锚固方法对FRP抗弯加固梁的力学性能影响研究

发布时间：2018-12-26 18:00

【摘要】：由于环境侵蚀、设计缺陷或使用荷载增加等原因,致使部分现役桥梁出现结构或功能缺陷,继而无法满足当前使用功能需求。因成本低、工期短,对缺陷桥梁进行加固成为上述问题的一个解决方法。近年来,纤维增强复合材料(Fiber Reinforced Polymer/Plastic,简称FRP)因其具有强度高、质量轻、耐腐蚀性好等优点已经被众多国家应用于混凝土结构、钢结构及其它结构的加固领域中。相较于传统加固法,如增大截面法、外包钢法、改变结构体系法、体外预应力法等,FRP加固法具有施工周期短、不需大型机械、几乎不增加原结构体积与重量等一系列优点。但该方法仍然存在例如易发生早期剥离的缺陷,锚固是解决此问题的有效技术手段。附加锚固措施能够有效提高FRP-混凝土界面间的粘结强度,推迟或者阻止FRP布材的早期剥离破坏;改善加固结构受力特性,提高加固结构的承载力、刚度、延性等力学性能。因此锚固方法对FRP加固法应用到实际工程具有重要意义。本文设计了钢板压条锚固、FRP-U形箍锚固及混杂锚固三种锚固方法对钢筋混凝土简支梁进行加固,并与对比梁作比较,通过抗弯试验,分析并解释了 FRP外贴法加固梁与未加固梁在承载力、跨中挠度、破坏模式等方面的差异;分析并对比了锚固对梁抗弯加固的力学性能影响。试验结果表明:相较于未加固梁,FRP外贴法能够有效提高梁的极限承载力及刚度;相较于传统FRP加固法,锚固加固法能显著提高梁的极限承载力、整体刚度、延性及FRP强度利用率,更为有效的发挥FRP作用;通过三种锚固方法的综合比较,FRP-U形箍锚固方法更为简单有效。另外,参考已有的FRP外贴加固法的粘结强度模型和极限承载力的设计公式,提出适用于端部FRP-U形箍加固梁的设计公式。
[Abstract]:Due to environmental erosion, design defects or increased load, some active bridges appear structural or functional defects, which can not meet the current functional needs. Because of low cost and short time limit, reinforcement of defective bridges becomes a solution to the above problems. In recent years, fiber reinforced composite (Fiber Reinforced Polymer/Plastic, (FRP) has been used in many countries for strengthening concrete structures, steel structures and other structures because of its high strength, light quality, good corrosion resistance and other advantages. Compared with the traditional reinforcement methods, such as the method of increasing section, the method of external steel, the method of changing the structure system and the method of external prestressing, FRP reinforcement method has a series of advantages, such as short construction period, no need of large machinery, and almost no increase in the volume and weight of the original structure. However, this method still has some defects such as early peeling, and anchoring is an effective technique to solve this problem. The additional anchoring measures can effectively improve the bond strength between the FRP- concrete interface, delay or prevent the early exfoliation of the FRP fabric, improve the mechanical properties of the strengthened structure, such as bearing capacity, stiffness, ductility and so on. Therefore, the anchoring method is of great significance to the application of FRP reinforcement method in practical engineering. In this paper, three kinds of anchoring methods are designed to reinforce reinforced concrete simply supported beams, such as steel plate compression bar Anchorage, FRP-U hoop Anchorage and hybrid Anchorage, and the results are compared with those of the contrast beams, and the flexural tests are carried out. The difference in bearing capacity, mid-span deflection and failure mode between beams strengthened with FRP method and unstrengthened beams is analyzed and explained. The effect of Anchorage on the mechanical properties of beams is analyzed and compared. The test results show that compared with the unstrengthened beams, the FRP method can effectively improve the ultimate bearing capacity and stiffness of the beams. Compared with the traditional FRP reinforcement method, the anchoring method can significantly improve the ultimate bearing capacity, overall stiffness, ductility and FRP strength utilization ratio, and play a more effective role in FRP. Compared with the three kinds of anchoring methods, the FRP-U method is more simple and effective. In addition, referring to the bond strength model and ultimate bearing capacity design formula of FRP external bonding reinforcement method, the design formula suitable for the end FRP-U reinforcement beam is put forward.
【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】：U445.72

【相似文献】