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IBRACON Structures and Materials Journal • 2012 • vol. 5 • nº 4
M. N. KATAOKA
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A. L. H. C. EL DEBS
tween the stiffnesses was lower than the left side because of
the detachment of the slab has occurred on this side, with stiff-
ness to the bottom of the connection equals to 28311.42 kNm/
rad and 23178.00 kNm/rad to the top. Based on the envelope
curve, the initial stiffness presented by the left side of the Model
1 was 34324.29 kNm/rad and the right side, 36360.76 kNm/rad,
resulting in an average for the stiffness equal to 35342.52 kNm/
rad. For this calculation it was determined the slope coefficient
of the line through the origin, whose value corresponds to the
stiffness of the connection.
It was observed in comparing the loss of stiffness that for posi-
tive bending moment, in both sides, the stiffness reduction was
the same, decreasing at about 23%. For the negative bending mo-
ment, which is resisted by the slab reinforcement, there was some
difference, justified by the fact that the detachment of the slab have
occurred on the right side of the model. On the left side the loss of
stiffness was only 2%, as shown in Table 1.
The connection which was examined experimentally was also
classified according to their degree of stiffness to negative bend-
ing moment following the instructions of Eurocode 3 [9]. For this
purpose some geometric properties of the beam had to be deter-
mined as the moment of inertia and modulus of plastic resistance
and plasticization moment, which are shown in Table 2. Figure 13
shows the classification scheme of connections according to Euro-
Figure 11 – Force versus displacement curves of Model 1
Left side
A
Right side
B
Figure 12 – Bending moment versus Rotation curves and envelope curves of Model 1
Left side
A
Right side
B