DOPs for caisson pumpout

The DOP pumps empty concrete caissons to allow them to float and be repositioned as a breakwater. An excellent job for the DOP which, according to Damen showcases the equipment’s ability to fit in confined spaces.

At Sao Joao de Barra, which is located along the South Atlantic coast some 150 miles North of Rio de Janeiro, Brazil, a large harbour construction project started a few years ago. Acciona was awarded the contract for the engineering, design and construction of two artificial breakwaters. Acciona decided to use their pioneering system of concrete caissons built in an auxiliary dock. Five of these sand-filled caissons now have to be emptied to be moved to their final position, together with another 37 caissons which have already been made and positioned in their final place.

Damen has delivered 2 DOP packages, which both include a DOP250 submersible dredge pump, a 403 kW diesel hydraulic power pack, a separate diesel driven jetwater pump feeding the dredge pump’s suction head plus a number of hoses, connections and spares. The DOP is connected to a crane. Each DOP250 has a mixture capacity of 1,250 m³/h, and is used to empty each partition of the caisson. The sand is put to good use as it used in a nearby beach replenishment.

The pumps arrived on site mid January. A Damen Field Service Engineer assisted during the start up and instructed the crew. All caissons were finished and emptied by the middle of May. Then Acciona finished the repositioning of the caissons and completed the breakwater construction.

By Jake Frith