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Parent Company Projects
Port of Jen Jen
Client: Ministre des Travaux Publics Wilaja de Jijel (Algeria)
Location: Algeria
Construction: 1986 -1990
Total length of quays: 2,300 m of which 126 caissons were employed with height ranging from 12 to 19,50 m. Caissons in two different 22 and 15 m diameter sizes feature a protrusion perpendicular to the perimetral wall with a 40 cm thickness, for placing the caisson onto the foundation bank. Caissons were precast on two 30 m jetties attached to a wharf of the service port with a -5.00 draft and on underwater yards featuring levelled riprap at increasing sea bottom depth. Caissons were precast on the jetties up to 6.50 m; then the other manufacturing steps (1 step for caissons up to 14 m and two steps for taller caissons) were carried out in the above mentioned underwater yards at -5.60 and -12.20 m depth respectively. For the handling of the caissons that were still without bottom, a special pontoon with catamaran hull and automated hoisting equipment was employed, specially designed and manufactured by Grandi Lavori Fincosit, with hoisting power of up to 1,200 t. The caissons were then placed at a depth ranging from -11.30 m and -19.00 m on a foundation of levelled quarry boulders. After launching in place of the caissons, vertical Diwidag bars inserted in the caisson walls were precompressed and used to hang the caissons during handling with the pontoon. The caissons were then filled with selected aggregates and sealed at the top with a concrete slab.
Main works carried out:
- Total volume of precast caissons: 475,000 m³
- Concrete: 42,700 m³
- Steel for reinforcement: 8,505 t
- Diwidag bars: 219 t