COMPUTATIONAL METHODS IN ENGINEERING AND SCIENCE EPMESC X, Aug. 21-23, 2006, Sanya, Hainan,China ©2006 Tsinghua University Press & Springer-Verlag Numerical Implementation and Calibration of a Hysteretic Model for Cyclic Response of End-Plate Beam-to-Column Steel Joints under Arbitrary Cyclic Loading Pedro Nogueiro 1 *, Luís Simões da Silva 2 , Rita Bento 3 1 Polytechnic Institute of Bragança,Bragança, Portugal 2 Department of Civil Engineering, University of Coimbra – Polo II, Pinhal de Marrocos, Coimbra Portugal 3 Department of Civil Engineering, Instituto Superior Técnico, Av. Rovisco Pais, Lisbon, Portugal Email: nogueiro@ipb.pt , luisss@dec.uc.pt , rbento@civil.ist.utl.pt , Abstract This work presents the implementation and calibration of Modified Richard-Abbott model for cyclic response of four end-plate beam-to-column steel joints under arbitrary cyclic loading. The joints parameters are found and the comparison between the analytical hysteretic results and the experimental hysteretic results is made, as well as the hysteretic energy dissipated evaluated for each cycle and obtained for both type of analyses. Key words: Implementation, Calibration, Hysteretic model, Hysteretic energy dissipation, Steel Joint. INTRODUCTION The recent publication of part 1-1 of Eurocode 8 [1] provides some rules for the design and detailing of joints subjected to seismic loading. In particular, for moment resisting frames, it is specifically allowed to use dissipative semi-rigid and/or partial strength connections, provided that all of the following requirements are verified: a) the connections have a rotation capacity consistent with the global deformations; b) members framing into the connections are demonstrated to be stable at the ultimate limit state (ULS); c) the effect of connection deformation on global drift is taken into account using nonlinear static (pushover) global analysis or non-linear dynamic time history analysis. Additionally, the connection design should be such that the rotation capacity of the plastic hinge region is not less than 35 mrad for structures of high ductility class DCH and 25 mrad for structures of medium ductility class DCM with the behaviour coefficient q greater than 2 (q > 2 ) [1]. The rotation capacity of the plastic hinge region should be ensured under cyclic loading without degradation of strength and stiffness greater than 20%. This requirement is valid independently of the intended location of the dissipative zones. The column web panel shear deformation should not contribute for more than 30% of the plastic rotation capability. Finally, the adequacy of design should be supported by experimental evidence whereby strength and ductility of members and their connections under cyclic loading should be supported by experimental evidence, in order to conform to the specific requirements defined above. This applies to partial and full strength connections in or adjacent to dissipative zones. It is clear that Eurocode 8 opens the way for the application of analytical procedures to justify connection design options, while still requiring experimental evidence to support the various options. In contrast, North American practice, following the Kobe and Northridge earthquakes, was directed in a pragmatic way