Finite element analysis of reinforced concrete beams shear-strengthened with CFRP

The strengthening of concrete structures with carbon fiber-reinforced polymers (CFRP) has become an attractive alternative to other conventional methods due to its characteristics, including low density, versatility, speed of application, high elastic modulus, high tensile and fatigue strengths, and corrosion resistance. More complex analyses are typically demanded when evaluating the behavior of a CFRP-strengthened structural element. Numerical methods, such as the Finite Element Method, allow highly complex processes, including nonlinear analyses of concrete structural elements. In this context, this work aims to perform computational modeling through the Finite Element Method of reinforced concrete beams strengthened in shear with CFRP sheets using customized ANSYS software. Special attention is given to the bonding stresses that develop at the interface between the CFRP sheets and the concrete, considering contact finite elements and bilinear Cohesive Zone models. Therefore, the computational simulations enabled the identification of premature rupture modes associated with CFRP sheet debonding and the inadequate utilization of its strengthening properties. Twelve simply supported beams, laboratory tested and with results reported in the literature, were simulated, both with and without CFRP strengthening to enhance shear. The numerical model developed proved to be capable of predicting their behavior in terms of load versus displacement, load versus strain, as well as their rupture modes with good accuracy.