Analytical model for bar slip and pullout capacity of straight bars

This paper presents an analytical model to determine the bar slip and pullout capacity of straight bars embedded in well-confined concrete. The model provides a closed-form solution of the slip experienced at the loaded end of a bar, which can be used to compute the end rotation of flexural members. The slip equations are obtained from the strain penetration resulting from a set of predefined bond stress distributions along the embedment length of a bar. For bars with relatively short lengths, the slip at the unloaded end is also considered. Additionally, the model can inform the pullout capacity of a bar. Its accuracy in predicting the loaded-end slip, strains distributions, and pullout strength has been verified with experimental data. Model predictions have been also compared with results obtained with two similar models available in the literature. Finally, the model has been used to determine the base rotations and lateral displacements of hinging columns.