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

4. SEISMIC RESPONSE OF PARTIAL-STRENGTH COMPOSITE JOINTS
boundaries with springs at the four corners. These springs simulate the resistance
of the elements surrounding the panel zone, in particular the bending resistance of
the column flanges.
z eq
d c
Figure 4.12. Mathematical
model for the web panel in
shear
If we use the mathematical model proposed by Krawinkler, it is possible to
calculate the elastic stiffness of the web panel as follows:
K = G ⋅( H − t ) ⋅ t
( 4.13 )
el el c cf cw
where Gel is the elastic shear modulus; Hc is the column height; tcf and tcw are he
thickness of the column flange and of the column web, respectively. This equation
is valid until γ < γy: this value is achieved when the shear force at general yielding is
equal to:
∗
y, cw
f
Vy = ( Hc − tcf ) ⋅tcw ⋅ ( 4.14 )
3
The f *
y,cw is the yield strength of the column web calculated adopting the Henky-
Von Mises yield reduction criterion, when the column axial force is not negligible.
The strength of the column web can be computed by means of the following
relationship:
y, cw
2
∗
σSd,
col
fy, cw = fy,
cw ⋅ 1−
( 4.15 )
f
K pl
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