Predicting the circumferential strains on a cylindrical concrete specimen during a pull-out test

In a recent experimental research, the authors measured the circumferential strains on the cylindrical envelope of concrete specimens during pull-out tests. This paper presents a theoretical approach, complementing the previous experimental study, aiming at predicting these measured circumferential strains and developing the understanding of the three-dimensional behavior of the concrete cylinder. The proposed approach accounts for the specimen materials and geometrical parameters including the ribs and strain gauges locations and proposes an expression for the normalized and absolute circumferential strains along the specimen circumference due to ribs actions. This paper presents a new three-dimensional model of the specimen behvior during a pull-out test, which provides new insight on bond mechanics and illuminates the role of the radial pressures developed as part of the bond action. Several simulations were performed on specimens with three different diameters, two concrete strengths, and a different number of bonded ribs. All the simulations show very good agreement with the measured strain data. This study enhances the understanding of bond resistance during a pull-out process and contributes to the understanding of the ring action that is developed in a concrete cylinder during a pull-out test.