The A41 North motorway (approximately 20 km), connects the existing A40 to the A41 South in order to provide a fast and safe road link between the cities of Geneva and Annecy in the Alps region.

This mountain section of toll motorway includes the following :
•a four-way interchange between the A40 and the A41, 1 one-side slip road and a pair of rest areas,
•a three-way interchange between the A41 and the A410 connected to 2 one-side slip roads, with a 29-lanes cross-lane toll barrier,
•a 3-km, double-tube tunnel,
•4 viaducts (212 m to 360 m long),1 cut-and-cover tunnel (290m) and retaining walls anchored in a reinforced floor (maximum height of 20m),
•1 winter maintenance area.

The construction required 4.6 million m³ of excavated soil (with 0.7M m³ of tunnel spoil and 1.3 million m³ excavated using explosives), and 1.7Mm³ of fill ; it generates 1.6 million m³ of excess materials.

Duration of design + works : 9 + 29 = 38 months


SETEC was commissioned by i-LAC to carry out all the studies for the operation (excluding the civil engineering for Mont-Sion tunnel, buildings and canopies):

•Preliminary motorway design, trunk road restoration design, right of evocation application
•Preliminary studies and preliminary design for the civil engineering structures (viaducts, cut-and-cover, La Ravoire civil engineering structure, retaining walls),
•Administrative paperwork regarding: Law on Water, Heritage Sites, historical monuments, disposal areas use permission, revision of urban planning documents, construction site noises, communications re-establishment agreement,
•Documents for public consultation,
•Detailed design,
•Review and approval of shopdrawings.