斜拉桥主梁钢-混结合段技术性能提升关键技术

为提升大跨径混合梁斜拉桥主梁钢-混凝土结合段的传力能力、抗疲劳性能和耐久性等综合技术性能,优选钢-混结合段的连接形式,提出改进钢-混结合段技术性能的路线。对比分析4种钢-混结合段连接形式,推荐采用"承压+传剪"复合传力的部分连接填充混凝土形式。针对早期部分连接填充混凝土形式的不足,提出从传力模式和构造方案、填充材料、施工工艺等方面进行改进的技术路线。在此基础上以某主跨820m的混合梁斜拉桥为背景,研究提升钢-混结合段技术性能的关键技术。结果表明:"承压+传剪"复合传力模式、"大尺寸钢格室+PBL剪力键+后承压板"构造方案、填充RPC高性能混凝土、短线法节段预制拼装施工工艺等技术措施,是提升混合梁斜拉桥主梁钢-混结合段综合技术性能的有效途径。

Key Techniques for Enhancing Technical Performances of Steel-Concrete Composite Segment of Cable-Stayed Bridges

In order to improve the comprehensive technical performances, such as bearing capacity, fatigue resistance, and durability, of the steel-concrete composite segment of the main girder of long-span hybrid girder cable-stayed bridges, we optimized the connection form of steel-concrete composite segment, and put forward a route to improve the technical performances of steel-concrete composite segment. Four kinds of connection forms of steel-concrete composite segment were compared and analyzed, and a form of partially connecting the filled concrete with a composite force transfer of the "bearing plus shearing" was recommended. In accordance with the early shortcomings of the form of partially connecting the filled concrete, we put forward a technical route of improvements in the force transfer mode, structure scheme, filling material, and construction technique. Thereby, taking a hybrid girder cable-stayed bridge with a main span of 820 m as a research background, we studied the key techniques for improving the technical performances of steel-concrete composite segment. The research shows that technical measures, such as adopting a composite force transfer mode of "bearing plus shearing", adopting a structure scheme of "setting large-sized steel lattice room plus PBL shearing connector plus back bearing plate", filling the RPC high performance concrete, and adopting a prefabrication and assembly construction technology of short-line segments, are effective ways to improve the comprehensive technical performances of steel-concrete composite segment of the main girder of cable-stayed bridges.