Anwendung des Struktur- und Kerbspannungskonzepts in der Praxis - Hinweise und Erfahrung für Quersteifenanschlussdetails

In general, for steel structures (bridges, crane runway girders) the fatigue verification and calculation of the remaining fatigue life is based on the nominal stress approach. Alternative numerical methods, considering the local stress field at the relevant notch of the detail, are currently available in other fields (mechanical engineering, off shore). They are increasing attractive also in civil engineering, due to forthcoming FEM-software packages and further code developments. In particular, for existing structures the application of numerical methods should improve the fatigue verification, due to consideration of the calculated local stress fields, and should increase the potential remaining fatigue life. For existing bridges, often the transverse stiffener attachment at girders of the carriageway is the decisive detail for the remaining fatigue life of the bridge. This paper therefore focuses on this detail. Based on a representative detail the results of nominal stress, geometrical stress and effective notch stress method are compared against each other. Based on modifications of the detail geometry, the effects of the thicknesses of flange and stiffener on the results are presented. Recommendations for accurate FE-models are given.

Finally, a new modification factor is suggested, in order to get similar results for geometrical stress and effective notch stress method, if the flange thickness is varied.