Experimental study on local bond-slip constitutive model between steel and steel fiber reinforced concrete structure of circular cross-section

Abstract

The interface slip between shape steel and concrete is one of the biggest problems in numerical simulation of composite structures, this paper aims to investigate interfacial bond-slip behavior between steel and steel fiber reinforced concrete. For this purpose, a series of push-out tests on 15 circular section specimens which were designed and fabricated with different steel fiber ratio, interface embedded length and concrete cover thickness have been done. Experimental results show that average bond strength versus free end slip curves of each specimen is similar, and then a basic average bond strength-free end slip constitutive model was proposed in this paper. Meanwhile, considering the distribution regularities of steel strains, local bond strength and relative slip along the interface embedded length at different load levels were obtained through the mechanical derivation, the results show that the maximum local bond strength was located near the free end, and the local bond strength away from free end tended to be steady. Based on the basic average bond strength-free end slip constitutive model, two position functions were proposed to describe the local bond-slip constitutive model considering the variation of positions. Two position functions are of great significance for further research on SSFRC non-linear properties by FEM.