Comparison between behavior of steel and composite Eccentrically Braced Frames with long links

Eccentrically Braced Frames (EBF) are used world-wide and represent the alternative to the Concentrically Braced Frames (CBF) and Moment Resisting Frames (MRF). Eccentrically braced frames are characterized by high lateral rigidity, while the dissipation occurs in link elements, by inelastic distortion. The strength and ductility of EBF is directly related to the strength and ductility of the links, development of plastic hinges is designed to be at the extremities of frame elements, preferably in the beams and only at limit states in columns. The seismic energy is dissipated by means of elasto-plastic shear cycles (for the short link), bending cycles (for the long link) and shear and bending cycles (for the intermediate link). This paper presents the result of numerical studies with the objective to investigate and compare the behaviour of 2D steel and composite eccentrically braced frames under seismic loading with active links which yield in bending.