摘要
常泰长江大桥为主跨1 208 m的公铁两用钢桁梁斜拉桥,其5号桥塔离岸1.3 km,设计总高350 m,为钢-混混合空间钻石形桥塔,中、下塔柱设计为四塔肢结构钢筋混凝土塔,上塔柱设计为钢核芯混凝土组合结构钢塔。针对大跨径桥梁远岸水中超高钢塔分块吊装施工测量难点,在施工测控时,充分结合桥塔结构设计特点,提前在钢混结合段预埋竖向测量视线通道,并基于高精度全站仪天顶竖向投点法,在中下塔最稳定状态时,先将塔下测量基点(平面和高程)传递到钢混结合段顶面并同步引测到两侧安全区域。在钢塔节段分块吊装时,以钢混结合段顶面两侧引测的测量基点为依据,基于高精度全站仪天顶竖向投点法,通过研制的测量工装将引测基点逐层传递到塔顶核心块外侧的加劲肋板顶口,设置全站仪远距离定向后对钢塔节段吊装线形进行测控。该施工测量技术可解决超千米远岸水中超高钢塔吊装过程中塔下测量基点无法满足需求、塔上测量作业空间有限、夜间有效测量作业时间短等问题,规避中下塔变形对钢塔吊装的影响,实现超高钢塔分块吊装空间线形姿态误差不超过±5 mm,全塔垂直度不超过1/8 000的质量控制目标。
The Changtai Yangtze River Bridge is a combined highway-rail steel truss cable-stayed bridge with a main span of 1208 meters.Its No.5 bridge tower is located 1.3 km offshore,with a total designed height of 350 meters,featuring a steel-concrete hybrid spatial diamond-shaped tower.The middle and lower tower columns are designed as four-limb reinforced concrete structures,while the upper tower column adopts a steel-core concrete composite structure.To address the construction survey challenges of segmented hoisting for ultra-high steel towers in long-span offshore bridges,the construction survey was made according to the structural design characteristics of the tower.A vertical measurement line-of-sight channel was pre-embedded in the steel-concrete transition segment.Based on the high-precision zenith vertical projection method using a total station,when the middle and lower tower columns were in their most stable state,the survey control points(planar and elevation)at the tower base were first transferred to the top surface of the steel-concrete transition segment and simultaneously extended to safe zones on both sides.During the segmented hoisting of steel tower sections,the extended survey control points on both sides of the steel-concrete transition segment served as references.Using the high-precision zenith vertical projection method,the control points were progressively transferred to the top of the stiffening rib plates on the outer side of the core block at the tower top via a specially developed survey fixture.After long-distance orientation with the total station,the alignment of the steel tower segments was monitored.The construction survey technique resolved issues such as insufficient survey control points at the tower base,limited survey space on the tower,and short effective nighttime survey windows during the ultra-high steel tower hoisting process over a kilometer offshore.It also mitigated the impact of deformation in the middle and lower tower columns on steel tower hoisting,achieving a spatial alignment accuracy of±5 mm and an overall tower verticality tolerance of 1/8000.
作者
解光路
周海生
詹益
XIE Guanglu;ZHOU Haisheng;ZHAN Yi(CCCCSHEC Fourth Engineering Co.,Ltd.,Wuhu 241060,China)
出处
《铁道勘察》
2025年第4期15-21,共7页
Railway Investigation and Surveying
基金
江苏省交通运输厅科技项目(CT-SGZT-16)。
关键词
公铁两用桥
斜拉桥
钢塔
分块吊装
天顶投点
施工测量
快速测控
combined highway-rail bridge
cable-stayed bridge
steel tower
segmented hoisting
zenith projection
construction survey
rapid measurement and control
