New design rules for bolted connections made of stainless steel

The tensile/shear behaviour of stainless steel bolts is significantly influenced by their specific material properties (non-linearity, strain hardening). However, this is currently only taken into account to a limited extent in the design. Essentially, the design according to EN 1993-1-4 is based on regulations of EN 1993-1-8, which were derived for bolts made of carbon steel. At national level, the shear capacities of stainless austenitic bolts have already been designed differently, based on a few investigations. For duplex stainless bolts, there have been no specific regulations at all so far Within the framework of the IGF research project no. 20651 N "Development of a normative basis of the load bearing capacity of bolted connections loaded in shear and tension made of austenitic and austenitic-ferritic (duplex) stainless steel M12 to M36", experimental and numerical investigations as well as statistical evaluations according to EN 1990 on the tensile, shear and combined tensile-shear load-bearing capacity of bolts made of stainless steel were carried out systematically for the first time. The results have currently been implemented into the revision of EN 1993-1-4. In addition, the bearing resistance of stainless steel plates was investigated. Ultimately, the new regulations lead to a more economical design of bolted connections made of stainless steel.