Peak displacement scaling effects in RC beams under varying impact velocities: Experiment, simulation, and prediction

Current research on scaling effects of reinforced concrete (RC) beams under impact loading remains constrained by insufficient experimental validation under rigorous similarity principles. To address this gap, this study comprehensively investigates the dynamic response of geometrically similar RC beams through combined experimental tests and numerical analyses, adhering to classical similarity laws. Key efforts focus on the scaling effects of peak displacements, with emphasis on their velocity dependence. Results reveal that as impact velocity increases, the gap between the damage patterns of geometrically similar beams becomes increasingly significant. The midspan displacement exhibits significant scaling effects that amplify with increasing impact velocity. In addition, as impact velocity increases, stiffness degradation in larger-scale beams is dominated by localized damage and multi-crack synergy, with velocity-dependent coupling effects exacerbating nonlinear displacement accumulation and non-similar responses under high-velocity conditions. In addition, a peak displacement prediction formula considering the coupling of strain rate and scaling effects was proposed and validated. These findings provide a quantitative framework for understanding scaling effects in impact-resistant RC structures, offering refined insights for predicting RC beam behavior under impact scenarios.