Facts and Figures

City of Helsinki


Terramare Oy

Koirasaaret and Stansvikinranta preconstruction| Client: City of Helsinki

Terramare is implementing a preconstruction contract at Koirasaaret and Stansvikinranta in Helsinki, including area dredging, sea-filling facilitating a new residential area called Kruunuvuorenranta, and implementation of a new swimming beach.









Project’s significance
The Koirasaaret and Stansvikinranta are southern areas of Helsinki’s Kruunuvuorenranta residential district. At the location, Terramare will implement a year-long preconstruction contract in which the Koirasaaret area will be extended by sea-filling. The preconstruction contract will facilitate the implementation of a new residential area project. Work at Stansvikinranta, located alongside Koirasaaret, will result in the creation of a new swimming beach.

Project’s implementation
Terramare has started the Koirasaaret and Stansvikinranta preconstruction contract with dredging work. Environmental dredging of contaminated soils and dredging of clay have taken place at the location. The dredging will be carried out by Terramare grab dredger Kahmari 2. Terramare’s towable SCG 3, SCG 4 and SCG 6 barges will serve as loading vessels.

Around 900,000 m3 of blasted rock will be used at the location. The contract also includes implementation of edge embankments and erosion protection at the sea-filling area. Sea-filling is carried out from land-based high-performance Caterpillar trucks. The blasted rock is taken from the city's blasted rock storage facility. Deep compaction of the sea-filling is carried out from onshore by dynamic compaction. 

Work on the preconstruction contract’s Stansvikinranta swimming beach will be implemented from the sea. Dredging at the location will result in the creation of the beach area, implemented with sand filling and edge embankment work. A total of 70,000 m3 of sand, transported by sea from Porvoo, will be used in the sand filling. The transports will be carried out by Terramare’s floating work pontoon Bolle VIII, which will be towed and assisted by the multipurpose vessel Eija.

The Koirasaaret preconstruction contract will take into account the area’s natural bedrock, islets and shoals, which are not harmed during the project. The onshore tree stand will also be retained undamaged in the work associated with the Stansvikinranta swimming beach. On the seaward side, the contract area will be protected with a floating protective pontoon screen. Garbage is collected from the beaches and sea of the contract area, sorted and transported for appropriate waste processing.

Read more > Boskalis Nordic Today magazine 01-2019