Within the Steelquake research program, a full scale experimental test hasshown that a two storey steel frame with welded connections can satisfy the resistance requirementsset by EC8 with wide safety margins. This result, however, may be compromised by brittlefractures occurring at the beam-to-columns connection, as it was shown also by experimentalinvestigations at Politecnico di Milano. It has not yet been completely understood under whichcircumstances such brittle collapses may take place; therefore, research is still active on thesubjects of defining proper welding procedures and interpreting plastic deformations at thelower beam flange. Three dimensional finite element models have been developed in order toget a deeper knowledge of the stress state in the lower portion of the beam, in proximity of thewelding zone. In the present work, the main results from the experimental research on the fullscale model are presented, together with numerical analyses performed on several structuralconfigurations. Different solutions for the node panel are discussed, some of which allow forplastic deformations in the node itself and reduced plastic rotations of the beam.
展开▼
