大尺寸CFRP约束混凝土方柱的轴心抗压试验研究

发布时间：2018-02-16 23:49

本文关键词： CFRP约束混凝土方柱轴心受压尺寸效应承载力有限元分析　出处：《湖南大学》2015年硕士论文　论文类型：学位论文

【摘要】：纤维增强塑料(FRP)因其优异的材料性能、施工简便、耐腐蚀性好等特性在混凝土结构加固及改造方面得到越来越广泛的应用。但就目前而言,基础性的研究工作还不充足,特别是对于大尺寸FRP约束混凝土方形截面柱的试验研究很少也不系统,是目前研究的盲区,制约了FRP约束混凝土的发展和应用。本次试验基于对7种不同倒角半径的大尺寸CFRP约束混凝土方柱的轴心抗压试验,获取了各组试件的破坏模式、抗压强度、应力-应变曲线、外包CFRP应变分布等基本力学性能,并与已有小尺寸试件的试验结果进行了比较和分析。研究结果表明:试件的抗压强度随倒角半径比的增大而增大,但外包CFRP对直角试件几乎无增强作用;所有试件的破坏都由外包CFRP的拉断导致,断裂位置均位于倒角范围内,应力集中现象明显;约束效应比MCR可以较好的反映尺寸效应对CFRP约束试件的抗压强度影响,试件尺寸的增大显著降低CFRP的约束效应;外包CFRP的极限应变低于其材性试验结果的35%以上,明显大于对应的小试件试验结果;已有FRP约束混凝土方柱的强度模型对本试验的抗压强度的预测,与实测结果差异显著,有必要考虑尺寸效应的影响;收集整理国内外已有的试验数据,归纳现有的比较具有代表性的FRP约束混凝土方柱强度模型,通过误差平方和为指标对现有强度模型进行评价,在已有的研究基础上,对FRP约束混凝土矩形柱强度模型进行修正,得到较好的结果。此外本文还确定FRP约束混凝土方柱的材料本构、单元类型等,运用ANSYS程序计算不同影响参数下的FRP约束混凝土方柱的极限承载力,将试验结果与计算结果进行对比分析,发现吻合程度较好,说明有限元模型选取的合理可以较好的预测纤维约束混凝土方柱的受力性能,同时利用有限元分析外包层数、纤维布种类对约束效应的影响,这对减少试验量,获取更多有益数据等有重要意义。
[Abstract]:Fiber reinforced plastic (FRP) materials because of its excellent performance, simple construction, good corrosion resistance and other characteristics in the reinforcement of concrete structure is widely used. However, the basic research work is not enough, especially for the testing of large size FRP confined concrete square columns there is little not system, is the research area, which restrict the development and application of FRP confined concrete. The test of axial compressive test of CFRP confined concrete square columns of 7 different chamfer radius size based on the failure mode, the group's compressive strength, stress-strain curve, basic the mechanical strain distribution of CFRP outsourcing performance, and the test results were analyzed and compared with the existing small size test. The results show that the compressive strength of the chamfer radius ratio increases, but the outsourcing CFRP The rectangular specimens almost no enhancement; all the specimens of the destruction caused by breaking the outsourcing of CFRP, fault location are located in the chamfering range, the stress concentration phenomenon is obvious; reflect the size effect of the confinement effect than MCR can be used to test the compressive strength of the CFRP constraint, the increase of specimen size significantly reduced constraint the effect of CFRP; more than CFRP below the limit strain of outsourcing material test results of 35%, significantly greater than the corresponding small specimen test results; strength model of FRP confined concrete square columns has forecast the compressive strength of the test, the difference with the measured results significantly, it is necessary to consider the influence of size effect; experimental data in China the existing collection, induction and comparison with FRP confined concrete square column strength model representative of the existing through square error and evaluation on the existing strength model in the existing index. On the basis of the study, on the strength of FRP confined concrete rectangular column model is modified, the result is good. In addition, FRP confined concrete square column material constitutive, unit type, calculation under different influence parameters of FRP confined concrete columns of the ultimate bearing capacity by using ANSYS program, the test results and calculation results comparative analysis found that consistent, mechanical properties of selected finite element model can well predict the reasonable fiber confined concrete square columns, and by using the finite element analysis of outsourcing layers, effects of fiber cloth type on the confinement effect, to reduce the amount of test, have important significance to get more useful data.

【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU37

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