Bridges experience cyclic loading which may introduce fatigue damage and eventually lead to fracture. To mitigate the related risks, several rulesets (incl. Eurocode, AASHTO and British Standard) require a fatigue life prediction, typically based on S-N curves and the linear damage accumulation of Palmgren-Miner. There are minor differences in terms of detail classification between standards, but larger differences between the path of the S-N curve in the very long life regime. It is known that the load spectrum has an influence on this regime due to load interaction and load sequence effects. To study the variation in the very long life regime as a function of the spectrum and the prediction accuracy of standards, this paper contains a compilation of variable amplitude fatigue tests with spectra containing multiple realistic loading levels (excluding overload-CA sequences) on steel welded joints. This database, obtained from literature, is supplemented with a prediction of the fatigue life following the rulesets from BS 7608:2024, AASHTO, EN 1993-1-9:2005 and prEN 1993-1-9:2024. Next to this, it identifies knowledge gaps in terms of available reference data and analysis methods.
Deul et al. (Wed,) studied this question.