Fatigue life prediction for the reinforced concrete (RC) beams under the actions of chloride attack and fatigue

Pitting corrosion of tensile steel bars, usually causes the failure of RC beams under the actions of chloride attack and fatigue. Based on the Fick's 2nd law and Paris law, a fatigue life prediction model for RC beams under these combined actions is proposed. Pitting corrosion is considered as a surface crack. Fatigue life is predicted by parameters of the service environment, service time and fatigue loading, which are available data for in-service RC structures. The model can produce reliable fatigue life predictions according to the validation results, and it is proved that the crack initiation significantly affects the fatigue life due to its large proportion. In addition, parametric studies indicate that the fatigue life obviously decreases as the stress ratio decreases from 0.4 to 0.1, and when the service time increases, the fatigue life rapidly decreases at first and then gradually decreases after 10 years of service. The fatigue life markedly reduces as the environmental temperature (greater than0 degree) increases, but the relative humidity rarely affects it.