Dynamic shear failure and size effect in BFRP-reinforced concrete deep beam

The purpose of this study is to investigate the size effect on dynamic shear failure of deep concrete beams with Basalt Fiber Reinforced Polymer (BFRP) bars. In order to accurately simulate dynamic shear failure behavior of BFRP-reinforced concrete deep beams, a three-dimensional meso-scale numerical model was established, which considered the heterogeneity of concrete, the interaction between concrete and BFRP bars, and the strain rate effect of meso-components. Firstly, the measured data of the existing experiments were input into the numerical model to obtain ideal numerical calculation results, which proved the rationality and accuracy of the simulation method. Then, the shear failures of geometrical-similar BFRP-reinforced concrete deep beams with different sizes under different strain rates were studied. The influence of beam depth, stirrup ratio and strain rate on the shear failure of BFRP-reinforced concrete deep beams and the corresponding size effect law were investigated. The results indicate that: 1) The failure modes of beams under dynamic loading are different from those under static loading; 2) Both the strain rate and the stirrup rate can effectively improve the bearing capacity of the beam and weaken the shear size effect, but the effect of strain rate is significantly greater than that of stirrup rate. In addition, a size effect law which can quantitatively describe the effects of strain rate and stirrup ratio on BFRPreinforced concrete deep beams was established. Finally, the size effect law was verified by the simulation results and the existing experimental results.