摘要
宁安铁路安庆长江大桥主桥连续钢桁梁斜拉桥全长1364.6 m,铁路4线,有砟桥面。道砟槽由底板、挡砟墙、防水层和耐磨层4部分组成,宽度9.5 m,底板和挡砟墙为钢筋混凝土结构。底板厚15 cm,纵向通长设置,通过剪力钉和钢桥面板结合成整体。挡砟墙高1.05 m,纵向设温度断缝。与道砟接触的耐磨层纤维混凝土厚6 cm,纵横向设有锯缝。耐磨层和底板之间采用聚氨酯卷材做防水层。道砟槽在4—7月期间施工,按底板→挡砟墙→防水层→耐磨层的顺序进行,分幅分段完成。对于主跨跨中道砟槽中线点位置,按照从两端钢梁分别联测至跨中处两者坐标差的分中值位置进行确定,挡砟墙高度均随钢梁面起算。采取底板预留后浇段,底板和耐磨层在夏季升温时间段浇筑、3~4次收浆抹面工艺等技术措施,实现长联薄底板全长无裂纹,耐磨层开裂少。采用端模包侧模的抽钎脱模法成形挡砟墙断缝。长联薄板结构道砟槽防开裂施工技术可为类似工程提供借鉴。
The main bridge of Anqing Yangtze River Bridge of Nanjing-Anqing HSR is a continuous steel truss girder cable-stayed bridge with a total length of 1364.6 m,4 railway tracks and ballasted deck.The 9.5 m-wide ballast trough consists of four parts:base plate,ballast retaining wall,waterproof layer and wear resistant layer,where base plate and ballast retaining wall are of reinforced concrete structure.The 15 cm-thick base plate is arranged longitudinally throughout the length,which is integrated by shear studs and steel deck slab.The ballast retaining wall is 1.05 m high,and temperature joints are set in the longitudinal direction.The fiber concrete of wear-resistant layer in contact with the ballast is 6 cm thick,with sawed joints in both longitudinal and transverse directions.Polyurethane coiled material is applied as waterproof layer between wear resistant layer and base plate.The ballast trough was constructed during April-July in the sequence of base plate→ballast retaining wall→waterproof layer→wear resistant layer,and completed in breadths and sections.The position of the centerline point of the ballast trough in the middle of the main span is determined according to the median position of the coordinate difference measured from the steel beams at both ends to the midspan,and the height of the retaining wall is calculated from the steel beam surface.Technical measures such as the segment casting of base plate after reservation,segment casting of base plate and wear-resistant layer during the temperature rise period in summer,and 3~4 times of setting and plastering process are taken for no cracks throughout the length of the long-unit thin base plate and few cracks on the wear-resistant layer.The break joint of ballast retaining wall is formed by chisel removal and stripping with end formwork covering side formwork.The anti-cracking construction technology for ballast trough of long-unit sheet structure can provide reference for similar projects.
作者
农代培
NONG Daipei(State Key Laboratory for Health and Safety of Bridge Structures,China Railway Major Bridge Engineering Group Co Ltd,Wuhan Hubei 430050,China)
出处
《中国铁路》
2022年第3期29-35,共7页
China Railway
关键词
安庆长江铁路大桥
斜拉桥
钢桥面
混凝土道砟槽
长联
底板
耐磨层
防裂
Anqing Yangtze River Railway Bridge
cable-stayed bridge
steel deck
concrete ballast trough
long-unit
base plate
wear-resistant layer
anti-cracking
