Three‐dimensional modelling of bond behaviour between concrete and FRP reinforcement

The purpose of this paper is to investigate the bond behaviour between fiber reinforced polymer (FRP) sheets and concrete elements, starting from available experimental evidences, through a calibrated and upgraded 3D mathematical‐numerical model.

The complex mechanism of debonding/peeling failure of FRP reinforcement is studied within the context of damage mechanics to appropriately catch transversal effects and developing a more realistic and comprehensive study of the delamination process. The FE ABAQUS© code has been supplemented with a numerical procedure accounting for Mazars's damage law inside the contact algorithm.

It has been shown that such an approach is able to catch the delamination evolution during loading processes as well.

A Drucker‐Prager constitutive law is adopted for concrete whereas FRP elements are assumed to behave in a linear‐elastic manner, possibly undertaking large strains/displacements. Surface‐to‐surface contact conditions have been applied between FRP and adjacent concrete, including the enhancement given by the strain‐softening law according to Mazars' damage model. The procedure has been introduced to describe the coupled behaviour between concrete, FRP and adhesive resulting in specific bonding‐debonding features under different load levels.