Investigations into the yield‐controlled tightening method for steel constructions

The yield‐controlled tightening of bolting assemblies is established in mechanical engineering but has not yet been normatively regulated in steel construction due to a lack of fundamental investigations under practical steel construction conditions. A transferability of the yield‐controlled tightening from mechanical engineering to steel construction is not possible without further investigations due to different safety concepts and unresolved issues such as the reliability of the method in combination with e.g. HV bolting assemblies according to EN 14399‐4/‐6 and DASt‐Guideline 021.

The purpose of this contribution is to provide an insight into experimental investigations carried out in the frame of the German IGF research project 20838 N, where the suitability of the yield‐controlled tightening process is evaluated on HV bolting assemblies M12 to M72. First results for diameters M12 and M24 are presented within this contribution. Herein, an evaluation of the application of the yield‐controlled tightening is provided based on the tests already carried out. The results of the yield‐controlled tightening are compared to test results achieved for the modified torque method according to DASt‐Guideline 024 and 021 and the combined method according to EN 1090‐2 and DASt‐Guideline 024.