Abstract: Taking a rectangular concrete-filled steel tubular truss bridge as an example，the K-type connections were divided into Y- type tension joints and Y-type compression joints. The nonlinear finite element analysis model was established from the most basic Y- type tensile joints. The influence of the parameters such as the concrete filled in the chord and the PBL stiffener on the deformation ，failure mode and stress distribution of the joints were analyzed. The results show that filling concrete in steel tube can increase anti-deformation ability and reduce stress level of the joints，but the phenomenon of debonding between the steel pipe and concrete is easy to occur; setting PBL stiffener can effectively increase the bonding force of the interface between steel and concrete，prevent interface debonding，greatly improve the node deformation resistance，obviously decrease the node stress level and effectively improve the ultimate bearing capacity of the node and the node stiffness.

Key words: bridge engineering, concrete-filled steel tube, truss, tension joint, Y-connection, ultimate bearing capacity, finite element analysis

摘要： 以在建广安官盛渠江特大桥为研究对象,采用Midas/ Civil 2015 分别建立4 个不同分环方案的有限元模型,并 进行了完整的施工阶段计算。探讨了在拱圈外包混凝土浇筑过程中,不同分环浇筑方案对结构受力的影响。发现 分环数量对劲性骨架及外包混凝土应力均有明显影响;分环越多,劲性骨架应力变化越平缓,其应力越小;m1 的大 小对外包混凝土应力影响较大,在满足劲性骨架承载力、稳定性及施工安全要求的前提下,m1 值越大,外包混凝土 的应力越小。最后,从兼顾施工速度及结构受力角度提出了一些建议。

关键词: 桥梁工程, 钢管混凝土, 桁架, 受拉节点, Y型, 极限承载力, 有限元分析