摘要
成贵铁路宜宾金沙江公铁两用桥主桥为(116+120+336+120+116)m双层桥面系杆拱桥,120 m和116 m跨副拱为混凝土简支系杆拱,副拱桥墩均采用钻孔桩基础,上层铁路梁为单箱单室预应力混凝土结构,下层公路梁为π形断面双边主梁预应力混凝土结构。根据副拱各桥墩施工场地特点,钻孔桩基础分别采用陆地钻孔桩、筑岛及水上钻孔平台方案施工;3号墩采用先平台后围堰方案施工,承台采用可拆装式大块双壁锁口钢板桩围堰施工,解决了普通钢套箱围堰的不足,实现了围堰的重复利用;桥墩墩身均采用翻模法施工。综合考虑结构特点及施工现场通行需求,副拱上部结构由下至上施工,公路梁采用现浇支架体系施工;拱肋以公路梁现浇支架和公路梁为基础建立现浇支架体系,拱上立柱直接依托拱肋浇筑,合理利用了主体结构,减小了结构工程量;根据铁路梁施工跨度不同,将现浇支架进行标准化分类,有效提升了施工效率;铁路梁分3段对称浇筑,确保了下部拱肋的对称受力。
The main bridge of Yibin Jinshajiang River Rail-cum-Road Bridge of the Chendu-Guiyang Railway is a tied-arch bridge accommodating two levels of decks,where the upper railway deck consists of single-cell prestressed concrete box girders and the lower roadway deck is formed ofπ-shaped prestressed concrete girders.The 336 m-main span is a tied-arch structure,while the 120 m-and 116 m-side spans are simply-supported concrete tied-arch structures(also function as secondary arches).The piers of the secondary arches are supported by bored pile foundations.To accommodate the characteristics of the construction sites of these piers,the bored pile foundations were constructed by the combined utilization of land bored piles,artificial islands and boring platforms in river.To construct pier No.3,the boring platform was installed ahead of the cofferdam,and the pile cap was cast with the aid of the detachable double-wall cofferdam of interlocking steel sheet piles,which overcame the deficiency of the traditional steel suspension box cofferdam and achieved the recycling of cofferdam.The pier shafts were cast by using turnover formwork.Given the characteristics of the structure and the accessibility of construction site,the superstructure of the side spans was constructed from the bottom to top.The roadway deck was cast on scaffolds.The arch ribs were cast on the scaffolds which incorporated the already-finished roadway deck and its scaffolds.The spandrel columns were cast with the support of the arch ribs,in a bid to effectively use the main structural system and reduce the engineering quantity.To suit the different span lengths of the railway deck,the scaffolds were assembled from standardized members to improve the construction efficiency.The railway deck was symmetrically cast in three segments to ensure the symmetrical force distribution in the lower arch ribs.
作者
沈炫
代皓
SHEN Xuan;DAI Hao(School of Civil Architecture and Environment,Hubei University of Technology,Wuhan 430068,China;China Railway Major Bridge Engineering Group Co.,Ltd.,Wuhan 430050,China;State Key Laboratory for Health and Safety of Bridge Structures,Wuhan 430034,China)
出处
《桥梁建设》
EI
CSCD
北大核心
2022年第3期133-139,共7页
Bridge Construction
基金
中国中铁股份有限公司科技开发计划项目(2014-重大-04)。
关键词
公路铁路两用桥
系杆拱桥
副拱
钻孔桩基础
现浇支架
施工技术
rail-cum-road bridge
tied-arch bridge
secondary arch
bored pile foundation
scaffolds for in-situ casting
construction technique
