On the preload-time behavior of slip resistant preloaded joints in steel construction under cyclic loads

For the design of mechanically maintenance-free connections, the preload loss of the bolts must be determined and considered in the design. Since parts in steel construction must often be coated to provide sufficient corrosion protection, an analytical calculation is not possible. For the experimentally determination of the preload losses, (IEC 61400-6, 2020) suggests two promising concepts-laboratory and field measurements. Investigations based on both methods were performed. The results were compared, and the test procedures were optimized. The aim was to provide a practically applicable method for the experimental determination of preload losses that delivers conservative results with justifiable experimental effort.