Damen Creates DOP Pump/Cutter Installation to Dredge Heavy Clay in Rotterdam City Center
Two cranes dig a hole for a four-level underground garage in Rotterdam. They are using special cutters on the hard clay, along with Damen’s patented DOP 1515 underwater dredge pumps.
The site is the Market Hall project, that contained 1950’s buildings that replaced those destroyed in the massive WWII bombardment of Rotterdam. It is near the Hotel New York, where travellers stayed before crossing the Atlantic with the Holland-America Line.
The dredging will provide area for a four-level underground parking garage for the Market Hall and apartments, which will be built at ground level.
Dredging contractor Martens & van Oord needed to remove clay but was hindered by the presence of the pilings. Damen Dredging Equipment worked with M&VO to solve the problem and meet a tight dredging schedule.
The DOP pump is a compactly built, hydraulically driven submersible dredge pump. Its suction side can be fitted out with different types of suction heads, depending on the job. For this job a new head – the disk-knife cutter – was designed by Damen and the contractor. The head has long vertical blades that cut the clay in layers without damaging the piles. The pump and cutting head are connected by hydraulic lines to the crane’s hydraulic system, which provides the standard DOP1515, 65 kW pump and cutter with operating power. The dredged clay mixture is pumped to a nearby dewatering station.
The maximum mixture capacity of the DOP1515 is 500 m3/h, (654 cubic yards/hour) working at a maximum dredging depth of 14 meters (46 feet) on a 200 mm (eight-inch) discharge line. Martens & van Oord owns a number of DOP pumps, two of which are working on the Market Hall project, each with a disk-knife cutter.
Martens & van Oord and Damen began planning for this project in January of this year. The disk-knife cutter was engineered and manufactured rapidly and by spring the two units were working on the job.
The dredging was scheduled for completion in mid-July.
Damen fitted out a standard DOP1515 pump with a specially adapted disk-knife cutter.