Bond of GFRP bar and concrete: numerical approach

Current practice of FRP (Fibre Reinforced Polymer) RC (Reinforced Concrete) structures mainly takes perfect bond as an assumption for modelling the structural behaviour. As distinct to that, present work deals with application of local bond-slip law for estimating the influence of the interaction of FRP bar and concrete at structural level. For this purpose, the investigation involves two scales. Small scale (pull-out test specimens) and full-scale (reinforced concrete beams) are considered for assessment of numerical models. 3D finite element (FE) model was developed to consider the non-linear behaviour of the interface, as well as of the concrete, using the commercial software Abaqus1. The bond interface properties were simulated considering the secant modulus-based damage evolution law using cohesive elements. The developed bond model, validated by pull-out tests, were subsequently adopted for the numerical predictions of the mechanical response of full-scale beams. The model showed great potential to simulate the behaviour of structural element reinforced with such FRP materials, particularly at ultimate loading level.