A combined experimental and numerical study of RC column-slab joints with adjacent openings

Reinforced concrete (RC) flat slabs are particularly vulnerable under seismic loading due to the complex interaction of shear forces and bending moments at slab-column connections, which may lead to punching shear failure. This vulnerability could be further exacerbated by openings near the connections, which are commonly introduced to accommodate mechanical and electrical systems. In previous research, the authors conducted experimental tests on two series of slab-column specimens featuring a nearby opening: the first series included specimens with a frontal opening, while the second comprised specimens with a lateral opening. In each series, the first specimen was subjected to static vertical loading only, whereas the second and third specimens were tested under combined static vertical and cyclic horizontal loading. Punching-shear reinforcement, consisting of closed stirrups, was provided only in the third specimen of each series. This study addresses the nonlinear finite element (FE) modelling of the test conducted on the third specimen with a frontal opening, through the refinement of a previously developed FE model. The numerical model is employed to investigate the influence of different modelling assumptions, with particular emphasis on the reinforcement-concrete bond behaviour. The numerical results are compared with experimental data, allowing an assessment of the model’s capability to reproduce hysteretic behaviour, stiffness degradation, energy dissipation, and slab deflection under cyclic loading conditions.