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Santos J.P.,National Laboratory for Civil Engineering | Cremona C.,Bouygues Travaux Publics | Orcesi A.D.,University Paris Est Creteil | Silveira P.,National Laboratory for Civil Engineering
Journal of Structural Engineering (United States) | Year: 2017

Structural health monitoring (SHM) relies on data acquired from sensorial systems installed on site, and is nowadays being used more often not only for asset management, but also in critical structures when there is the need to detect damage in an early stage, before it impairs structural performance and safety. Early detection of damage in critical structures relies on the acquisition of continuous streams of information and on reliable techniques capable of analyzing it in real time, without generating false alerts. In this context, the combination of data fusion strategies, capable of converting large amounts of data into small pieces of information, with pattern recognition algorithms, which are able to analyze this information in real time, is addressed in the present paper with the objective of developing an original strategy capable of (1) removing the effects of regular actions imposed to structures without the need to measure them and of (2) compressing entire SHM data sets of arbitrary dimensions into a sensitive single-valued damage index. These capabilities are achieved by combining principal component analysis, the broke-stick rule, clustering methods, symbolic data objects, and symbolic distances. The proposed strategy was tested and validated with a numerical model of a cable-stayed bridge, using experimental data as input. From this analysis it was observed that, under the noise levels measured on site, the proposed strategy is able to automatically detect damage as small as 1% of stiffness reduction in a single stay cable. This sensitivity evidenced by the proposed strategy can be considered particularly high because it was obtained from a small amount of inexpensive sensors with a static character and because it was associated with a false detection incidence of only 0.1%. © 2016 American Society of Civil Engineers.


Cremona C.,Bouygues Travaux Publics | Cremona C.,Technical Center for Bridge Engineering | Poulin B.,West Territorial Direction
Structure and Infrastructure Engineering | Year: 2016

In recent years, the condition of deficient bridges has reached such a level that the volume of required repair actions becomes significant for many countries. As budgets for maintenance, repair and rehabilitation are always limited and demands are constantly increasing, to find an optimal balance between cost and safety is today a new trend in bridge maintenance. Optimising bridge maintenance and management is a strong expectation for owners and stakeholders facing ageing bridge stocks and increasing aggressive traffic. In this context, the assessment of the structural performance may be necessary for various reasons thorough its lifetime. In France, there are no standards or regulations for structural assessment of existing structures. The studies on a new Eurocode standard for the ‘Evaluation and rehabilitation of existing structures’ are just starting and it will be published in several years. For this reason, the French Ministry of Transport has decided to develop recommendations for the assessment of the structural performance of existing bridges. In a first part, the paper summarises today’s practice in France, but it also details the ongoing calibration process for setting appropriate partial factors for existing bridges. Implementation is given as example for the assessment of reinforced concrete slabs. © 2016 Informa UK Limited, trading as Taylor & Francis Group


Rubrecht S.,Bouygues Travaux Publics | Padois V.,University Pierre and Marie Curie | Bidaud P.,University Pierre and Marie Curie | De Broissia M.,Bouygues Travaux Publics | Da Silva Simoes M.,CEA Fontenay-aux-roses
Autonomous Robots | Year: 2012

In this paper we propose a methodology to ensure safe behaviors of multibody robots in reactive control frameworks. The permanent satisfaction of constraints being insufficient to ensure safety, this approach focuses on the constraints expression: the compatibility between these constraints is studied, and safe alternatives are ensured when compatibility cannot be established. Case studies involving obstacles, joint position, velocity and acceleration limits illustrates the approach. A particular method is developed to take full advantage of a smooth state of the art avoidance techniques (Faverjon and Tournassoud in Proceedings of the 1987 IEEE international conference on robotics and automation, pp. 1152-1159, 1987) while maintaining safety. Experiments involving a 6-DOF manipulator operating in a cluttered environment illustrate the reliability of the approach and validate the expected performances. © 2011 Springer-Verlag.


