Experimental Investigation on the Post-impact Behavior of Normal-Strength Reinforced Concrete Beams Subjected to Drop-Weight Impact Loads

The behavior of a reinforced concrete beam under a dynamic load, i.e., an impact load, affects the overall structural system by altering its static and dynamic features. This study investigates the performance of large-scale reinforced concrete (RC) beams under different impact loads and the residual load-bearing and displacement capacities of impact-damaged beams through static loading tests. Identical test beams were designed to fail in flexure based on conventional reinforced concrete theory without the consideration of potential impact loads, as is usually done. One of the specimens was identified as the reference beam and was tested only under static flexural loading, whereas impact tests were performed on the other four identical large-scale beams. These beams were subjected to different intensities of impact through drop-weight tests. The impact-damaged beams were then subjected to static flexural tests to determine their residual capacities. The dynamic impact and static flexural test results were analyzed. The results were also evaluated in terms of the dynamic force balance, maximum rotational capacity, usability and reparability of the impact-damaged beams. When the analysis results were examined, it was observed that the flexure-dominated behavior of RC beams turns into combined flexural-shear behavior under impact loading, and RC members can reach failure with shear critical behavior. In addition, it was possible to predict the maximum impact energy to be applied to a normal strength beam when we know its static load-carrying and displacement capacity.