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[Display omitted] • Tests to prequalify EC8-compliant extended stiffened end-plate joints are presented. • Design procedure is proposed and verified against tests and finite element simulations. • Two alternative dissipation mechanisms are promoted, i.e., full and equal strength joints. • Tests showed plastic deformations solely in the connected beam for full strength joints. • Tests showed plastic deformations in the beam and the connection for equal strength joints. An experimental and numerical campaign was carried out to validate the design procedure and prequalify extended stiffened end-plate (ESEP) joints for ductile seismic resistant moment-resisting frames in the framework of Eurocodes. In fact, the tested ESEP joints have been designed with the aim of guaranteeing ductile and dissipative seismic response in accordance with the principles of the hierarchy of resistances to enforce plastic deformations in ductile components of the joints. Two alternative types of dissipation mechanisms are promoted, namely either (i) plastic deformations solely in the connected beam using full strength joints or (ii) plastic deformations in both the beam and the connection using equal strength joints. The adopted design criteria and technological details are described and discussed. The results of experimental tests confirmed the expected yielding mechanisms of the joints, which satisfied the acceptance criteria for both North American and European prequalification. Finite element simulations of ESEP joints have been validated against the experimental results and have been used to investigate the local response of the joints, thus highlighting the influence of both geometrical and mechanical parameters. [ABSTRACT FROM AUTHOR]

[Display omitted] • Seismic resisting joints exhibit satisfactory performance at elevated temperature. • Pre-damage of joints has limited influence on the response at high temperature. • The performance of the joints is investigated by means of finite element analyses. • The resisting temperature largely depends on the vertical loads acting on the beam. • Lateral-torsional restraints are crucial to guarantee ductility and resistance. The mechanical features of beam-to-column joints may highly affect the resistance of steel structures at elevated temperature. Therefore, the behaviour of steel joints under elevated temperature has been widely studied. However, few studies have been specifically devoted at investigating the response of bolted end-plate joints under elevated temperature that were formerly damaged by seismic actions. Hence, the study summarized in this article was addressed to: (i) to analyse the response of seismically prequalified extended stiffened end-plate joints under high temperature; (ii) study the influence of the seismic damage on performance of this type of joints at elevated temperature. Parametric finite element simulations were carried out to achieve these purposes varying the dimensions of members, the design criteria of the joints, the vertical loads, the presence of lateral-torsional restraints and the level of imposed damage. The obtained results in terms of moment-rotation-temperature characteristics and pattern of plastic deformations showed in which terms the type of cyclic damage may affect the performance of the joints under high temperature as well as the influence of the efficiency of bracings to restrain the beams against lateral-torsional buckling. [ABSTRACT FROM AUTHOR]

Different types of seismic dampers are available on the market of constructions. The more effective solutions are characterized by (i) stable and predictable response, (ii) localisation of demand into the dampers minimizing the post-earthquake damage in easily replaceable parts. Friction dampers typically satisfy both requirements. These dampers are very versatile since they can be equipped in different structural arrangements. One of the most promising solutions is their application in the moment-resisting beam-to-column joints where they can effectively dissipate the seismic energy and limit plastic deformations into easily replaceable elements. Furthermore, their resistance and deformation capacity can be easily designed without interfering with the structural geometry, thus allowing the standardisation of friction connections for a wide range of beam-to-column assemblies. The current work presents a parametric study based on finite element (FE) simulations of steel beam-to-column joints equipped with a set of five predefined friction dampers specifically conceived to cover the most representative range of profiles used in Eurocode-compliant multi-storey moment resisting frames. The FE models were calibrated against recent experimental tests performed by the authors in a former study. The analyses were aimed at extending these experimental results, investigating the local behaviour of the dampers and the connections as well as the influence of member scaling on the monotonic and hysteretic behaviour of each assembly. The results confirm that the non-linear performance of connections equipped with friction dampers is almost independent on the dimensions of the connected profiles, and it is fully replicable within a predefined range of geometries [Display omitted] • A set of five predefined symmetric friction dampers was proposed for predetermined ductility and resistance. • A design chart for steel beam-to-column joints equipped with the proposed dampers was provided • The dissipative response of the examined friction joints does not depend on the size of connected members. • The flexural response of the joints equipped with the proposed dampers is not symmetric • The shear forces ìn bolted connections are significantly greater than the shear force developing in the beam. [ABSTRACT FROM AUTHOR]