摘要
宜昌夷陵长江大桥为中央索面三塔预应力混凝土斜拉桥,斜拉索采用平行钢绞线拉索体系,经特殊检测斜拉索已达换索条件,设计对全桥236根斜拉索全部更换。新斜拉索采用性能更好的单丝涂覆环氧涂层钢绞线拉索体系,直径、钢绞线股数与原斜拉索相同,标准抗拉强度优化为1 960 MPa。斜拉索更换采用三塔同步施工方式,根据有限元计算和试验索监控测量结果,按照“中塔从长索到短索、边塔从短索到长索、三塔同步倒序交叉”施工。采用等值张拉法控制新索索力。为解决斜拉索张拉端钢绞线外露量不足导致无法完全放张的问题,研制钢绞线斜拉索整束放张工艺装备,保证斜拉索卸载至无应力状态,并提高了施工进度。全桥236根钢绞线斜拉索历时152 d完成更换,并达到设计目标状态。
The Yiling Changjiang River Bridge in Yichang is a three-pylon prestressed concrete cable-stayed bridge.The original 236 stay cables,which were all parallel-steel-strand cables,were arranged in three central cable planes.Due to that the stay cables reached service life,a replacement plan was determined.The new stay cables consist of parallel steel strands,featuring the epoxy-coated individual steel wires with a standard tensile stress of 1960 MPa,but analogous to the original ones in diameter and the number of steel strands.The original stay cable was difficult to be detensioned,due to the insufficient exposed length at its live end.To address this issue,the equipment allowing the detensioning of a whole stay cable was employed,which could deload the stay cables to free-stress state and improve the replacement efficiency.In accordance with the numerical simulation and the monitoring data of the trial cable,the longer stay cables in the central pylon were removed first,while in the side pylons,the shorter stay cables were removed first,and the stay cable replacement at the three pylons was carried out simultaneously,but in reverse order and in an alternate manner,in terms of the number of the stay cables.An isotensioning approach was employed to control the tensions of new stay cables.The replacement of the whole 236 stay cables lasted 152 d,and all the new stay cables reach the design target state.
作者
王永鹏
WANG Yongpeng(Wuhan Bridge Special Technology Co.,Ltd.,China Railway Major Bridge Engineering Group,Wuhan 430074,China;State Key Laboratory of Bridge Intelligent and Green Construction,Wuhan 430034,China)
出处
《世界桥梁》
2025年第5期111-118,共8页
World Bridges
基金
中国中铁股份有限公司科技研究开发计划项目(2023-专项-02)。
关键词
斜拉桥
钢绞线斜拉索
更换
整束放张
无应力状态
三塔同步
施工技术
cable-stayed bridge
steel-strand stay cable
replacement
whole stay cable detensioning
free-stress state
synchronized replacement at three pylons
construction technique
作者简介
王永鹏(1993-),男,工程师,2016年毕业于兰州理工大学土木工程专业,工学学士(E-mail:632021891@qq.com)。
