Proposal of AASHTO Fatigue Detail Categories for Structural Steels Containing Thermally Cut Edges and Cut Holes

Thermal cutting is a common engineering practice that is used to obtain the final shape of structural components. The characteristics of the cut surface and the material transformations caused by the cutting method determine the corresponding fatigue behavior. However, design codes, including the AASHTO LRFD bridge-design specifications, provide fatigue design curves for a limited number of situations. In the case of cut edges, only flame cutting is covered, whereas plasma and laser cutting are not associated to any category. In the case of cut holes, AASHTO specifications only consider the fatigue performance of drilled and punched holes, limiting the use of thermal cutting processes to, for example, produce bolt holes. All this restricts the use of thermal cut technologies in many applications. This paper analyzes the effects of flame, plasma and laser cutting on the fatigue behavior of cut edges and cut holes performed on structural steels. With this aim, an experimental program composed of 300 fatigue specimens has been completed. The obtained S-N results have been used to estimate the corresponding proposal of AASHTO detail categories.