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Sito designs a safe, green motorway

The ‘E18 Koskenkylä–Kotka’ project run by the Pulteri consortium received the ‘Worksite of the year’ award and is ahead of schedule. With its safety-enhancing and environmental features, the motorway will become an international forerunner. Sito’s contributions to the motorway include the design of the handsome tied-arch bridge over Ahvenkoski and the Markkinamäki tunnel, where solar energy is used to power the LED lighting.

The purpose of the ‘E18 Koskenkylä–Kotka’ project is to upgrade the present road for motor vehicles to a motorway over a 17-km stretch from Koskenkylä to Loviisa and to build 36 km of new motorway from Loviisa to Kotka in Finland. The motorway will have six new interchanges and 68 bridges. The construction work will be completed at the end of 2015, but the entire motorway will be opened to traffic in the autumn of 2014. The agreement period for this lifecycle project covering financing and maintenance extends to the year 2026.

When completed, the motorway will relieve traffic jams on highway 7, prevent accidents and cut travel time between Koskenkylä and Kotka by about 8 minutes.

Exemplary cooperation

The jury of the ‘Worksite of the year’ competition commended the ‘E18 Koskenkylä–Kotka’ project particularly for the excellent cooperation between the partners. The Pulteri consortium is formed by Destia and YIT. The design and planning work was jointly undertaken by Sito, Destia and Ramboll. Sito designed the Ahvenkoski tied-arch bridge – the ‘showcase feature’ of the project – and also the Markkinamäki tunnel and about one third of the roads and bridges in the project. The project has involved road planners, geoplanners, bridge designers, pile slab designers, noise barrier designers, tunnel designers, environmental planners, lighting designers, traffic guidance experts and telematics designers. The technical and foundation structures in the project comprised the first major infrastructure project to be implemented in compliance with Eurocodes.

Project manager Jere Keskinen from YIT has good things to say about the cooperation, mutual trust and the participants’ enthusiasm. “This is a very committed team, in both planning and implementation. Cooperation with the Finnish Transport Agency and the authorities has also been smooth,” he says.

There are plenty of boulders in the area. “We have broken some up for use as aggregate, but we have also used a lot of them for landscaping!” Keskinen says with amusement.

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New solutions

Running a major lifecycle project on a tight schedule is a considerable challenge, especially since the project involves cutting-edge information and technology.

“We have gained good experiences of machine-guided earth construction and machine automation. We have improved motorway safety with telematics, including collision avoidance devices. The new drop-shaped layout in the interchanges prevents drivers from entering a ramp in the wrong direction,” explains Keskinen. New materials have also been used, such as foamed glass for a lighter road structure.

Respecting the environment

The ‘E18 Koskenkylä-Kotka’ site belongs to the Green & Smart Motorway concept where construction complies with environmental values. The restaurants in the service areas will get their energy from the earth, and recharging points for electric cars will be provided in the park-and-ride car parks. Some of the lighting in the Markkinamäki tunnel will be solar-powered. “The need for artificial lighting in the tunnel is greatest when the sun shines the brightest,” says Keskinen.

The motorway design respects the sensitive Natura 2000 protection areas for instance in the magnificent landscape of Ahvenkoski. Wildlife tunnels and five wildlife bridges 35 m wide are being built. Success appears to have been achieved in safeguarding the habitat of the protected Thick Shelled River Mussel at Ahvenkoski and in the Langinkoski branch of the river.

Aesthetic values are prominent in the design solutions. Users of the motorway sections that are already open have particularly commended the transparent, ornamental noise barriers. The bridge over Ahvenkoski, located within a Natura 2000 protected area, was conceived as an eye-catching feature worthy of its setting. A simple tied-arch bridge proved to be the most handsome solution and also the most advantageous in terms of structure and cost. The central span is a tied-arch structure, where the deck is suspended on cables from a single steel arch and the outward thrust of the arch is translated to tension in the deck. The principal designer of the bridge was Jussi Luokkakallio M.Sc.(Tech.), assisted by Niklas Gordin M.Sc.(Tech.) and Mikko Tuominen M.Sc.(Tech.).

Text and interview: Dakota Lavento