The structural performance of concrete structures reinforced using glass-fibre-reinforced-polymer (GFRP) rebars is sometime compromised by debonding failure. For better analysing the GFRP bar-concrete bond behaviour, this study presents two damage-based approaches for assessing the bond damage evolution under static loading. One is the secant modulus-based model and other is exponential damage model (Fig. 1a,b). Using the exponential damage approach, a simplified analytical model based on one curve fitting parameter was developed to predict the bond stress-slip relationship. Then, another damage-based approach was developed to simulate the deterioration of the bond between concrete and GFRP bar under fatigue cycles (Fig. 1c,d). Next, 3D finite element (FE) models were developed and both proposed damage-based approaches for the static bond behaviour, as well as the developed damage-based approach for fatigue bond behaviour were implemented, to simulate the GFRP bond behaviour. The FE models consider the nonlinear behaviour of the concrete and the GFRP bar-concrete interface. The analytical and numerical predictions of the GFRP bar-concrete bond behaviour are validated by comparing with the relevant results of the experimental programs focused on quasi-static and fatigue pullout tests. At the end, a parametric study was carried out to numerically assess the influence of some critical parameters on the bond behaviour.
Three point bending test: shear failure