Probabilistic Assessment of Welded Joints versus Fatigue and Fracture

This paper presents a probabilistic reliability assessment procedure for steel components damaged by fatigue. The crack growth model is based on the principles of fracture mechanics theory. It is compared to experimental results and gives a good prediction. The fatigue safety margin includes the crack growth from an initial crack depth to a final crack depth determined according to the fracture mechanics theory: brittle and ductile fractures. The reliability calculus is performed using a first-order reliability method. The sensitivity analysis of different parameters shows that some variables can be taken as deterministic. Applications are made on a transverse-stiffener-to-bottom-flange welded joint of a typical steel bridge.