Barges to keep Turku bridge from collapsing

Sagging Myllysilta closed to traffic

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Two barges are to be brought to the Myllysilta bridge in the city of Turku to keep it from collapsing. The bridge was closed during the weekend, after it was noticed that it was sagging on Saturday. At the end of the day, the middle part of the bridge was about a metre lower than before.
      There were concerns that the 93-metre-long bridge might collapse, but on Sunday the process slowed down; the bridge slipped down only a few more centimetres, and an inspection did not reveal any ruptures or cracks. Investigators still do not know why the bridge started to dip, although pressure from the large amounts of ice in the Aura River has been offered as a reason.
     
Attempts are being made to break the ice enough to get barges beneath the bridge to shore it up. However, this is no easy task, as standard icebreakers will not fit underneath another bridge.
      The closing of the bridge did not lead to serious traffic problems on Monday.
     
There was something of a carnival atmosphere in the area Sunday, as hundreds and possibly thousands of people passed by the area in the bright sunshine to look at the forlorn bridge.
      The owner of a café near the bridge tried to attract customers with a sign advertising “collapse coffee”. The owner noted that business had not been as good since the Tall Ships’ Race last summer.
     
The designers of the bridge, Eero Paloheimo and Matti Ollila, said that the probable reason for the sagging is the pressure from the ice in the river. Paloheimo does not believe that the situation resulted from excessive weight on the bridge.
      “Very exceptional natural conditions would be needed for something like this to happen”, Paloheimo said.
     
According to Jukka Mikkola, chairman of the City Council of Turku, the bridge had been tested with an excessive load when it was built in 1975.
      Mikkola recalls that when it was completed, as many lorries loaded with crushed stone as would fit were driven onto the new bridge - a load that the bridge never would have had to withstand in a real-life situation.
      In any event, sagging is not such a new phenomenon for the bridge.
      It slipped downwards in the middle soon after it was opened and had to be shored up in 1987 at a cost to the city of 4 million markka.
      The architect's office took partial blame, but charged that the non-destructive testing carried out by the city at the time had been... well, a bridge too far.
     
Five bridges cross the Aura River in Turku, and the loss of one - it seems unlikely that Myllysilta will reopen to traffic, but will instead be dismantled and replaced - is certain to cause traffic problems in the future. The bridge in question is used by around 25,000 cars each day.
      One possibility is to open the neighbouring Martinsilta bridge to two-way traffic.
      This occurred on Monday morning, and at least the morning rush-hour passed off without undue chaos.


Links:
  Live webcam footage of the sagging bridge in Turku (from YLE Turku)
  A set of photos of the sagging Myllysilta on Flickr

Helsingin Sanomat