Influence of the geometry of butt welds and longitudinal attachments on their fatigue resistance

Abstract

Many constructions, such as wind turbines, bridges and crane runways, are cyclic loaded so that fatigue failure may occur. Therefore, in the course of the revision of Eurocode 3, two research projects funded by AiF-DASt re-investigate the classification of constructional details of EN 1993-1-9. This paper focuses on the geometrical influence on the fatigue resistance of butt welds and longitudinal attachments. First, the influence of the plate thickness on butt welds was investigated. Both a meta-study based on test results of various research projects and our own test series on butt welds up to 80 mm thickness led to interesting conclusions. Furthermore, the influence of the length and radius of longitudinal attachments on the fatigue resistance was investigated. By experiments and numerical analysis, clarification has been sought whether the transition radius larger than 150 mm or the ground weld toe is decisive for the improvement of the fatigue resistance. Since previous meta-studies could not provide a clear result on the influence of the longitudinal attachment length, this was also investigated. A database established in the projects allows to integrate and assess the specified details of butt welds and longitudinal attachments in the context of the overall approach in EN 1993-1-9.