Strengthening Details for Low-Damage Seismic Dissipative Beam-to-Column Joints in Case of Column Loss Scenario

Low-damage beam-to-column steel joints equipped with friction devices have been recently prequalified for European applications within FREEDAM and FREEDAM+ research projects. Despite their excellent seismic performance, these joints may exhibit limited ductility in the case of column loss scenarios. Therefore, a numerical study has been conducted to investigate the behavior of this type of joint under column removal utilizing refined finite element simulations. The results for the seismically prequalified configurations confirmed poor ductile behavior due to the premature failure of the upper T-stub connecting the beam flange to the column flange. Therefore, a local strengthening solution was designed to enhance the T-stub ductility without interfering with the joint seismic performance. The effectiveness of the adopted solution was numerically investigated by means of refined numerical model. The performed analyses showed that the designed strengthening details allow for increasing the ductility of the whole connection without modifying the flexural resistance of the joints.