3 February 2015

Vestfold in Norway – an unusual landslide takes out a major highway bridge

Posted by Dave Petley

Vestfold, Norway

Yesterday afternoon a really interesting landslide occurred at Vestfold, to the south of Oslo in Norway.  This is the site of an elevated two lane in each direction highway – the major road that runs southwest from the capital.  The landslide, which occurred on the edge of a small river, destabilised one of the pillars supporting the motorway, causing massive deformation of the road deck.  Fortunately no-one was hurt.  The event is described nicely in this report in English.  These two images, from this forum, show the landslide and the deformation of the bridge deck:



This looks like a classic Norwegian quick clay landslide to me, but that is just speculation.  Such landslides are often triggered by a comparatively minor disturbance that then triggers massive instability – the Rissa landslide being the most famous example.  And interestingly, the images suggest that there was work going on under the bridge, because right in the middle of the landslide there is a bulldozer:


Unconfirmed posts on the forum suggest that this machine was doing some work reprofiling the field without the knowledge of the highways agency.  Unfortunately this is going to take a long time to repair.