预应力砼连续T梁桥危险状态下的力学性能研究

发布时间：2018-06-27 20:33

本文选题：先简支后连续T梁桥 + 有限元　；参考：《南昌大学》2014年硕士论文

【摘要】：预应力混凝土T型连续梁桥具有变形小、刚度大、伸缩缝数量少等优点，而且行车舒适，施工及养护方便，往往在各类桥梁的比选中受到业主们的青睐。在连续T型梁桥的几种施工方法中，，先简支后连续施工方法是一种经济有效的施工方法，与普通混凝土连续梁桥相比，此种方法造价低廉，施工便捷，周期较短，受到了设计者和施工者们的欢迎。但我国先简支后连续梁桥还处在发展阶段，施工技术和设备相对落后，在建设施工和使用过程中产生了诸多问题和病害，造成了大量经济损失，故对这些病害加以分析研究很有必要。本文通过利用大型有限元软件Midas/Civil，以典型预应力T梁桥作为研究对象，对其上部结构进行整体仿真计算与分析研究。分析支座病害发现，支座脱空和支座异常变形对结构受力影响均较大，边梁支座脱空比中梁支座脱空更不利。分析了不同预应力损失量下的负弯矩钢束张拉对结构受力的影响，其中主要的影响主要在支座附近的截面。除了对负弯矩所在的主梁受力产生明显影响，还对其相邻的主梁造成了影响，但其他相隔的主梁无明显变化。分析施工顺序表明，同一墩顶处各片主梁负弯矩张拉施工次序中，优先选择对称张拉各片主梁负弯矩钢束；纵桥向施工顺序中，先浇筑所有主梁间湿接缝，然后对称浇筑或者间隔浇筑湿接头，并张拉负弯矩钢束。最后采用大型有限元软件ANSYS对后连续段湿接头部分进行局部分析，对其成桥阶段分析表明，湿接头中间部分和底缘部分容易受到较大的拉应力，此处应该提高配筋率、采用高强度混凝土等方法来加强结构刚度，并减少预应力损失。
[Abstract]:Prestressed concrete T-type continuous beam bridge has the advantages of small deformation, large stiffness, small number of expansion joints and so on. It is also comfortable in driving, convenient in construction and maintenance, and often favored by the owners in the comparison and selection of various kinds of bridges. Among several construction methods of continuous T-beam bridge, the method of simple support and then continuous construction is an economical and effective construction method. Compared with ordinary concrete continuous beam bridge, this method is cheap, easy to construct and has a shorter period. It was welcomed by designers and builders. However, the construction technology and equipment are relatively backward, which has caused many problems and diseases in the process of construction and use, resulting in a large number of economic losses. Therefore, it is necessary to analyze and study these diseases. By using the large-scale finite element software Midas / Civil, this paper takes the typical prestressed T-beam bridge as the research object, carries on the overall simulation calculation and the analysis to its superstructure. Based on the analysis of the bearing diseases, it is found that the bearing void and the abnormal deformation of the support have great influence on the stress of the structure, and the side beam support is more disadvantageous than the middle beam support. In this paper, the influence of negative moment steel bundle tension on the stress of the structure under different prestressing loss is analyzed, in which the main influence is on the section near the bearing. In addition to the negative bending moment of the main beam force has a significant impact on its adjacent main beam, but the other separated main beam has no obvious change. The analysis of the construction sequence shows that in the construction sequence of negative moment tension of each piece of main beam at the same pier top, priority is given to symmetrical tensioning each piece of negative moment steel beam, and in the construction sequence of longitudinal bridge, the wet joints between all main beams are first cast. The wet joints are then poured symmetrically or at intervals, and the negative moment steel bundles are tensioned. Finally, the local analysis of the wet joint part of the back continuous segment is carried out by using the large-scale finite element software ANSYS. The analysis of the bridge stage shows that the middle part and the bottom edge part of the wet joint are vulnerable to large tensile stress, and the reinforcement ratio should be increased here. High-strength concrete is used to strengthen the stiffness of the structure and reduce the loss of prestress.
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441

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