ABSTRACT
The lessons delivered by the Northridge 1994 earthquake and the damages induced into multi-storey steel structures, mainly with welded beam-column connections emphasized the important role of ductile connections beam-column for both, the reduction of the level of damages (cracks in the welds) and the possibility of repairing of cracked welded connections. Among the important lessons that have been learned, is that the structure has to be equipped with several levels of ductility (structural level, member level, joint level). The need of ductility and the beneficial role it plays during an earthquake, raised the ductility requirement of seismically acted structures at the same level as the strength and serviceability requirements. Today ductility is, in structural design, a top priority the structure has to be ensured with and provided for.
