Dynamic behaviors of corroded RC column under low-velocity impact loading

Navigating bridges are susceptible to vessel collision and chloride-induced corrosion, and bridge pier columns must be designed to withstand both episodic (vessel collision) and chronic (structural deterioration) threats. This study aims to examine the dynamic responses and failure patterns of corroded reinforced concrete (RC) columns subjected to impact loads by using the nonlinear explicit finite element (FE) program LS-DYNA. Firstly, the FE model and analysis approaches of RC column with consideration of corrosion-induced deteriorations are established and validated through the drop hammer impact test on corroded RC columns, by assessing the time histories of impact force and lateral displacement, as well as the damage failure of the corroded RC column specimens. Then, based on the validated FE models and analysis approaches, parametric numerical simulations are performed to examine the influence of longitudinal reinforcement ratio, corrosion degree, and impact location (i.e., symmetrical and asymmetrical impact scenarios) on the dynamic behaviors of corroded RC columns. The impact process, impact force, lateral displacement and damage failure of corroded RC column, as well as the energy dissipation during the impact are comprehensively discussed. Finally, the dynamic behaviors of corroded RC columns strengthened with specialized stirrup configurations in the impact zone are analyzed and assessed. It derived that: (i) the total absorption energy of the corroded RC column is predominantly dissipated by longitudinal reinforcements under symmetrical impact loads; (ii) compared to symmetrical impact cases, corroded RC columns subjected to asymmetrical impact loads exhibit more severe damage; (iii) the shear damage failure of corroded RC column is reduced with the increase of stirrup ratio in the impact zone.