Computational simulation of shear behavior of scaled GFRP-reinforced concrete beams

Empirical evidence has recently highlighted a significant size effect on the shear strength of slender concrete beams reinforced with corrosion-resistant glass fiber-reinforced polymer (GFRP) bars. Existing nominal strength algorithms are based on fundamentally different hypotheses on the governing mechanisms. Advanced numerical models can aid with understanding the role of size-dependent mechanisms. To this end, this paper demonstrates the validation of a Lattice Discrete Particle Model (LDPM) for concrete. The LDPM represents the physical heterogeneity of concrete, and incorporates constitutive laws that are suitable to simulate meso-scale friction and fracture damage mechanisms. The calibrated LDPM was used to model slender GFRP-reinforced concrete beams with effective depth of 146 and 292 mm, for which load tests revealed a size effect up to 62%. The simulations yielded accurate predictions, which were used to better understand the contribution of aggregate interlocking and shear-compression fracture mechanisms to strength and size effect.