Bond-slip relationship for smooth steel reinforcement

In this paper a theoretical approach for the pullout mechanism is proposed, in order to improve the bond-slip relationship proposed by the CEB-FIP Model Code of smooth steel reinforcement. In particular, a reduced number of parameters and a softening branch in the τ-s model are introduced. With a view to use this relationship both for RC and SFRC elements, the dependence of the model on the size of reinforcement is also considered. Despite the limited number of parameters used in the calibration of bond-slip, there is a good agreement between the results obtained with the proposed model and the experimental ones.