Fracture Mechanics-Based Modelling of Post-Installed Adhesive FRP Composite Anchors in Structural Concrete Applications

Adhesively bonded fibre-reinforced polymer (FRP) anchors have emerged as a progressive alternative to traditional steel anchors in concrete structures, owing to their superior corrosion resistance, high tensile strength, and light weight. Despite their increasing use, a robust mechanics-based bond model capable of accurately predicting the load transfer behaviour has not yet been developed. This study presents a fracture mechanics-based analytical bond model for post-installed adhesive FRP anchors embedded in concrete. The model formulation is derived from fundamental equilibrium and compatibility principles, incorporating a bilinear bond–slip law that captures both elastic and softening behaviours. A new expression for the effective bond length is also proposed. Validation of the model against a comprehensive database of direct pull-out tests reported in the literature shows excellent agreement between predicted and experimental pull-out forces (R2 = 0.980; CoV = 0.058). Future research should aim to extend the proposed model to account for confinement effects, long-term durability, the impact of adhesive type, and cyclic loading conditions.