Construction of a wildlife crossing over the A3 motorway

2022 - 2023


PublicCivil Engineering

Construction of a wildlife crossing over the A3 motorway

Construction of a game crossing to allow safe movement of wildlife.

As part of the project to widen the A3 motorway to 2x3 lanes, the Ponts et Chaussées have entrusted us with the construction of a new ecoduct that will allow wildlife to travel in complete safety.

Located on the Franco-Luxembourg border, the structure not only has impressive dimensions, but also an original geometry. The ecoduct will be shaped like an arch, tapering at its highest point. It will be made up of two very wide piers on either side of the roadway. These parameters make its construction all the more complex, especially as the work will be carried out close to the motorway, where traffic is heavy.

67 x 40 x 8,6 m

Dimensions of the structure

480 m3

Concrete in the arch

120 t

Steel in the arch

Highly technical

Impressive dimensions for the ecoduct

With a length of 67 m, the ecoduct will span the tracks over a width of 40 m and reach a height of 8.60 m.

The structure is made up of a dense metal and concrete structure, the vaulted piers of which have been produced using a curved concreting carriage that allows the walls to be 12.5 m long.

Once the base of the vaults was complete, formwork tables were installed above the road to proceed with the reinforcement and concreting of the vault. An operation to be carried out in September 2023 that began in the early hours of the morning

The structure began to emerge from the ground a few weeks ago. The thousands of motorists who cross the border every day can see our partner Ferrac's ironworkers gradually weaving its skeleton using an iron carriage placed on rails. 

A tight schedule

Deadlines are also a challenge.

Another challenge is the timeframe for completion. Begun in May 2022 with a major preparatory phase (including clearing and earthworks), the work should be completed in just a few months, by the end of this year. Thanks to the good mobilisation, organisation and anticipation of our teams, the schedule will be kept