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Danish railway bridges are being secured against cloudbursts

Danish railway bridges are being secured against cloudbursts

19-11-2012
After one of the largest cloudbursts on record in Danish history, and the subsequent collapse of a watercourse crossing and an embankment at Adsbøl in South Jutland, Rail Net Denmark has now investigated all watercourse crossings under railways.

In future, more frequent cloudburst episodes with violent and extreme rainfall will result in the renovation of five railway bridges, if they are to be safe in the long term.

Immediately after the collapse of a watercourse crossing and an embankment in Adsbøl, Rail Net Denmark initiated extraordinary inspections and checks of the about 600 watercourse crossings leading larger or smaller watercourses under railways in Denmark. Studies showed that five watercourse crossings are at risk in the event of extreme downpours. These five crossings are located at watercourses and embankments, in which the topography and construction of the crossings mean that they are at risk of being damaged in extreme rain events.

Rail Net Denmark receives warnings of cloudbursts from the Danish Meteorological Institute and in this connection has a number of procedures for how to deal with such situations. For example, exposed railway lines will be closed for trains during cloudburst episodes and the lines will be inspected by Rail Net Denmark personnel after the cloudburst has ended. If watercourse crossings have been full (exposed to episodes with considerable increases in the flow-rate of the watercourses), they must be inspected by a bridge engineer before the line can be opened again. As an example of this, the coastal line was closed in connection with the downpours in Copenhagen and North Zealand in 2010 and 2011. Subsequent inspection of the Nive Å bridge, one of the five crossings monitored, showed no signs of damage whatsoever.

Although Rail Net Denmark is working to secure specific crossings, problems with the more extreme weather of the new climate may still arise. Therefore, future cloudbursts, rising groundwater levels, and salt water impacting crossings as a consequence of rising sea levels may pose a problem for the Danish railway network.

The same problem applies for some stretches of road where water on the road in connection with cloudbursts can be a serious problem. The Danish Road Directorate has investigated whether the 550 road bridges for which the Directorate is responsible have been safeguarded against climate change. The investigation reveals problems at four bridges and six more look like following suit in connection with future climate change. Initiatives aiming at dealing with these problems include establishing a warning system to reduce the number of road accidents in connection with heavy downpours.

However, the Danish Road Directorate is only responsible for bridges on motorways and large main roads, and the Task Force on Climate Change Adaptation has assessed that problems associated with rain on the road and erosion of road bridges can be even more serious on smaller municipal roads.

 

Source: The national newspaper Politiken and Rail Net Denmark