- Design and construction: Groupement VINCI
- Mission: G2-PRO & G3
- Cost of the mission: 90 k€
- Mission date: 2014-2015
BRIEF DESCRIPTION AND CHARACTERISTICS OF THE PROJECT
The study carried out by GEOS is part of the project to build the second bridge over the Wouri River in Douala (Cameroon). It concerns the accesses to the structure, which are 700 m long on the right bank (Bonabéri) and 2,000 m long on the left bank (Deïdo). They support a road and a railway line. The longitudinal profile of the accesses is mainly embankment, up to 9 m high. The accesses also include three engineering structures and twelve hydraulic structures.
The study area is located in the alluvial geological context of the Wouri: alternating fine soils (clayey to silty) and sandy soils, over significant thicknesses (in excess of 30 m), with highly compressible layers (soft clays, mud, etc.).
The resulting problems, particularly settlement (consolidation, creep), necessitated the use of soil reinforcement (rigid inclusions) at the abutment on the left bank. In addition, a test embankment is currently being constructed. GEOS will use the results for the rest of the project.
GEOS carried out the design and execution level studies (missions G2 and G3 as defined by standard NF P 94-500) for the accesses to the second bridge over the Wouri.
These studies covered the following points in particular:
- Geotechnical hypothesis notes for the earthworks, engineering structures and hydraulic structures of the accesses,
- Design and construction geotechnical studies for the earth structures of the accesses and the technical blocks of the bridge.