进行了3个组合拱节点及1个对比钢管混凝土节点的试验研究,并探讨了节点的失效机理。结果表明：组合拱节点首先发生弦杆外包混凝土开裂,最终发生钢管混凝土节点破坏;外包混凝土对受拉和受压腹杆的受力影响很小;相比钢管混凝土节点而言,组合拱节点受拉腹杆的接头刚度较大;弦杆外包混凝土的厚度只影响外包混凝土的开裂荷载,外包混凝土越厚,开裂荷载越大,但不影响组合拱节点的极限承载力;结合钢管混凝土劲性骨架混凝土柱的研究成果,建议组合拱节点的混凝土外包系数取0.50左右,其承载力可按照受拉节点发生冲剪失效模式和受压节点发生有效宽度失效模式进行计算,但其计算结果偏于安全。研究成果可为钢腹杆-SRC弦杆组合拱桥的设计提供依据,也可为类似连接节点的设计提供参考。

英文摘要：

To increase the span capacity of arch bridges, combined with structure and construction characteristics of stiff-skeleton reinforced concrete arch bridge, the structure of steel brace-steel reinforced concrete （SRC） chord composite truss arch was proposed, using steel braces instead of concrete webs, so it was helpful to save the pouring of concrete webs and reduce self-weight with this new composite truss rib, to meet the goals of enlarging the arch bridge span. To investigate the mechanical characteristics of this kind of connections of composite arch, test on 3 composite connections and 1 concrete filled steel tube （CFST） connection were carried out and the failure mechanic of connections was also analyzed and discussed, taking thickness of chord outsourcing concrete as main parameters on the basis of design research of steel brace-SRC chord composite truss arch bridge. The results show that all composite connection specimens are failed firstly by cracks of chord outsourcing concrete, and the failure of concrete-filled steel tube connections occurred finally. Outsourcing concrete has little effect on the force of tensile brace and compressive brace. Stiffness of composite tensile connections is larger than that of CFST tensile connections. Crack load of outsourcing concrete, the thicker of the outsourcing concrete, the larger of crack load are affected by thickness of chord outsourcing concrete, but thickness of chord outsourcing concrete has little effect on the ultimate bearing capacity of composite connections. The outsourcing concrete coefficient of composite connection is advised as 0.50 or so. The ultimate bearing capacity of tensile connection can be calculated in light of punch failure mode, and compressive connection can be calculated by effective width failure mode, but the calculation results of connections are conservative. The research achievements can be references for the design of steel brace-SRC chord composite truss arch bridge, and the design of such similar connections.