摘要
重庆白帝城长江大桥主桥为主跨916 m的单跨双铰简支悬索桥。该桥主桥采用静力限位和动力阻尼组合约束体系。受两岸地形及索鞍位置限制,中跨主缆垂跨比为1∶11,采用预制平行钢丝索股(PPWS)法施工。主缆采用标准抗拉强度1 860 MPa的热镀锌铝高强钢丝,选用“S型缠丝+防护带弹性包裹+主缆干燥空气除湿”综合防护体系。为适应加劲梁的横向摆动,短吊索采用关节轴承构造与加劲梁吊耳、索夹相接。加劲梁采用流线型扁平钢箱梁,总宽33 m、高3.2 m,标准横隔板采用空腹桁架式结构。为减轻结构疲劳效应,桥面系采用钢-超高性能混凝土(UHPC)组合桥面板体系。桥塔采用钢筋混凝土门形塔,桥塔基础采用分离式承台+群桩。奉节岸锚碇区围岩较破碎,且受公路隧道及坡上建筑物限制,采用折线型隧道式锚碇,利用适用于大倾角隧洞的铣挖机机械开挖工艺施工;巫山岸锚碇位于瞿塘峡互通匝道桥内,采用埋置式重力式锚碇,利用原槽现浇工艺增加锚碇的侧向摩阻力。
The main bridge of Baidicheng Changjiang River Bridge in Chongqing is a simply-supported suspension bridge that is hinged at two ends.The bridge has a main span of 916 m with hanger cables.A restraint system characterized by the combination of static restriction and dynamic damping is adopted.Limited by topological conditions and locations of saddles,the sag-to-span ratio of main cables in the central span is set at 1∶11.The main cables erected by prefabricated parallel wire strands(PPWS) method are made of hot-dip galvanized high-strength steel wires with a standard tensile strength of 1 860 MPa,protected by the combined utilization of S steel wires,elastic wrapping tapes and a dehumidification system.To accommodate the lateral oscillation of the stiffening girder,the short hanger cables are connected with the lifting lugs in the stiffening girder and the cable clamps via the kind of spherical plain bearing details.The stiffening girder consists of streamlined flat steel box girders that measure 33 m wide and 3.2 m deep,with Vierendeel trusses as diaphragms.To reduce the fatigue effect of the structure,the deck system is designed as a steel-UHPC(ultra-high performance concrete) composite system.The towers are reinforced concrete portal-framed towers supported on split pile caps and piles beneath.On the Fengjie shore,the fractured rocks are found in the anchorage zone,as a result,a polyline tunnel anchorage is built,to overcome the limitations of the highway tunnels and buildings on the slope,and the excavation was mechanically done using the milling machine suitable for tunnels of large inclination angles.The anchorage on the Wushan shore is located inside the Qutangxia Interchange,which is designed as a embedded gravity anchorage that took form by on-site casting technique so as to enhance its lateral friction.
作者
刘小辉
郑升宝
陈奉民
李忠评
邓耀
LIU Xiao-hui;ZHENG Sheng-bao;CHEN Feng-min;LI Zhong-ping;DENG Yao(China Railway Changjiang Traffic Design Group Co.,Ltd.,Chongqing 401121,China)
出处
《桥梁建设》
EI
CSCD
北大核心
2022年第5期100-106,共7页
Bridge Construction
基金
重庆市自然科学基金项目(cstc2021jcyj-msxmX1159)。