Traffic Load Effects on Fatigue Lives of Cable Wires

Abstract:

The fatigue lives of wires are mainly affected by live loads, especially traffic load. This paper studies the fatigue lives of wires on account of the traffic load effects on the fatigue crack growth and the critical crack length. First, the Paris Law is simplified for the analysis of crack growth, which shows that the mean value of stress range has great effects on the fatigue lives despite of the distribution function of the stress range. Then, based on the distribution of maximum traffic load from Rice equation, the traffic load effects on the critical crack length are analyzed and the failure probability of fatigue lives is proposed. The above approaches are applied to stayed cable wires of an actual bridge. It is found that the variability of stress range has little effect on the fatigue lives. And it can be drawn from the results that the maximum traffic load has some effects on the fatigue lives and the standard deviation of fatigue lives can be up to 9 weeks.