demolition of the A7 motorway bridge in Bourg-lès-Valence

Since the summer of 2021, Vinci has been carrying out work to replace the A7 motorway bridge which spans the Nationale 7 at Bourg-lès-Valence. The demolition work began this Friday, June 10 in the evening and should end on Monday, June 13 in the early morning. Throughout this period, the National 7 is cut off to traffic at this level.

Demolish a bridge without cutting the highway

The operation is exceptional. As of February 2022, a replacement bridge had been built to divert traffic from the freeway. It was put into service on May 17. The motorists realized almost nothing since that traffic has never been completely cut off.

For a few hours, the bridge which accommodated up to 75,000 vehicles per day, is being demolished. No question of dynamiting it! Too risky: the bridge is located above National 7, stuck next to the SNCF tracks, not far from a gas station. The bridge will therefore be nibbled at to dismantle it little by little throughout the weekend. “It’s a one-shot operation“explains Nelly Destève, communication manager at Vinci.

Almost 3000 cubic meters of demolition materials

Large resources are used: 20 large machines (hydraulic shears, a bulldozer in particular). A crane makes it possible to hoist a kind of screen to prevent potential projections from arriving on the A7. The National 7 is also protected by a carpet to cushion the fall of large elements that come off the bridge. The rubble is going to be”derailed then crushed on site“adds Nelly Destève. They will be reused as backfill.

The operation this weekend mobilizes between 70 and 90 people. From Monday, the new phase of work will begin: the reconstruction of a new bridge. The end of this work is estimated in the spring of 2024.