Systematic calibration procedure for CFRP sheets and rods strengthened RC T-beams by using RBSM

In this study, a nonlinear 2D rigid body spring model (RBSM) was developed to verify the experimental works of Carbon Fiber Reinforced Polymer (CFRP) sheets and rods strengthened reinforced concrete (RC) T-shape beam (RC T-beam) section under a combination of bending and shearing loads. Modified Mohr-Coulomb criteria were adopted for modeling the plastic damage of concrete material. The orthotropic smeared layers representing the steel and CFRP materials were laminated on the concrete surface to model the reinforcing steel bars, stirrup steel, and CFRP sheets and rods. A mechanical behavior-based approach to fit the experimental results was discussed using the numerical results at each calibration stage. This study shows how the gradient of compressive and ultimate tensile strength of concrete affects the initial flexure behavior of the load-displacement curve of an RC T-beam. In contrast with finite element modeling, the RBSM can exhibit the crack propagation processes of element separation during the simulation. The calibrations showed the agreement of the models used in predicting the flexural behavior, ultimate load, and strengthening effects of the CFRP sheets and rods to the RC T-beam under bending loads. A systematic calibration procedure combined with the recommended use of energy-based criteria to evaluate the results of calibrated load-displacement curve was proposed.