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The Project 

Context
The RN87 bypass south of Grenoble is part of a wider urban development project in the Grenoble area. The cover is part of efforts to boost transportation links between the city center and towns to the south. In particular, the cover must facilitate links between Grenoble and Echirolles, while freeing up construction land around the bypass.

Project
The area under study stretched from avenue Victor Hugo to avenue des FTPF. The study involved checking the feasibility of creating a cover, using three development scenarios and taking into account the constraints related to:

  • The environment (geology, risk of soil liquefaction during earthquakes, air quality, noise, etc.)
  • Technical aspects (converting the RN87 into a 2×3 lane system, the presence of numerous sensitive networks, tunnel safety, gauges, etc.)
  • Construction (maintaining operations on the 2×2 lane bypass and the Sillon Alpin railway)

Challenges

Project owner
GAM (Grenoble-Alpes Métropôle)

Period
2012

Key figures
RN87 cover: 18,000 m²
Cover for the Sillon Alpin railway: 4,500 m²
Reinforced concrete dual portico with an opening 14.65-20,80 m wide

Challenge
Invent technical solutions and methods for scheduling and implementation while maintaining road traffic (at the time, saturated with 90,000-110,000 vehicles daily) on 2×2 lanes throughout the construction work.

The Assignment

GAM selected setec als to conduct technical feasibility studies for the partial covering of the RN87 and the Sillon Alpin railway as part of a wider urban redevelopment project.