Sud Europe Atlantique high-speed rail line

The Sud Europe Atlantique high-speed rail line (LGV SEA) is the largest civil engineering project in Europe this decade and the most extensive railway infrastructure concession contract ever awarded in Europe. This 300-kilometre-plus project is designed to reduce travel time between Paris and Bordeaux by nearly an hour. VINCI Construction Grands Projets was part of the consortium in charge of designing and building this new rail line whose operation by private interests is set for a period of 50 years. This rail project required the building of more than 500 standard engineering structures along the 302-kilometre line, including 24 viaducts, 15 grade separations, and 7 cut-and-covers.

BACKGROUND

The project’s ambitious objective was to build a 302-kilometre high-speed rail line linking Tours and Bordeaux, along with 38 kilometres of connections between the new rail line and the existing conventional line. The line, which crosses fourteen Natura 2000 sites where 223 protected species have been surveyed, is considered a major development project since it is designed to contribute to development along the Atlantic seaboard. The project is designed, on the one hand, to improve connections between major cities such as Tours, Poitiers, Angoulême, and Bordeaux as well as more remote areas, and, on the other, to connect the region with European capitals. This is the largest public-private partnership project ever undertaken in the railway sector in France and one of the largest infrastructure initiatives ever carried out in Europe. Following the six years required to design and build this rail line, which crosses 113 communes, six departments, and three regions, Bordeaux is a mere two-hour-and-five-minute journey from Paris.

TECHNICAL OVERVIEW

The spectacular structures erected as part of this project include the Migné-Auxances viaducts, the Folie à Poitiers low bridge (a major engineering structure featuring two decks, 940 and 918 metres in length, respectively, that spans national route RN147 and departmental route RD910) and the Couronne en Charente low bridge (720 metres long, crossing an area with geotechnical constraints in the communes of Roullet-Saint-Estèphe and La Falaise, enabling the high-speed train to cross the Falaise sector).

However, in terms of the resources used and the size of the structure, it is the Dordogne viaduct that represented the biggest challenge: at 1,319 metres, it is the longest viaduct along the rail line and rests partly on a riverbed, which made its construction even more challenging. Ten cranes and 200 people were deployed to carry out various operations, including building foundations in clay soil and raising the deck-supporting piers, each resting on eight to thirteen piles driven as deep as 41 metres into the ground. The bridge was built using successive cantilever segments. Each segment was poured in place using formwork. As much as 45,000 m2 of concrete was needed to build this huge bridge.

Construction of the high-speed rail line mobilised more than 8,500 people, including about 2,000 local workers, at peak periods in the summer of 2013.
In an effort to minimise the impact on the various natural habitats encountered along the new rail line, the construction and concession consortia implemented specific measures to preserve water during the construction and operation phases of the line.

IMPACT

The project is part of a broad regional development scheme based on decisions made by Grenelle de l’Environnement (France’s national environment round table) and will enable economic development in the southwestern regions of the country. The new Sud Europe Atlantique rail line will play a key role in reinforcing European transport connections between the Atlantic seaboard, northern and eastern Europe, southwest France, and the Iberian peninsula.
In an effort to ensure optimally effective worksite mobilisation, an employment charter was signed in July 2011 by the government, COSEA, Pôle Emploi and Conseil régional Poitou-Charentes. The charter helped create a one-stop-shop for recruitment and training in response to project and employer needs. As a result, for example, nine training platforms for earthworks and engineering structures were created in proximity to project worksites.
Given the development of local activity generated by the project, significant numbers of direct and indirect jobs were created (in hotels, restaurants, and elsewhere). In addition, we made a commitment on this project to protect the environment and biodiversity. Our environmental watchwords were “avoid, reduce and compensate.” In support of our environmental approach, concession company LISEA created two corporate foundations. The mission of “Fondation d’entreprise LISEA Biodiversité” is to provide long-term support to environmental and restoration projects to protect natural habitats along the rail line. The mission of “Fondation LISEA Carbone” is to make public buildings more energy-efficient, develop more eco-friendly transport modes, and implement energy transition in the agricultural sector.

Project participants

Client
LISEA

Project management
COSEA

Key figures

Implementation dates
June 2011 to July 2017

Engineering structures 
More than 500

Backfill materials 
38 million m³

Excavation
70 million m³

Testimonial

“This huge project, which was a true challenge in terms of organisation, production, and management, mobilised up to 8,500 people during peak periods.”

Xavier Huillard, CEO, VINCI

Find out more

www.lisea.fr

www.youtube.com / Embarquez pour le survol du chantier

Puente de Kincardine (Clackmannanshire Bridge)

Kincardine

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