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

4. SEISMIC RESPONSE OF PARTIAL-STRENGTH COMPOSITE JOINTS
4.9 Numerical analyses of the prototype structure
The behaviour of the prototype structure described above was simulated by means
of a 2D numerical model of the main frame. All the constitutive elements, i.e.
composite beams, composite partially encased columns, base joints, were
modelled by using their actual geometrical and mechanical characteristics.
Moreover, on the basis of the results obtained from the analyses of the tested
specimens, it was possible to calibrate the analytical model of the semi-rigid partial
strength joint, both for the exterior and for the interior configuration. As said before,
the composite beam-to-column joint is modelled using a rotational spring to
simulate the connections and a rectangular articulated polygon with a translational
spring simulating the column web panel. Due to the inaccuracy of the analytical
model obtained by applying the component method (Eurocode 3, 2001), the
experimental response was reproduced by means of a hysteretic Bouc-Wen model
with damage rules implemented in the program IDARC 2D (Valles et al, 1996): the
smooth hysteretic model of Sivaselvan and Reinhorn (1999). In Figure 4.46 a
scheme of the numerical model used for the simulations is represented.
402 mm
3098 mm
402 mm
2760 mm
290 mm
150
242 mm 6748 mm
262 mm
4748 mm
242 mm
+6.85 m
+3.35 m
0.00 m
Figure 4.46. Scheme of the numerical model used for the simulations
By means of this numerical model both the non-linear static pushover (NSP)
analysis and the incremental dynamic analysis (IDA) have been conducted.
Hereinafter, the main results of these analyses will be discussed. The results of
these analyses in term of maximum plastic rotation at the joint, total amount of
dissipated energy and cumulated damage in the dissipative zones, have permitted
to choose the correct accelerogram to impose on the prototype structure in the
ELSA laboratory by means of the Pseudo-Dynamic (PsD) technique.