Elements for steel-concrete interface

by M. David, E. Lorentz and S. Michel-Ponnelle, EDF R&D / AMA

Thanks to the thesis of M. David, you now have the possibility to represent the macroscopic decohesion of reinforcement layers in a concrete structure. The steel sheet is represented by a membrane via the model GRILLE_MEMBRANE while the steel-concrete link is described by an interface law (CZM_LAB_MIX) on an interface element.

To validate these developments, a pull-out test on a reinforced concrete plate was simulated with a 3D modeling of steel then with a membrane representation (using periodic boundary conditions to minimize the size of the 3D calculation).

Image 1 : pull-out test on a reinforced plate (a) general scheme (b) periodic pattern

There is a very good agreement between the two models as shown in Figure 2.

Image 2 : comparison of both solutions obtained with a 2D or 3D modeling of steel.

Note also that, at the same time, a model of orthotropic membrane was introduced. Potentially more accurate than the previous one with tension and shear, it is devoted for the linear case. It is accessible by MODELISATION = ’MEMBRANE’ which supports mesh cells can be either triangles or quadrangles.