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477
IBRACON Structures and Materials Journal • 2012 • vol. 5 • nº 4
M. N. KATAOKA
|
A. L. H. C. EL DEBS
ed were the averages of values obtained from tensile tests. Table
3 summarizes the properties adopted for each element.
5.1.2 Constitutive Models
n
Concrete
The constitutive model used for the concrete was suitable
for brittle or quasi-brittle materials (CONCRETE AND BRIT-
TLE MATERIALS). To characterize the distribution of crack
was used the TOTAL STRAIN model, whose the advantage
is the simple concept. In the program DIANA the TOTAL
STRAIN can be represented by ROTATING CRACK MOD-
EL or FIXED CRACK MODEL. In the composite connection
studied in this paper was used the FIXED CRACK MODEL.
The tensile concrete behaviour was assumed as brittle and
in compression was used an ideal elastic-plastic model.
n
Steel
Related to steel profiles, their constitutive model need to be de-
scribe by only two features: the yielding stress and hardening.
The plasticity models of Tresca and von Mises are applicable
to steel elements because they are ductile materials.
The model of maximum energy distortion of Von Mises, cho-
sen for the steel elements, admits that the maximum energy
accumulated in the distortion of the material cannot be equal
or greater than the maximum distortion energy for the same
material in uniaxial tensile test.
In summary, METAL model was adopted with the criteria of
von Mises plasticity with IDEAL PLASTICITY, without consid-
eration of the hardening or strain hardening. In the model of
ideal plasticity, or also known as perfectly plastic, the material
does not support efforts after to reached the yielding stress.
n
Interface
The DIANA has two families of interface elements: structural in-
terface, for structural analysis, and structure-fluid interface, used
for analysis of fluid and dynamic structure. There is another type
of finite element that can be used in place of interface elements,
which were the contact elements. These elements are usually
used to analyze the contact between structural elements. The
interface elements used in this study were structural interface.
For the two joints considered in numerical models, between
the column and endplate and between the beam and slab, the
interface was represented by constitutive model for cracking
Table 3 – Material properties adopted in modeling
COLUMN CONCRETE CORE
Tensile
Strength (MPa)
Compressive
Strength (MPa)
Elastic Modulus (MPa)
Fracture
energy
2
(Nm/m )
Poison (
u
)
3,59
54,81
38415,51
0,136
0,2
SLAB CONCRETE
Tensile
Strength (MPa)
Compressive
Strength (MPa)
Elastic Modulus (MPa)
Fracture
energy
2
(Nm/m )
Poison (
u
)
3,77
51,41
34333,65
0,136
0,2
STEEL PROFILES
Yielding Stress (MPa)
Elastic Modulus (MPa)
Poison ( )
u
350,00
235000,00
0,3
BOLTS
Yielding Stress (MPa)
Elastic Modulus (MPa)
Poison ( )
u
350,00
200000,00
0,3
SHEAR CONNECTORS
Yielding Stress (MPa)
Elastic Modulus (MPa)
Poison ( )
u
250,00
200000,00
0,3
REINFORCEMENT
Yielding Stress (MPa)
Elastic Modulus (MPa)
Poison( )
u
525,81 (f12,5mm)
201245,00
0,3