This paper investigates the fatigue behavior of non-load-carrying transverse welded steel attachments by reporting on an experimental characterization under constant and variable amplitude loading. Fatigue cracks have been monitored using DIC and ACPD techniques and fracture surfaces are analyzed to obtain information about nucleation sites and crack depth. The applied variable amplitude load history has been obtained from traffic measurements from a Swiss road bridge. A procedure has been proposed resulting in a Markov transition matrix representative for the measured strain signal and the random resampling of the stress history to be applied for the variable amplitude fatigue tests.