摘要
连镇铁路五峰山长江大桥主桥为主跨1092 m公铁两用钢桁梁悬索桥,大桥设2根直径1.3 m的主缆,主索鞍是实现主缆传力过渡的重要构件。主索鞍受力达7.06×10^(5)kN,设计采用双纵肋传力、铸焊结合、纵向三块式结构,上部鞍槽采用ZG270-480H铸钢铸造、下部鞍体采用Q345R钢板焊接,鞍体纵向长9.12 m(下部)、横向宽4.04 m、高4.30 m,单块鞍体重120 t,主索鞍顶推复位滑移系统采用格栅+不锈钢滑板+四氟板装置。主索鞍结构设计计算分析表明:结构应力在容许范围内,结构受力安全。主索鞍由2个厂家制造,分别采用鞍槽朝下、鞍槽朝上2种铸造方位方案,成型采用组芯造型及双层浇道、双浇口浇铸系统、底注式浇铸的铸造工艺方案;鞍体焊接顺序总体由内向外,以二氧化碳气体保护焊为主;鞍体制造机加工采用单块单独机加工和3块整体机加工2种方案。主索鞍在工厂内制造后分块运到施工现场,由塔顶门架依次将边跨侧、中间、主跨侧鞍体吊至塔顶后纵移到位,利用高强度螺栓连接成整体,经多次顶推后顺利到达设计成桥位置。
The main bridge of Wufengshan Changjiang River Bridge of Lianyungang-Zhenjiang Railway is a rail-cum-road steel truss girder suspension bridge with a main span of 1092 m.The bridge has two main cables of 1.3 m diameter each.As the primary load transfer components,each main cable saddle is capable of carrying a force of 7.06×10^(5) kN.Each main cable saddle consists of three blocks longitudinally,featuring the double longitudinal force transfer ribs and combined casting and welding formation.The upper grooves are made of ZG270-480H cast steel,the lower saddle body is made of welded Q345R steel plates.The saddle body measures 9.12 m long(the base)in the longitudinal direction,4.04 m wide in the transverse direction and 4.30 m high,and an individual saddle body weighs 120 t.The jacking,resetting and sliding system of the main cable saddle consists of grates,stainless steel sliding plate and Teflon pad.The design calculation analysis of the main cable saddle structure indicates that the structural stresses are within the allowable ranges,and the saddles are in safe loading condition.The saddles were made by two manufacturers,one taking a scheme of keeping the grooves facing down and the other making the grooves facing up during the fabrication process.A series of measures were used to make the saddles take form,including the core molding,a casting system of double-layer casting channel and double casting inlets,and bottom casting.The saddle body was welded from inside out,mainly using carbon dioxide gas shielded welding.In the manufacturing of the saddle bodies,two schemes were followed,one was to fabricate the three blocks separately,and the other was to manufacture the three blocks monolithically.The main cable saddles were manufactured in blocks in the factory and shipped to the construction site.With the support of the tower-top portal frames,the saddle bodies next to the side spans,in the central and next to the main span respectively were lifted to the tower top first and then longitudinally moved into position.The blocks were connected into an entirety using high-strength bolts,after multiple times of jacking,located in the design position of the completed bridge.
作者
唐贺强
徐恭义
TANG He-qiang;XU Gong-yi(China Railway Major Bridge Reconnaissance&Design Institute Co.,Ltd.,Wuhan 430056,China)
出处
《桥梁建设》
EI
CSCD
北大核心
2022年第6期8-15,共8页
Bridge Construction
基金
中国铁路总公司科技研究开发计划项目(2015G002-A)。
关键词
公路铁路两用桥
悬索桥
三块式主索鞍
主索鞍设计
鞍槽铸造
鞍体焊接
机加工
顶推施工
rail-cum-road bridge
suspension bridge
three-block main saddle
main saddle design
saddle groove manufacturing
saddle body welding
machining
saddle jacking
