This project connects the village of Brocas to a hiking trail within the Landes Forest. The 55-meter long (1.5-meter wide) steel and wood footbridge, was installed on site by a 350 ton crane.
The location is difficult to access because of a slope to one side, and the Landes Forest on the other side of the stream.
Year: July 2022
Dealer/Installer: Techno Pieux Landes
Client: Brocas Town Hall- work completed by Techno Pieux Landes in collaboration with ID Verde Messages and DL Aquitaine.
Location address: Impasse de la passerelle, BROCAS 40420 (France).
The infrastructure must be able to withstand the tension, compression and lateral forces of the 55-meter long steel and wood footbridge.
The site, which is classified as a "Natura 2000" natural zone, must not be disturbed or damaged. The trees bordering the stream are to be preserved, so the helical piers were installed close to the edge, to avoid disrupting the area.
The 24 piers were augured in, at a depth of 6 to 10 meters, into a sandy area.
Access became difficult due to the natural zoning, slopes and constricted conditions. The EM2 known as Techno Metal Posts' drilling machine, is equipped with special traction which allows it to access the most difficult places.
The quality control office approves the loads to be absorbed, along with the type of piers to be installed. To successfully carry out the project, some of them were screwed in at a 45-degree angle to withstand the pressure.
Each helical pier can support up to 15 tons.
Soil type: sandy
Installation time: 10 days
Number of people on site: 1 installer and 1 welder
For the foundations- galvanized piers and concrete blocks
For the footbridge- galvanized steel and wood
Equipment used: EM2
The footbridge weighs 20 tons (weight over its entire length). Torque power per pier-between 1300 and 2100 psi.
The project is approved by the internal design office which recommends-
- 4 TMP piers-model P4-12 and 8 TMP piers-model P5-12 (compression / tension)
- 12 TMP piers model P3-16 (lateral forces)
Driving depth: 6 to 10 meters
Details of the structure resting on the piers:
The structure is a galvanized steel footbridge boarded with wood at the bottom and on the railings.
Brocas-les-Forges : une spectaculaire opération (sudouest.fr)