Numerical Modeling of Post Tensioned Concrete Slab

Resumo

The fragile failure of concrete is a complex problem where reinforcement steels are
employed at regions subjected to tension. The other important solution in order to improve the
structural behavior corresponds to inclusion of prestress steel reinforcement in concrete. This
introduces a precompression avoiding cracks during service lifetime. Nowadays, post-tensioned
concrete remains not fully controlled where the numerical modeling plays a relevant role to improve
the knowledge concerning to structural behavior. Therefore, this paper focus on numerical evaluation
of the post tensioning influences on the global behavior of concrete slabs. The numerical model has
been created taking into account the experimental results. In details, it was modeled one simple
support concrete slab that was carried out up to its ultimate loading. This test measured important
aspects, such as deflections, yield lines, and cracks development. The specimen has a square geometry
and uses straight prestressing wires. The numerical model has been developed using the Abaqus
software. It is known that the standard solver could not advance much after cracking load because of
many nonlinearities introduced. The viscosity parameter on the concrete damaged plasticity model
was the only way to pass through this point, but this technique weakens the results and raises doubts
about it. An attempt with explicit solver has been used to overcome those nonlinearities during the
analysis and showed good results. Contact problems between concrete and steel wires, concrete
damage plasticity modeling, and explicit analysis require to scrutinize many topics during pre- and
post-processing analysis. This paper presents the whole process of modeling a post-tensioned concrete
slab using Abaqus Explicit taking into account its applicability, advantages, disadvantages and the
validation procedure. This paper presents a method to identify the cracking load in an Explicit analysis
based on the plastic deformation energy.