大跨径混凝土桁式组合拱桥长期变形实测分析

发布时间：2018-11-14 16:35

【摘要】：混凝土桁式组合拱桥将悬臂桁架与拱桥相结合,发挥了二者的优势且施工方便,在我国大跨径拱桥中占有独特位置。同时,近年来该桥型桥面变形大并伴随开裂等问题开始出现,为研究大跨径混凝土桁式组合拱桥结构的长期变形机理及开裂原因,以一座主跨138m桁式组合拱桥为背景,对其长期变形和混凝土开裂情况进行实测和规律分析;采用有限元模型,分析收缩、徐变及温度作用引起的挠度变化,讨论了结构在不同荷载作用下的受力特征。实测及分析结果表明,桁式组合拱桥长期线形呈M形,且在年温差作用下双立柱间的桥面发生上拱和下挠的交替变化,混凝土的收缩徐变及年温差作用是影响跨中实腹段长期变形的主要因素;结构在双竖杆处的下弦杆位置、跨中位置以及空实腹段交界位置处承受的荷载作用较大,导致在使用阶段的裂缝不断发展。
[Abstract]:The concrete truss composite arch bridge combines the cantilever truss with the arch bridge, exerting their advantages and convenient construction, and occupies a unique position in the long span arch bridge of our country. At the same time, in recent years, the deformation of the deck of the bridge began to appear along with cracking. In order to study the long-term deformation mechanism and cracking reason of the long-span concrete truss composite arch bridge, a 138m truss composite arch bridge with main span is taken as the background. The long-term deformation and cracking of concrete are measured and analyzed. The finite element model is used to analyze the deflection changes caused by shrinkage, creep and temperature, and the stress characteristics of the structure under different loads are discussed. The measured and analyzed results show that the long term linear shape of truss composite arch bridge is M shape, and under the action of annual temperature difference, the upper arch and the lower deflection of the bridge deck between the two columns change alternately. The shrinkage and creep of concrete and the annual temperature difference are the main factors that affect the long-term deformation of the mid-span solid section. At the bottom chord position of the double vertical bar, the middle span position and the junction position of the empty and solid belly section, the structure is subjected to great loads, which leads to the continuous development of the cracks in the service stage.
【作者单位】：长安大学公路学院;旧桥检测与加固技术交通行业重点实验室;
【基金】：国家自然科学基金项目,项目编号51208056 中央高校基本科研业务费专项资金,项目编号310821161013
【分类号】：U446;U448.22

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