International audienceCorrosion induced by chloride ions has become a critical issue for many reinforced concrete structures. The chloride ingress into concrete has been usually simplified as a diffusion problem where the chloride concentration throughout concrete is estimated analytically. However, this simplified approach has several limitations. For instance, it does not consider chloride ingress by convection which is essential to model chloride penetration in unsaturated conditions as spray and tidal areas. This paper presents a comprehensive model of chloride penetration where the governing equations are solved by coupling finite element and finite difference methods. The uncertainties related to the problem are also considered by using random variables to represent the model's parameters and the materials' properties, and stochastic processes to model environmental actions. Furthermore, this approach accounts for: (1) chloride binding capacity; (2) time-variant nature of temperature, humidity and surface chloride concentration; (3) concrete aging; and (4) chloride flow in unsaturated conditions. The proposed approach is illustrated by a numerical example where the factors controlling chloride ingress and the effect of weather conditions were studied. The results stress the importance of including the influence of the random nature of environmental actions, chloride binding, convection and two-dimensional chloride ingress for a comprehensive lifetime assessment

Operators of marine structures have to ensure that structural integrity is maintained at a sufficient level during in-service life or in the case of the structure life prolongation. This can be achieved by Inspection, Maintenance and Repair plans (IMR), as rational aid-tools for decisional purposes. Such plans are complex and can be expensive. This leads to their global optimization, particularly regarding inspections. In this context, original results on inspections data in IMR plans are presented. The approach is based on decision and detection theories and include both the probability of false alarm and the probability of detection. It is shown how to introduce these probabilities in a decision scheme. The effect of false alarms and miss detections on the global cost of inspection planning is underlined through a basic example.

SUMMARYAn eXtended Stochastic Finite Element Method has been recently proposed for the numerical solution of partial dierential equations dened on random domains. This method is based on a mariage between the eXtended Finite Element Method and spectral stochastic methods. In this paper, we propose an extension of this method for the numerical simulation of random multi-phased materials. The random geometry of material interfaces is described implicitly by using random level-set functions. A xed deterministic nite element mesh, which is not conforming the random interfaces, is then introduced in order to approximate the geometry and the solution. Classical spectral stochastic nite element approximation spaces are not able to capture the irregularities of the solution eld with respect to spatial and stochastic variables, which leads to a deterioration of the accuracy and convergence properties of the approximate solution. In order to recover optimal convergence properties of the approximation, we propose an extension of the partition of unity method to the spectral stochastic framework. This technique allows the enrichment of approximation spaces with suitable functions based on an a priori knowledge of the irregularities in the solution. Numerical examples illustrate the eciency of the proposed method and demonstrate the relevance of the enrichment procedure.