Thiercault J.,BOUYGUES Travaux Publics | Egels C.,BOUYGUES Travaux Publics
IGT International Liquefied Natural Gas Conference Proceedings | Year: 2013

Over the last couple of years the LNG industry has shown a continuous trend for: - Being more cost effective - Improving land area utilization - Being able to provide larger and larger tanks to accommodate the progressive increase in the gross capacity of ocean going methane carriers - Reducing construction schedules - Reducing carbon footprint. The aim and purpose of the proposed paper is to compare the different technologies of above ground storage tanks with regards to: - Safety and integrity of the tank (including seismic event) - Construction cost and schedule - Carbon footprint. Note: This comparison will reflect latest development in storage tank technologies. Special attention will be paid to the comparison of carbon footprints from a life cycle perspective, knowing that it appears that membrane tanks provide a significant reduction compared with conventional self standing technologies.


Cremona C.,Bouygues Travaux Publics | Calado L.,University of Lisbon | Orcesi A.D.,University Paris Est Creteil
Structural Control and Health Monitoring | Year: 2016

Structural health monitoring (SHM) strategies should ideally consist of continuous on-line damage detection processes, which do not need to rely on the comparison of newly acquired data with baseline references, previously defined assuming that structural systems are undamaged and unchanged during a given period of time. The present paper addresses the topic of SHM and describes an original strategy for detecting damage in an early stage without relying on the definition of data references. This strategy resorts to the combination of two statistical learning methods. Neural networks were used to estimate the structural response, and clustering methods were adopted for automatically classifying the neural networks' estimation errors. To ensure an on-line continuous process, these methods were sequentially applied in a moving windows process. The proposed original strategy was tested and validated on numerical and experimental data obtained from a cable-stayed bridge. It proved highly robust to false detections and sensitive to early damage by detecting small stiffness reductions in single stay cables as well as the detachment of neoprene pads in anchoring devices, resorting only to a small amount of inexpensive sensors. © 2015 John Wiley & Sons, Ltd.


Chamberlin Y.,Bouygues Travaux Publics | Combe B.,Bouygues Travaux Publics
Underground - The Way to the Future: Proceedings of the World Tunnel Congress, WTC 2013 | Year: 2013

The second tunnel of the Toulon highway crossing is a 1.8km bored tunnel having a 120m2 excavation section. The Employer - DREAL - awarded the contract to a Joint Venture (JV) led by Bouygues Travaux Publics, and the Project was realized between 2007 and 2011. This is the last major tunnel using conventional means performed in France since many years. In order to master variable and complex geotechnical conditions under a sensitive and dense urban environment, the designers defined a heavy ground support system with very dense excavation face bolting, umbrella arch, arch ribs, and shotcrete for the full length of the tunnel. To install this heavy support system, the JV decided to use a suspended platform equipped with boomers, a drilling rig, and an arch rib erector arm. The main advantage is having less equipment moving on the floor, making the work not only safer for workers but also more efficient. Suspending "logistics equipment" from a tunnel vault several meters behind the excavation face is not unusual in tunnelling work, but except in mining it is much rarer for civil engineering equipment directly involved in the excavation cycle, and this was the first French experience with this type of equipment. This paper focuses on the project conditions, the development of the solution, including the problems that arose and how they were dealt with, and the limits of the approach and possible improvement for future projects. © 2013 Taylor & Francis Group.


Combe B.,Bouygues Travaux Publics | Moulin P.,Bouygues Travaux Publics
Proceedings - Rapid Excavation and Tunneling Conference | Year: 2013

Mobydic is the unique disc cutter monitoring system running on pressurized TBM allowing optimizing the excavation process with controlling TBM cutting parameters. It is based on wireless instrumentation embedded in the cutting tools which transmit data, on real time basis, to the TBM supervision system. Data measured are forces, rotation speed and temperature of disk cutter. It helps for • cutter disk wear monitoring making then the maintenance prevision more reliable, • identifying the presence of obstruction like piles in urbanized areas or boulders allowing then either to adapt the TBM excavation speed or to organize an intervention in the excavation chamber for removing the obstacle, • being informed on the excavations face geotechnical conditions especially useful when mixed ground is encountered by computing real average density and allowing a better control of excavated volume. Mobydic has been developed since few years by the R&D department of Bouygues Travaux Publics, has been tested first on open mode TBM in France (A41 Highway) and Hong Kong (CLP), and later on a pressurized face EPB TBM (Gautrain) in South Africa. Then, a slurry mixed shield TBM equipped with Mobydic has been used for the excavation of the WIL703 Project in Hong Kong under pressure higher than 3.5bars. Parts of the results from this last utilization are shared in this article. Mobydic become an essential system for tunneling in hazardous geological conditions and also for tunnels built under high water pressure conditions.


