Numerical simulation of double-sided concrete corbels internally-reinforced with GFRP bars

Three-dimensional (3D) finite element (FE) models were developed in this study to simulate the nonlinear structural behavior of double-sided concrete corbels internally-reinforced with glass-fiber reinforced polymer (GFRP) bars. The accuracy of the numerical models was demonstrated by comparing their results with published experimental data of twelve specimens tested previously by the authors. Two sets of models were first developed. In one set, a perfect bond assumption was adopted between the GFRP bars and the concrete. In the other set, a bond stress-slip law was adopted at the GFRP-concrete interface. Numerical results were in good agreement with those recorded experimentally, except for the specimens with a high concrete strength and high GFRP reinforcement ratio, which failed prematurely in a diagonal splitting mode of failure. In an effort to capture such a mode of failure numerically, additional four models were developed without considering the tension-softening curve in the concrete material constitutive law. Results of the models with the bond-slip law were insignificantly lower than those with perfect bond assumption at GFRP-concrete interface. Eliminating the tension-softening curve from the concrete material constitutive law used in modeling specimens with a high concrete strength and high GFRP reinforcement ratio yielded numerical results closer to those obtained from the tests.