Crown Bridges alliance, Helsinki
We demolished the old Kalajoki railway bridges and replaced them with new tensioned, continuous beam concrete-structure bridges, the superstructures of which were joined with a second stage concrete lane in 2017 so that they form a single bridge. The contract forms part of the Seinäjoki–Oulu railway project.
Kalajoen ratasillan työmaa.
The two steel-framed railway bridges crossing the Kalajoki river in Ylivieska had reached the end of their life cycle. We demolished the existing bridges and built an approximately 120-metre railway bridge that meets the up-to-date load-bearing capacity requirements defined by current standards.
The contract started in 2015 with the construction of the eastern bridge. The first work phase was to build temporary embankments in the Kalajoki river, needed for removing the old bridge blocks of the eastern bridge. Removal lifting was carried out during the Midsummer, with rail traffic interrupted for 24 hours. For the following year, rail traffic was directed onto one bridge only. During that period, we built the new bridge. After that, the procedure was repeated for the western bridge in 2016.
Rock-supported concrete-structure abutments were built at both ends of the new bridges and the section that crosses the river was equipped with four intermediate concrete-structure supports that are located in the fast-flowing, easily flooding Kalajoki river. Underwater excavation and ground cutting were some of the most demanding phases in the project.
The bridge superstructure was moulded from approximately 1,200 cubic metres of concrete. After the moulding of the superstructure, the prestressing steel tendons (8 per bridge) in the bridge’s superstructure were tensioned and grouted. Next, the concrete surface of the superstructure was sandblasted and insulated with double rubberised bitumen insulant. Finally, asphalt sheet insulation was covered with a protective concrete deck.
When both bridges were completed, we joined them with a 1.5-metre second stage concrete lane into a single bridge.
The contract also included soil exchange in the railway embankment for a distance of approximately 60 metres at both ends of the bridge.
We built 60 metres of sheet pile wall at both ends of the bridge and the walls were anchored in their place with cable cord anchors. In addition, sheet pile walls were reinforced with RD220-270 bored piles.
The contract was carried out within the budget and schedule agreed with the customer.
The contract was part of the Finnish Transport Agency’s Seinäjoki–Oulu railway project, which is one of the largest infra projects ever in Finland. The track improvement shortens the travel times, makes it possible to increase rail traffic and decreases rail traffic’s susceptibility to disturbances.
Watch the time lapse video of the demolition of the old Kalajoki railway bridge on the Finnish Transport Agency’s website.
Watch the aerial video of the same situation.