Project Namur, Belgium

Project Confluence

Foundations & archaeology

Sector: Buildings

At the feet of the Citadel, at the Confluence of the Meuse & Sambre rivers, Franki Foundations realized the foundations of a modern and sustainable project ... for another 10 000 years?

Technical specifications

Secant piles wall

Precast concrete columns in bored piles

  • 35 no.,
  • Ø 1800 mm,
  • 15 m long

Hard work and tight timing

The soil at this place is made of schist containing very hard quartz, among other materials. Boring large diameter piles has not been easy on the whole site, and for some, we even had to use a micro piles rig in order to deconstruct the rock and permit to ends up the drilling.

Another particularity of this site is the presence of archaeologists. To give them more time to discover the remnants of the past in the soil, we installed precast concrete columns, that will stay as the car park columns. With this method (known as 'Stross' method), it is now possible to work above (constructing the building) and under (archaeological research) the slab at the same time.

10 000 years history under the sun

In the last year, and for at least another one, 30 archaeologists are working hard every day on the work site of the Grognon to discover and preserve more than 6000 years history buried in the soil: houses, caves, roman walls, temples, streets... ; each level brings a new century back to life. Some specialists think they could even find out remnants of the Mesolithic period (8500 years before Christus)!

One can follow the work and the finds on the official website of Wallonia Heritage:

The Confluence project

As far as people in Namur can remember, the neighborhood of the Grognon has always been under work progress. But this time, almost 50 years after the last houses have been demolished, it's settled: the "project Confluence" is about to become real.

An underground 4-storey car park, a passive building including a restaurant and a "Living Lab", and green leisure spots will take place at the confluence of the two rivers, Meuse & Sambre.

Next to it, a new pedestrian and cycling bridge is built to connect the Confluence to the centre of Jambes, on the other side of the Meuse.

Project details

Project name

Project Confluence


Car Parks, Commercial


Pile wall, Large diameter bored pile under casing

Contract type



Namur, Belgium


THV Degraeve - Nonet

Building Period

2017 - 2018


3XN & BeeArchtichect

Total value

€ 2 million

Working in the fog

Precast concrete column installation

The Walloon Parliament next to the work site

Confluence project (Illustration: Duchêne - Degraeve - Nonet)

View from the Citadel

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