6 January 2015

The Scorciavacche Viaduct in Sicily: an earthworks failure that has become a national scandal

Posted by Dave Petley

The Scorciavacche Viaduct in Sicily

In Italy there is something of a scandal developing around the newly completed Scorciavacche Viaduct, a new (very impressive) elevated highway not far from Palermo.  The road opened a couple of days before Christmas, but has now had to be closed again because of the collapse of a section built on an embankment.  The story has attracted considerable attention from the international media, who are generally describing the problem as “subsidence”.

The best images that I can find of the site are on the Repubblica website (text in Italian), which has an excellent portfolio.  This includes a good picture of the roadway – it’s not hard to see why the highway has been closed:


The problem appears to be the failure of a set of remarkably steep earthworks alongside one of the bridge abutments (the abutment itself seems to be intact):


A closer view of the problem gives a better indication of the problem:



The failure seems to have affected quite  long section of the embankment:


This is clearly an earthworks failure – i.e. a landslide in the embankment.  I am not really familiar with the construction technique here – others ate probably better placed to comment.  The embankment seems to be founded on gabians.  Above this is some sort of slope protection covering a steep earth bank.  Close to the abutment (see the second picture) this might be soil nailed (comments – experts have subsequently suggested that these are not likely to be soil nails, it is not clear what these objects are), but this doesn’t seem to be the case for most of the embankment.  The major failure seems to be in the first section without the soil nails, which is showing distress directly above the base of the embankment.  Further to the right the failure is more complex and difficult to understand.

This case is now subject to formal investigation by an Italian magistrate, so hopefully the cause will become apparent soon.  It will be very interesting to see what emerges.  In the meantime, I’d welcome comments from those who know about embankments.