Experimental study on the reinforced concrete beams with varied stirrup reinforcement ratio under static and impact loads

Abstract

With the increasing utilization of reinforced concrete (RC) beams in eco‐friendly and fast‐paced construction practices, evaluating their impact performance becomes imperative. These beams are susceptible to unforeseen impact loads resulting from accidents or terrorist incidents throughout their service lifespan. Five groups of RC beams, each subjected to different curing periods, stirrup reinforcement, and drop hammer heights, were fabricated. Among these groups, one underwent static load testing, while the remaining groups were subjected to impact load testing utilizing the drop hammer test system. The failure modes, static response, dynamic response, and energy dissipation of RC beams were analyzed. Static tests revealed that RC beams exhibited a flexure‐governed failure mode with top surface concrete crushing, aligning with expectations. With increased stirrup reinforcement ratios, shear and flexural‐shear cracks during impact tests decreased, with high impact loads causing diagonal shear failure, severe concrete crushing, additional diagonal shear cracks, and a broader crack distribution. Higher drop hammer heights were found to increase overall energy dissipation, whereas increased stirrup reinforcement ratios resulted in moderate decrease. Specifically, the overall energy dissipation increased with higher drop hammer heights. Conversely, an increase in the stirrup reinforcement ratio was linked to a certain degree of decrease in overall energy dissipation.