BruCity

Soil nailing works to secure the existing peripheral wall

• 80 nails, Ø 130 mm, 16 m long

Waterproof reinforced excavation with 7500 m² diaphragm wall

• 400 linear metres
• 50 panels
• 600 mm thick

Anchors

• 115 anchors in one row
• 1.000 kN tension

Struts

• 32.6 m long
• Ø 1016 mm x 20 mm

Tension piles

• 133 Atlas soil displacement screw piles
• installed to accommodate the uplift water pressures under the concrete slab in the construction pit

After preparatory nailing works to secure the existing peripheral wall (the old “Mur des Halles”), Franki Foundations realised 400 linear metres of diaphragm wall which constitute the walls of the future car park.

The particularity of this project was, in addition to the number of technologies applied such as soil nails, anchors, a diaphragm wall and Atlas displacement piles, the use of struts to support the walls of the excavation before and during the placement of the slab. These steel tubes fitted with hydraulic jacks and a monitoring system make it possible to do away with banquettes and the issue of watertightness when installing anchors under the level of the water table, as originally planned. 

Advantages? Struts adapt easily to a very dense urban environment, they reduce the risk of waterproofness problems associated with anchors installed under the water table level, and they allow a phased approach with earth works done in parallel with a number of civil engineering works (see our article on the subject).

Handing over the construction site to the client at the beginning of 2020, Franki Foundations is convinced it ensured solid and sustainable foundations for this new project!