Crack Propagation-Based Fatigue Life Prediction of Corroded RC Beams Considering Bond Degradation

Corrosion increases the nominal stress of reinforcing bars and accelerates the fatigue crack propagation. The stress redistribution induced by bond degradation between concrete and rebars makes the fatigue life prediction of reinforced concrete (RC) structures more complicated. This paper proposes a crack propagation-based fatigue life prediction method for corroded RC beams incorporating fatigue damage of concrete, fatigue bond degradation, and pitting corrosion. The fatigue damage of concrete is modeled based on plastic strain analysis. For the fatigue-worsened bond degradation between concrete and corroded rebars, a novel strain-incompatibility analysis method is developed to quantify the slip of reinforcements in concrete. The fatigue crack propagation parameters of rebars and the corrosion pit-induced stress concentration are experimentally obtained. The stress intensity for the fatigue crack at the corrosion pit root is calculated by an asymptotic interpolation method. Then, the fatigue failure analysis of corroded RC beams is performed, where the reinforcement fracture, concrete crush, and bond degradation-induced anchorage failure at beam ends are checked. The proposed method is verified by the test data. The effects of bond degradation and concrete damage on the fatigue life prediction are analyzed and discussed. The proposed method for fatigue life prediction gives a reasonable estimate of the service life of corroded RC beams.