Identification of causes of fatigue damage in connections between stringers and floorbeams in steel railway trusses

Much fatigue damage has been observed in connections between stringers and floorbeams in initiallywelded steel railway bridges. In this study, analysis of fatigue cracking, stress measurement and finite element analysis on the actual bridges were carried out to identify the mechanisms of fatigue damage, in order to develop life extension methods for connections between stringers and floorbeams. In particular, it was noted that position of the train load influenced stress at crack locations. As a result, we were able to explain characteristics of stress and deformation primarily responsible for fatigue cracks in this type of bridge.