Dynamic behaviour of RC flat slabs under instantaneous column removal

Quasi-static investigations have demonstrated that continuous reinforcement traversing the columns enhances the load-bearing capacity of reinforced concrete (RC) flat slab systems subjected to progressive collapse initiated by column removal. Nevertheless, the dynamic behaviour of older structures lacking reinforcement remains insufficiently understood. To address this gap, high-fidelity numerical models were developed in LS-Dyna and validated against experimental data. In addition, the load redistribution and internal force transfer mechanisms were examined in this study. The results revealed that, following the removal of a central column, inertial effects amplified the applied load by a factor of 1.12, with more than 60% of the load ultimately redistributed to the edge columns. The influence of varying column removal scenarios and structural scales on the dynamic response and collapse resistance of flat slab systems was also explored. Findings indicate that the simultaneous loss of opposite edge columns imposes a greater collapse risk than the concurrent loss of adjacent edge columns. Moreover, the evaluation results of scaled RC flat slab structures tend to overestimate both their dynamic load-bearing capacity and punching shear resistance.