带肋钢筋与混凝土粘结滑移本构关系的理论和试验研究

发布时间：2018-01-09 02:03

本文关键词：带肋钢筋与混凝土粘结滑移本构关系的理论和试验研究　出处：《大连理工大学》2016年硕士论文　论文类型：学位论文

【摘要】：钢筋与混凝土之间的粘结性能是决定钢筋混凝土构件承载力、延性和使用性能的重要因素。钢筋-混凝土粘结滑移本构关系又是开展钢筋混凝土结构数值分析的重要条件。本文首先基于能量守恒定律通过理论分析推导得到了变形钢筋-混凝土粘结滑移本构关系,进而通过试验测量了粘结滑移过程中混凝土握裹层对变形钢筋的约束作用,进一步揭示了变形钢筋与混凝土之间的粘结锚固机理。论文主要研究内容和结论如下：(1)针对钢筋-混凝土粘结滑移的劈裂破坏模式,将整个破坏过程分为未开裂的弹性阶段和带裂缝阶段。弹性阶段采用弹性厚壁圆筒模型；带裂缝阶段采用考虑混凝土软化特性的厚壁圆筒模型。基于以上两种模型,研究了粘结劈裂破坏过程中的能量变化规律,推导出了两种模型的能量计算公式。基于能量守恒定律建立了钢筋-混凝土粘结滑移本构关系的微分方程,并通过数值积分方法得到了粘结滑移本构模型。该本构模型能够体现混凝土和钢筋材料参数和几何参数的影响,对不同形状的粘结滑移关系曲线具有较好的适应性。最后,将得到的粘结滑移本构关系与文献中的试验结果进行了对比,分析了模型中参数的变化规律和取值范围。(2)通过特殊设计的钢筋拉拔粘结试验,测量了粘结劈裂破坏过程中混凝土握裹层作用在变形钢筋上的径向压力。试验中,将带肋钢筋沿纵肋劈成两半,在钢筋内开槽布置两个微型荷载传感器测量混凝土握裹层的径向压力。通过对6个试件开展的拔出粘结试验,测定了不同厚度混凝土握裹层对变形钢筋的约束作用。试验发现,在试件劈裂破坏过程中,钢筋肋前有效角不断变小,粘结应力与混凝土握裹层的径向压力成正比；试件劈裂破坏时,粘结应力沿钢筋锚固段的分布受保护层厚度的影响,影响规律为：当保护层厚度适中时,粘结应力分布均匀；保护层厚度过大或者过小都会造成粘结应力分布不均匀。另外,试验测得的混凝土握裹层径向压力最大值与考虑裂缝间粘聚力的厚壁圆筒理论模型预测值吻合较好。
[Abstract]:The bond behavior between reinforcement and concrete determines the bearing capacity of reinforced concrete members. The important factors of ductility and performance are the important conditions for numerical analysis of reinforced concrete structures. Firstly, based on the law of conservation of energy, it is deduced from theoretical analysis that the bond-slip constitutive relationship between steel and concrete is an important condition for the numerical analysis of reinforced concrete structures. The bond-slip constitutive relation of deformed steel bar and concrete is studied. Furthermore, the restraint effect of the concrete cladding layer on the deformed steel bar during the bond-slip process is measured through experiments. Furthermore, the mechanism of bond anchoring between deformed steel bar and concrete is revealed. The main contents and conclusions of this paper are as follows: 1) the split failure mode of reinforced concrete bond-slip. The whole failure process is divided into the elastic stage without cracking and the stage with crack. The elastic thick wall cylinder model is used in the elastic stage. The thick-walled cylinder model with concrete softening characteristics is adopted in the crack stage. Based on the above two models, the energy variation in the process of bond splitting failure is studied. Based on the conservation law of energy, the differential equation of bond-slip constitutive relation between steel bar and concrete is established. The bond-slip constitutive model is obtained by numerical integration method. The constitutive model can reflect the influence of the parameters of concrete and reinforced material and geometric parameters. The bond-slip relationship curves with different shapes have good adaptability. Finally, the bond-slip constitutive relations are compared with the experimental results in literature. The variation rule and value range of parameters in the model are analyzed. The radial pressure of concrete cladding layer acting on the deformed steel bar during bond splitting failure was measured. In the experiment, the ribbed steel bar was split in half along the longitudinal rib. Two micro load sensors were arranged in the steel bar to measure the radial pressure of the concrete cladding layer. The pull-out bonding test was carried out on 6 specimens. The restraint effect of different thickness concrete cladding layer on deformed steel bar is measured. It is found that the effective angle of steel bar front becomes smaller in the process of splitting failure. The bond stress is proportional to the radial pressure of concrete cladding. The distribution of bond stress along the Anchorage section of steel bar is affected by the thickness of the protective layer during the splitting failure of the specimen. The influence law is as follows: when the thickness of the protective layer is moderate, the distribution of the bond stress is uniform; Too large or too small the thickness of the protective layer will cause uneven distribution of bond stress. The experimental results show that the maximum radial pressure of concrete cladding layer is in good agreement with the theoretical model of thick wall cylinder considering the cohesive force between cracks.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU375

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