满堂支架现浇预应力混凝土连续箱梁桥开裂分析及对策

发布时间：2018-03-10 21:39

本文选题：满堂支架　切入点：连续箱梁　出处：《长安大学》2015年硕士论文　论文类型：学位论文

【摘要】：现阶段,我国桥梁事业发展迅速,取得了显著成果。其中预应力混凝土箱梁桥应用较多,但箱梁桥开裂现象也较为普遍。国内外也对箱梁开裂机理做了不少研究,但是进展较慢,并没有形成系统的理论体系。此时,箱梁开裂研究变得尤为重要。本文以满堂支架现浇预应力混凝土连续箱梁桥为研究对象,针对箱梁底板开裂病害,建立有限元模型,对箱梁底板进行应力分析。主要考虑了支架不均匀沉降、温度变化、预应力损失对混凝土箱梁底板受力状态的影响,提出了混凝土开裂的对策。主要内容如下:1、阐述了本文的研究背景和研究的意义,以及现阶段国内外对箱梁开裂研究的现状,介绍了混凝土强度理论和开裂分析方法,总结了连续箱梁桥的开裂形态及影响因素;2、利用有限元软件进行建模,深入探究箱梁底板开裂的主要原因,针对支架不均匀沉降、温度变化、预应力损失等原因,进行了箱梁底板开裂机理分析,分析了支架整体不均匀沉降和局部不均匀沉降作用引起的箱梁底板的应力变化规律,温度梯度作用下箱梁底板的应力变化规律,预应力损失作用下箱梁底板的应力变化规律;3、通过对箱梁开裂原因的分析以及根据主被动加固方案的对比,本文提出采用箱室内布置体外预应力进行加固,经过加固前后的应力对比,得出体外预应力加固对减小底板主拉应力是行之有效的,简要概括了混凝土的修补方法,总结了满堂支架现浇桥梁施工中的几种防裂措施。
[Abstract]:At the present stage, the bridge industry in China is developing rapidly, and remarkable achievements have been made. The prestressed concrete box girder bridge is widely used, but the cracking phenomenon of the box girder bridge is also relatively common. Many researches have been done on the cracking mechanism of the box girder at home and abroad. But the progress is slow and there is no systematic theoretical system. At this time, the research of box girder cracking becomes particularly important. In this paper, the in-situ prestressed concrete continuous box girder bridge with full support is taken as the research object, aiming at the crack disease of box girder bottom slab. The finite element model is established to analyze the stress of the bottom slab of the box girder. The influence of the uneven settlement of the support, the change of temperature and the loss of prestress on the stress state of the bottom slab of the concrete box girder are considered. The countermeasures of concrete cracking are put forward. The main contents are as follows: 1. The research background and significance of this paper, the present situation of box girder cracking research at home and abroad, and the concrete strength theory and cracking analysis method are introduced. This paper summarizes the cracking form of continuous box girder bridge and its influencing factors, and makes use of finite element software to model the main reasons of box girder bottom slab cracking, aiming at the reasons of uneven settlement of support, temperature change, prestress loss, etc. The cracking mechanism of the bottom plate of the box girder is analyzed, and the stress variation law of the bottom plate of the box girder caused by the integral uneven settlement of the support and the local uneven settlement is analyzed, and the stress change law of the bottom plate of the box girder under the action of temperature gradient is analyzed. Under the action of prestress loss, the stress variation law of box girder bottom slab is 3. Through the analysis of box girder cracking reason and the comparison of active and passive reinforcement schemes, this paper puts forward that the box interior layout external prestress is used to reinforce the box girder. Through the stress comparison before and after reinforcement, it is concluded that external prestressing reinforcement is effective in reducing the main tensile stress of the floor slab. The repairing method of concrete is summarized briefly, and several anti-crack measures in the construction of cast-in-place bridge with full support are summarized.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U448.213;U445.7

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