Steel Beam-to-Column Friction Joint under a Column Loss Scenario

Abstract

FREEDAM joints have been recently seismically prequalified for applications in European seismically prone countries. Despite their excellent seismic response, FREEDAM joints are not purposely conceived for exceptional loading conditions, such as in the case of a column loss scenario. Therefore, a comprehensive parametric numerical study has been carried out to investigate the robustness of this type of joint, varying the geometry of the beam–column assembly and the associated friction device. The results of the performed finite-element simulations allowed the identification of the critical components of the joints such as the upper T-stub connecting the upper beam flange to the column. This component is characterized by significant demand, due to the concentration of tensile and shear forces when catenary action develops in the beam. In order to enhance the ductility of the beam-to-column joint under large imposed rotations, the details of the upper T-stub connection were modified and numerically analyzed. The obtained results allowed for the verifying of the effectiveness of the amended details as well as characterizing the evolution of the tensile forces in the bolts.

Keywords

• friction damper
• beam-to-column joints
• steel structures
• column loss scenario
• finite-element analysis