The project consists in building a road link alongside the river Congo to improve access to downtown Brazzaville. The Congo government awarded the construction contract to the Chinese company CRBC. The project had to overcome a number of geotechnical difficulties:
- alluvial environment of the river banks necessitating soil reinforcement,
- cable-stayed structure with heavy loads, necessitating deep foundations of large diameter,
- presence of compressible and changing materials.
All the structures have been founded on piles because of the poor characteristics of the superficial materials and the need to account for strong horizontal loads.
The embankment sections have necessitated the use of retaining walls on reinforced soil (stone columns), and the high embankments the use of rigid inclusions in order to meet the stability and deformation criteria.
Construction lasted from 2013 to 2016.
Terrasol’s mission, providing geotechnical support to Setec TPI, consisted in:
- revision and adaptation of the geotechnical synthesis,
- checking the contractor’s calculation reports for the foundation aspects,
- geotechnical stability,
- soil/structure interaction,
- geotechnical recalculations using Foxta and Talren software,
- signing off the contractor’s documents (procedures,calculation reports, summaries),
- assistance to SGI’s local control team.
The mission required many meetings with the project stakeholders (control, contractor, owner) both in Paris and on site, demonstrating Terrasol’s capacity for rapid reaction to client’s requests worldwide.
- Geotechnical summary,
- Recalculation on a complex structure,
- Use of the latest geotechnical developments (ASIRI),
- Complex calculation of pile groups under multiple loads, using the Foxta software,
- Reactivity, including on site.