部分粘贴CFRP加固钢筋混凝土抗弯构件的延性研究

发布时间：2018-03-03 03:04

本文选题：CFRP　切入点：部分粘贴　出处：《安徽理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：纤维复合材料(Fiber Reinforced Plastics 或 Fiber Reinforced Polymer,简称FRP),用于加固混凝土结构始于20世纪80年代中期,瑞士联邦实验室首先采用碳纤维(CFRP)加固钢筋混凝土梁,紧接着经过快速的发展,各国学者的不断深入研究,FRP加固混凝土结构得到了广泛的应用。随着研究数据的增多,越来越被人们所熟悉了解,发现采用FRP加固混凝土梁时它的受弯承载力得到提高,同时却降低了其延性,这是它的两个主要特征。在工程结构应用中,延性的降低是一种脆性破坏的主要表现。本文主要通过对比梁试验研究部分粘贴碳纤维布加固钢筋混凝土抗弯结构时,加固梁的承载力以及延性等的影响因素。这个研究对实际工程应用有着很好的推广和应用价值。本文实验一共采用6根实验梁,一个未加固的对比梁,还有5根分别是跨中位置未粘贴部分为0、20、40、60、80cm的加固梁,采用控制变量法对这六根梁进行抗弯试验,试验主要测量出梁的极限承载力和最大挠度以及碳纤维布的应变和梁跨中侧表面应变。通过对数据的处理分析,对比发现跨中未粘贴部分越大的梁,它的承载力得到提升的前提下,延性也相对的有所提高。观察它的破坏形态,可以发现,跨中脱空部分比较大的梁,它的底部的裂缝比较多,且开展的比较缓慢,也正是因为这样一种原理,结构的延性得以提高。本文在规范操作的试验下,对部分粘贴加固钢筋混凝土抗弯结构的各项特性进行了研究分析,试验发现部分粘贴加固梁破坏时挠度变形较大,中部的弯曲裂缝比较密集,且跨中未粘贴部分越大,裂缝越密集,挠度变形也越大;在试验梁从加载至破坏的过程中,部分粘贴加固梁和未加固梁的刚度也是有显著提高的,加固梁在加压过程中裂缝开展的比较缓慢,裂缝宽度也比较小;本文通过对全粘贴梁的常规性分析结合Chen and Teng公式推导出部分粘贴加固梁的抗弯承载力计算公式并对其进行了简单的验证,发现与试验结果基本吻合。当然,在本文试验中,CFRP的材料利用率并没有达到最理想的状态,使得其并没有很好地发挥它的特性,我们应该想办法改变它的受力状态,提高它的利用率,这也是我们研究者后续工作之一。
[Abstract]:Fiber Reinforced Plastics or Fiber Reinforced Polymer, or Fiber Reinforced Polymer, began in the middle of 1980s to reinforce concrete structures. The Swiss Federal Laboratory first used carbon fiber reinforced concrete (CFRP) to strengthen reinforced concrete beams, followed by rapid development. With the increasing of research data, more and more people are familiar with it. It is found that the flexural bearing capacity of concrete beams strengthened with FRP is improved. At the same time, it reduces its ductility, which is its two main characteristics. The reduction of ductility is the main manifestation of brittle failure. The influence factors of the bearing capacity and ductility of the strengthened beams. This study is of great value to the practical engineering application. In this paper, six experimental beams and one unreinforced contrast beam are used in the experiment. In addition, five beams were strengthened in the middle of the span, which were not pasted in the middle of the span. The bending tests of the six beams were carried out by means of the control variable method. The ultimate bearing capacity and the maximum deflection of the beam, the strain of the carbon fiber sheet and the strain of the middle side of the beam are measured. Through the analysis of the data, it is found that the larger part of the beam is not attached in the middle of the span, If its bearing capacity is raised, its ductility is also relatively improved. By observing its failure pattern, it can be found that the beam with a larger gap in the middle of the span has more cracks at the bottom and develops slowly. It is precisely because of this principle that the ductility of the structure is improved. In this paper, the characteristics of partially bonded reinforced concrete flexural structures are studied and analyzed under the standard operation test. It is found that the deflection of partially bonded strengthened beams is larger, the bending cracks in the middle of the beams are dense, and the larger the unbonded part of the span is, the more dense the cracks are, and the greater the deflection of the beams is, the greater the deflection of the beams is during the process of loading to failure. The stiffness of the partially bonded and unstrengthened beams is also significantly improved. The crack develops slowly and the crack width is smaller during the compression process of the strengthened beam. This paper deduces the calculation formula of flexural bearing capacity of partially bonded beams by combining with Chen and Teng formula through the conventional analysis of fully bonded beams, and makes a simple verification. It is found that the calculation results are basically consistent with the experimental results. Of course, the calculation results of the flexural capacity of partially bonded beams are in good agreement with the experimental results. In this paper, the material utilization ratio of CFRP has not reached the ideal state, which makes it not give full play to its characteristics. We should find a way to change the stress state of CFRP and improve its utilization ratio. This is also one of our researchers' follow-up work.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU375.1;TU599

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