9th International Conference on Fracture Mechanics of Concrete and Concrete Structures FraMCoS-9 V. Saouma, J. Bolander and E. Landis (Eds) 1 MODELING THE EVOLUTION OF A CRACK IN A PRESTRESSED CONCRETE STRUCTURE †† AND F.FEYEL † E.LORENTZ † PONNELLE - , S.MICHEL † * E.LEFEBVRE riaux é Ecole des Mines ParisTech, Centre des Mat * Paris, France e-mail : eric-lefebvre@mines-paristech.fr , CNRS/EDF/CEA/ENSTA , UMR 9219 IMSIA † Paris, France e-mail : sylvie-michel.ponnelle@edf.fr, eric.lorentz@edf.fr , , Safran SA Safran Tech †† Saclay, France e-mail : frederic.feyel@safran.fr Key words: Prestressed concrete structure, Fracture, Steel-Concrete debonding stressed concrete structure - This work focuses on following an existing crack in a pre : Abstract an estimation of the overall leakage of leads to . This the early stages of damage describing without is proposed that represents most phenomena interacting with the ” global model “ A the structure. he model is built from a real cracking pattern. The existing cracks T existing crack. of an behaviour stressing - taken into account through a cohesive zone model; steel reinforcements and pre are concrete - steel ; the debonding of homogenized membrane models tendons are modelled by means represented by another specific cohesive zone model. The constitutive law used for modelling the is concrete takes into account basic creep (through a rheological model distinguishing the deviatoric d drying creep. ), shrinkage an cal part and the spheri part 1 Introduction EDF- the major French electricity Company-manages 73 nuclear reactors. For some of them, the third protective barrier consists in a concrete double-walled containment building. The key point of such predictions consists in describing the behaviour of potential cracks. However, the size of the structure coupled with the important proportion of reinforcements along with the non- linear constitutive behaviour of concrete are challenging issues. The diameter of the prestressing cables is 10 times smaller than the thickness of the wall and its density is significant. A 3D model of the cables is the straightforward answer in this case but it leads to prohibitive simulation times so that alternative methods need to be employed. An usual solution [1,2] consists in modelling the cables with truss elements. Unfortunately, such modelling results in spurious stress concentrations in the surrounding volume [3] and it generally assumes a perfect steel- concrete bond. Therefore we prefer to use a membrane element, for which the behaviour is obtained by homogenization [3,4,5]. Numerically, this type of modelling – less common in the literature – does not generate stress concentration. Pre-stressed structures also require to take into account delayed deformation phenomena of concrete such as creep. In the long term, the delayed strains cause a significant pre-stress drop. They are usually modelled by means of constitutive laws based either on rheological intuitions or on homogenization methods [6]. Regarding the fracture process of concrete, damage models may simulate crack initiation and propagation while taking into account the complex DOI 10.21012/FC9.126