Probabilistic fatigue analysis under constant amplitude loading

Use of a fracture mechanics-based fatigue analysis for bridge details requires that the random nature of fabrication, crack growth, fatigue-fracture failure and applied loading be properly accounted for. Prior to investigating the last item, the others may be addressed by comparing with corresponding S-N curves, which have been established over many years of experimental code development. In this paper, four typical fatigue-sensitive details are examined under constant amplitude loading and the 50 and 97.7% probability of survival lines are obtained using appropriately selected stress intensity factors, a bi-linear crack growth model and a failure assessment diagram. To this end, various material and geometric parameters, are treated as random. The good agreement observed between the fracture mechanics-based S-N curves and their code-specified counterparts, especially for low stress ranges, increases confidence in the model parameters used and hence in subsequent bridge reliability analyses using probabilistic fracture mechanics. (C) 2003 Elsevier Science Ltd. All rights reserved.