BFRP加固钢筋混凝土梁的抗弯性能试验研究

发布时间：2018-06-18 11:31

本文选题：玄武岩纤维布 + 加固　；参考：《石河子大学》2017年硕士论文

【摘要】：目前,我国存在大量的混凝土结构由于材料老化、荷载变化等迫切需要进行一定程度的加固及修复处理。纤维增强复合材料以其突出的力学性能、良好的耐久性以及便捷的施工优势,近年来在结构加固改造中得到了广泛应用。本文通过对玄武纤维布加固钢筋混凝土梁的抗弯性能进行研究,分析了不同纤维布加固量、不同U型箍锚固方式及不同钢板加固量对加固效果的影响,得到以下结论:(1)粘贴玄武岩纤维布后,加固梁的开裂荷载、屈服荷载、极限荷载都有不同程度的提高,尤其是极限荷载提高幅度最大,极限荷载分别提高8%(1层)、23%(2层)、29%(3层),加固效果明显。(2)对比不同粘贴层数的加固梁承载力发现,随着纤维布层数的增加,加固梁抗弯承载力也在不断提高,但其提高程度并不与纤维布粘贴层数成正比。设置U型箍可以有效防止纤维布发生剥离破坏,但对加固梁承载力的提高作用并不明显。(3)使用玄武岩纤维布加固可以有效抑制试验梁裂缝的发展,与基准梁相比,加固梁裂缝数量多,平均间距小,裂缝分布较均匀,裂缝发展速度慢。(4)通过对加固梁荷载-挠度曲线分析可知,使用玄武岩纤维布加固的钢筋混凝土梁的刚度与基准梁相比有一定程度的提高,且随着加固层数的增加,刚度提高更明显。设置U型箍对加固梁刚度影响不大,但可以有效抑制玄武岩纤维布的早期剥离,使加固梁后期挠度不断增加,延性系数提高,梁的延性得到改善。(5)钢板与纤维布联合加固,能够弥补单一材料加固法的不足,在有效提高受损混凝土梁刚度和承载力的同时还能够更好的改善混凝土结构的延性,加固效果更好。(6)推导了不同破坏形式下玄武岩纤维布加固钢筋混凝土梁的正截面承载力计算公式,并用试验结果进行验证,结果表明极限承载力的计算值与实测值符合良好,且计算结果偏于安全。
[Abstract]:At present, a large number of concrete structures in our country need to be strengthened and repaired to a certain extent because of the aging of materials and the change of load. Fiber reinforced composites have been widely used in structural strengthening and reconstruction in recent years because of their outstanding mechanical properties, good durability and convenient construction advantages. In this paper, the flexural behavior of reinforced concrete beams strengthened with Black Tortoise fiber sheets is studied, and the effects of different fiber sheets, different U-hoop anchoring methods and different steel plate reinforcement on the strengthening effect are analyzed. The following conclusion is drawn: (1) when the basalt fiber cloth is bonded, the cracking load, yield load and ultimate load of the strengthened beam are increased in varying degrees, especially the ultimate load. The ultimate load is increased by 8 / 10 / 1 / 2 / 2 / 2 / 2 / 2 / 2 / 3 / 3, respectively, and the effect of strengthening is obvious. (2) compared with the bearing capacity of beams with different adhesive layers, it is found that the flexural bearing capacity of the strengthened beams increases with the increase of the number of fiber layers, and the flexural bearing capacity of the strengthened beams is also increasing with the increase of the number of fiber layers. However, the degree of improvement is not proportional to the number of layers attached to the fabric. U type hoop can effectively prevent fiber cloth from peeling, but the effect of strengthening beam bearing capacity is not obvious.) using basalt fiber cloth can effectively restrain the development of test beam crack, compared with reference beam. Through the analysis of load-deflection curves of strengthened beams, the number of cracks is large, the average spacing is small, the distribution of cracks is more uniform, and the crack development speed is slow. The stiffness of reinforced concrete beams strengthened with basalt fiber sheets is higher than that of reference beams to a certain extent, and the stiffness increases more obviously with the increase of the number of strengthened layers. The installation of U-type hoop has little effect on the stiffness of the strengthened beam, but it can effectively restrain the early exfoliation of the basalt fiber cloth, so that the deflection of the strengthened beam in the later stage increases continuously, the ductility coefficient increases, the ductility of the beam is improved, and the ductility of the beam is improved by the combination of steel plate and fiber cloth. It can make up for the deficiency of single material strengthening method and can improve the ductility of concrete structure while improving the stiffness and bearing capacity of damaged concrete beam. The calculation formula of normal section bearing capacity of reinforced concrete beams strengthened by basalt fiber sheets under different failure forms is derived. The results are verified by the experimental results. The results show that the calculated values of ultimate bearing capacity are in good agreement with the measured values. The calculated results are more secure.
【学位授予单位】：石河子大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU375.1

【参考文献】