摘要
兰州中山桥为5跨简支钢桁架桥,采用圬工桥墩,建于1907年。由于要在不中断交通、较小桥下净空及较大流速的卵石河道复杂边界条件下对桥墩进行加固,在既有桥墩上安装支撑架施工钢围堰。钢围堰外围尺寸为8 900mm×18 620mm,采用Q235钢材,为全焊接结构。为减少水流阻力,钢围堰迎水面为尖角形。钢围堰施工采用分节运输吊装、现场安装连接。单片的钢围堰吊装上船,运输至桥墩,通过导向架和挑梁上的吊点,利用手拉葫芦逐片吊起钢围堰,然后整体调整拼装,最后焊接钢围堰。钢围堰分节安装完成后,需通过导向架调整钢围堰着床位置。围堰下沉到位,封堵抽水后进行封底混凝土施工。
The Zhongshan Bridge in Lanzhou is a five-span simply-supported steel truss frame bridge.The piers are masonry piers built in 1907.The piers needed to be strengthened without interruption to traffic,and also limited by complicated boundary conditions,like the small vertical clearance beneath the bridge and the gravel water channel with high water flowing velocity.The selected scheme was to install supporting frames on the piers to construct the steel cofferdam.The steel cofferdam is a fully-welded structure made of Q235 steel,the external dimension of which is 8 900 mm×18 620 mm.To reduce the water flowing resistance,the water-facing side of the cofferdam is designed as triangular shape.The steel cofferdam was shipped and hoisted by sections,and then assembled and connected at the bridge site.The individual sections of the cofferdam were hoisted into the barge,shipped to the piers.Then,the chain block was used to hoist cofferdam section by section through the hoisting points on the guiding frame and the cantilever beam.The individual sections were assembled and adjusted to form an integral cofferdam,and the last step was to weld the cofferdam.After the completion of the cofferdam assembly,the guiding frame was used to adjust the sinking location of the steel cofferdam.Once sinking into position,the cofferdam was blocked and water inside the cofferdam was pumped out,and the casting of the base sealing concrete began.
作者
袁鑫
郑伟
YUAN Xin;ZHENG Wei(School of Civil Engineering,Suzhou University of Science and Technology,Suzhou 215011,China;School of Civil Engineering,Southeast University,Nanjing 210096,China;Suzhou Zhonggu Building Science and Technology Co.,Ltd.,Suzhou 215100,China)
出处
《世界桥梁》
北大核心
2018年第5期69-73,共5页
World Bridges
基金
国家自然科学基金项目(51508368)
2017江苏省政府留学奖学金项目
江苏省省建设厅科技计划项目(2015ZD78)
江苏省结构工程重点实验室开放课题(ZD1401)
关键词
钢桥
桥墩
抗震加固
复杂边界
钢围堰
导向架
设计施工
steel bridge
pier
anti-seismic strengthening
complicated boundary condition
steel cofferdam
guiding frame
design construction
