Rehabilitation of the ‘French Quay’. Port of Kamsar, Republic of Guinea | 2007

An important step in the economic development of the Republic of Guinea

The Republic of Guinea possesses one of the world’s largest reserves of bauxite, the raw material used for the production of aluminium. The ‘Compagnie des Bauxites de Guinée’, CBG, is engaged in developing and exploiting the local bauxite reserves located in the North West of Guinea.  

The Port of Kamsar has three quays: the 'Mineral Quay' for bauxite export, the 'Italian Quay' for tug boats and small vessels, and the 'French Quay' as the main import facility for mine and township supplies.

Early in the 21th Century, CBG decided to extend the service life of their facility. As could be expected after such a long period of use, the structure needed to be rehabilitated. The most cost-effective solution that matched all the design criteria and construction constraints was the installation of a new sheet pile wall in front of the existing diaphragm cells.

AZ 36 700
French Quay 2007
French Quay
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A 116 m long quay wall made of AZ 40-700 sheet piles was installed in front of the existing quay, connected by 50 mm tie-rods to an anchor wall created with AZ 36-700 sheet piles. 16 temporary fenders, made of CU 32 box piles, were driven to protect against the deterioration of the new quay wall elements from mooring vessels. 

The sheet piles were driven with a PVE 50M vibratory hammer. Due to very compact soil conditions in certain spots, some sheet piles had to be driven with a 9 tonne hydraulic impact hammer BSP 357. A two-level template connected to the existing quay was used to ensure the plumbness of the sheets during installation. 

An important requirement of the contract was to keep the quay operational throughout the construction period. Instead of installing the tie-rods in an open trench, the contractor chose to drive horizontal steel pipes through the existing straight web cofferdam cells, and to install the tie-rods using the steel pipes as casings. This innovative installation method for the tie-rods allowed the construction and port operation equipment, as well as crews, to operate on the full length of the quay during the entire construction period.

Steel sheet piles were selected for the rehabilitation of the quay wall because of their good structural performance, their short construction time, their cost-efficiency, and last but not least, because of environmental aspects (AZ sheet piles are manufactured from recycled steel and thus have low impact on the environment).