A NUMERICAL 3D MODEL OF SFRC PIPES: PARAMETRIC STUDY OF THE STRENGTH CAPACITY.

Resumo

The incorporation of steel fibers to concrete is beneficial from the structural point of view,
giving place to the use of the composite material called Steel Fiber Reinforced Concrete (SFRC) in
several applications, among which concrete pipes are found. The main contribution of the fibers is
their ability to improve the tensile strength and tenacity of plain concrete. This contribution depends
mainly on the geometric characteristics and mechanical properties of the fibers, the amount incorporated
and the properties of the cement matrix itself. All these factors together will determine the mechanical
performance of the structural piece under consideration. This work contributes to a better understanding
of the mechanical behavior of this composite material applied to pipes through a parametric study of the
strength capacity of pipes considering variations in the dosage and type of fibers as well as variations in
the concrete class used. The fibers are represented as discrete elements and randomly distributed in the
concrete mass whose characteristics are adopted from fibers available in the local market. The proposed
model is simulated in combination with the Monte Carlo method in order to obtain average probabilistic
values of strength capacity of pipes, considering the variability of the orientation and distribution of steel
fibers within the concrete mass. The maximum load values are obtained by simulating the three edge
bearing test (TEBT) according to the IRAM 11503 standard, which is implemented in a finite element
analysis tool (ABAQUS

R ). A constitutive model of damage-plasticity was used for plain concrete and
a model of steel for the fibers which takes into account the pull-out phenomenon. Finally, results of the
simulations are shown through tables of maximum loads, load-displacement curves and histograms.