In seismic areas, steel frame structures are typically designed to withstand seismic actions by dissipating the earthquake-induced energy through plastic deformations in specific structural elements or regions identified as dissipative zones. In EN 1998-1 [1], for dissipative structures, a particular emphasis is given to the ductility of the dissipative zones so that the energy is dissipated through a ductile hysteretic behaviour. Generally, in structures with moment resisting frames (MRFs), the dissipative zones are concentrated at the extremities of the beams where plastic hinges are assumed to develop, while the beam-to-column joints are designed as non-dissipative regions. This may frequently lead to uneconomical joint solutions since, according to the principles of Capacity Design, the joints should be designed to account for the possible overstrength of the dissipative regions (i.e., the beam ends).

Recent research on beam-to-column connections for seismic-resistant steel structures focused on the development of smart connections equipped with seismic dampers with the aim of reducing the structural damage occurring under destructive seismic events. Such dampers provide the dissipation of the earthquake input energy and, therefore, they practically substitute the dissipative zones of traditional moment-resisting frames.

Through the present webinar, the basis of seismic design of steel structures and the importance of joints in the design process will be first introduced. Then, possible smart joint solutions will be presented with a specific emphasis on the innovative “Free from Damage” joint solution developed in the framework of the recently finalised RFCS (Research Fund for Coal and Steel) FREEDAM project. Finally, the design of structures equipped with such FREEDAM joints will be exemplified describing also the specifically dedicated tools made freely available.