The renovation work on the Mannerheimintie bridge can continue as the Helsinki Nature Conservation Association withdrew its building protection proposal and the ELY Centre made a decision on the expiry of the ban on endangerment.
The bridge will be renovated in two parts
The overhaul of the bridge will be carried out in two parts: first the east side of the bridge and then the west side. Once the east side has been completed, traffic on the bridge can be moved there and the other side can be renovated. According to the preliminary schedule, the renovation work will continue into the new year. If the progress of the work allows, it is possible that the Baana underpass will be temporarily opened for a few weeks in the autumn. This will be announced later.
The work will begin with the organisation of traffic on the evening of Monday, 3 July. Driving on the bridge along Mannerheimintie will be possible throughout the renovation, meaning that motor vehicles, cyclists and pedestrians can cross the bridge during the construction work.
Pedestrian traffic and cyclists diverted
Pedestrian traffic and cyclists will be diverted from the underpass. The shortest detour from west will be up the ramp next to the Little Parliament annex and across the pedestrian crossing at Kiasma to Kansalaistori Square.
An alternative route after the ramp is to pass in front of the Parliament Building, cross Mannerheimintie at Musiikkitalo and take Töölönlahdenkatu to Kansalaistori Square or Töölönlahti Bay. Detours will be marked along the route.
The concrete arch of the bridge will be replaced but the stone facade will remain unchanged
The Mannerheimintie bridge dates from 1894. The bridge consists of a concrete arch, a stone foundation and a stone facade.
“The concrete arch will be replaced, but the stone foundation, which is in good condition, and the stone facade of the arch will not be altered. They will be restored as part of the renovation. The new bridge will therefore be supported on the old foundation, and the original stone facade will be preserved,” says Riku Kytö, bridge construction specialist and project manager at the City of Helsinki.
The new concrete arch structure will be similar to the original, and the dimensions of the arch will not change. The concrete arch will have steel reinforcements to better carry the loads caused by current and future vehicle and tram traffic.
Alternatives to repairing the bridge were explored
Other options were also considered and investigated when planning the repair of the bridge. The idea of repairing and reinforcing the original arch had to be abandoned because the condition of the concrete arch proved too poor in the studies.
The implementation of a new bridge structure on top of the old arch was also considered a poor alternative. It would have required significant changes to the surroundings of the bridge, and the original stone wall of the bridge might also have needed to be raised.
