FRP加固RC柱承载能力分析

发布时间：2018-03-17 22:21

本文选题：RC圆柱　切入点：承载能力　出处：《华南理工大学》2013年硕士论文　论文类型：学位论文

【摘要】：因地震等自然灾害、年久失修及人为因素等影响，现有桥墩出现了诸如承载力不足、延性较差等不同程度的问题，亟需对其进行加固补强。纤维增强复合材料（FRP）片材因其高强高效、轻质、适应性强等特点使其在土木工程中的应用越来越广泛。使用FRP材料包裹钢筋混凝土（RC）柱能够有效地提高RC柱的受剪承载力，改善RC柱的延性。为此，本文采用本课题组发明的新型FRP片材——碳纤维薄板（CFL）和芳纶纤维薄板（AFL）加固RC圆柱，并对纤维薄板加固RC柱的承载能力进行探讨，主要研究内容和研究结果如下： 1）本文首先以RC柱“强剪弱弯”的设计理念为出发点，研究FRP加固RC圆柱抗剪承载力的计算方法。对《碳纤维片材加固修复混凝土结构技术规范》、叶列平建议公式、ISIS规范、CEB规范等文献中记载的关于FRP加固RC圆柱抗剪承载力的计算方法进行对比分析，并对收集到的25根加固柱的实验结果进行验算，探讨了各公式计算结果的可靠性和FRP的抗剪贡献值，提出了实用建议公式。 2）采用本课题组研发的纤维薄板加固RC圆柱，并对其进行拟静力实验研究。RC圆柱的加固方式分AFL螺旋缠绕和CFL竖向粘贴加固。根据实验测量数据，对圆柱加固前后的破坏形态、承载能力、位移延性系数、滞回曲线、骨架曲线、荷载退化、刚度退化及纤维应变分布等进行了分析。研究结果表明，加固柱的承载力和延性均得到了显著的提高，荷载退化和刚度退化均小于未加固柱，且在侧向位移较大时其水平承载力表现得较为稳定；沿柱高方向从上到下纤维应变呈递增分布，柱底部纤维发挥更为充分。 3）采用有限元分析软件ANSYS对纤维薄板加固RC柱的承载能力进行有限元计算，并与实验结果进行对比分析。研究结果表明，有限元计算结果与实验结果吻合得较好。利用上述有限元分析模型，探讨了纤维用量、纤维缠绕高度、轴压比、是否受载加固等因素对AFL加固RC柱极限承载力和延性的影响。有限元分析结果表明，，AFL加固RC圆柱的增强作用并不随AFL缠绕厚度的增加呈线性增长；在柱塑性铰区缠绕AFL就能够达到良好的加固效果；随着轴压比的增大，RC柱水平承载力有所提高，但延性会降低；受载加固柱的延性相对于非受载加固柱有所降低。
[Abstract]:Due to natural disasters such as earthquakes, years of disrepair and human factors, the existing piers have had problems of varying degrees, such as insufficient bearing capacity and poor ductility. It is urgent to reinforce and strengthen it. Fiber reinforced composite material (FRP) sheet is of high strength, high efficiency and light weight. The application of RC columns in civil engineering is more and more extensive due to its strong adaptability. The use of reinforced concrete columns wrapped with FRP materials can effectively increase the shear capacity of RC columns and improve the ductility of RC columns. In this paper, a new type of FRP sheet, carbon fiber sheet (CFL) and aramid fiber sheet (AFL), are used to reinforce RC columns, and the load-bearing capacity of RC columns strengthened by fiber sheet is discussed. The main research contents and results are as follows:. 1) in this paper, the design concept of "strong shear and weak bending" for RC columns is first taken as the starting point. This paper studies the calculation method of shear bearing capacity of RC columns strengthened with FRP. For the Technical Code for strengthening and repairing concrete structures with CFRP sheet, the suggested formula of Ye Leping and the Code of FRP for RC columns are recorded in the literature on shear resistance of RC columns strengthened by FRP. The calculation method of bearing capacity is compared and analyzed. The experimental results of 25 reinforced columns collected are checked, the reliability of the calculation results and the shear contribution of FRP are discussed, and the practical formulas are put forward. 2) the fiber thin plate developed by our research group is used to reinforce RC cylinder, and its quasi-static experimental study is carried out. The reinforcement method of RC cylinder is divided into AFL spiral winding and CFL vertical bonding reinforcement. According to the experimental data, the failure form of the column before and after strengthening is studied. The load-bearing capacity, displacement ductility coefficient, hysteretic curve, skeleton curve, load degradation, stiffness degradation and fiber strain distribution are analyzed. Load degradation and stiffness degradation are smaller than those of unreinforced columns, and the horizontal bearing capacity is stable when the lateral displacement is large, and the fiber strain increases gradually from top to bottom along the direction of column height, and the fiber at the bottom of the column plays more fully. 3) the finite element analysis software ANSYS is used to calculate the bearing capacity of RC columns strengthened by fiber thin plates, and the results are compared with the experimental results. The results of finite element calculation are in good agreement with the experimental results. Using the above finite element analysis model, the fiber dosage, filament winding height and axial compression ratio are discussed. The finite element analysis results show that the reinforcement of RC columns strengthened by AFL does not increase linearly with the increase of AFL winding thickness. With the increase of axial compression ratio, the horizontal bearing capacity of RC columns increases, but the ductility decreases. The ductility of loaded columns is lower than that of unloaded columns.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU375.3;U445.72

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