Modeling locally corroded reinforced concrete structures in non‐linear finite element analyses

Abstract The ingress of chlorides, originating from the use of de‐icing salts or proximity to the sea, may cause severe local reinforcement corrosion in concrete structures such as bridges, tunnels, galleries, and retaining walls. Methods are urgently required to realistically assess the load‐bearing capacity of such deteriorated structures, accounting for the effects of the local damage. However, modeling local corrosion in concrete structures using the finite element method is not straightforward. On the one hand, analyzing the local effects of corrosion requires finite elements that are magnitudes smaller than appropriate element sizes used to efficiently model an entire concrete structure, making this approach unviable even when using high‐performance computers. On the other hand, when modeling a structure with comparingly large elements, local damage introduces a discontinuity in the affected FE, which are thus no longer a continuum as presumed in standard element formulations. Hence, the influence of the discontinuities needs to be captured consistently and independently of the element size. This paper presents a mechanically consistent approach to deal with discontinuities by defining an influence volume and a correspondingly aligned constitutive relationship. The approach is demonstrated using the existing Corroded Tension Chord Model as a constitutive relationship and validated against the analytical solution for a reinforced concrete tie affected by local corrosion and three experiments on continuous slab strips with and without local damage. The load–deformation behavior of the reinforced concrete tie is accurately captured by the numerical simulation. The load–deflection behavior and failure modes observed in the experiments can be accurately predicted without mesh size dependency, thus proving the suitability of the proposed approach.