Numerical analysis of the effects of corrosion on the punching shear capacity of reinforced concrete flat slabs with openings

Abstract The reinforcement corrosion is one of the main degradation mechanisms in reinforced concrete structures. Its effects can harm structural elements by reducing mechanical capacity, mainly due to diminished reinforcement properties and expansive reactions within the concrete. In addition, the effects of punching shear on flat slabs can be detrimental, as failure of the slab‐column connection can trigger a progressive collapse of the entire structure. This study focused on investigating three reinforced concrete flat slabs, based on experimental results concerning punching shear capacity when subject to reinforcement corrosion. The slabs, without shear reinforcement and including openings adjacent to the slab‐column connection, were subjected to a corrosion degree of 20%. Finite element models were developed using ABAQUS software. Modeling methods were applied to analyze the effects of corrosion on the geometric and mechanical properties of reinforcement, concrete, and steel‐concrete adhesion. The results showed that, as corrosion increased, the ultimate load of the slabs decreased. Specifically, there was an average reduction of 23.4% for 20% corrosion. The stiffness and ductility of the slabs were affected, especially those with openings adjacent to the column. Following load–displacement analyses of the slabs, the punching load capacity results were compared to the estimates from Eurocode 2, NBR 6118, ACI 318, fib Model Code, and FprEN 1992 1‐1 codes. The normative codes underestimated the strength capacity of corroded slabs, proving conservative, with Eurocode 2, NBR 6118, and FprEN 1992 1‐1 providing the most precise and least dispersed results.