Load-bearing capacity of lockbolt systems made from carbon steel subjected to combined tension and shear loading

For bearing type connections subjected to combined tension and shear loading (category A+D, EN 1993-1-8), the interaction verification according to Eurocode 3 is required. The use of so-called lockbolt systems is an alternative to conventional bolted connections in steel structures. The linear interaction approach according to technical bulletin DVS/EFB 3435-2 is a conservative assumption, due to the lack of knowledge about the behaviour of lockbolts under combined loading. In more than 900 tests, the interaction resistance of tensile test pieces, fully and partially threaded bolts and lockbolt systems was examined, and additional numerical analyses were carried out. Based on a statistical evaluation, a new design proposal for the interaction verification of lockbolts is pointed out.