Maintenance Port of Antwerp 5th harbour dock
Project specifications
Location
Port of Antwerp, 5th harbour dock
Client
Besix NV and Port of Antwerp NV
Contractor
DC Industrial
Technique
Mechanical dredging with pontoon and excavator + crane vessel
Period
2015 - 2018
Equipment
Hitachi 870 LR and crane vessel
Contact person(s)
Luc Nizet
Description of the works
At the 5th harbour dock in Antwerp, a bottom protection (consisting of mats of open stone asphalt) was installed in front of the new quay wall (approx. 16m below the water surface). Previously, dredging works (92.532 m³) had to be carried out which involved following items:
- Obtaining the permits and environmental sediment research, taking samples and analysis.
- Cleaning up and disposal of foreign objects in the zone.
- Maintenance dredging of contaminated sludge (TBT, VOCl, ...).
- Infrastructural dredging of contaminated sand (TBT, VOCl, ...).
- Applying strict safety measures.
- Levelling at approx. 16m below the water surface with precision +/-10 cm.
- Removing grout mass with regard to dredging pontoon with concrete cutter.
- Sorting and screening of dredged material.
- Disposal of residual materials not recovered by sorting and sieving.
- Dehydration of the dredged material.
- Storage, fysico-chemical and thermal treatment of the contaminated sludge and sand.
- Transport after dehydration to a licensed final destination for reuse.
Our added value
Particular attention was paid to the following points:
- The sand layers to be dredged and levelled are very hard.
- The dredging works had to be carried out in such a way that no soil shear occurred outside the area to be dredged. In the immediate vicinity of the quay wall, the necessary attention had to be paid to prevent damage to the construction.
- The imposed ground level had to be achieved in an even manner by means of accurate levelling.
- Delivery and installation of filling material, with a tolerance of +0/-15 cm compared to theoretical level.
- At zone 4B there was a concrete pipe shaft, which was stabilized by an overlying grout mass. 30cm of grout had to be removed at the top of the solid to achieve the target depth of the asphalt mats. This was done by using our own cutter.
- Physico-chemical treatment at the licensed facility of Group De Cloedt in Genk and thermal treatment in the Netherlands.