施工阶段误差对大跨PC连续梁桥长期工作性能的影响

发布时间：2018-03-21 10:54

本文选题：大跨径梁桥　切入点：结构长期性能　出处：《长安大学》2014年硕士论文　论文类型：学位论文

【摘要】：桥梁作为跨越路线障碍的主要构造物在交通基础设施建设中被广泛使用，其中大跨径预应力混凝土连续梁桥在我国已建桥梁中占有相当大的比例。近几年发现，大跨径梁桥在服役若干年后就发生跨中下挠过大，梁体产生裂缝等病害，本文首次从施工阶段对桥梁结构长期力学性能影响的角度考虑这个问题。首先对施工阶段的误差进行了合理分类，，其次考虑了不同种类的误差对桥梁结构长期工作性能的影响，以期对桥梁的施工和设计提出合理建议。施工阶段对结构的影响可以分为施工质量问题和施工误差，施工质量问题又可以分为已经暴露出的质量问题和潜在的质量问题；而施工误差又可以分为规范做出规定的误差与规范未做出规定的误差，不同类型的施工误差对桥梁结构长期力学性能影响方式与程度不同。本文对与收缩徐变相关的两项误差以及合龙高差进行了分析。不同的收缩徐变模型计算的结构长期内力与变形差别较大，我国现行规范计算值总体比其他规范要小。由于目前非标准条件下混凝土收缩徐变规律研究较少，因此不排除这也是桥梁长期病害的一个因素。加载龄期对桥梁结构长期内力与变形存在影响：就大跨径梁桥而言，主跨相比边跨更加敏感，主墩墩顶应力比边墩墩顶应力更加敏感，理论数据表明由在我国现行规范下由加载龄期导致的结构性能与设计值的偏差经过十年收缩徐变后在5%以内。合龙高差对桥梁结构长期内力变形的影响随强迫合龙高差的增大而增大，理论分析表明，强迫合龙对跨中长期挠度控制是有益的，但对跨中两侧结构影响不同：对被压重一侧，强迫合龙使得边跨跨中上挠、墩顶压应力减小，另一侧则相反，总体上来说强迫合龙对被压重一侧影响较大。数据表明对于百米跨径梁桥当强迫高差小于5cm时，可以保证其对结构长期力学性能的影响小于5%。
[Abstract]:Bridge is widely used in the construction of transportation infrastructure as the main structure of crossing route obstacle, in which the long-span prestressed concrete continuous beam bridge occupies a large proportion of the bridges that have been built in our country. After several years of service, long span beam bridges suffer from diseases such as excessive span deflection and cracks in the beam body. This paper considers this problem for the first time from the point of view of the influence of the construction stage on the long-term mechanical performance of the bridge structure. Firstly, the errors in the construction stage are classified reasonably, and then the influence of different kinds of errors on the long-term working performance of the bridge structure is considered. In order to put forward reasonable suggestions on the construction and design of the bridge. The influence of construction stage on structure can be divided into construction quality problems and construction errors, and construction quality problems can be divided into exposed quality problems and potential quality problems. And the construction error can be divided into the error specified in the code and the error not specified in the code. Different types of construction errors affect the long-term mechanical properties of bridge structures in different ways and degrees. In this paper, two errors related to shrinkage and creep and the height difference of closure are analyzed. The long-term internal forces and deformation of structures calculated by different shrinkage and creep models are quite different, and the calculated values of current codes in China are generally smaller than those of other codes. Because of the lack of research on shrinkage and creep laws of concrete under non-standard conditions at present, Therefore, it is also a factor of long-term disease of bridge. The effect of loading age on the long-term internal force and deformation of bridge structure is as follows: for long-span beam bridges, the main span is more sensitive than the side span, and the stress at the top of the main pier is more sensitive than the top stress of the side pier. The theoretical data show that the deviation between the structural performance and the design value caused by the loading age is less than 5% after ten years of shrinkage and creep. The influence of closing height difference on the long-term internal force deformation of bridge structure increases with the increase of forced closure height difference. Theoretical analysis shows that forced closure is beneficial to the control of mid-long span deflection. However, the effects on the middle and middle side of the span are different: for the compressed side, the forced closure causes the upper deflection of the middle span of the side span, the pressure stress at the top of the pier decreases, and the other side is opposite. The data show that when the forced height difference is less than 5cm, the influence of forced closure on the long-term mechanical properties of the bridge is less than 5cm.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U445;U448.215

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