An Experimental Study of the Effects of Different Reinforcement Ratios on the Impact Resistance Behaviors of Reinforced Concrete Beams

In this experimental study, for the purpose of furthering the understanding of the effects of different reinforcement ratios on the impact resistance behaviors of reinforced concrete (RC) beams, a series of vertical impact tests were conducted on five RC beams with different reinforcement ratios using a domestically advanced ultrahigh heavy drop hammer impact testing machine system. The impact velocities and force of the drop hammer during the impacts, displacements, and strain of the test points, as well as the crack propagation process, were collected and analyzed. The experimental test results revealed the following. (1) When the reinforcement ratios ranged between 0.58 and 1.63 %, the RC beams had mainly suffered bending failures. However, when the reinforcement ratios were increased, it was observed that the overall stiffness of the beams had been effectively improved; displacements, steel strain, and damages were reduced; and the impact resistance abilities of the beams had been enhanced. (2) When the reinforcement ratios had ranged from 1.63 to 2.57 %, shear failures were found to be the main failure mode of the RC beams. It was found that increases in the reinforcement ratios could not effectively reduce the damages and were not conducive to the beams' resistance to impact loads. (3) It was determined that because of the shearing effects of the impact loads, the shear force of the RC beams had increased.