Strengthening of RC beams with rectangular web openings using externally bonded FRP: Numerical simulation

Making web openings in reinforced concrete (RC) beams is frequently required for the passage of utility ducts and/or pipes. Such web opening(s) leads to reduction of the strength and stiffness of the beam. To ensure the safety of the beam, a strengthening system applied around the web opening is needed. Existing experimental studies have confirmed the feasibility of using externally bonded FRP to compensate for the strength loss of the beams caused by the creation of web openings, while there have been very limited finite element (FE) approaches for predicting the behavior of such RC beams. Against this background, three alternative FE models developed using ABAQUS for the simulation of RC beams with an FRP-strengthened rectangular web opening are presented in this paper, including two models based on the brittle cracking model of concrete and one model based on the concrete damaged plasticity model. By comparing their predictions with test results collected from the published literature, the most proper FE approach is identified. By using this FE approach, parametric studies are conducted for the design of the FRP-strengthening system for a typical web opening-weakened RC beam, and a reliable FRP-strengthening system is recommended for use in practice.