跨营运铁路双层公路钢桁腹-板桁组合桥施工方案设计  

Research on Method Statement Design of Double-deck Highway Bridge of Steel Truss Web&Plate Truss Overpassing Operational Railway

作　　者：陈健 CHEN Jian(Department of Planning and statistics,China Railway Guangzhou Group Co.,Ltd.,Guangzhou Guangdong 510088,China)

机构地区：[1]中国铁路广州局集团有限公司计划统计部,广东广州510088

出　　处：《中国铁路》2023年第8期15-23,共9页China Railway

摘　　要：以某上跨营运铁路2×85 m双层公路连续钢桁腹-板桁组合桥为背景,针对混凝土与钢结构施工先后顺序提出3种主梁施工方案:方案一为先浇筑混凝土,再拼装钢结构;方案二为先拼装全部钢结构,再浇筑混凝土;方案三为先拼装钢主桁,再浇筑混凝土,最后安装钢桥面板。通过建立有限元模型,对比分析3种方案在施工及运营阶段结构的受力性能,并对其转体施工安全性及临近既有线防护进行设计分析。结果表明:(1)方案一受力性能最优,但3种方案混凝土及钢结构应力均能满足规范要求,且应力水平差别较小;(2)综合考虑施工难易程度、施工风险、施工经济性、对铁路运营安全影响等因素,本桥采用方案二施工;(3)转体施工选用竖向承载力2.9万t级球铰,转体过程中结构的强度、刚度及稳定性均满足要求;(4)本桥采用的地基加固处理、防倾覆措施等一系列设计,确保临近既有线施工的安全性,可为后续此类临近既有线双层转体桥施工提供参考。The paper studies a 2x85 m double-deck highway bridge of continuous steel truss web and plate truss overpassing an operational railway,and proposes three method statements of main girder regarding the construction sequence of the concrete and the steel structure.In Scheme I,the concrete pouring takes place before the assembly the steel structure,while Scheme II does the opposite(steel structure before concrete pouring).In Scheme III,the main stell truss is assembled first,followed by the pouring of concrete and the installation of the bridge deck.A finite element analysis helps compare the force-bearing performance of the schemes amid both construction and operation,and looks into the safety of the swing method as well as the safety precaution taken at existing lines nearby.The results show that:(1)Scheme I leads the others in force-bearing performance,but the stress of the concrete and the steel structure in all three cases with only limited stress difference meets the specification requirements;(2)Scheme II is adopted for the bridge construction after a thorough consideration of difficulty,risks,economic performance and impact on railway safety;(3)Spherical hinges with a vertical bearing capacity of 29,000t are selected for swing construction,during which the strength,rigidity and stability of the structure meet the requirements concerned;(4)A series of designs-foundation reinforcement and anti-overturn-adopted ensure construction safety by railway lines,providing valuable reference to future projects of a similar nature.

关 键 词：营运铁路 双层公路桥 桥梁施工 转体法 稳定性 钢桁梁 

分 类 号：U448.14[建筑科学—桥梁与隧道工程] U445.465[交通运输工程—道路与铁道工程]