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The project 

The A41 North motorway (approximately 20 km) links the existing A40 and A41 South motorways, and offers a fast, safe route to Geneva and Annecy.

This mountainous section of toll road includes:

  • An interchange between the A40 and A41 motorways, a partial interchange and a pair of rest stops
  • A fork with the A410 motorway, with two partial interchanges and a 29-lane toll station
  • A 3 km dual-tube tunnel
  • 4 viaducts (212-360 m), 1 cut and cover section (290 m) and anchored retaining walls with reinforced soil (20 m maximum height)
  • A winter service point

The project required 4.6 million m3 of excavation (including the removal of 0.7 million m3 by tunneling and 1.3 million by explosives) and 1.7 million m3 of backfill, while generating 1.6 million m3 of debris.

Challenges

Project owner
ADELAC

Period
2006 – 2008

Assignment
Integrated project management

Key figures
20 km 2×2 lane motorway link in a mountainous area

The Assignment

The consortium in charge of designing and building the A41 North motorway selected i-LAC (75% setec and 25% construction companies) to coordinate the entire project, including engineering, design and works supervision.

In addition, setec handled all the design work for the project (except the civil engineering for the Mont Sion Tunnel, buildings and awnings):

  • Preliminary design for the motorway and main road, and documents for regional authorities
  • Road sanitation
  • Landscaping and architectural planning
  • Hydraulic design
  • Geotechnical study
  • Environmental studies
  • Interchange design study
  • Toll station design study
  • Viaducts, cut and cover section, structure (la Ravoire) and retaining walls: preliminary and detailed design
  • Regulatory documents
  • Documents for the consultation process
  • Other project documents
  • Design verification