Terramare Boskalis’ Ferry Terminal Quay S1 project in Turku, Finland, is one crucial part of the port’s expansion. The Ferry Terminal Turku project is transforming the passenger harbor into a modern maritime hub designed for fast, smooth, and safe sea travel. The new terminal will serve up to 4,000 passengers at a time, even during quick vessel turnarounds. The port expansion project includes a new joint terminal, major upgrades to quay structures, traffic routes, and rail connections, as well as improvements to the surrounding urban infrastructure. It also supports the future development of the Linnanniemi district, aiming to create a lively waterfront area around the medieval Turku Castle for both residents and visitors.

Terramare Boskalis is carrying out the foundation work with Project Manager Marko Saarelma leading the job. Terramare is a highly experienced marine contractor with over 60 years of expertise in quay construction, dredging, and underwater blasting. Now part of the Dutch marine engineering group Boskalis, the company continues to bring its specialized knowledge to demanding projects across Europe.

A key part of Terramare’s success lies in trusted, long-term partnerships, such as with Junttan, whose piling equipment has been a reliable choice on numerous projects over the years. Pile driving supervisor Mats Brunnsberg highlights the value of this relationship: “Junttan’s size as a manufacturer works to our advantage – their spare parts, support, and maintenance services are fast and reliable, which isn’t always the case with larger, more distant corporations.”

Constructing the new passenger quay at Turku is no conventional task. For heavy-duty marine work in such conditions, the question was whether to use land-based equipment via a temporary bridge or deploy the Nordic Titan jack-up barge, and the latter proved essential for the depth and load profile of the task.

The port’s seabed is rich in deep layers of soft clay, pushing the technical requirements far beyond typical port developments. The load-bearing moraine layer only appears 15–30 meters down, while bedrock lies as deep as 70 meters. Due to these unique ground conditions, the design calls for a robust piling solution.

To ensure stability and long-term durability, more than 300 steel piles, each ranging from 40 up to 52 meters in length and measuring 700 mm in diameter, are being driven into the seabed with protective erosion caps. The piles are pre-assembled in the harbor and equipped with welded pile shoes on site. Approximately two-thirds of the piles arrived at the site directly from the factory at full length by ship, while the remaining third were assembled by welding on location. Once prepared, a tugboat hauls the piles onto a barge for driving into the seabed.

The steel piles are placed both vertically and at challenging angles to resist multidirectional forces, such as the lateral pressure from soft clay and the strain of winter ice loads and vessel impact. The use of oblique piles and tension piles is a central component of this engineering strategy. The latter are driven deep into moraine layers and verified through PDA testing to ensure their integrity under extreme pulling forces. With sea depths ranging from 10 to 18 meters, this submerged structure will be one of the most robust in Finland.

The piling is being performed from a jack-up barge, supported by an over 300t crane with a 60-meter-high mast. In this project, Junttan’s HHK16S hydraulic impact hammer with Terramare’s own crane attached leader proved to be the best set-up for the job. Throughout the process, Junttan’s hammer has proven indispensable. “We’ve driven 157 piles without needing to replace a single impact pad,” Pile driving supervisor Mats Brunnsberg noted – a testament to both machine resilience and efficient operation.

The Junttan hammer has also won praise from operator Miikkael Virkilä and piling guide Marek Saare, who commend the “powerful and reliable tool” for its handling of complex pile orientations and underwater dynamics. The precision required is substantial: pile placement must adhere to a 10 cm tolerance, ensuring exact fit within the structural design.

The overall construction scope for Terramare includes the new quay structure, a vehicle ramp, a foundation anchor plate, and associated terminal infrastructure. The anchor plate alone contains 128 piles, each 38 meters long, supporting a 30 cm-thick concrete slab. The onshore piling was carried out using a trusted Junttan PM20 piling rig.

The piling work began in March 2025, with a scheduled completion by July 2025. The port expansion construction work will continue until the turn of 2026–2027.

More about the piling project:
https://aboard.portofturku.fi/en/2025/03/one-foot-in-the-water-the-other-on-the-shore/
https://aboard.portofturku.fi/en/2025/04/the-port-quays-most-imposing-pile-is-taller-than-the-tower-of-turku-cathedral/