坑蚀钢筋疲劳寿命预测的等效表面缺陷模型

It is a complicated and engineering related issue to predict the fatigue lives of pitted corroded steel reinforcement effectively. Based on the current experimental and theoretical outcomes, an equivalent initial flaw model for fatigue life prediction was proposed. Considering the comprehensive effect of pit length, width and depth, a correction formula of stress concentration was proposed. By taking into account the crack initial life, short crack propagation life and long crack propagation life, the depth-to-width ratio and length-to-width ratio of corrosion pits were equalized to surface initial flaw. The fatigue lives of pitted corroded steel reinforcements were predicted based on the formulae of fatigue life of steel bars with surface flaw and stress concentration. Test data were used for regression of model parameters and to predict the fatigue lives of steel reinforcements with semi-elliptical and triangular pit respectively. The predicted fatigue lives agree well with the experiment results. Therefore, the equivalent initial flaw model is validated.