混锚薄板加固混凝土梁受力分析

发布时间：2018-01-23 04:33

本文关键词： 端锚混锚薄板混凝土梁加固预应力　出处：《中南大学》2013年硕士论文　论文类型：学位论文

【摘要】：摘要：钢板、FRP片材等薄板已被广泛应用于对既有结构的加固工程中。通常采用结构胶将薄板粘贴在受弯构件受拉区。这种做法虽然施工方便,但容易发生剥离破坏,这被视为该加固技术的致命缺陷。薄板端部剥离缘于该处的应力集中。为了降低对粘胶材料性能和粘贴施工质量的依赖性,将薄板按传统工艺沿全长粘贴的同时,可在其端部附加机械锚固装置,这种锚固方式不妨简称为混锚。与纯粘贴薄板端部纵向正应力为零、界面剪应力高度集中具有本质不同,混锚薄板端部可以承担很大的纵向拉力,剪应力集中现象也能得到大大缓解,故对抵抗端部剥离十分有利。若在粘贴或粘胶固化之前给薄板施加预应力,即形成预应力混锚系统,可望有效解决常规粘贴所不能解决的裂缝控制问题。本文的工作包含以下两点。 1、进行了混锚薄板加固梁的理论分析,推导了混锚薄板加固梁弹性阶段的界面正应力和剪应力的公式。利用有限元软件对被混锚薄板加固混凝土梁进行了数值分析。进行了理论解、有限元解和试验值的对比,三者吻合较好,证明了理论公式的正确性以及有限元模型的准确性。根据公式、有限元解及试验值,得出混锚系统能够有效缓解界面应力集中的结论。 2、利用有限元软件对混锚薄板预应力加固的混凝土梁进行了非线性全过程模拟。得到了预应力反拱值、开裂荷载、屈服荷载等,绘制了荷载-挠度曲线,并与试验梁的结果进行了对比,误差在合理范围内。有限元解与试验结果均表明施加预应力可以有效延迟开裂并提高被加固梁的承载力。本研究的意义在于对混锚薄板抗弯加固梁首次推导了界面应力解答,建立了合理的有限元模型,能够较准确地预测剥离荷载及承载力等,对加固设计和相关研究具有参考价值。
[Abstract]:Absrtact: FRP sheet has been widely used in the reinforcement of existing structures. Usually, the sheet is bonded to the tensile zone of the flexural members by structural glue. This method is convenient in construction. But it is easy to peel and destroy, which is regarded as the fatal defect of the reinforcement technology. The end peeling of thin plate is due to the stress concentration. In order to reduce the dependence on the properties of viscose material and the construction quality of bonding. The mechanical anchoring device can be added to the end of the thin plate while sticking along the full length of the plate according to the traditional technology. This kind of anchoring method may be referred to as mixed anchor for short. The longitudinal normal stress of the end part of the pure adhesive thin plate is zero. The high concentration of interfacial shear stress is essentially different, the end of the mixed anchor plate can bear a large longitudinal tensile force, and the phenomenon of shear stress concentration can be greatly alleviated. Therefore, it is very advantageous to resist peeling. If prestress is applied to the thin plate before bonding or viscose solidification, the prestressing mixed anchor system will be formed. It is expected that the problem of crack control which can not be solved by conventional pasting can be effectively solved. The work of this paper includes the following two points. 1. The theoretical analysis of composite anchor thin plate strengthened beam is carried out. The formulas of interface normal stress and shear stress in elastic stage of concrete beams strengthened with mixed anchor thin plates are deduced. The numerical analysis of concrete beams strengthened with mixed anchor thin plates is carried out by using finite element software, and the theoretical solution is given. The comparison between the finite element solution and the experimental value shows that the theoretical formula is correct and the finite element model is accurate. According to the formula, the finite element solution and the test value. It is concluded that the interfacial stress concentration can be effectively alleviated by the mixed anchor system. 2. The nonlinear whole process simulation of concrete beam strengthened by prestressed concrete with mixed anchor thin plate is carried out by using finite element software. The prestressed inverse arch value, cracking load, yield load and so on are obtained, and the load-deflection curve is drawn. The finite element solution and test results show that the prestressing force can delay cracking and improve the bearing capacity of strengthened beams. The significance of this study is that the interface stress solution is derived for the first time, and a reasonable finite element model is established, which can accurately predict the peeling load and bearing capacity and so on. It has reference value for reinforcement design and related research.
【学位授予单位】：中南大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU375.1

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