La Défense and the Neuilly Tunnel

Modernisation of the underground A14xA86 Complex at La Défense and the Neuilly Tunnel


MEEDDAT / DIR Ile de France


2008 - 2013


Docalogic (groupe BG) / Algoé

Total costs

> 100 mio EUR

Project description

The below-ground A14xA86 complex is a structure with unusual technical characteristics: the A14 main road crosses the linked structures; the complex has seven levels; it is below the forecourt of La Defense; and it is connected to the metro, the RER, car parks and commercial premises. Supporting a flow of over 140'000 vehicles per day, it includes:

  • 15 km of underground tunnels
  • 2 main roads with 14 slip roads or access/egress locations, completely in a covered structure
  • 26 ventilation plantrooms
  • 67 emergency exits
  • 2 underground routes with 3 and 4 lanes of traffic
  • Fire safety engineering of structures (300'000m2)
  • The creation of new exits
  • The renovation of the ventilation system and the electrical installations

The works were largely undertaken overnight.

Services provided

Technical, administrative and financial assistant (AMO) to the client for the project to bring the tunnel and the A14xA86 complex up to date in terms of safety and security, the latter being carried out as part of a design and construction contract. The scope included the drafting of the tender documentation, the analysis of the applications and offers, and then the monitoring of contracts.

  • Project manager and construction manager for the Neuilly tunnel
  • The design and construction works for the A14xA86 complex (including the development of a detailed functional programme)
  • Related studies, for example geotechnics, topography, air/noise, traffic, fire and safety expertise, technical monitoring, site safety and security coordination and comms.

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