Swinoujscie, Poland
At Swinoujscie an LNG terminal was constructed. The 3 kilometre long breakwater required for this terminal was built by a joint venture of Boskalis, Hochtief, Per Aarsleff and Doraco.
The breakwater consists of a steel cofferdam structure with Xbloc concrete armour on a rock core on the outside.
On the main breakwater Xblocs of 5, 2.5 and 1 m3 were applied. The Xblocs were cast in the port of Swinoujscie.
The Xblocs were transported by barge to the inside of the breakwater and were subsequently placed by hydraulic excavators.
Model testing has been carried out in the laboratory of DMC in Utrecht, Netherlands.
Xbloc underwater placement is assisted by the Echoscope 3D real time sonar. With the Echoscope, the excavator driver is able to see the Xbloc he is placing underwater in real time. Also the previously placed Xblocs are visible on the screen in the drivers cabin in their actual position.
When the Xbloc moves because the lifting chain is pulled out from below the Xbloc, this is visible to the excavator operator. An Echoscope image of placed Xblocs is shown below.
The Xbloc project at Swinoujscie is the third Xbloc project where Xblocs are placed by Boskalis.
Location
Project milestones
- Start of casting: August 2011
- Trial placement: September 2011
- Start placement 1 m3 Xblocs: September 2011
- Start placement 2.5 m3 Xblocs: October 2011
- Start placement 5 m3 Xblocs: August 2012
- Casting completed: October 2012
- Placement completed: November 2012
Project details
- Hs = 4.0 m
- Length of breakwater = 3 km
- Size of Xblocs = 1, 2.5 and 5 m3
- Number of units = 27,500
