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Ait-Mokhtar A.,University of La Rochelle | Belarbi R.,University of La Rochelle | Benboudjema F.,Ecole Normale Superieure de Cachan | Burlion N.,Lille Laboratory of Mechanics | And 19 more authors.
Cement and Concrete Research | Year: 2013

One of the main objectives of the APPLET project was to quantify the variability of concrete properties to allow for a probabilistic performance-based approach regarding the service lifetime prediction of concrete structures. The characterization of concrete variability was the subject of an experimental program which included a significant number of tests allowing the characterization of durability indicators or performance tests. Two construction sites were selected from which concrete specimens were periodically taken and tested by the different project partners. The obtained results (mechanical behavior, chloride migration, accelerated carbonation, gas permeability, desorption isotherms, porosity) are discussed and a statistical analysis was performed to characterize these results through appropriate probability density functions. © 2012 Elsevier Ltd.

Desceliers C.,University Paris Est Creteil | Soize C.,University Paris Est Creteil | Yanez-Godoy H.,OXAND Inc | Houdu E.,OXAND Inc | Poupard O.,OXAND Inc
Computational Geosciences | Year: 2013

Geologic storage of CO2 must respond to demonstrations of safety, control, and acceptability with authorities and public. The wells are essential elements of the storage system and constitute the only man-made intrusive element in the geologic systems. The role of containment of components of wells must then be ensured for hundreds of years, despite degradation mechanisms that affect their properties. Probabilistic approaches are used to take into account the uncertainties on the quantities of CO2 which migrate from the reservoir of CO2 towards the surface and towards the aquifer. Uncertainties are taken into account by using the generalized probabilistic approach which allows both the system-parameter uncertainties and the model uncertainties induced by modeling errors to be performed in the stochastic computational model. These probabilistic tools, applied to industrial projects, allow owners and operators to set up decisions and provide a strong support to long-term safety demonstration with a high level of confidence, even in presence of uncertainties in the computational models. © 2013 Springer Science+Business Media Dordrecht.

Godoy R.,Statoil | Fontan M.,OXAND Inc | Capra B.,OXAND Inc | Kvalsund R.,Statoil | Poupard O.,OXAND Inc
Society of Petroleum Engineers - Abu Dhabi International Petroleum Exhibition and Conference, ADIPEC 2015 | Year: 2015

The cement height requirements for primary cement jobs, or annulus cement, are stated as absolute values in some parts of the world. For example the Norsok Standard, D-010, "Well integrity in drilling and well operations" states that one cement barrier is either 50 meters when verified by displacement calculations, or 30 meters when verified by bonding logs. The requirements do not distinguish between reservoirs with high pressure/temperature- and reservoirs with typical low pressure/termperature conditions. A numerical method has been developed which considers the current or future well conditions as part of the cement evaluation process. This numerical approach is an additional tool in the decision making process and does not replace existing verification practices. The time to run the analysis has also been an issue to address, since existing tools in the industry (FEM-analysis etc.) can be quite time consuming to run. Additionaly it is also possible to perform analysis up-front the operations and various pre-defined cement length intervals can be compared to the requirements or other upper acceptable cases. Offshore well cases from the Norwegian Continental Shelf have been used as basis in the development and demonstration of the method. The numerical model is based on monophase or multiphase Darcy flow calculations through the cement sheath involving uncertainties like cement permeability, reservoir pressure in the eternal perspective etc. The model allows a parametric analysis in a reasonable computation time and building of a well case library making the process efficient in an industrial comparison perspective. The method is an 'engineering approach' taking place in the decision making process of well integrity. Copyright 2015, Society of Petroleum Engineers.

