STRATEGIES FOR MODELLING BY FINITE ELEMENT METHOD THE DEFORMED STEEL BARS EMBEDDED IN PLAIN CONCRETE

Resumo

In the study of connections between structural elements of concrete must be guaranteed the
transfer of efforts through connection and sufficient strength to avoid the failure on connections. The
connection strength depends of the bond characteristics of deformed reinforcing steel bars embedded
in concrete. This paper aims to study the bond behaviour of deformed steel bars embedded in plain
concretes from computational modelling of pull out test of high strength ribbed steel bars available in
the literature. Three strategies for modelling the ribs of the steel bar using the finite element method
and two models for characterization the bond between steel and concrete were analysed. The strategies
for modelling ribs of the bars were circular ribs or two longitudinal ribs interspersed by oblique ribs.
In these cases, it was used the real geometry of the ribs. The last strategy modify the geometry of the
ribs from the angle of sliding plane between steel and concrete after crushing. For bond characteristics
of the interface between steel and concrete, the elastic-linear model and the non-linear Coulomb
Friction model were used. The computational results were also compared to the analytical models
available in the literature for deformed bars embedded in plain concrete. The results showed that the
bond characteristics of the interface and the shape of the ribs influence the bond strength. The strategy
modelling with modified ribs to incorporate the crushed concrete in front of the ribs and the Coulomb
Friction model for the interface is the one that shows best approximation of the computational and
experimental tests.