Analysis and modelling of the seismic behaviour of high ... - Ingegneria

3. SEISMIC BEHAVIOUR OF BOLTED END PLATE BEAM-TO-COLUMN STEEL JOINTS
• the end plate in bending (component 7).
It is evident that the contribution of the column web panel is significant in all cases.
ENERGY ABSORBTION (KJ)
! "
! # $! ! # %
Figure 3.18. Percentage of energy dissipated by the components
The mean energy ratios as well as the ultimate ductility ratios indicate a
satisfactory cyclic performance. All joint components can reach mean energy ratios
higher than 0.5, while ultimate rotational ductilities φj,u/φj,y range from 8 to 21. The
results for the component 6 (column flange in bending) and for the component 7
(end plate in bending) of the specimens JA1-2 and JB1-3 are illustrated in Figure
3.19. Joint JA2-4, which also reached plastic rotations greater than 30 mrad, was
characterized by a mean energy ratio below 0.5.
As far as the joint classification is concerned, it is important to underline that the
Eurocode 3 (2001) permits a classification valid only for monotonic loads. In this
study this approach is taken into account for an extension under seismic loading
history. The response envelopes lie within the semi-rigid range of Eurocode 3 for
unbraced frames, when typical beam lengths ranging from 4 to 8 m are taken into
account.
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