Seabed preparation is a special application for rock placement and calls for close cooperation with the main contractor, consultant and the client.
DEME's subsidiary Tideway has developed a wealth of expertise concerning seabed preparation, which includes: pre-lay crossing rock placements, construction of supporting berms for a pipeline in rough terrain/coral area, gravel blankets and ramps for PLEMs and PLETs, building pre-lay freespan supports such as at the Malampaya Gas Pipeline in the Philippines.
The main clients for seabed preparation contracts are pipe-laying companies and oil and gas operators. However, the same techniques are applied in other markets such as in port construction or in the offshore wind farm industry. Before the mighty foundation towers could be sunk at the Thornton Wind Turbine Farm off the Belgian coast, the seabed had to be levelled and a gravel bed had to be laid for stabilisation purposes. And at Le Havre’s Port 2000, the seabed was levelled to a tolerance of approximately 10 cm before the two massive concrete caissons that close off the breakwaters could be positioned.