基于FRP加固的钢筋混凝土梁悬链线效应研究

发布时间：2018-10-13 08:41

【摘要】：在偶然荷载作用下,钢筋混凝土框架结构的承重构件失效破坏继而无法继续支撑上部结构,导致结构发生局部倒塌,由于建造的连贯性和整体性,局部倒塌易引发结构不成比例的整体连续性倒塌。如何通过对RC框架结构进行加固来提高其抗连续倒塌能力已成为工程加固的研究热点。考虑CFRP片材较强抗拉强度、不增加结构附荷、耐腐蚀等优良特点,利用CFRP片材对结构进行加固从而提高结构抗连续倒塌性能的方法正逐渐成为一种趋势,该种加固技术具备良好的使用前途。为探究CFRP加固RC框架结构提高结构抗连续性倒塌性能的影响,本文通过对比研究未加固试件和加固试件的抗连续倒塌性能,对两榀梁柱子结构分别进行了抗连续倒塌试验和理论分析。主要研究内容如下所示:1、对两榀相同的单层、4跨RC梁柱子结构分别进行抗连续倒塌拟静力试验,其中一榀为未加固试件,另外一榀为在梁上表面进行CFRP布加固。通过对比分析试件失效柱荷载—位移曲线、梁关键截面钢筋应变、试件破坏形式、结构最终倒塌承载力及极限变形等影响因素,讨论CFRP加固方案对结构抗连续倒塌能力的提升效果。2、根据RC框架梁柱子结构在连续倒塌过程中的抗力来源方式,将抗力机制分为梁端弯矩作用、压拱效应作用及悬链线机制作用,提出各机制作用阶段的简化承载力峰值计算公式,比较承载力计算值和实际值,与实际较吻合。3、对两组试验分别进行基于OpenSees软件的有限元数值分析,比较荷载—位移曲线的分析值和实际值,分析结果实际结果吻合度较高。在此基础上,分析了CFRP布加固层数对结构抗连续倒塌承载力的影响,得出加固层数与承载力提高之间并不呈线性关系。
[Abstract]:Under the action of accidental load, the failure of the load-bearing members of reinforced concrete frame structure leads to the failure of supporting the superstructure, which leads to the local collapse of the structure, due to the consistency and integrity of the construction. Local collapse can lead to the continuous collapse of the whole structure which is out of proportion. How to strengthen the RC frame structure to improve its continuous collapse resistance has become the focus of engineering reinforcement. Considering the excellent characteristics of CFRP sheet, such as strong tensile strength, no increase of structural load, corrosion resistance, etc., the method of strengthening the structure by using CFRP sheet to improve the continuous collapse resistance of the structure is becoming a trend gradually. This kind of reinforcement technology has good application prospect. In order to investigate the effect of CFRP on the continuous collapse resistance of RC frame structures, the continuous collapse resistance of unreinforced and strengthened RC frame structures is studied by comparison. Two Liang Zhu substructures were subjected to continuous collapse test and theoretical analysis. The main contents of the study are as follows: 1. Two identical monolayer and four-span RC Liang Zhu substructures were subjected to continuous collapse pseudostatic tests, one of which was unreinforced and the other was strengthened with CFRP sheet on the top surface of the beam. By comparing and analyzing the load-displacement curve of the failure column, the strain of the key section of the beam, the failure form of the specimen, the ultimate collapse bearing capacity and the ultimate deformation of the structure, and so on, The effect of CFRP reinforcement scheme on continuous collapse resistance of structure is discussed. 2. According to the resistance source mode of RC frame beam-column structure during continuous collapse, the resistance mechanism is divided into bending moment at the end of beam. The pressure-arch effect and catenary mechanism are analyzed. A simplified formula for calculating the peak value of bearing capacity is put forward, and the calculated value of bearing capacity is compared with the actual value. 3. The finite element numerical analysis based on OpenSees software is carried out for the two groups of tests, and the analysis value of load-displacement curve is compared with the actual value. On this basis, the influence of the number of strengthened layers of CFRP cloth on the bearing capacity of the structure against continuous collapse is analyzed, and it is concluded that there is no linear relationship between the number of strengthened layers and the increase of the bearing capacity.
【学位授予单位】：苏州科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU375

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