Experimental analysis of total energy absorption capacity in RC beams subjected to single or repeated drop-weight impacts

Reinforced concrete (RC) protective structures require a large energy absorption capacity if they are to effectively withstand impulse loading due to blast or impact. Such structures may be subjected to both single and repeated impulse loading but there are just a few studies for the latter case. Therefore, in this study, experiments were conducted on RC beams, which were subjected to single or repeated drop-weight impacts. The beam response during impact was studied using a high-speed camera and digital image correlation. To determine the total energy absorption capacity, the impact-loaded beams were subjected to static loading until failure and the results compared to those of statically loaded reference beams. The total energy absorption capacity was of the same order or higher for beams previously subjected to impact loading, with a strong impact resulting in a greater increase. For tests in which the total impact energy was kept constant, repeated impact loading caused increased local damage, whilst decreasing the total energy absorption capacity.