Demathieu Bard delivers the Pôle d'Echanges Multimodal de Nantes

The inauguration of this new structure concludes three years of work carried out by DEMATHIEU BARD CONSTRUCTION and gives a new dynamism to regional mobility.

The birth of a regional Multimodal Exchange Hub

A modernized station for more services

Under the contracting authority of SNCF Mobilités - Gares & Connexions, the project included the construction of a 160-meter-long mezzanine footbridge culminating at 18 meters in height to connect the North station with the South station. It also included the renovation of part of the North and South passenger buildings of the station as well as spaces dedicated to the public in order to increase user comfort. This project is central to the development of the metropolis and the region.

Nantes station is the leading regional station in terms of attendance and traffic. It is also the gateway which provides service to the entire region and is the sixth station in France. In 2009, it welcomed 11 million travelers per year: by 2030, it should accommodate 25 million.

Mobility is at the heart of the challenges of the Pays de la Loire territory: seeking a balance between urban and rural areas, connections to territorial dynamics, improving accessibility, and daily travel for its inhabitants.

The new Pôle d'Echanges Multimodal (PEM) provides the Metropolis with a modern rail transport infrastructure capable of meeting all its future challenges and thus instilling a new territorial dynamic.

Before works

A North station dating from 1967 and a South station from 1989
Connected by two underground passages with access to the platforms

After works

A unique and modern station with a mezzanine overlooking the tracks and providing access to the platforms
Increased reception volume
Adding businesses

An architectural project with an international signature

The mezzanine footbridge, an emblematic piece of the new station, was designed by Rudy Ricciotti, a world-renowned architect (MuCEM in Marseille, Passerelle pour la Paix in Seoul, Department of Islamic Arts at the Louvre Museum, etc.) .

The architectural project is based on a massive use of concrete, the signature material of Rudy Ricciotti's achievements. The footbridge is in the form of a concrete parallelepiped placed on huge organic piles of varying shapes that act as trees that support the structure. In the extension of the frame, on the outside, are horizontal shades made of Ultra-High Performance Fiber Concrete (UHPC), works of Méditerranée Préfabrication, which regularly collaborates with Rudy Ricciotti. These fine lace tongues refer to the allegory of branching and make one think of those of the MuCEM in Marseille.

The architectural project was carried out in collaboration with an associate architect, the Nantes agency Forma6.

DEMATHIEU BARD synergies at the service of a high-tech project

The Nantes station project is a multi-business operation which combined
all of DEMATHIEU BARD CONSTRUCTION's expertise and know-how in the field of Civil Engineering and building. Indeed, the site was a real technical challenge by its design, a covered civil engineering structure built on existing buildings.

It was supervised by the Infrastructures - Civil Engineering and West Building DEMATHIEU BARD teams, as well as by a Group subsidiary, André BTP. From the design phase, the teams combined their expertise in engineering and internal work to meet the multiple challenges of the project. The design work was carried out in collaboration with the Technical Design Offices, bringing together all the skills in building and engineering structures: Lamoureux & Ricciotti Ingénierie (structure), BERIM (TCE) and AGID2D (HQE).

For the outsourcing missions, the DEMATHIEU BARD teams have relied on the expertise and know-how of companies mainly from the local fabric.

A major project, the construction of the new Nantes station has contributed to the economic dynamism of the Nantes metropolis and the job market. 11.000 hours of professional integration were carried out on this project.

They have enabled people removed from employment to be trained in civil engineering and building trades.

A constrained environment for a multi-business operation

The worksite environment was one of the main challenges for the DEMATHIEU BARD CONSTRUCTION teams. Located in the heart of town, the station welcomes 40 travelers every day. During the works, the station was kept in full operation. This concerned both rail traffic and ancillary services (shops, services, etc.). To carry out specific work phases, such as laying the beams for the deck of the future mezzanine, the teams intervened at night with a short-term (000 hours) rail lockout.

The main challenges of the site:

Work carried out on an occupied site: use of equipment limiting congestion
Asbestos removal, lead management and soil remediation
Partial demolition and restructuring of the Passenger Buildings
Respect for architecture: choice of clear concrete or white concrete with high demands on the elevations
Extraordinary dimensions of the metal frame and curtain walls of the mezzanine
Displacement games on white concrete tree stacks
Seismic design of a building designed as a bridge
500 nights of work necessary during the 3 years of construction