A7 Bourg-Lés-Valence – France

Project Overview

The A7 motorway in Valence carries an average of 75,000 vehicles per day and up to 180,000 during holiday periods, while the National Road carries 16,000 vehicles per day. Keeping these roads open during works to replace the motorway bridge over the National Road was vital, utilising a temporary bridge to divert traffic, allowing demolition of the old bridge and construction of the replacement new bridge. During works soil movement occurred between the timber solders and steel mesh forming the facing material. To avoid further movement the decision was taken to reinforce the facing material using earth anchors with a threaded bar solution.

Solution

In six days 300 Platipus Stealth Anchors were manufactured, transported, and installed, allowing the motorway to reopen on the following Monday as planned, during which further anchors were installed. A total of 400 Percussion Driven Earth Anchors (PDEA^®) were driven 3m through the facing material between layers of engineered soil, before being loadlocked at a verifiable working load of 11kN. The threaded bar anchoring solution allowed engineers to adjust the load applied to the facing material should it be necessary. Following the completion and diversion of traffic to the new bridge, construction plans called for the temporary bridge to be dismantled, and the surrounding land returned to its original state.