Saillio M.,University Paris Est Creteil | Baroghel-Bouny V.,University Paris Est Creteil | Barberon F.,Bouygues Travaux Publics
Construction and Building Materials | Year: 2014

Carbonation and chloride ingress are the main causes of reinforced concrete structures degradation. Usually, these two phenomena are studied individually. Here, chloride ingress has been investigated on sound and carbonated cementitious materials (cement pastes and concrete). The supplementary cementitious materials (SCM) are fly ash, slag and métakaolin. The materials were carbonated by exposure to accelerated conditions (1.5% CO 2 and 65% RH) in laboratory. Chloride binding isotherms of sound and carbonated samples were assessed by the equilibrium method (exposure to various alkaline NaCl solutions). The microstructure was characterized not only by usual techniques such as XRD and TGA-DTA, but also by 29Si and 27Al NMR spectroscopy. The results show that carbonated samples bind less chlorides than sound ones. The use of a combination of various techniques of microstructural characterization reduces the number of the possible explanations of these findings. In carbonated materials, both the quantity of Friedel's salts and of chlorides bound by C-S-H decrease. The first decrease can be explained by a lack of portlandite and modification of aluminate phases equilibrium. The second decrease seems to be due to a modification of the C-S-H (change of surface charge) during the carbonation process. Moreover, differences according to the nature and the amount of supplementary cementitious materials (SCM) were observed. © 2014 Elsevier Ltd. All rights reserved.


Patent
Bouygues Travaux Publics | Date: 2014-11-04

The invention relates to a cutter holder (1) for a tunnel boring machine, comprising:


News Article | October 10, 2016
Site: www.rechargenews.com

The 2MW floater, currently being built with contractor Bouygues Travaux Publics at its Saint-Nazaire facility, is slated for installation next year in the Atlantic Ocean off Le Croisic, The FloatGen unit, a square, open-centred design measuring 36 metres x 36 metres x 10.8 metres and with a draft of eight metres, will be the world's first all-concrete model, engineered with an eye on mass production for future wind farms, as well as cutting the cost associated with manufacturing in steel. "The V80 wind turbine has effectively been delivered at Saint-Nazaire," Ideol chief executive Paul de la Guérivière tells Recharge. "The floating foundation construction is progressing well and, according to our initial planning, the wind turbine will be erected onto the floater in spring 2017." The flagship unit, which was originally to have flown a 2MW Gamesa machine, will be towed out and moored in around 35 metres of water at SEM-REV, the Ecole Centrale de Nantes' grid-connected ocean-energy demonstration site, 19km off the coast of Brittany. FloatGen, co-financed by the European Commission's 7th Framework Programme for Research and Technological Innovation, will be the second outing on a floating unit for the V80-2.0 design, which was also flown by the recently decommissioned WindFloat 1 (WF1) demonstrator off Portugal. Prototype floating wind turbines are installed off Norway, Portugal and Japan, with arrays moving ahead in these regions, and  France has announced two of the five winning consoritia in its pilot tender, seen as having the potential to spark a floating offshore build-out of up to 6GW by 2025. Last June, the Scottish government released a far-reaching study on floating wind power that points to its fast-approaching commercialisation. Produced by government-industry body the UK Carbon Trust, the report found that floating wind concepts have the potential to cut generated levelised cost of energy (LCoE) to below £100 ($144) per MWh in utility-scale deployments, with Hywind calculated to be on track to reach an LCoE of £85-£95/MWh. MAKE Consulting estimates that 3.4GW of floating wind power will be switched on by 2030, led by Japan and France.

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