采用塔锚式架设法施工自锚式悬索桥可行性研究  

Feasibility of Using Tower-Anchor Erection Technique to Construct Self-Anchored Suspension Bridge

作　　者：王晓明[1] 李鹏飞 WANG Xiao-ming;LI Peng-fei(School of Highway,Chang′an University,Xi′an 710064,China)

机构地区：[1]长安大学公路学院,陕西西安710064

出　　处：《桥梁建设》2023年第2期127-134,共8页Bridge Construction

基　　金：国家自然科学基金项目(52178104);陕西省交通科研项目(21-52K)。

摘　　要：针对自锚式悬索桥“先梁后缆”法施工影响交通和环境的问题,提出塔锚式架设法。该方法借助边跨加劲梁延长主缆力的传递路径,通过塔梁临时锚固装置将主缆水平力由边跨加劲梁临时传递至桥塔,实现中跨加劲梁的“先缆后梁”架设。为研究塔锚式架设法的可行性及桥塔的复杂受力行为,以某双塔三跨自锚式悬索桥为背景,采用MIDAS Civil软件建立全桥模型,同时建立桥塔ANSYS实体模型和桩基与桩周土体FLAC 3D有限差分模型,分析桥塔压弯耦合失效、塔柱变形失效、桥塔基础推移失效3种桥塔失效模式,并分析垂跨比、加劲梁自重、边中跨比、桥塔墩高对桥塔压弯耦合失效模式的影响。结果表明:在中跨加劲梁吊装过程中,桥塔关键截面内力均在允许承载能力范围内,3种失效模式下各项指标均满足规范要求,说明塔锚式架设法可行。桥塔压弯耦合失效模式下,随垂跨比的减小、加劲梁自重的增加,桥塔塔底截面和塔梁连接处截面内力轨迹均呈现增大趋势;随桥塔墩高的增加,桥塔塔底截面内力明显增大,而塔梁连接处截面内力几乎没有变化;边中跨比对桥塔关键截面的内力轨迹影响程度有限,可以忽略。建议塔锚式架设法主要应用于加劲梁自重较小(如钢箱梁、钢-混组合梁等)、桥塔墩高较矮、塔基抗推性能较好的双塔三跨自锚式悬索桥。For a self-anchored suspension bridge,the conventional way is to construct the stiffening girder ahead of the main cables,however,this would bring unavoidable interruption to the traffic in the vicinity.In this paper,a tower-anchor erection technique is proposed,which aims to extend the main cable forces transfer paths by taking advantage of the side-span stiffening girders,the main cable forces are temporarily transferred from side-span stiffening girders to bridge towers via the temporary tower-to-girder anchor devices,so as to allow the main cables to be erected before the central-span stiffening girders.To study the feasibility of the technique as well as the load bearing behavior of the towers,an existing two-tower self-anchored suspension bridge was used as a case,based on which a full-bridge finite element model was developed in MIDAS Civil,and the solid-element tower model was built up in ANSYS,and a pile-soil model was established in FLAC 3D,to analyze three tower failure modes,including tower failure caused by compression and bending interaction,failure induced by tower column deformation,and tower foundation failure due to thrust.Additionally,the parameters related to the tower failure caused by compression and bending interaction were analyzed,including sag-to-span ratio,self-weight of stiffening girder,side span to central span ratio,and pylon pier heights.It is shown that during the erection of stiffening girders in midspan,the internal forces of key cross-sections were all within the allowable ranges,and all the indexes met the code requirements when any of the three failure modes occurred,indicating that the proposed tower-anchor erection technique was applicable.With tower failure caused by compression and bending interaction,as the sag-to-span ratio decreased and the self-weight of stiffening girder significantly increased,the internal forces in the tower bottom cross-section and the tower-girder connections showed signs of growing.As the heights of the tower piers increased,the internal forces

关 键 词：自锚式悬索桥 塔锚式架设法 失效模式 压弯耦合 受力性能 参数分析 有限元法 

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]