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混凝土梁侧嵌贴CFRP-PCPs复合筋的抗弯及抗剪加固试验研究

发布时间:2019-02-11 21:36  文章来源:笔耕文化传播
【摘要】:近年来,随着碳纤维(CFRP)等新型复合材料大量应用于土木结构工程中,将其嵌入加固混凝土结构等新技术的研究逐渐得到了工程界的广泛关注,在取得了一些理论研究成果和工程实践经验的同时,也面临着一些理论及技术问题。非预应力CFRP筋在嵌入式加固钢筋混凝土梁时,存在下列问题,如加载过程中梁的挠度过大,延性较差,裂缝宽度及高度较大,CFRP筋在试件极限承载力时远未达到设计屈服强度,即其高强度无法有效发挥等。预应力CFRP筋嵌入式加固钢筋混凝土梁时,目前为止与其配套的预应力张拉锚固体系与装置较少,预应力张拉工艺复杂,锚具造价较高。针对以上所述问题,本课题组提出CFRP-PCPs复合筋(Carbon Fiber Reinforced Polymer prestressed concrete prisms,本文简称为CFRP-PCPs复合筋)嵌入式加固钢筋混凝土梁的方法,并进行了试验和理论分析,收到了预期的效果。本文采用自行研制的CFRP-PCPs复合筋,分别进行了钢筋混凝土梁抗弯加固试验研究和钢筋混凝土梁抗剪加固试验研究,主要研究内容和成果如下:第一,本文基于国内外关于复合筋混凝土构件试验研究已取得成果的基础上,分别完成了8根复合筋嵌入式抗弯加固混凝土梁的试验研究,以及8根复合筋嵌入式抗剪加固混凝土梁的试验研究,详细描述了试验过程和相关试验现象,全面分析了所得的试验结果。通过试验现象观察,获得了各试验梁的裂缝分布及发展形态,通过试验数据分析,得到了各试验梁的荷载挠度曲线关系,绘出了各试验梁复合筋内CFRP筋的荷载-应力增量对比曲线。第二,通过嵌入式CFRP-PCPs复合筋抗弯加固钢筋混凝土梁的试验研究,对嵌入式CFRP-PCPs复合筋抗弯加固混凝土梁的破坏模式进行了系统的分析;提出了不同锚固长度复合筋加固混凝土梁剥离破坏时极限承载力的计算方法,计算结果与试验结果吻合较好;提出了复合筋加固混凝土梁开裂荷载计算方法,对复合筋嵌贴加固混凝土梁的裂缝、挠度、延性等进行了分析,并提出了相关的计算方法。第三,通过嵌入式CFRP-PCPs复合筋抗剪加固钢筋混凝土梁的试验研究,对嵌入式CFRP-PCPs复合筋抗剪加固混凝土梁的破坏模式进行了分析;提出了加载过程中因复合筋棱柱体断裂而导致试验梁发生剪切破坏的承载力计算方法,与试验结果吻合较好。
[Abstract]:In recent years, with the extensive application of carbon fiber (CFRP) and other new composite materials in civil engineering, the research on the new technology of embedding and strengthening concrete structures has been paid more and more attention by the engineering field. At the same time, it faces some theoretical and technical problems. The following problems exist in the reinforcement of reinforced concrete beams with unprestressed CFRP tendons, such as excessive deflection, poor ductility, large crack width and height during loading, and the CFRP bars are far from reaching the design yield strength in the ultimate bearing capacity of the specimens. That is, its high strength can not be played effectively. In the reinforcement of reinforced concrete beams with prestressed CFRP tendons, so far, there are fewer prestressed tensioning anchoring systems and devices, complex prestressing tensioning technology and high cost of anchors. In view of the above problems, our group put forward the method of strengthening reinforced concrete beam embedded with CFRP-PCPs composite reinforcement (Carbon Fiber Reinforced Polymer prestressed concrete prisms, which is referred to as CFRP-PCPs composite reinforcement in this paper, and carried out experimental and theoretical analysis. The desired effect was achieved. In this paper, the experimental research on flexural strengthening of reinforced concrete beams and shear strengthening of reinforced concrete beams are carried out using CFRP-PCPs composite tendons developed by ourselves. The main research contents and results are as follows: first, In this paper, based on the achievements of the experimental research on concrete members with composite reinforcement at home and abroad, eight concrete beams with embedded composite tendons have been tested and studied respectively. The experimental study of 8 composite tendons embedded shear strengthened concrete beams is carried out. The experimental process and related experimental phenomena are described in detail, and the experimental results are comprehensively analyzed. Through the observation of experimental phenomena, the crack distribution and development pattern of each test beam are obtained. Through the analysis of test data, the relationship of load deflection curve of each test beam is obtained. The load-stress increment contrast curves of CFRP tendons in the composite tendons of each test beam are plotted. Secondly, the failure mode of the reinforced concrete beams strengthened with embedded CFRP-PCPs composite tendons is analyzed systematically through the experimental research on the flexural strengthening of reinforced concrete beams with embedded CFRP-PCPs composite tendons. The calculation method of ultimate bearing capacity of concrete beams strengthened with different Anchorage length composite bars is put forward. The calculated results are in good agreement with the experimental results. This paper presents a method for calculating the cracking load of concrete beams strengthened with composite bars, and analyzes the cracks, deflection and ductility of concrete beams strengthened with composite tendons, and puts forward the relevant calculation methods. Thirdly, the failure mode of reinforced concrete beams strengthened with embedded CFRP-PCPs composite tendons is analyzed through the experimental research on the shear resistance of reinforced concrete beams strengthened with embedded CFRP-PCPs composite tendons. A method for calculating the shear failure of test beams caused by the fracture of prisms with composite tendons during loading is proposed, which is in good agreement with the experimental results.
【学位授予单位】:广西科技大学
【学位级别】:硕士
【学位授予年份】:2015
【分类号】:TU375.1

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本文编号:2420130


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