Viaduc du Charmaix

About

The viaduct du Charmaix is a motorway bridge located in France on the commune of Fourneaux in the department of Savoie in the Auvergne-Rhône-Alpes region. With a length of 346 meters, it crossed the Charmaix torrent, nestled at the bottom of a valley, and allowed the A43 motorway to reach the Fréjus road tunnel. Opened in 1978, it is the victim of a design error discovered two years after its opening in 1980: the stability of the soil was overestimated, which means that the foundations of the batteries are not deep enough and thus move with the ground.

An unprecedented viaduct reclamation technique was developed and applied three times in 1990, 1997 and 2003, but the estimated life of the structure is only 40 years. Thus, the construction of a new structure was started in 2016, for commissioning in 2023.