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 is closed for up to 40 minutes an hour.

The new bypass will provide 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 eliminating its level crossing for greater safety.

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

• a 125 m-long cut-and-cover tunnel, with two 50 m-long access hoppers, which will run under the roundabout towards Bettange-sur-Mess ;
• an 85 m mixed metal and concrete footbridge for soft mobility;
• 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.

This is why our teams have opted for a different methodology and will be using the top-down construction technique. The area will first be stabilised with 400 90 cm diameter piles, on which a covering slab will be placed. 

Our teams will then come and dig eight metres below the structure to pour its 70 cm invert and its walls, representing 20,000 m³ of material to be evacuated.

A curved trajectory

This underpinning work is one of the greatest challenges of this project. Added to this is the fact that the trajectory of the trench is curved. A formwork carriage will be used to pour concrete over the entire height of the walls, in 10 m increments, to ensure that the curvature of the structure is respected.

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 will be processed on site and reused for the pavement boxes.