The Reina Sofía Dyke, Port of Las Palmas

The Reina Sofía Dyke is the main protection of Gran Puerto de La Luz, Las Palmas of Gran Canaria. In 1927, SATO (a subsidiary specialising in maritime works, now part of the OHL Group) began its activity in the port to construct the new breakwater and, sixty years later, in 1991, again took over its extension works.

The dam extension works were due to the huge growth in container traffic experienced over the last few years and the need for a gradually longer pier for remaining port activities. After three years' work, in February 1991 this important project was completed. It provided a 997-meter extension and a new pier for the berthing of vessels with up to 20-meter draught.

Extension works began with a new reflecting vertical dike, 397 meters long, running next to one of the port piers. Its position then changed in order to run next to the former Reina Sofía dam, along 550 meters. The construction works involved 33 hollow vessels of reinforced concrete resting on an all-in-one dyke cemented to a breakwater up to 60 meters deep.

The outside banks were protected with a 1,500 kg breakwater, obtaining a platform with 32.6 m wide crest. On the caissons, a 60-cm. thick slab was placed to support a reinforced concrete shelter wall shaped as a trapeze, 12 meters over sea level at the very top.

The huge caissions, 30 metre long, 21 metre wide and 24 metre deep, were built at the port itself, using sliding fromwork, in two stages. First, work was carried out on a submersible barge in sufficient depth to enable the caissons to float on their own. Next, the caissons were completed berthed to a pier. To ensure that they floated, the caissons were made lighter with circular cells, 3.8 m. in diameter, which were filled with water when anchored at their final location.

The significance of the project is reflected in the 204,771 m³ of reinforced concrete used, 105,746 m³ of which were exclusively used for the caissons; the manufacturing of 1,300 blocks, of 60-tonne blocks, 315 39-tonne blocks and 170 40-tonne blocks,which adds up to the application of 675,000 tonnes to the breakwater and 4,550,000 tonnes on the all-in-one dyke.