摘要
纤维增强材料(FRP)在土木工程中的应用是目前国际土木工程领域研究开发的一个热点,碳纤维材料(CFRP)加固修复混凝土结构技术是其中研究、开发和应用最广泛的技术。
本文研究采用在混凝土构件侧面粘贴碳纤维板这种新形式加固受弯构件的受力性能。试验研究共设计了7根适筋梁,通过简单静力加载试验,重点研究了该种加固梁的破坏特征、极限荷载、变形、开裂和碳纤维板粘贴形式对加固效果的影响。试验结果表明,该种加固梁承载力和抗弯刚度均有显著提高,尤其是当碳纤维板接近梁底部时,效果更佳,但延性有所降低;碳纤维板可以有效的改善梁底裂缝的分布形态。
碳纤维板加固钢筋混凝土结构是由钢筋、混凝土和碳纤维板三种性质差别很大的材料组合而成,而且混凝土常常是带裂缝承担荷载的。混凝土材料和钢筋材料本身复杂的非线性特性及其两者之间复杂的粘结特性,给碳纤维板加固钢筋混凝土结构设计分析带来了很大的困难,国内外学者为此做了不少工作。本文就是在前人研究的基础上,利用ANSYS有限元软件对普通钢筋混凝土梁和CFRP板加固钢筋混凝土梁受弯极限承载力进行非线性有限元分析,着重从模型建立、网格划分、参数选取、单元形式、收敛准则、求解方法等方面展开研究。通过选取合理的各种材料的本构模型,系统地介绍了普通钢筋混凝土梁和CFRP加固钢筋混凝土梁受力性能的有限元分析方法。有限元分析结果和实验结果吻合良好。本文的分析方法对从事混凝土结构加固补强施工和设计的工程科研人员具有一定的参考价值。
The use of fiber reinforced polymer (FRP) in civil engineering is a hot topic in research and development of the international civil engineering area. The technology of using carbon fiber reinforced polymer (CFRP) on strengthening and repairing concrete structures is the most extensive one in research, development and application.
In this paper, the behavior of the flexural RC member bonded with CFRP board on its vertical sides was investigated by the authors recently. A total of seven reinforced concrete beams were elaborately devised and cast. The failure character, ultimate load, deformation, cracking, CFRP bonding scheme for the specimens were examined by static loading test. The experimental result shows that the flexural strength and flexural rigidity of this kind of retrofitted beam could be markedly increase, when the CFRP board access to bottom of beam especially. But the ductility of retrofitted beam will decrease; The distribution of crack in the bottom of beam could be markedly improved.
Reinforced concrete structures strengthened with CFRP board are combination with three very difficult materials (reinforcing steel bars, concrete and CFRP board), moreover the concrete often endure loads with crack. The inherent complex nonlinear characters of concrete material and reinforcing steel bars and intricate felt identity between them, which entail many difficulties in design and analysis, many scholars both in domestic and overseas have worked much in this field. Based on the research of predecessors, this paper analyze the flexural ultimate strength of RC beams and RC beams strengthened with CFRP with nonlinear finite element method by using finite element program ANSYS, emphasis research on model establishment, mesh demarcate, parameter selection, element type, converge criterion and solution method. The simulation analysis method of RC beams strengthened with CFRP board through select reasonable constitutive equation was discussed. The agreement of FEM result between the experiment results is satisfactory. The result of this paper has reference value of structure strengthening engineers and researchers in reinforced concrete.
引文
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