Effect of impact energy on failure and deformation scaling similarity of RC beams: a physical and numerical study

Conducting geometrically similar beam tests under drop hammer impacts from scaled-down to prototype is the most effective way to discuss the scaling effects of impact response. This study conducted impact tests on geometrically similar beams at three impact velocities. The failure modes, midspan displacement time history curves, and peak values were compared. Based on the test results, finite element extension analysis was conducted. The effect of scaling form of impact mass and velocity on the deformation scaling similarity of geometrically similar beams was analyzed. Then, in-depth mechanism explanations and discussions were carried out. From the test observations, it was concluded that the damage to large-sized beams is more severe than that of small-sized beams, and there is a scaling effect on the normalized peak midspan displacement. As the impact mass increases and the impact velocity decreases at the same energy, the scaling effect is enhanced, which is related to the differences in failure modes and response processes of large-sized beams. Finally, a similarity model of midspan displacement for geometrically similar RC beams was further verified. A design expression for determining the limiting impact energy based on laboratory scaling results or allowable displacements is presented. This study is expected to enrich the drop hammer impact database and provide a reference for designing and evaluating the impact resistance of large-sized and prototype beams.