Introduction

Flat slab systems are increasingly utilized in contemporary construction due to their architectural flexibility, reduced formwork complexity, and efficient space utilization. However, the absence of deep beams and drop panels renders slab-column connections particularly susceptible to punching shear failures. This vulnerability is further exacerbated when the structure is subjected to dynamic actions such as low-velocity impacts, which can arise from falling objects, vehicular collisions, or operational machinery in industrial settings.

To reduce self-weight while maintaining structural efficiency, voided slab systems—employing hollow plastic spheres or other lightweight fillers—have gained traction. These systems offer material savings and reduced environmental loads, yet their discontinuous internal geometry can significantly impair shear resistance and crack propagation behavior, especially near critical connection zones.

Enhancing the impact resistance of such systems requires innovative reinforcement strategies. One such approach involves the incorporation of steel sheets or plates within the slab-column connection region. Steel sheets have demonstrated potential in redistributing impact-induced stresses, improving ductility, and delaying localized failure. However, limited research exists on their effectiveness within voided slab configurations under impact conditions.

This study aims to analyze the behavior of interior voided slab-column connections strengthened with embedded steel sheets under low-velocity impact loads. The research investigates the influence of steel sheet geometry, void arrangement, and impact parameters on energy absorption, cracking patterns, and failure modes. The outcomes are intended to inform design practices and enhance the resilience of voided slab systems in scenarios involving accidental or operational impacts.