Fatigue behaviour of Friction Stir Welded aluminium bridge deck segment

The paper discusses the experimental fatigue assessment of a recently developed aluminium bridge deck system utilizing Friction Stir Welded (FSW) elements. The FSW effect on the material and the fatigue behaviour is studied. Critical region of the butt weld detail is defined and the mechanical properties are determined by tensile test. Severity and extent of softening in the heat affected zone is characterised. By full-scale fatigue test series on girder specimens representing the global transverse behaviour of the deck, fatigue crack propagation is described, fatigue strength is determined for the detail, and compared to MIG welding. Based on the results, practical applicability of the conceived deck configuration is evaluated.