Fatigue behaviour and detailing of slotted tubular connection

Tubular elements are used in steel structures not only for bracing of other members but also as cross girders diaphragms. They are a competitive solution both due to the lightweight and structural efficiency. Slotted tube-to-plate connections are the natural and most common choice. However, fatigue design of the abrupt transition and differences in the stiffness corresponding to the welded connection, is a critical part of the design. Although such a fatigue connection is classified in different standards (e.g. EN1993-1-9, IIW recommendations), no guidance is given on the specific detailing. In this paper, the existing fatigue datasets for this connection are reviewed. An assessment of the different fatigue details constituting the connection (welds end, hole, etc.) using FEM models and the notch stress method is then made. The results are compared with the experiments and recommendations are issued in order to achieve the best fatigue performance.