Numerical analysis of the corrosion impact on the punching shear capacity of flat slabs with openings

The effects generated by punching shear failure in flat slabs are catastrophic, as the failure of the slab-column joint can cause a progressive collapse of the building. Furthermore, when exposed to aggressive environments, reinforced concrete structures can be degraded due to the penalization of the mechanical and geometric properties of the reinforcement and concrete. Therefore, this study intends to investigate the behavior of corroded reinforced concrete flat slabs with adjacent openings to the column. Three nonlinear finite element models of flat slabs based on experimental results were constructed and validated in the ABAQUS software and subsequently subjected to a parametric analysis to investigate the effects of different corrosion degrees on their punching shear capacity. The results demonstrated that corrosion of the reinforcement significantly affected the load capacity of the numerical models, reducing the ultimate load by up to 30%. Furthermore, the increase in corrosion caused an intensification of the cracking of the slabs, indicating that the cracking patterns increased as the degree of corrosion increased. The results obtained by experimental tests and numerical simulations were compared with predictions by the codes Eurocode, fib Model Code, American Concrete Institute 318, FprEN 1992 1-1, and The Brazilian Association of Technical Standards Brazilian Regulatory Standard 6118. The results showed that most codes generate very conservative results.