郑万铁路大宁河大桥设计关键技术  

Key Design Techniques for Daning River Bridge on Zhengzhou-Wanzhou Railway

作　　者：宋随弟[1] 陈克坚[1] 赵启华 冯振兴[1] SONG Sui-di;CHEN Ke-jian;ZHAO Qi-hua;FENG Zhen-xing(China Railway Eryuan Engineering Group Co. , Ltd. , Chengdu 610031, China;Sichuan Communication Surveying & Design Institute Co. , Ltd. , Chengdu 610017, China)

机构地区：[1]中铁二院工程集团有限责任公司,四川成都610031 [2]四川省交通勘察设计研究院有限公司,四川成都610017

出　　处：《桥梁建设》2021年第4期96-102,共7页Bridge Construction

摘　　要：郑万铁路大宁河大桥主桥采用一跨282 m的中承式钢筋混凝土拱桥。主拱拱脚采用新型大直径斜桩+竖桩基础,能更好地与地形地质匹配,结构更经济、更环保;主拱圈采用2个平行单箱单室拱肋,由劲性钢管混凝土骨架外包C55无收缩混凝土构成,拱圈劲性骨架采用钢管混凝土桁架拱结构,通过外包混凝土特殊分层分段方案改善拱圈各构件的内力;主梁采用钢混连续结合梁,双纵肋形截面;桥面由预制混凝土板和现浇混凝土层两部分组成,既可以省去桥面现浇层的模板,又能加强主梁的整体性;吊杆采用Φ7 mm平行钢丝成品索;在拱肋横梁支座处设置专门研发的钢棒式阻尼器,在正常使用及地震作用下对结构进行适度约束。采用有限元法对全桥及各结构进行受力分析,结果表明:全桥满足安全及舒适性要求;主拱桩顶及承台应力分布较复杂,与普通群桩基础有很大不同;拱圈强度及裂缝宽度满足规范要求;拱圈外包混凝土、劲性骨架钢管及管内混凝土的承载能力均得到充分发挥。The main bridge of Daning River Bridge on Zhengzhou-Wanzhou Railway is a half-through reinforced concrete arch bridge spanning 282 m.The arch seats are supported on foundations formed of large-diameter battered and vertical piles,which match the topographical condition at the bridge site and allow the bridge structure to be more economical and environment-friendly.The two parallel arch ribs,which are of single-cell box cross-section,contain the stiff concrete-filled steel tubular skeletons and the encasing non-shrinage C55 concrete.The internal forces in different components of the arch get improvement,when the encasing concrete is cast in layers and segment by segment.The stiff skeleton is a truss arch structure formed of concrete-filled steel tubes.The superstructure consists of steel-concrete continuous composite girders ofΠcross-section,precast concrete slabs and cast-in-situ concrete layer.The formwork for in-situ casting of deck slab is not needed and the integrity of the main girder is enhanced.The hangers are finished cables made ofΦ7 mm parallel steel wires.Bearings are installed on the cross beams of the arch ring,where steel bar dampers are added,to ensure that the bridge can be properly restrained in the normal service state and during earthquake events.The load bearing performance of the overall bridge structure and various components were analyzed by finite element method.The results show that the bridge reaches the safety and user-comfort requirements.The stress distribution in pile head and pile caps was complex and quite different from the conventional pile foundation.The strength and crack width of the arch ring meet the code requirements.The design of the structure can allow the encasing concrete,steel tubes of the sfiff skeleton and the concrete filled in the tubes to give their load bearing capacities into full play.

关 键 词：高速铁路桥 中承式拱桥 大直径桩基础 主拱圈 劲性骨架 结合梁 钢棒阻尼器 桥梁设计 

分 类 号：U448.22[建筑科学—桥梁与隧道工程] U442.5[交通运输工程—道路与铁道工程]