Full-scale experimental research on staged re-tightening effect of cable clamp bolts in suspension bridges

Journal Information

J. Hefei Univ. Tech. (Nat. Sci.), Dec.2025, Vol.48 No.12: 1713-1721, 1728

DOI: 10.3969/j.issn.1003-5060.2025.12.019

Authors

ZHOU Yongjun $ ^{1} $, JIA Liqiang $ ^{1,2} $, WEN Dean $ ^{3} $, LUO Zhiran $ ^{1} $, ZHAO Yu $ ^{1} $, MU Fengrui $ ^{1} $

(1. Engineering Research Center for Large Highway Structure Safety of Ministry of Education, Chang'an University, Xi'an 710064, China; 2. Guangxi Xingang Communications Investment Co., Ltd., Nanning 530000, China; 3. CCCC Second Highway Engineering Co., Ltd., Xi'an 710065, China)

Abstract and Keywords

Abstract: In order to enhance the efficiency of cable clamp bolt staged re-tightening during the operation period of suspension bridge, taking the SJ5 cable clamp of the Longmen Bridge as an example, an indoor full-scale model test was conducted to study the staged re-tightening effect. The research focused on the impact of single and double tensioners on the magnitude and distribution of effective bolt preload. Additionally, an analysis was performed on the effects of tightening sequence, initial effective preload, and final tension force on the efficiency of bolt tightening. The research results indicate that when tightening the bolts symmetrically from two ends toward the center of the clamp, the preload distribution is more uniform with less loss. A larger initial effective preload results in a smaller impact on the staged re-tightening effect. It is recommended to re-tighten the bolts in two rounds. In the first round, 0.9 times the design bolt force is suggested to reduce the staged re-tightening effect and achieve a more uniform distribution of effective bolt preload. Increasing tension force appropriately in the second round can reduce the preload loss and yield a greater effective bolt preload. If only one round of re-tightening is used, the tension force can be set to 1.25 times the design bolt force, and if two rounds of re-tightening is used, the tension force can be set to 1.15 times the design bolt force. The conclusions can provide technical support for the staged re-tightening and testing of bolt preload in practical engineering applications.

Keywords: suspension bridge; bolt; preload; staged re-tightening; tightening sequence; tightening efficiency

作者信息

周勇军 $ ^{1} $，贾利强 $ ^{1,2} $，文德安 $ ^{3} $，罗之然 $ ^{1} $，赵煜 $ ^{1} $，穆丰睿 $ ^{1} $

（1.长安大学公路大型结构安全教育部工程研究中心，陕西西安710064；2.广西欣港交通投资有限公司，广西南宁530000；3.中交第二公路工程局有限公司，陕西西安710065）

摘要和关键词

摘要: 为研究悬索桥索夹螺杆复拧时分批紧固效应以提高运营期间螺杆紧固效率,文章以龙门大桥SJ5索夹为背景,开展分批紧固工艺室内足尺模型试验,分别研究单拉伸器和双拉伸器作用对螺杆有效紧固力大小和分布的影响规律,并分析紧固顺序、初始有效紧固力和最终复拧张拉力对螺杆紧固效率的影响。研究结果表明:从索夹两端向中间对称紧固螺杆时紧固力分布较均匀且损失较小;螺杆初始有效紧固力越大对分批紧固效应影响越小。建议采用两轮次对螺杆进行复拧,其中第1轮次采用0.9倍设计值作为最终张拉力可减小分批紧固效应的影响,使螺杆有效紧固力分布更加均匀;第2轮次可适当提高张拉力,既可减小分批紧固效应的影响又可以获得更大的最终螺杆有效紧固力;若采用1轮次张拉可设置1.25倍超张拉系数,若采用2轮次张拉可设置1.15倍超张拉系数。该研究结果可为实际工程螺杆力分批紧固和检测提供技术支持。

关键词: 悬索桥；螺杆；紧固力；分批复拧；紧固顺序；紧固效率

Funding

国家自然科学基金资助项目(52278738); 陕西省“科学家+工程师”资助项目(2025QCY-KXJ-136)和广西科技重点研发计划资助项目(桂科AB23026125)

合肥工业大学学报(自然科学版)

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