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IBRACON Structures and Materials Journal • 2012 • vol. 5 • nº 1
Simplified damage models applied in the numerical analysis of reinforced concrete structures
compared to the isotropic ones, such as, the selective stiffness
deterioration and evolution of cracking configuration supplying a
more realistic numerical response, see Pituba [6]. This feature can
be more evident in three-dimensional analyses. However, it must
be observed that structures with low reinforcement rates can evi-
dence some numerical problems due to plane analysis, see Pituba
[6], Pituba [18] and Comi [19]. In these cases, the cracking process
starts to present a localized distribution limiting the employment of
the damage models. In order to overcome numerical problems a
non-local version of the anisotropic model can be proposed and
implemented in a computational code, for instance, with so-called
Generalized Finite Element Method.
On the other hand, it is important to observe that the proposal
and parametric identification of evolution laws for damage vari-
ables D
4
and D
5
must increase the accuracy of the anisotropic
model. In fact, these cracking processes related to shear behav-
ior of the concrete are significant contributions to the released
energy. This feature has been studied by Pituba [20] and a theo-
retical analysis has shown that the anisotropic model has ad-
vantage upon constitutive models that use the so called “shear
retention factor”.
The 1D analysis has shown an efficient and practical employment,
without numerical problems and low computational cost. Besides,
the parametric identification is simple. In this case, the anisotropic
or isotropic damage models could be used in estimative analyses
of structures in practical situations, such as: numerical simulation
of displacement in cracking concrete beams in order to propose an
alternative procedure to the Brazilian Technical Code (Pituba [21]),
estimative of ultimate load capacity of frames and beams and col-
lapse configuration of reinforced concrete frames (Pituba [22] and
Pituba [23]), included the numerical analyses of the structures sub-
mitted to cyclic loading (Pituba [24]) . Finally, this work has dem-
onstrated that simplified damage models are a good alternative to
estimate the mechanical behavior of reinforced concrete structures.
6. Acknowledgments
The authors wish to thank to CNPq (National Council for Scientific
and Technological Development) for the financial support.
7. References
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