Tension-shear interaction of high-strength bolts during and after fire

Connections in steel structures play an essential role in the structural stability of the entire construction. This is also true in the event of a fire. The difficulty in designing connections for fire lies in the fact that not only material properties, but also loads applied to the connections change depending on temperature. In addition, the temperature-dependent decrease in the tensile strength of high-strength bolts does not coincide with the decrease in shear strength. So far, the influence of combined tension and shear loading on high-strength bolts has not been studied in detail.
This project included carrying out interaction tests on high-strength bolts of property class 10.9 (fu = 1000 N/mm2). Post-fire performance was examined in addition to observing the loadbearing behaviour during fire. The examinations were completed with additional material tests. The results were compared with earlier research on the temperature-dependent loadbearing capacity of high-strength bolts during and after temperature loading as well as on the loadbearing behaviour of bolts in steel structures under combined tension and shear loads. This investigation contributes to a better understanding of the loadbearing capacity of high-strength bolts under combined loading during and after a fire.