Comparison of different local design concepts for the structural durability assessment of welded offshore K-nodes

The structural durability design of complex welded structures should not rely only on one single design method but should apply different methods for assuring the reliability of the assessment. In this context the application of the structural stress (hot-spot), notch stress, notch strain and crack-propagation concepts are discussed through the example of K-nodes used in energetic offshore constructions like oil platforms or wind power plants, presenting the state of the art. While the hot-spot, notch stress and crack-propagation concepts show a good agreement between calculated and experimental results and do not differ significantly from each other, the notch strain concept fails significantly.