Evaluation and degradation mechanism of residual performance of RC beam after drop hammer impact

The residual load-carrying performance after impact is a key index to evaluate the impact-resistant capacity of engineering-used structure member. A multi-functional experimental facility was developed to conduct both the impact test and post-impact static loading test on two types of flexural-failure-dominated RC beam specimens with different tensile reinforcement ratios. Three-dimensional nonlinear finite element(FE) analysis was conducted to reproduce the impact process and to investigate the plastic damage of RC beam in depth. The degradation mechanism of load-carrying performance of RC beam after impact was investigated through fibersection analysis with uniaxial damaged material models of concrete and reinforcement. The experimental and numerical results demonstrate that the resistance and stiffness of impact-damaged RC beam decrease in different levels. The residual flexural resistance and stiffness ratios are greatly affected by the longitudinal reinforcements. The yield state of compressive reinforcements plays critical effect on the residual performance of RC beam after impact.