Comparisons between Numerical and Experimental Results for Fibre-Reinforced Polymer Strengthened Concrete Elements

In this paper the bond behaviour between FRP sheets and concrete elements is investigated. The complex mechanism of debonding/peeling failure of FRP reinforcement is studied, with a three-dimensional approach, within the context of damage mechanics to appropriately catch transverse effects and develop a more realistic and comprehensive study of the delamination process. The system is viewed as composed by three different physical basic layers: the concrete support, the adhesive layer and the composite strip. The adhesion has been reconstructed by means of a contact model and an elastic-damage constitutive law which relates interlaminar stresses acting in the sliding direction. The F.E. ABAQUS code has been supplemented with a numerical procedure accounting for Mazars's damage law inside the contact algorithm. The coupled behaviour between concrete, FRP and adhesive, resulting in specific bonding/debonding features under different load levels, has consequently been attained. It is shown that such an approach is able to catch the delamination evolution during loading processes.