Evaluation of punching strength of RC flat slabs with openings with different positions, size, and number: Experimental, analytical, and superposition approaches

In this study, three-stage research was carried out to investigate the adverse effects of openings in flat slabs. In the first stage of the study, full-scaled reinforced concrete two-way slabs were produced and exposed to a punching load. One of the test specimens was the reference test element produced without openings. For the other test specimens, the number of openings, the location of the opening, and the size of the opening were chosen as variables. The punching strength, initial stiffness, and energy dissipation capacity of the slabs were calculated with the load-displacement data recorded during the experiment. In the second stage of the study, the punching capacities of the test specimens were calculated by means of the punching capacity estimation equations presented in international regulations and compared with the experimental data. In the last stage of the study, the superposition principle, which is among the general principles of mechanics and has not been used before in the literature, was utilized. Considering the opening conditions presented in this study and the literature, it was investigated whether the new opening condition that will arise can be predicted with experimental data via the superposition principle.