A simple method for evaluating the maximum slip of anchorages

Abstract

The analytical solutions to the bond problem for monotonically increasing loads are developed for a monomial exponential local bond stress-slip relationship (law) – “exact solution” –, a linear local law – “proposed solution” – and a constant bond stress distribution, such as that recommended by the Eurocode. The three solutions are thoroughly developed for the pull-out of a bar embedded in a cylindrical element, with longitudinal concrete in tension. For short anchorages, which undergo a rigid motion and whose “exact solution” requires a complex iterative procedure, the “proposed solution” explicitly provides very accurate bond stress distributions. On the basis of this accuracy, an approximate expression for the slip distribution is derived. The proposed approximate solution is the first one providing a direct slip expression for short anchorages. Approximate explicit expressions for the maximum bond stress and the maximum slip are also given. The comparison between the maximum slip values measured during experimental tests and the corresponding values obtained from the proposed approximate expression demonstrates the accuracy of the latter.