Research on Interface bond strength and bond-slip constitutive models for rectangular CFST columns

More recent studies have suggested that parameters such as cross-section type, cross-sectional dimensions, interface length, concrete compressive strength, slenderness ratio, steel strength, roughness of interface, concrete casting style, and concrete curing conditions potentially have some influence on the value of the bond strength. In this paper, a brief review of previous research and literature that are pertinent to the present study of the interface bond strength and T-S constitutive models are presented first. According to the previous laboratory testing results, three equations are designed to calculated are average elastic limit bond strength, average ultimate bond strength and average post-peak residual bond strength, respectively. Moreover, a new simplified four-part model has been proposed to describe the T-S response.