Constructional Details with Thermal Cut Edges in Steel Structures - Influence of the Surface Quality on the Fatigue Strength

Fatigue strength verification is essential for components or structures under cyclic loading. In the field of civil engineering, the fatigue strength verification follows the nominal stress concept of EN 1993-1-9. The so called Δσ-concept does not consider the material strength when defining detail categories, a limitation expected to persist in the second generation of the standard. For a more resource efficient design, higher detail categories are required by the wind energy branch, for ex- ample. This can be realized from the authors point of view with the help of higher quality and the consideration of the material strength. This paper focuses on non-welded constructional details made of structural steels (S235JR, S355J2+N, S690QL) with thermal cut edges from oxy-fuel, laser and plasma cutting. Fatigue tests led to new detail categories diverging from the current EN 1993- 1-9 and from the 2nd generation of EN 1993-1-9. It also examines the effect of post-treatment meth- ods like grinding and blast cleaning on fatigue strength. Additionally, material analyzes were con- ducted to assess edge hardening, surface roughness, and mechanical properties. A literature review was carried out to evaluate existing data for components with thermal cut edges. Based of 150 own and 685 given data, new detail categories for the design were recommended.