Response of ultra-high-performance fiber-reinforced concrete beams with continuous steel reinforcement subjected to low-velocity impact loading

To investigate the effect of the reinforcement ratio on the flexural behavior of ultra-high-performance fiber-reinforced concrete (UHPFRC) beams under impact loading, a total of four large-sized (200 × 270 × 2900 mm) beams were fabricated and tested using a drop-weight impact test machine. The incident kinetic energy and impact velocity were 4.2 kJ and 5.6 m/s, respectively. A higher reinforcement ratio exhibited lower maximum and residual deflections and better deflection recovery. The test results also indicate that the maximum crack width at a certain drop stage decreased with the reinforcement ratio. A nonlinear analytical model for predicting the impact behavior of a UHPFRC beam was developed using multi-layer sectional analysis and single-degree-of-freedom analysis, and the model was verified through comparison with the experimental results.