平行钢丝斜拉索更换施工新索无应力长度确定方法研究

Methods to Determine Stress-Free Lengths of New Stay Cables Replacing Original Parallel-Steel-Wire Stay Cables

为准确确定平行钢丝斜拉索更换施工新索无应力长度,基于悬链线法和无应力状态法,并结合斜拉索索力、锚点间距、斜拉索原始加工长度和实际锚固位置等数据,综合提出5种针对不同数据场景下的平行钢丝斜拉索新索无应力长度快速计算方法。以攀枝花炳草岗大桥为背景,采用5种方法计算该桥新索无应力长度,分析其合理性,并进一步提出6项新索无应力长度复核计算准则。结果表明:在充分研判炳草岗大桥基础资料并对照6项复核计算准则的合理性后,基于无应力状态法,并结合旧索加工总长和实测锚具伸出量,准确给出了新索无应力长度。该桥新索张拉锚固完成后,塔、梁端实际锚固位置合理、可控,成功解决了其基础资料混乱、斜拉索锚固位置不当的问题。

This paper presents five rapid calculation methods to determine the stree-free lengths of stay cable replacements under varying data combinations,based on the catenary method and stress-free method,counting the data associated with stay cable forces,intervals of anchorages,original lengths of stay cables and actual locations of anchorages.The methods have been applied to the Bingcaogang Bridge in Panzhihua,to calculate the stress-free lengths of the new stay cables.The effectiveness of these five methods was analyzed.Furthermore,six calculation verification philosophies of the stress-free lengths of new cables were proposed.After thorough evaluation of the documents of the Bingcaogang Bridge and comparison of the plausibility of the six verification calculation philosophies,the stress-free lengths of the new stay cables were given by the stress-free state method,considering the original cable length and measured protrusion of anchorages.After the installation of the stay cables,the anchorages of the stay cables in the pylons and the deck were in the designated locations and were placed under control.