Structural zooming method for the simulation of large reinforced concrete structures
Résumé
Massive reinforced concrete structures, such as nuclear containment buildings, may undergo potential localized cracking when submitted to hypothetic loads in accident. This phenomenon is difficult to
quantify by simulation because it requires nonlinear modelling at a refined scale, which cannot be applied on a large civil engineering structure. Therefore, focusing the computational effort on areas of interest, where cracking occurs, seems an interesting approach. This paper presents a structural zooming method that allows reducing the size of the nonlinear problem while still providing the same results as a full nonlinear computation. The method follows several steps at each load increment:
- Condense the undamaged areas (linear-elastic behaviour) and the associated loading (Guyan,
1965)
- Apply the computed equivalent stiffness and loading as boundary conditions for the areas of
interest
- Solve the reduced problem (areas of interest and boundary conditions)
- Update the list of areas of interest depending on two criteria: deformation criterion on the condensed areas (based on nonlocal Mazars’ equivalent deformation) and damage propagation criterion on interfaces. This method is applied on the computation of two test cases: the first one represents a five meter reinforced concrete beam which has been experimentally tested under three-point loading (Ghavamian et al., 2003). The second one is a simplified and reduced model (nine meters height) of a reinforced concrete containment building under internal pressure. On both test cases, the computational effort is substantially
reduced and the results (damage profile and mechanical response) are equivalent to the full nonlinear simulation.