抗剪加固FRP与混凝土界面粘结性能的试验研究

发布时间：2018-03-25 00:38

本文选题：FRP　切入点：界面粘结　出处：《广东工业大学》2015年硕士论文

【摘要】：纤维增强复合材料(F iber Reinforce Polymer,简称FRP)具有强度高、材质轻及耐腐蚀的优点,已经被广泛应用于各种土木工程结构加固中。外贴FRP抗剪加固钢筋混凝土结构是FRP应用于结构加固的一个重要方面。FRP的剥离破坏是FRP抗剪加固混凝土梁中常见的一种破坏模态。现有抗剪强度模型及规范公式中,一般直接将基于FRP与混凝土搭接接头试验(单剪试验或双剪试验)得到的粘结强度模型用于分析FRP剥离破坏时的FRP抗剪贡献,而抗剪加固混凝土梁中的FRP与混凝土界面的受力状况与搭接接头试验中的FRP与混凝土界面的受力状况有明显的不同,因此直接基于搭接接头试验数据得到的抗剪强度模型,可能会高估FRP的抗剪贡献,甚至导致不安全的后果。针对这一研究背景,本研究采用一种新的小梁试验方法,通过侧面粘贴FRP于预置裂缝小梁来进一步研究抗剪加固混凝土梁中FRP与混凝土界面的粘结性能,分析一系列因素对FRP与混凝土界面粘结性能的影响。本文的研究内容主要包括以下两部分：(1)设计了20根小梁,通过四点弯曲试验来定量研究FRP粘结长度、条带宽度及纤维受拉角度(FRP纤维方向与裂缝张开方向的角度)对抗剪加固中FRP与混凝土界面粘结性能的影响。试验结果表明：(a)所有小梁的破坏模态均为FRP的剥离破坏,说明本试验方法可以用来对FRP与混凝土的界面粘结性能进行试验研究；(b)FRP粘结长度、条带宽度及纤维受拉角度对FRP与混凝土的界面粘结性能有明显的影响；(c)沿着FRP宽度方向的受力是不均匀的,相应应变分布也是不均匀的,且是非线性的,这主要是由于裂缝的不均匀开展导致了FRP在裂缝开展较大的一边先剥离。(2)采用粒子图像测速(Particle Image Velocimetry,简称PIV)技术方法,对4根小梁进一步研究了抗剪加固中FRP与混凝土的界面粘结性能。试验结果表明：(a)PIV技术的图像数字化可以应用于本试验FRP与混凝土界面粘结性能研究中；(b)由输出的界面剪应力分布可知,随着荷载增加,界面最大剪应力从FRP长度方向中线处向两自由端发展,且沿宽度方向,界面剪应力分布是不均匀的。
[Abstract]:Fiber reinforced composite F iber Reinforce Polymer (FRP) has the advantages of high strength, light material and corrosion resistance. Reinforced concrete structure strengthened with FRP is an important aspect of FRP used in structural strengthening. The peeling failure of FRP is common in concrete beams strengthened by FRP. A failure mode. In existing shear strength models and specifications, The bond strength model based on FRP and concrete lap joint test (single shear test or double shear test) is generally used to analyze the shear contribution of FRP in the process of FRP peeling failure. However, the stress state of FRP and concrete interface in shear strengthened concrete beam is obviously different from that of FRP and concrete interface in lap joint test, so the shear strength model is obtained directly based on the test data of lap joint test. The shear contribution of FRP may be overestimated and even unsafe. In order to further study the bond behavior between FRP and concrete interface in shear strengthened concrete beams, FRP is pasted on the side of the prefabricated cracked trabeculae. This paper analyzes the influence of a series of factors on the bond behavior between FRP and concrete interface. The main contents of this paper include the following two parts: 1) 20 trabeculas are designed, and the binding length of FRP is quantitatively studied by four-point bending test. The width of strip and the angle of tension angle between fiber direction and crack opening direction) resist the influence of bond behavior between FRP and concrete interface in shear strengthening. The experimental results show that all the failure modes of trabeculae are FRP peeling failure. The results show that this method can be used to study the bond length of FRP and concrete. The width of the strip and the tensile angle of the fiber have obvious influence on the bond behavior of the interface between FRP and concrete. The stress along the direction of the width of the FRP is not uniform, and the corresponding strain distribution is also uneven and nonlinear. This is mainly due to the uneven development of the crack, which led FRP to peel off the larger side of the crack first.) Particle Image velocimetric (PIV) technique was used to measure the velocity of the fracture. The interfacial bond behavior between FRP and concrete in shear strengthening is further studied for four trabeculas. The experimental results show that the digital image of FRP can be used in the study of interfacial bond behavior between FRP and concrete in this experiment. The interfacial shear stress distribution of. With the increase of load, the maximum shear stress of the interface develops from the midline in the direction of FRP length to the two free ends, and along the width direction, the distribution of the interfacial shear stress is uneven.
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU377.9

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