Fatigue strength of the joint of steel cantilevers in composite bridges

Abstract Box girders with steel cantilevers underneath the deck are frequently used in design of composite bridges. Hereby, welded joints between main girder and transverse system have to endure fatigue loads. Current specifications for this joint, e.g., a tapering thickness top flanges at same position transition radius, complex manufacture provide higher resistance than necessary. This article addresses optimization structural detail, which is realized hundreds times per structure. Several laboratory tests numerical simulations were carried out regarding load‐bearing behavior safety as double‐T‐sections box girders. Additionally, 60 conducted on small‐scale specimen classify resulting simplified variants detail categories nominal stress concept. As result, two recommendations proposed joint intersecting flanges. Moreover, effect an unplanned axial misalignment strength bottom flange quantified.