ABSTRACT
This chapter presents a probabilistic fracture mechanics method of calculating the risk of fatigue failure of a steel structure. With regard to highway bridges, it is very useful in determining how long one can extend the service life without exceeding a specified risk of failure. The chapter aims to develop a model for calculating the risk of fatigue failure of a steel bridge. This required a probabilistic fracture mechanics calculation of crack growth with stochastic inputs for crack growth rate, fracture toughness, crack size, and load history. The model was checked against the known service failure of a highway bridge. The load history of a bridge is given by the stress range induced by trucks crossing the bridge and by the average daily truck traffic. The four independent input variables were the crack growth rate, fracture toughness, initial crack size, and equivalent stress range.
