RLD++ - Improved remaining fatigue life predictions based on fracture mechanics

Predictions for the remaining fatigue life of steel railway bridges, based on SN-curves, often lead to very conservative results. Based on a fracture mechanics approach the remaining fatigue life can be extended significantly. The key aspect are fatigue test on fifty years old longitudinal girders of a steel girder bridge, without any remaining fatigue life. At the critical positions notches were applied, leading to cracks. The crack front and crack growth was measured and documented. Numerical calculations in parallel, based on fracture mechanics, were carried out, to end up with simplified calculation procedures for the practical application.