ABSTRACT
With reference to moment resistant (MR) steel frames in seismic area, the current study intends to assess the reliability of the Reduced Beam Section (RBS) connection as an upgrading or a retrofitting system. It has been already demonstrated by means of either a wide program of experimental test (SAC 96–03, 1997; Chen et al., 2001) or analytical studies on classical MR steel frames (Faggiano & Landolfo, 2002) that the RBS elements are able to protect nodes from plastic deformations. In particular, inelastic deformations in the beam do not involve connection welds, the RBS undergoing inelastic deformations instead of beam-ends. As a consequence, the presence of dog-bones enhances the dissipation capacity of structures. On the bases of results of previous studies on this topic, presented in Faggiano & Landolfo, 2002, in this paper a parametrical investigation is presented in order to optimize the simplified analytical formulation for the determination of the dog-bone location within the beam, as a function of the amount of beam section reduction. A 2 bays, 5 stories and a 2 bays, 8 stories MR steel frames have been analyzed. Structures are preliminarily designed according to Eurocodes 3 and 8 and then modified by introducing the dog-bone connection. The global seismic performance of the obtained structures is evaluated by means of static inelastic pushover analyses.
