NUMERICAL MODELS FOR SHEAR BEHAVIOR OF REINFORCED CONCRETE BEAMS WITH FRP STIRRUPS

This paper presents the results of comprehensive numerical and experimental investigation of shear behavior of in reinforced concrete beams with FRP shear reinforcement. A finite element modeling approach is proposed using Abaqus FEA, incorporating the measured physical and mechanical properties of materials, including the nonlinear behavior of concrete represented by the Concrete Damage Plasticity (CDP) model. The accuracy of the developed numerical models is validated through comparison with experimental results obtained by the authors and other researchers. A strong agreement was observed between the calculated and experimental values of beam deflections and load-bearing capacity for beams with both steel and FRP shear reinforcement. For cases involving failure due to stirrup rupture, the models account for the orthotropic properties of FRP reinforcement and the observed trajectories of shear cracks. It was found that, due to non-uniform normal stress distribution induced by local bending in the region of crack-stirrup intersection, the strength of FRP bars may decrease to 80% of their axial tensile strength. The proposed modeling methodology enables reliable assessment of the load-bearing capacity and deformability of beams with both steel and FRP shear reinforcement and is recommended for practical application in shear design of reinforced concrete beams.