Effect of Concrete/CFRP Interface Modeling on Failure Assessment of RC Beams Strengthened with CFRP Plates: A Cohesive Element Model

Abstract

The present paper investigates the effect of concrete/CFRP interface modeling on failure assessment of RC beams strengthened with CFRP plates using finite element technique (FE). From the previous studies, it was found that most of the FE studies neglected the interaction between concrete/CFRP interface by either assuming perfectly bond or using simple solid element between the interfaces. This can affect the accuracy of the results obtained from FE model especially the failure pattern of RC beams strengthened with CFRP plates. Therefore, in order to capture the real behavior of concrete/CFRP interface which influences the prediction of failure pattern of the beams, cohesive elements, which have the ability on modeling adhesives and bonded interfaces, are used to model traction and shear behavior of concrete/CFRP interface. Ten case studies with various parameters, i.e. thickness of FRP plates, length of FRP plates and types of reinforcement, are chosen from the literatures to perform analysis using ABAQUS. The results obtained from FE models show good agreement with the experimental data in terms of loading capacity, failure pattern, shear stresses distribution at concrete/CFRP interface and strains distribution in CFRP plates. It is evident that the discontinuities of the shear stresses distribution along concrete/ CFRP interface are actually associated with the location of cracks occurring at concrete beams whereas the progressive de-cohesion of the laminate from the concrete face initiating in the area near to the point of high shear stresses. In addition, cracks location can be obtained with close agreement with experimental data.