Dippach-Gare bypass

For many years now, the Route des Trois Cantons - the main thoroughfare for the municipality to the west of the capital - has been saturated. More than 8,000 vehicles pass through every day, slowed down by the PN5 level crossing, which was closed for up to 40 minutes an hour.

The new bypass provides a direct link between the municipalities of Reckange-sur-Mess and Bettange-sur-Mess, offering an alternative to the Route des Trois Cantons, which runs through the conurbation, and eliminated its level crossing for greater safety.

With a length of 2.2 km, the route includes two lanes of traffic and two junctions at each end to ensure that traffic flows smoothly. It comprises a number of structures and facilities:

• a 125 m-long cut-and-cover tunnel, with two 50 m-long access hoppers, which runs under the roundabout towards Bettange-sur-Mess ;
• an 85 m mixed metal and concrete footbridge for soft mobility, 85 m long and 3 m wide ;
• a reinforced concrete overpass 15 m long and 5 m wide;
• cycle paths;
• a farm track;
• hydraulic structures such as canals and a retention basin;
• a crossroads;
• noise protection measures such as noise barriers.

For the earth works our teams have opted for a different methodology and have used the top-down construction technique. The area was initially  stabilized by installing 400 piles with a diameter of 90 cm, on top of which a cover slab was placed. 

Our teams dug eight meters below the structure to pour its 70 cm thick foundation slab and walls, which required the removal of 20,000 m3 of material.

A curved trajectory

This underpinning work was one of the biggest challenges of this project. Added to this was the fact that the trench was curved. A rail-mounted formwork carriage was installed to concrete the walls to their full height in 10-meter sections in order to follow the curve of the structure.

The environment also plays an important role in this new route. In order to protect the local fauna, our teams have installed protective netting and will build in crossings under the road to allow frogs, in particular, to cross in complete safety.

The Moulterbach stream will also be restored and enhanced, with a new bed meandering peacefully along the new road.

In keeping with the environmental approach, 85,000 m³ of material from the earthworks were processed on site and reused for the pavement boxes.

Optimized water management

A retention basin with a capacity of 370 m² has been constructed to collect runoff from the road. A control system regulates flow rates to ensure the safety of the construction site and the environment. Excess water is then redirected to the stream, ensuring responsible and sustainable water management.

The project is part of a strong environmental initiative. The Moulterbach stream has been renaturalized and collects water from the fields.