Robustness of Steel Frame Structures Equipped with FREEDAM Dissipative Joints

In the framework of a recent RFCS project, innovative joint solutions named FREEDAM were developed with the objective of proposing beam-to-column joints able to dissipate the seismic energy with limited or even no damages. The efficiency of the proposed solutions was validated through experimental, numerical, and analytical investigations on moment resisting frames (MRFs) and dual concentrically braced frames (D-CBFs). However, according to modern design codes, including the Eurocodes, structures subjected to accidental events such as impact, explosion, or loss of a bearing element should not undergo damages disproportionate to the initiating cause. Accordingly, to validate the proposed solutions, it was also required to demonstrate the ability of structures equipped with FREEDAM joints to exhibit an appropriate level of robustness in case of such accidental events. This paper presents the robustness assessment performed on 20 MRFs and D-CBFs. The loss of a supporting column was considered in full agreement with the Eurocode requirements. Analytical and numerical studies are conducted to demonstrate how the request for robustness influences the design of the joints which were initially tailored for seismic performances.