DESIGN FOR ROBUSTNESS OF STEEL STRUCTURES WITH DISSIPATIVE FREEDAM JOINTS

The high seismic performance of steel frame structures equipped with FREEDAM dissipative joints has been demonstrated through experimental and extensive numerical studies in the framework of a recent RFCS project. In particular, the performance of moment-resisting frames (MRFs) and dual concentrically braced frames (D-CBFs) was thoroughly investigated under seismic actions. Although the research has shown that such structures can dissipate the earthquake-induced energy with limited or even no damage, their robustness in case of accidental actions was not yet addressed. Hence, as required by the current version of Eurocodes, their ability to survive accidental events should be demonstrated. This paper presents the robustness assessment performed on 20 MRFs and D-CBFs under a Eurocode-compliant column loss scenario. In addition, analytical and numerical studies were conducted to demonstrate how the request for robustness influences the design of the joints initially tailored for seismic performances.