型钢高强混凝土界面黏结滑移推出试验及其本构关系研究

Push-out test on interface bond behavior between shape steel and high-strength concrete and interfacial bond-slip constitutive relation

为研究型钢高强混凝土界面黏结性能,对9个型钢高强混凝土试件进行推出试验,分别考虑混凝土强度、配箍率、保护层厚度和型钢锚固长度对型钢高强混凝土界面黏结性能的影响。观察试件的加载过程和裂缝发展形态,分析了试件破坏形态,得到试件加载端荷载-滑移曲线。通过分析沿型钢锚固方向应变和界面黏结应力的分布规律,运用灰色关联理论建立了黏结应力计算式,并推导出荷载-滑移曲线关系表达式。讨论了影响界面滑移损伤变量的关系。结果表明:各试件加载端荷载-滑移曲线走势基本相同;灰色关联理论能够较好地反映黏结应力与各影响因素之间的关系,其中保护层厚度与黏结应力相关性最好;推导的黏结应力算式的计算精度能达到98%;提出的黏结应力-滑移的本构关系数学表达式拟合度较好;界面损伤发展程度与各影响因素关系紧密。

In order to reveal the mechanism of interface bond performance between shape steel and high-strength concrete, nine shape steel high strength concrete specimens were designed to conduct push-out testing. The concrete compressive strength, concrete cover thickness, shaped steel embedment length and stirrup ratio were considered to determine the relation of interface bond properties. The loading process, cracks development, failure patterns, load- slip curves of the loading ends, steel strain and bond stress distribution along steel embedded length were obtained and analyzed. The computational formulas of bond stress using the grey correlation theory were established. The constitutive relation of bond-slip curves was deduced. The damage variable was defined and the relationships between damage variable and influencing factors were discussed. The results show ： the bond-slip curves of the loading end are similar; the grey correlation themy could be applied to analyze the relationships between bond stress and influencing factor, the concrete cover thickness are well related with bond stress; the deduced formulas results accuracy could reach 98% ; the suggested constitutive relations of bond-slip curves have good fitting degree; the relationship between interface damage and each influencing factor is close.