A project is underway in Helsinki, Finland to build a completely new tram line, along with new municipal infrastructure and green spaces. The contractor Destia is using a wide range of Robit wear parts for soil and rock drilling in the project.

The alliance model project will involve the construction of approximately 4.5 kilometres of tramway and associated street areas and municipal engineering between Nihti and Pasila. The project will also include the renovation of street areas as well as improved pedestrian and cycling connections. Preconstruction started in Nihti in July 2021.

A massive groundwork project

An alliance group led by Destia is working in challenging street conditions in the middle of urban Kalasatama. The group’s share of the construction work on the new line comprises some three kilometres of road, the entire cross-section of which will be rebuilt in the course of the project.

“The section will be built on a pile slab structure, covering a total area of over 36,000 square meters, or about the size of five football pitches. During the project, about 100 kilometres of individual piles 15 to 20 meters in length will be used for road foundations,” says Alexei Kesonen, Project Manager for Foundation Engineering at Destia Oy.

At the same time, a ramp will be built for the possible future construction of a tunnel to Sörnäinen.

“The support structures of the ramp and tunnel walls combine three techniques: pipe pile wall, sheet pile wall and combi wall. Based on excavations, each was chosen to save time and, of course, to achieve a highquality result. The ground on the site varies widely from soft clay to hard rock to bouldery fill.”

“A wide variety of drilling equipment, sheet pile drivers and piling rigs are needed on site, allowing the choice of optimal working methods. With skilled workers, the right equipment and careful planning, even the largest projects can proceed on schedule,” says Kesonen.

Using domestic wear parts is an asset

Destia has a long history of solid cooperation with Robit on wear parts for soil and rock drilling.

“You can always trust the quality of Robit’s products and their service level as a domestic manufacturer. Speed of delivery is also excellent, which is an absolute must, as the schedules are tight, and work cannot stop because of missing parts. Robit supplies us with drilling consumables directly from their factory in Lempäälä. Of course, we also store them onsite, which ensures there is no downtime.”

“The pipe piles are installed using Robit’s 18″ DTH hammers, 508 mm SR XL2 ring bits, 508 mm SR pilots and L-model impact shoes, which arrive on site pre-welded to the pile ends. For the installation of combi wall piles, Robit Prime ring bits and pilots are used. For the supporting wall anchors, we are using Robit’s DT (Drill Through) technology, which allows us to drill the pilots into the rock through the ring bit assembly,” Kesonen says.

Construction of the new tramway line started in the summer of 2021. If all goes according to plan, the line will be operational by the end of 2024, greatly streamlining cross-town traffic: you can get from Kalasatama to Pasila by tram in 15 minutes. The route will also conveniently link trams to trains and the metro at several transport hubs.

Picture: Construction Engineer Alexey Selivonchyk of Destia presenting the Robit SR pilot.

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