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IBRACON Structures and Materials Journal • 2012 • vol. 5 • nº 4
Parametric study on the behaviour of bolted composite connections
code 3 [9] for unbraced and braced structures.
The classification was done for the situation that the connection
was subject to negative bending moment, because it is the effort
imposed to the structure for the most time of its life. The results
obtained for both sides was that the slab contributed to resist the
efforts, therefore the connection had the resistance enhanced and
reached the classification of rigid with full resistance to braced
structures, as can be seen in Figure 14.
Table 1 – Experimental stiffness of reference model
Left Side
Right Side
Inicial
Final
Inicial
Final
Positive
Moment
Negative
Moment
Positive
Moment
Negative
Moment
Stiffness (k)
kNm/rad
34324,29 26398,87 33656,42
36360,76 28311,42 23178,00
k /k
final
inicial
-
0,77
0,98
-
0,77
0,64
Table 2 – Beam properties used
in the classification of the stiffness
Beam Properties
4
Moment of inertia (Iz) cm
2887,30
3
Modulus of plastic resistance (Zx) cm
253,60
Plasticization Moment (Mp) kNm
88,76
Length (Lb) mm
1650,00
Yielding Stress (fy) MPa
350,00
Elastic Modulus (E) MPa
230000,00
Figure 13 – Connections classification specified
by Eurocode 3
5. Numerical modeling
5.1 Materials
5.1.1 Properties
The material properties used in the numerical model were deter-
mined in the characterization tests, and others, such as fracture
energy of concrete, which could not be determined experimentally,
was determined based on requirements of the CEB MC 90 [10],
assuming that in the production of concrete was used aggregates
with maximum dimension of 19 mm. For the steel profiles the elas-
tic modulus and yielding stress were determined by tensile tests
according to ABNT NBR 6892:2002 [11] code.
The shear connectors used in the model were the same used in
research [7], and the properties adopted for them were taken from
there. For elastic modulus of the bolts and shear connectors were
adopted nominal values characteristic of each material.
Related to the reinforcement bars of the slab, the properties adopt-
Figure 14 – Classification of model 1
by Eurocode 3