截面高宽比对CFRP约束型钢混凝土矩形柱轴压性能的影响

发布时间：2018-04-13 20:22

本文选题：碳纤维布 + 约束型钢混凝土矩形柱　；参考：《合肥工业大学》2017年硕士论文

【摘要】：从试验、数值和理论三个方面研究截面高宽比对碳纤维(Carbon Fiber Reinforced Polymer,简称CFRP)布约束型钢混凝土矩形柱轴压性能的影响。试验设计并制作了9个型钢混凝土柱进行轴压加载试验,考虑高宽比的影响,试验全面认识了约束型钢混凝土柱的破坏过程和机理。试验中所有的CFRP布约束型钢混凝土矩形短柱最终都以碳纤维布断裂为破坏标志。相较于小高宽比构件,大高宽比构件的破坏征兆要更明显,突然性会有所减缓。随着高宽比的增加,峰值荷载和极限荷载下CFRP布的有效拉应变系数逐渐降低,且碳纤维布的环向应变分布越不均匀,破坏模式由强约束破坏向弱约束破坏转化。采用ABAQUS软件建立了有限元模型对试验中的CFRP布约束型钢混凝土矩形柱进行了模拟分析,计算结果与试验结果吻合很好。在数值模拟的基础上,又进行了参数分析,扩展设计了钢筋混凝土柱和高宽比范围。计算结果表明:随着高宽比的增加,约束混凝土柱的承载力提高幅度逐渐减小,变形提高倍数不断增加;与约束钢筋混凝土柱相比,约束型钢混凝土柱的承载力提高幅度随高宽比增加而降低的曲线更缓和;约束柱中大高宽比试件实施加固呈现延性加固模式,小高宽比试件实施加固呈现承载力加固模式;同高宽比下,约束型钢混凝土柱达到强约束状态需要更多碳纤维布层数包裹。约束柱截面内的混凝土存在高低应力分布区域,约束型钢混凝土柱在型钢附近还存在增强的高应力分布区;随着高宽比的增加,高应力分布区占比逐渐减小;高宽比达到2.0时,约束型钢混凝土柱的高应力分布区占比仍然较大,约束效果并没有明显减弱。根据已有研究,理论公式推导了约束钢筋混凝土柱的高宽比限值的由来;推导得到与高宽比相关的短边侧向约束应力和长边侧向约束应力计算式;为了考虑型钢的影响,引入相对刚度比K,相对刚度K为型钢混凝土柱的环向刚度与轴向刚度的比值。最后,通过数据拟合分析提出了适用于本文研究CFRP布约束型钢混凝土矩形柱的强度计算模型。
[Abstract]:The axial compression behavior of steel reinforced concrete rectangular columns confined by carbon Fiber Reinforced Polymer (CFRP) is studied from three aspects: experimental, numerical and theoretical.Nine steel reinforced concrete columns were designed and manufactured for axial compression test. Considering the effect of aspect ratio, the failure process and mechanism of confined steel reinforced concrete columns were fully understood.In the test, all the short columns of steel reinforced concrete (SRC) confined by CFRP cloth are ultimately marked by the fracture of carbon fiber sheet (CFRP).Compared with the small aspect ratio component, the failure symptom of the large aspect ratio component is more obvious, and the sudden will be slowed down.With the increase of aspect ratio, the effective tensile strain coefficient of CFRP cloth decreases gradually under the peak load and limit load, and the more uneven the circumferential strain distribution of carbon fiber cloth is, the more the failure mode changes from strongly constrained failure to weakly constrained failure.The finite element model of CFRP confined steel reinforced concrete rectangular column is established by using ABAQUS software. The calculated results are in good agreement with the experimental results.On the basis of numerical simulation, parameter analysis is carried out, and the range of reinforced concrete column and aspect ratio is designed.The results show that with the increase of aspect ratio, the bearing capacity of confined concrete columns decreases gradually, and the increase times of deformation increase, compared with confined reinforced concrete columns,The increasing range of bearing capacity of confined steel reinforced concrete columns decreases more gently with the increase of aspect ratio, and the ductile strengthening mode appears when the specimen with large aspect ratio is strengthened, and the specimen with small height ratio is strengthened with bearing capacity mode.At the ratio of height to width, more CFRP layers are needed for the confined steel reinforced concrete columns to reach the state of strong constraint.There is a high and low stress distribution area in the confined column section, and a high stress distribution area in the confined steel reinforced concrete column near the section steel. With the increase of the aspect ratio, the proportion of the high stress distribution area decreases gradually, and the ratio of height to width ratio reaches 2.0.The proportion of high stress distribution in confined steel reinforced concrete columns is still large, and the restraint effect is not obviously weakened.Based on the previous research, the origin of the limit value of aspect ratio of confined reinforced concrete columns is derived, and the formulas for calculating the lateral confinement stress and lateral restraint stress of short side and long side are derived in order to consider the influence of section steel.The relative stiffness ratio K and the relative stiffness K are introduced as the ratio of the circumferential stiffness to the axial stiffness of the steel reinforced concrete column.Finally, through the data fitting analysis, the strength calculation model of CFRP reinforced concrete rectangular columns is proposed.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU398.9

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