Numerical analysis of reinforced concrete beam subject to pitting corrosion

Resumo

This paper presents a numerical study about the effects of chloride-induced corrosion on the service life of structures. A two-dimensional geometrically nonlinear mechanical model based on Finite Element Method (FEM) was developed for reinforced concrete structures. The corrosion initiation stage was evaluated by Fick's diffusion laws. The corrosion propagation was carried out by deterministic models based on Faraday's law. Pitting corrosion was simulated in the reinforcements by pit elements, distributed longitudinally on the steel rebars, which degrade the physical properties over time. The service life was determined by the crack width. Two parametric analyses were performed. In the first analysis, five models were created with a variable cover thickness and water/cement ratio (w/c). In the second analysis, the reduction in yield stress due to corrosion was considered. The results showed that the concrete cover thickness and the w/c ratio significantly influence the service life. The reduction of the cover thickness from 30 mm to 25 mm resulted in 21.26% reduction in service life, while the increase in the w/c ratio from 0.50 to 0.55 caused 32.98% reduction in service life of the structural element analyzed.