Influence of Axial Load and Transverse Impact Velocity on the Behavior of Concrete Shear Walls Reinforced with GFRP Bars

A three-dimensional numerical model was established to investigate the impact resistance of concrete shear walls reinforced with fiber-reinforced polymer (FRP) bars, considering the strain rate effect of FRP reinforcement and concrete materials. After validating the numerical model, the failure mechanism of concrete shear walls reinforced with glass fiber-reinforced polymer (GFRP) bars under impact load was studied. The influence of impact velocity and axial load ratio on the impact resistance of GFRP-reinforced concrete shear walls was discussed. The results showed that GFRP-reinforced concrete walls have similar behavior to conventional reinforced concrete walls under impact loadings. The former experienced more considerable deformation due to the lower elastic modulus of GFRP bars. The peak and residual displacement at the center of the wall increased linearly with the impact energy. In addition, the peak value, plateau value, impulse, and duration of impact force grew linearly with respect to impact velocity. The proportion of energy absorbed by concrete increased in the cases of larger impact velocity. From the perspective of the internal force envelope along the wall height, the dangerous sections under impact were located at both ends of the wall under axial load. The peak value of the internal force improved with an increase of the axial load ratio. When the axial load ratio was between 0.3 and 0.4, the impact force of the wall reached the largest, and the minimum deformation occurs, indicating the best impact resistance of the shear walls. As the axial load ratio increased from 0.1 to 0.5, the total energy consumption increased from 68% to 89%, among which the external force work is 57 times that of the 0.1 axial load ratio, aggravating the failure of walls.