Building a boat dock without getting our feet wet
Boat docks are typically built using a raft as the working platform. We discovered that using a temporary bank made of blasted rock brings considerable cost savings.
The City of Oulu placed an order for a boat dock for Toppilansalmi. They suggested a traditional solution where the foundation work would be carried out using a raft as the working platform. We suggested a new implementation method: temporarily moving the shoreline forward by five metres and carrying out the foundation work from a bank made of blasted rock.
The customer accepted our suggestion and we started filling in the six-metre deep water by the shoreline. The blasted rock was transported from another Lemminkäinen site: an underground car park in the centre of Oulu.
Around 15,000 cubic metres of rock was transported to the shore. The ten-metre sheet piles for the new dock were installed from the bank, and the dock was fixed to the bedrock using 20-metre rope wires. All this without getting our feet wet.
The blasted rock needed to be removed after the project was completed. In co-operation with the customer we ended up to the solution where the blasted rock was used for landscaping the 450-metre shoreline next to a pedestrian and bicycle route we had previously built in the area. The City of Oulu had planned to do the landscaping later but now they got it sooner. The landscaping will be finished off with a lawn and plants.
Our solution was cost-efficient for the client. According to Vilho Vanhatalo, Construction Engineer at the City of Oulu, the new method made the construction site safer for people and the environment.
"The cost of construction was lower than estimated, and the water became less turbid than with the traditional method. We were also able to landscape the shore sooner and at a lower cost than expected."