宽翼缘预应力混凝土箱梁裂缝成因分析及加固方法研究

发布时间：2018-02-14 16:40

本文关键词： 宽翼缘箱梁应力裂缝成因分析加固方法体外预应力　出处：《长安大学》2014年硕士论文　论文类型：学位论文

【摘要】：预应力混凝土连续箱梁桥由于其诸多优点被广泛应用于国内外桥梁中，但是随着我国交通量的急剧增加，，该桥型出现病害的现象越来越普遍，其中尤以裂缝问题最为突出。本文主要以某宽翼缘预应力混凝土连续箱梁为工程背景，进行结构计算分析其裂缝成因，同时对裂缝的维修加固方案进行研究。本文主要研究内容如下：（1）对箱梁的计算理论进行了研究分析,详细论述了箱梁力学特性及分析方法,然后对宽翼缘箱梁的弯曲应力、剪力滞效应、刚性扭转、畸变效应、温度效应及收缩徐变效应的计算分别进行了理论分析研究。（2）采用Midas/Civil的剪力—柔性梁格法并考虑剪力滞后效应，按照B类预应力构件计算原则，对该桥进行模拟计算分析。分别从恒载、活载、温度效应、收缩徐变作用等方面来分析其控制截面的应力结果，计算结果表明主梁的应力均符合规范要求。（3）考虑旧桥修正系数、部分预应力管道压浆不饱满、钢筋上浮及钢绞线松弛等因素的影响，截面计算偏安全地按照对其钢绞线设计强度进行20%折减进行修正计算。计算结果表明：在主跨跨中截面下缘产生最大的法向拉应力和最大主拉应力，严重超出规范限值。结合计算结果分析顶、底板和腹板裂缝产生的原因。最后对底板结构性横向裂缝提出两种加固方案，并对既定方案—体外预应力加固法进行加固后的结构计算分析，结果表明加固后的主梁的应力情况得到很大改善，最大主拉应力提高34.2%，应力曲线变化较为均匀，且均满足规范要求。本文对具有斜交跨的宽翼缘预应力混凝土连续箱梁桥的裂缝成因及加固方法做了初步的分析研究，对其它同类型桥梁的维修加固具有现实的借鉴意义。
[Abstract]:Prestressed concrete continuous box girder bridge is widely used in bridges at home and abroad because of its many advantages. However, with the rapid increase of traffic volume in China, the phenomenon of bridge type disease is becoming more and more common. The crack problem is the most prominent one. In this paper, the structural calculation and analysis of the causes of the crack are carried out, taking the prestressed concrete continuous box girder with a wide flange as the engineering background. The main contents of this paper are as follows:. 1) the calculation theory of box girder is studied and analyzed, and the mechanical characteristics and analysis method of box girder are discussed in detail. Then, the bending stress, shear lag effect, rigid torsion and distortion effect of wide flange box girder are analyzed. The calculation of temperature effect and shrinkage creep effect are studied theoretically. (2) adopting Midas/Civil 's shear flexible beam method and considering the lag effect of shear force, the bridge is simulated and analyzed according to the calculation principle of class B prestressed members. The effects of dead load, live load and temperature are analyzed respectively. The stress results of the control section are analyzed from the aspects of shrinkage and creep. The calculation results show that the stress of the main beam meets the requirements of the code. (3) considering the influence of the correction coefficient of the old bridge, the partial prestressing pipe grouting is not full, the steel bar floats and the steel strands are relaxed and so on, The section calculation is calculated safely according to the 20% reduction of the design strength of the steel strand. The calculation results show that the maximum normal tensile stress and the maximum main tensile stress are produced at the lower edge of the middle section of the main span. The causes of cracks in top, bottom and web are analyzed in combination with the calculation results. Finally, two kinds of reinforcement schemes are proposed for structural transverse cracks of floor. The results show that the stress of the strengthened main beam is greatly improved, the maximum principal tensile stress is increased by 34.2%, and the stress curve is more uniform. And all meet the specification requirements. In this paper, the causes of cracks and reinforcement methods of prestressed concrete continuous box girder bridge with wide flange with skew span are analyzed and studied, which is of practical significance for the maintenance and reinforcement of other bridges of the same type.
【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】：U445.7

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