Development and Application of a Fatigue Class Catalogue for Riveted Bridge Components

The assessment of the remaining fatigue life of existing, riveted railway and road bridges is gaining increased significance due to the advanced age of many of these structures. Therefore, the problem of determining adequate fatigue strength values for riveted components of older steel bridges arose during the elaboration of a pertinent research project initiated by bridge owners in Austria. The aim of this project was to address the discrepancies between different international provisions on this topic and to bridge them by way of an improved, more consistent assessment recommendation. The research project was subdivided into an experimental part and an analytical/statistical part; only the latter is discussed in this paper. A classification of details in riveted components that takes into account the specific fatigue proneness of different constructional details proved to be appropriate. It has led to more consistent Δσ-N design curves when compared to the single Δσ-N line discussed in most international literature on the subject. The resulting catalogue of assessment curves is presented in the first part of this paper. A proposal for the integration of the new fatigue classes into a coherent fatigue life assessment procedure is then described in a form that can immediately be put to use in compliance with the Eurocodes. Finally, a practical application of the proposed assessment procedure is demonstrated by means of an example that deals with a riveted railway bridge.