22 July 2014
Last Tuesday a landslide at Erzurum in Turkey destroyed an almost new, and extremely expensive, ski jumping facility. The ski jumps were constructed for the 2011 Winter Universiade, at a reported cost of 20 million Euros. The lower part of the Kiremitliktepe ski jumps collapsed. Three of the jumps have been completely destroyed (image from here), whilst the two larger jumps have been severely damaged:
Pleasingly, the collapse event was in part captured on video and is buried on Youtube:
Whilst this video provides a pretty good overview of the aftermath of the landslide
There is also an excellent gallery of images of the collapse in motion here.
This is a Google Earth perspective view of the site, taken in 2012:
Compare this with the image below of the slope, taken in 2009:
It is hard to read the topography from these images given the quality of the digital elevation model, but I would make a few initial observations. First, the topographic shape of the slope appears to have been modified – in particular, there may have been some excavation of the toe to create space for the landsliding and runout zones. The main part of the failure seems to follow the excavated and modified area for the smaller jumps on the right hand side. Second, there has been considerable additional material placed on the middle part of the slope for the main jumps (on the left side), which may have added weight to the unstable mass. And third, there is a new lake at the top of the slope, presumably to provide water for the snow-making machines.
An article in a Turkish newspaper yesterday also suggests that there were major construction defects at the site:
Prosecutors have initiated a fact-finding mission and launched an investigation into last week’s collapse. The team includes four construction and geology engineers from Atatürk University in Erzurum. The mission’s initial report has revealed some fatal problems in the construction of the towers that supported the ski jumps. The expert report shows how poorly the towers were built. An expert at the site in Erzurum found that the contractor used only one meter of steel piles in the towers’ foundations, Turkish media outlets reported on Sunday. The reports said that Sarıdağlar was required to sink 50-meter-long steel piles into the ground to support the towers. Taking a deadly risk, the contractor first poured concrete into the tower foundation then sank only a one-meter-long pile in it, a critical fault. Construction experts said, according to global standards, steel piles have to be at least 25 meters deep for towers this high. Even worse, the contractor incorrectly calculated the angle of the slopes on which the ski jumps were placed.
Thus, overall this is looking like this could be a major design and construction failure, although we’ll need to see what the official report states in due course. Given the above, the likelihood of being able to reinstate the facility without complete demolition and reconstruction look slim.