Contribution of spatially variable pitting corrosion on fatigue life prediction of RC beams

Abstract

Pitting corrosion induces stress concentration in steel bars, significantly reducing the fatigue life of reinforced concrete (RC) beams. Moreover, spatially variable pitting corrosion can cause fatigue fractures in tensile steel bars at various cross-sections of beams, not just at the mid-span section. This will further increase the failure probability of beams but is rarely considered by existing studies. Thus, this study proposes a fatigue life prediction method for RC beams experiencing spatially variable pitting corrosion. First of all, the spatial variability of pitting corrosion in tensile steel bars in RC beams is simulated through the three-dimensional laser scanning method and the spectral representation method, in which the steel bar diameter, length, distance, corrosion level, and the correlation between corrosion pits are systematically considered. Subsequently, the fatigue crack initiation and propagation of pitting corroded steel bars are modeled based on fracture mechanics. The spatial analysis is then conducted on corroded RC beams until fatigue failure occurs. The proposed prediction method is verified with results from existing references. The findings highlight that neglecting the spatial variability of pitting corrosion leads to an overestimation of the fatigue life of corroded RC beams, especially under uniformly distributed loadings and high corrosion levels. This study provides a reasonable prediction for the lifespan of corroded RC beams.