钢管混凝土界面抗剪粘结滑移力学性能试验

Shear bond behaviors at interface of concrete-filled steel tube

为探讨钢管混凝土界面抗剪粘结滑移性能,研究钢管混凝土界面应力分布规律,确定界面抗剪粘结应力和粘结滑移本构关系,进行了方、圆钢管混凝土试件的纵向抗剪粘结性能试验研究,试验结果表明:钢管纵向应变沿长度方向基本成呈三角形分布,粘结应力沿钢管混凝土界面均匀分布;方、圆钢管混凝土界面粘结—滑移曲线具有相似的变化规律,圆钢管混凝土界面抗剪粘结强度较方钢管混凝土要大,基于试验结果,提出了平均粘结应力和相对滑移的本构关系。分析比较了钢管混凝土界面粘接性能的主要影响因素,粘结强度受混凝土强度的影响不明显;随混凝土龄期的增大而略有增大;随钢管长径比的增大而增大;随钢管径厚比(宽厚比)的增大而减小。

In order to study mechanical behaviors of the shear bond of concrete filled steel tube （CFST）, analyze shear stress distribution and establish the relationship between shear stress and bond-slip of the shear bond, tests on 15 specimens of concrete filled circular steel tube （CFCST） and 5 specimens of concrete filled rectangular steel tube （CFRST） were carried out. The test results show that strain distribution of the steel tube was triangle along the longitudal direction and the bond shear stress distributes homogeneously. All specimens had similar bond-slip curves and the shear bond strength of CFCST was greater than that of CFRST. Based on the test results, the relationship between shear stress and bond-slip of the shear bond, was established. The shear bond strength of CFST was not considerably affected by the concrete strength, but it increased with the concrete ages and the length to diameter ratio and decreases with diameter to thickness ratio （ or width to thickness ratio） of the steel tube.