Static analysis of adhesively bonded anchorages for CFRP tendons

• An experimental static study of adhesively bonded anchorages was undertaken.
• Adhesive thickness and length of the anchors at failure load were assessed.
• An analytical formulation was developed for adhesives with elastic behaviour.
• Numerical simulations of the anchors with different adhesive material models.
• A cohesive zone model with progressive damage in the bond predicted the failure load.

In pre-stressed concrete structures, consideration is being given to replacing the steel tendons with CFRP rods. One of the challenges associated with this is to develop a suitable anchorage for the CFRP rods. A bonded anchorage was investigated, where the CFRP is potted in a steel tube using epoxy adhesive. Experimental static tests of different configurations were undertaken with failure occurring in the bond. A set of numerical simulations were carried out with different adhesive material models to investigate the static response of the bonded anchorage and its failure mechanism. The adhesive was modelled with linear elastic properties, von Mises plasticity, Drucker–Prager plasticity and progressive damage. A cohesive zone model with progressive damage in the bonded joint was found to be in reasonable agreement with the experimentally recorded data. Also, an analytical formulation was developed (and validated) in order to provide an approximate distribution of shear stress in the bonded joint for circular anchors for adhesives with mainly elastic behaviour.