Experimental And Theoretical Study On The Bond-Strength Of Concrete-Filled Circular Steel Tubes

The bond strength and the bond-slip constitutive equations at the interface between the steel tube and the concrete of concrete-filled circular steel tubes (CFCST) is one which is further concerned by more and more construction engineers and researchers. The study on the bond-slip behaviors at the interface of CFCST is significant on the theory and practical value.In this paper, axial push-out test of CFCST is carried out. Based on the results of experiment, the bond strength of the interface between the steel tube and the concrete in CFCST is studied. The influencing factors on the bond strength are discussed. According to the experimental results, the constitution of bond force is analyzed and the characteristics of PS curves are summed up. Based on the data of this test and the former tests, a calculation formula of the bond strength considering several factors is established. The comparison and error analysis of the calculated results are conducted to evaluate the formula accuracy. The checking computations of the bond strength of the joint of CFCST is given. This method can be used in the practical structure.