摘要
鹤洞大桥为主跨360 m的双塔双索面混合梁斜拉桥,全桥共有144根斜拉索。由于斜拉索超出原设计使用寿命,经专项检测斜拉索已不能满足安全使用需求,因此需进行全桥斜拉索更换。新索采用∅7 mm低松弛高强度镀锌平行钢丝索,设计采用多重防护体系进行全寿命周期防护;原设计索长和竣工图纸索长误差较大,为确保新索锚固合理,采用计算索长和竣工合理索长确定新索长度,指导新索生产;采用“长索到短索、双塔先后反对称、单塔对称”的顺序进行斜拉索更换;对旧索索力放松、旧索拆除、新索安装和新索张拉等步骤进行施工监控,以桥面标高控制为主,斜拉索索力控制为辅。全桥144根斜拉索历时83 d更换完成,斜拉索更换前、后桥面标高偏差≤1 cm、索力偏差≤4%,满足施工控制目标,桥梁状态整体上已恢复至换索前状态。
The Hedong Bridge is a two-pylon hybrid girder cable-stayed bridge with a main span of 360 m.The bridge has a total of 144 stay cables that are arranged in double cable planes.The stay cables had already exceeded the design life,and special inspection also revealed that the stay cables could not meet the requirements of safety service.It was determined that all the stay cables be replaced.The new stay cables consist of the 7 mm-diameter low-relaxation high-strength galvanized parallel steel wires,which are life-cycle protected by multiple protection systems.As there are great bias between design lengths and as-built lengths of the original stay cables,to ensure the effective anchoring of new stay cables,the lengths of new stay cables are determined taking into account both the calculated and as-built stay cable lengths,to guide the new stay cable manufacturing.The stay cables were replaced following the sequence of from long to short stay cables,asymmetrical replacement of stay cables of the two pylons and symmetrical replacement of the stay cables of one single pylon.The processes of deloading and demolition of original stay cables,and the installation and tensioning of new stay cables were monitored,where the deck elevation governed the replacement,and the stay cable forces were important referencing indexes.It took 83 d to replace all the 144 stay cables,the deck elevation bias and stay cable forces bias before and after the replacement do not exceed 1 cm and 4%,respectively,meeting the control objective.The service condition of the bridge has restored to the level before stay cable replacement.
作者
晏国泰
张方杰
窦昕玥
YAN Guo-tai;ZHANG Fang-jie;DOU Xin-yue(CCCC Second Harbor Engineering Co.,Ltd.,Wuhan 430040,China)
出处
《世界桥梁》
北大核心
2023年第1期108-114,共7页
World Bridges
基金
广州交通投资集团有限公司科技研究开发计划项目(ALX-CSNP-2021-003)
中交第二航务工程局有限公司科技研究开发计划项目(EHYF-2021-B-19-077)。
关键词
斜拉桥
斜拉索
换索
索长确定
更换顺序
施工控制
施工技术
cable-stayed bridge
stay cable
cable replacement
cable length determination
replacement sequence
construction control
construction technique
