Fatigue Failure of runway beams due to wheel loads

Abstract

The introduction of the Eurocode 3 led to a significantly stricter fatigue classification, especially for flange to web connections of runway beams of heavy duty cranes compared to former national design rules like DIN 4132. At present, this leads to a doubling of the cross‐sectional thicknesses, which e.g. can result into web plates with extreme thicknesses of 80 mm. Execution as well as monitoring of such flange to web connections using full penetration tee‐butt welds are quite critical and thus no longer to be realized reasonably.On this account new fatigue strengths for the runway beam specific fatigue detail “Top flange to web junction of runway beams” in EC3‐1‐9 Table 8.10 have been established within the FOSTA‐research project “Fatigue failure of runway beams due to wheel loads in heavy smeltery cranes” as recommendations for an eventually modification or even extension of the current codes. In Particular, the detail executed using full penetration tee‐butt welds has been investigated in the framework of this research project.The essential core of the methodical approach is that real existing crane runway girders have been examined, documented and evaluated in regard of fatigue failure of the flange to web connection. In this way, a direct quantitative assessment of safety against fatigue failure for the investigated detail could be derived. In addition, synthetic notch cases have been investigated numerically. The results of both methodologies have been prepared for a proposal of amendment of the current codes. This paper provides an insight into the methodological approaches and the main results achieved.