Behavior of unbonded prestressed concrete slabs subjected to low-velocity impact loading

This study examines the structural performance of unbonded prestressed concrete slabs subjected to low-velocity impact loading. The experiment involved impact loading tests on reinforced concrete (RC) slabs and prestressed concrete (PC) slabs using a drop hammer impact test system. The prestressing force was monitored using intelligent steel strands before the PC slabs were subjected to impact testing. The failure mode, impact force, and displacement response of the specimens were recorded. The study investigated the effects of impact energy, prestress level, and boundary conditions on dynamic damage and response of the specimens. Results showed that RC slabs and unidirectional simply supported PC (PCU) slabs exhibited typical flexural failure modes, while bidirectional supported PC (PCB) slabs experienced a combination of flexural and shear failure modes. Furthermore, PC slabs demonstrated superior impact resistance. A finite element (FE) model was developed to predict the impact behavior of RC and PC slabs and was validated using the failure modes, impact forces, and displacements obtained from the experimental results. The impact process and energy dissipation were also analyzed using the FE model.