In this contract commissioned by the City of Helsinki, professionals from Kreate use an array of construction solutions as we tear down the current shore and pool structures, build a new shore wall out of concrete elements and create structural layers in the area up to the upper surface.
One of the most challenging stages in the project is the construction of the massive shore structures and the undersea installation of retaining walls. We will build 44 footed retaining walls with a maximum weight of up to 140 tonnes that will be moulded and cast in situ and lifted into place in the sea using a crane. The installation of the retaining walls, which is performed by divers, is preceded by underground excavation and dredging, among other things. Following the installation of the retaining wall elements, we will carry out the backfill where we use crushed concrete that has been produced on site from the concrete pier structures we have dismantled. Approximately 75,000 m³ of sea filling will be performed in the area.
The load-bearing capacity and firmness of the area, originally built with artificial fill, will be improved using deep stabilisation, loading berms and pipe trenches supported by sheet piles that extend below the sea surface. For the upcoming Tihtaalinkatu, Ahtaajankuja and Koukkopojankuja streets that will be constructed in Nihti, we will be constructing water supply and installing protecting tubes for cables.
The contract will be executed as a low-emission worksite as part of the Carbon-neutral Helsinki 2030 programme. The project efficiently utilises the material streams generated by the disassembly of the piers and other structures on site – as well as those from other nearby contracts – in the backfilling of the shore wall, for example, which makes the work more efficient and also shortens the transport distances. The carbon footprint of construction will also be reduced by using low-carbon concrete as well as machinery and equipment subject to strict emission control requirements that are either fully electric or use renewable diesel fuel.
The value of this contract, commissioned by the City of Helsinki, is nearly EUR 10 million and the contract period is 8/2023 – 5/2025.