摘要
新白沙沱长江大桥主桥为主跨432m的钢桁梁斜拉桥,在1号～2号墩间跨既有铁路。跨铁路的A11～A19节间钢桁梁采用支架上拼装、整体顶推的方式安装。顶推施工前,在2号墩旁安装4个辅助支架,支架均采用钢管桩支撑,桩顶设纵向分配梁,在分配梁上焊接不锈钢板滑道,滑道与铸钢件滑块间涂抹硅脂润滑;采用自动顶推控制系统（包括2台350t纵向连续千斤顶）同步顶推,千斤顶采用钢绞线和工具锚（设置于A19节间下弦尾端）作传力装置;每顶推13.5m,卸载顶推力,采用竖向顶升系统（在支架对应主桁下弦杆节点处各设置2台1 000t千斤顶和1台液压油泵）起顶钢桁梁,将滑块拖移至滑道始端后卸载顶升力,继续进行顶推;顶推施工时,采用设置在支架两侧的横向导向装置纠偏。通过采取了一系列安全防范措施,该桥钢桁梁安全顺利地顶推到既定位置。
The main bridge of the new Baishatuo Changjiang River Bridge is a steel truss girder cable-stayed bridge with a main span of 432 m, the part of which between pier No. 1 and pier No. 2 crosses the existing railways. The steel truss girder sections All-A19 crossing railways were erected on the scaffoldings and then integrally launched into position. Before the incremental launching construction, four auxiliary scaffoldings were installed beside the pier No. 2. The scaf- foldings are formed of steel piles capped with longitudinal distributive beams, on which stainless steel plate slides were welded, and between the slides and the steel sliding blocks, silicon grease was mopped for lubrication. Synchronized incremental launching was realized by using the automated launching control system, including two longitudinal continuous jacks each with a capacity of 350 t. The steel strands and the anchorages （installed at the ends of the lower chord in the A19 section） are the force conveying devices in the jacks. After the launching of a distance of 13.5 m, the launching force was unloaded, and the longitudinal jacking system was used to jack up the steel truss girder （at each panel point in the main truss lower chord over the supports, two jacks each with a capacity of 1 000 t and one hydraulic oil pump are installed. ）. When the sliding blocks were dragged to the starting point of the slides, the jacking force was unloaded and the incremental launching went forward. During the incremental launching construction, the transverse guiding devices installed at the two sides of the scaffoldings were used for offset modification. The steel truss girder was safely and smoothly launched into the designed positions by adopting a series of safety protection measures.
出处
《世界桥梁》
北大核心
2016年第3期30-33,共4页
World Bridges
关键词
斜拉桥
跨线桥
钢桁梁
拼装
顶推法施工
自动顶推控制系统
施工技术
cable-stayed bridge
overpass
steel truss girder
assembly
incremental launching construction
automated launching control system
construction technique
