NUMERICAL INVESTIGATION ON DYNAMIC REPONSE OF REINFORCED CONCRETE COLUMNS SUBJECTED TO IMPACT LOADING

To study the dynamic response of reinforced concrete (RC) columns subjected to the impact loading, a numerical model is established for the impact analysis of RC structural members based on the LS-DYNA finite element code. The typical drop hammer tests on RC beams are simulated so as to confirm that the impact loading and structural deformation can be accurately captured via the developed model. Based on the model, the effect of various factors on the impact load and the structural deformation of the RC columns is investigated. The factors are the velocity, the mass and the shape of the impactor, the longitudinal and transverse reinforcement ratios of the columns, the strength of concrete and the strain rate of material. Three typical damage modes of the RC columns subjected to impact loading are found from the numerical analysis, including a local damage mode, a global bending failure mode and a local shear failure mode. The factors which influence the impact loading can be classified into three types, i.e., the impactor-related factor, the column-stiffness-related factor and the column-strength-related factor. The effects of these factors on the peak load, the average load and the duration of the impact action are discussed for the purpose of providing a valuable reference to establish the simplified impact loading model for the impact-induced collapse analysis of building structures.