Innovative cross-sections of steel-concrete composite bridges - Part 2: Fatigue strength of the joint of steel cantilevers

Innovative cross-sections of steel-concrete composite bridges – part 2: fatigue strength of the joint of steel cantilevers. Nowadays, box girders with steel cantilevers underneath the deck are often used for the design of composite steel bridges. For the welded joints between the longitudinal main girder and transverse system partially conservative specifications – e. g., a tapering in thickness of the top flanges – must be observed to ensure a fatigue-resistant design. In order to optimize the detailed design, which has to be carried out hundreds of times per structure, various studies were carried out with regard to load-bearing behaviour and fatigue safety on cantilever girders as double-T-sections or as box girders. Numerous fatigue tests were carried out to classify the resulting simplified design variants in detail categories of the nominal stress concept. As a result, two simplified design recommendations classified in terms of their fatigue strength are proposed for the joint at the intersecting top flanges and the effect of an unplanned increased axial misalignment on the fatigue strength of the joint at the bottom flange can be quantified. © 2023, Ernst und Sohn. All rights reserved.