悬索桥成桥阶段索夹螺杆紧固张拉控制技术研究  

Study of Cable Clamp Bolts Tightening and Tensioning Techniques for Completed Suspension Bridge

作　　者：施飞 代明净 伊建军 荆国强 赵龙 SHI Fei;DAI Ming-jing;YI Jian-jun;JING Guo-qiang;ZHAO Long(China Construction Third Engineering Bureau Urban Investment Operation Co. ,Ltd. ,Wuhan 430074,China;Yichang City Construction Investment Development Co. ,Ltd. ,Yichang 443003,China;State Key Laboratory for Health and Safety of Bridge Structures,Wuhan 430034,China;China Railway Bridge Science Research Institute,Ltd. ,Wuhan 430034,China)

机构地区：[1]中建三局城市投资运营有限公司,湖北武汉430074 [2]宜昌市城市建设投资开发有限公司,湖北宜昌443003 [3]桥梁结构健康与安全国家重点实验室,湖北武汉430034 [4]中铁大桥科学研究院有限公司,湖北武汉430034

出　　处：《世界桥梁》2022年第4期102-107,共6页World Bridges

基　　金：武汉市科技计划项目(2020010602011969);浙江省科技计划项目(2021C03185)。

摘　　要：为确定悬索桥二期恒载施工与索夹螺杆成桥阶段张拉工作同步进行的可行性与实施效果,以宜昌伍家岗长江大桥为背景,对成桥阶段索夹螺杆紧固张拉控制技术进行研究。首先基于主缆钢丝堆积模型及二期恒载导致的主缆承力后截面面积变化,研究二期恒载对螺杆轴力损失的影响;然后在二期恒载施工前对2次紧固张拉后的螺杆轴力进行监测;最后基于分析结果,制定成桥阶段索夹螺杆张拉工艺。结果表明:二期恒载导致螺杆轴力损失仅为37 kN,在二期恒载施工时可适当提高螺杆张拉荷载,并同步进行成桥张拉与后续的猫道拆除工作;主梁吊装后、桥面铺装前螺杆轴力衰减速度逐渐降低,根据螺杆轴力的长期衰减规律,预估638.7 d后螺杆轴力下降180 kN;制定张拉荷载提高至110%设计张拉力、螺母转角定量控制和稳压持荷等成桥张拉工艺,成桥螺杆轴力可达到设计张拉力的94.7%,满足设计要求,在主缆状态不变情况下638.7 d后的索夹抗滑移安全系数为2.82,仍具有充足的安全空间。The Wujiagang Changjiang River Bridge in Yichang is used as a case to analyze if the secondary dead loads of suspension bridge can be applied in parallel with the tensioning of cable clamp bolts in the as-built condition of bridge and what the implementation effect will be.The tightening and tensioning control techniques for cable clamp bolts are studied.Firstly,based on the packing model of the main cable steel wires and the variation of cross-sectional area of main cables induced by the application of secondary dead loads,the effect of bolt axial load loss caused by secondary dead loads is studied.Secondly,the bolt axial force after two-phase tightening and tensioning was monitored prior to the application of secondary dead loads.At last,the tensioning techniques for the cable clamp bolts in the as-built condition of bridge were selected on the basis of the analysis results.It is shown that the bolt axial force loss caused by secondary dead loads is only 37 kN,during the application of secondary dead loads,the tensioning loads of bolts can be increased,and the bolt tensioning in the as-built condition of bridge can be performed coinciding with the catwalk demolition.After the installation of the stiffening girder,but before the placement of the deck pavement,the decay rate of the bolt axial force is gradually decreased,which would drop to 180 kN after 638.7 days,considering the long-term decaying law of bolt axial force.When the tensioning load is increased to 110%of the design value,the rotation of bolts is controlled in increments,the pressure is kept constant and the load-sustaining time is ensured,the bolt axial force in the as-built condition of bridge can reach up to 94.7%of design tensioning force,meeting the design requirements.Supposing that the main cable state is constant,the anti-slip safety factor of the cable clamp is 2.82 after 638.7 days,indicating that there is still sufficient safety margin.

关 键 词：悬索桥 索夹螺杆 轴力 二期恒载 成桥阶段 张拉控制 

分 类 号：U448.25[建筑科学—桥梁与隧道工程] U445.4[交通运输工程—道路与铁道工程]