外粘AFRP布加固RC梁的耐冲击性试验分析

发布时间：2018-03-27 05:05

本文选题：RC梁　切入点：冲击试验　出处：《河南理工大学》2014年硕士论文

【摘要】：近些年频发的地震及由此引起的山体落石等次生自然灾害,对建筑结构造成不同程度的冲击损伤。以往针对FRP加固结构在静荷载条件下的相关研究,已不能准确解决目前的动载荷问题,满足不了现行工程的需求和设计理论的更新。本论文在全面了解FRP加固研究基础上,在重锤冲击加载下,进行外粘AFRP(芳纶纤维增强复合材料,英文名称:Aramid Fiber Reinforced Polymer,简称AFRP)布加固RC梁的耐冲击性试验分析。根据试验方案,本论文共制作11根混凝土梁,其中3根未加固,作为对比梁,4根采用A415加固,4根采用A830加固。首先,在静力加载方式下通过分析三种试验梁的荷载-挠度、AFRP应力应变来研究它们的极限承载能力和受力主筋的屈服荷载,并比较它们的损伤形态。试验表明,与未加固梁相比,两种加固梁的极限承载能力和主筋屈服荷载均有明显提高,且经过外粘AFRP布加固后,梁体损伤形态得到明显改善。未加固梁在跨中位置出现了明显的弯折角,裂缝集中分布在跨中区域,加固梁因具有较高的弯曲弹性而表现出良好的弯曲变形,裂缝在纯弯段内呈对称形态均匀分布。然后,通过重锤冲击加载方式分析试验梁的重锤加载变量、挠度变形、塑性变形、AFRP应力应变以及梁体损伤形态。进一步研究每种试验梁在不同冲击高度下的耐冲击性能。比较不同冲击高度下三种梁体的损伤形态和裂缝分布规律,从而得出冲击高度、AFRP类型与梁体损伤形态的相关性,根据试验研究得出每种梁体的冲击损伤机理和耐冲击性影响因素。试验表明,经过外粘AFRP布加固后,混凝土梁体的挠度变形及塑性变形均得到有效抑制,同时这种加固措施还可以延缓梁体裂纹开裂,限制裂缝开裂宽度,减轻重锤冲击加载对梁体造成的冲击损伤。AFRP布类型和冲击高度在一定程度上决定着梁体的损伤形态。
[Abstract]:The frequent earthquakes in recent years and the secondary natural disasters such as rock fall caused by the earthquake have caused different degree of impact damage to the building structure. The problem of dynamic load can not be solved accurately, and the demand of current engineering and the renewal of design theory can not be satisfied. On the basis of a comprehensive understanding of the research of FRP reinforcement, this paper is under the impact loading of heavy hammer. The impact resistance of RC beams strengthened with external adhesion Fiber Fiber Reinforced Polymer (AFRP) cloth was analyzed. According to the test scheme, 11 concrete beams were made in this paper, three of which were not strengthened. As a contrast, 4 beams are strengthened by A415 and 4 by A830. Firstly, by analyzing the load-deflection AFRP stress and strain of three kinds of test beams, the ultimate load-bearing capacity and yield load of the main tendons are studied. The experimental results show that the ultimate bearing capacity and yield load of the two strengthened beams are obviously increased compared with the unstrengthened beams, and strengthened by external adhesive AFRP sheets, and compared with the unstrengthened beams, the ultimate bearing capacity and the yield load of the main tendons of the two kinds of strengthened beams are obviously increased. The damage form of beam is improved obviously. The bending angle of the unstrengthened beam appears in the middle of the span, the crack is concentrated in the middle span, and the strengthened beam shows good bending deformation because of its high bending elasticity. The cracks are uniformly distributed in symmetrical form in the pure bending section. Then, the deflection of the test beam is analyzed by means of the weight hammer impact loading method. Plastic deformation AFRP stress strain and beam damage morphology. The impact resistance of each test beam at different impact heights was further studied. The damage patterns and crack distribution of three beams at different impact heights were compared. The relationship between the impact height and the damage form of the beam is obtained. According to the experimental study, the impact damage mechanism and the impact resistance factors of each beam are obtained. The results show that the impact damage mechanism and the impact resistance of each beam are strengthened by the externally bonded AFRP sheets. The deflection and plastic deformation of concrete beam are effectively restrained, and the reinforcement measures can also delay the crack cracking and limit the crack width. To reduce the impact damage caused by heavy hammer impact loading. The type of AFRP cloth and impact height determine the damage form of beam to a certain extent.
【学位授予单位】：河南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU375.1

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