Contractors have removed the last rock pillar supporting the 60m long, 35m wide roof of Gallery UX15, part of the giant, £992M particle accelerator being built at the Cern physics research centre in Switzerland. CCC joint venture, bringing together Swiss contractor Zschokke Loscher, German firm Baresel and Austria's Porr-Asdag Tunnelbau, has so far excavated the gallery to a depth of 10m. Access to the gallery is by two shafts, each the diameter of a Channel Tunnel bore.
Casting of the gallery's reinforced concrete roof vault and crane beams is set to start early next year. Up to 66 Freyssinet tension ties will then be installed to support the roof while CCC excavates the gallery floor below to give a final height of 40m. Consultants for this part of the Cern contract are Electricite de France with Knight Piesold.