Frenette R.,Oxand Canada Inc. | Bernard O.,OXAND Suisse | Putallaz Y.,OXAND Suisse | Gerard B.,OXAND Inc
Canadian Journal of Civil Engineering | Year: 2010

Characterizing the relevance, the level and the type of uncertainty can help a manager find the best ways to manage the potential consequences of aging on an infrastructure service level. In the presence of high uncertainty, the manager must have a formalized decision-making process to protect its global resources. The cost of the treatment and the potential consequences of risk associated with these resources constitute a "risk provision" liability. In order to communicate with financing agencies, this provision can be combined with the system's residual value to obtain a "heritage index". Finally, in order to follow the evolution of an infrastructure system, the manager can use the notion of turbulence that arises from combining the heritage index and the net present value of the maintenance plans. This turbulence index monitors the equilibrium between the economical efficiency of the action plans and the heritage sustainability. The control of this equilibrium and its uncertainty are two key elements for the sustainable development of our infrastructures.

Asali M.,OXAND Inc | Asali M.,Lille Laboratory of Mechanics | Capra B.,OXAND Inc | Mazars J.,Grenoble Institute of Technology | Colliat J.-B.,Lille Laboratory of Mechanics
Journal of Advanced Concrete Technology | Year: 2016

In the context of life extension of nuclear reactor buildings while ensuring safety and regulatory requirements, a numerical strategy is proposed to compute and forecast the air leakage rate evolution of inner containments in double-wall reactor buildings under standard long-term operation. In order to reduce the numerical cost of such complex computations, the proposed strategy is based on a coarse but adapted mesh together with a chained weakly-coupled thermohydro-mechanical modeling. The total leakage rate is then computed with a specially-designed tridimensional finite element based on a non-linear thermal analogy. This methodology is used to model the behavior of the VeRCoRs mock-up, a simplified nuclear reactor building at scale 1:3, built and monitored by EDF. Results obtained until the first pre-operational pressurization test have been discussed in a dedicated benchmark organized by EDF. The proposed methodology provides delayed strains and leakage results in good agreement with available experimental data. A blind prolongation until the first decennial test of the mock-up is presented and analyzed. Copyright © 2016 Japan Concrete Institute.

Thillard G.,OXAND Inc | Baillis C.,Ec2 Ms | Filippi R.,Ec2 Ms | Auge L.,OXAND Inc
Proceedings of the 13th International Conference on Civil, Structural and Environmental Engineering Computing | Year: 2011

This paper presents an example of application of a process, based on a quality assurance methodology, defined and used in the context of a risk analysis conducted for the possible extension of operation lifetime of industrial facilities. First, this process helps to assess the consequences of an aircraft crash on the mechanical behaviour and the confinement capacity of a cylindrical prestressed and reinforced concrete structure using numerical simulations. Then, this process also takes into account the various constraints related to the considered industrial project (authorities requirements, costs, deadlines, etc.). © Civil-Comp Press, 2011.

Fontan M.,OXAND Inc | Breysse D.,University of Bordeaux 1 | Bos F.,University of Bordeaux 1
Computers and Structures | Year: 2014

The aim of structural monitoring is to get mechanical and valuable information concerning structural parameters. A generic frame was developed in order to identify unknown parameters thanks to an iterative process using a meta-heuristic algorithm. It combines data obtained through structural monitoring, a mechanical model and an optimization algorithm. The quality of identification depends on the quality of the data set, on that of the mechanical model and on the algorithm efficiency. It is shown through several tests on two case studies how uncertainty or errors arising from various sources can impact the accuracy of predicted values.© 2014 Elsevier Ltd. All rights reserved.

Oxand will actively participate to the second edition of WNE (World Nuclear Exhibition) which will take place in Paris Le Bourget on June 28, 29 and 30. This event will bring together the international community of civil nuclear power ...

OXAND Inc | Entity website

Wie zijn we Oxand in Nederland is ontstaan in 2008 en was tot 1 januari 2015 bekend onder de naam Iter Fidelis. Oxand biedt totaaloplossingen in Asset Management, Ageing & Risico Management en heeft met 9 vestigingen in Europa en Noord-Amerika aan meer dan 1 ...

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