Experimental and numerical study on the flexural properties of RC beams with different CFRP-strengthened schemes

This study conducted a four-point bending experiment investigation on the flexural performances of the RC beams strengthened with various CFRP schemes. Four beams were employed, i.e., the ordinary RC beam (L0), the RC beam bonded with CFRP sheet (L1-C), the CFRP U-wrapped RC beam (L2-U), and the RC beam using CFRP rivets (L3-A). Test results highlighted the obvious improvement in the flexural performances of CFRP-strengthened beams in terms of enhancing load-carrying capacities and limiting overall deformations compared to beam L0. In addition, end anchorage systems, including CFRP U-hoop and CFRP rivets, changed the failure mode, restricted crack propagation, and mitigated the bottom CFRP sheet debonding effectively. The ultimate loads of beams L1-C, L2-U, and L3-A were 27.4 %, 36.4 %, and 41.6 % higher than beam L0, respectively, indicating that CFRP rivets performed the best in improving the beams' flexural properties. Finite element analysis was developed to simulate the bending experiment process. The numerical results comply well with the experiments in terms of the crack distribution pattern and bending force history. Then, parametric studies for the design suggestions with the use of the modes reveal that the implementation of the CFRP rivet with a depth of 80 mm and a diameter of 10 mm seems to be an ideal optimization plan for the beams herein.