The influence of moment resisting beam-to-column connections on seismic behavior of chevron concentrically braced frames

Chevron concentrically braced frames (C-CBFs) are very popular lateral-resisting systems, often opted for steel buildings due to their improved architectural functionality and reduced cost of fabrication and erection as X bracings. According to EN 1998-1 these systems are expected to provide limited ductility, thus penalizing the design of C-CBFs with smaller values of the behavior factor (namely q = 2 and q = 2.5 for medium “DCM” and high ductility class “DCH”, respectively). To improve the ductility and the energy dissipation capacity of chevron bracings, the influence of the secondary frame effect provided by moment resisting beam-to-column connections belonging to the braced bays is investigated in this paper. To this aim, parametric non-linear analyses are carried out on a set of structural archetypes representative of low, medium and high-rise multi-story buildings. The results show that fully restrained joints can have beneficial effects providing an additional reserve of strength, stiffness and ductility.