SPANNING A CENTURY

First conceived in the last century, several different plans have been considered for a fixed Great Belt crossing between the islands of Zealand to the coast of Funen in Denmark. The accepted design consists of a 6.6km long viaduct carrying both road and rail traffic from Funen to the small island of Sprogo. From Sprogo road vehicles will travel over the eastern bridge, a suspension structure with a 1600m free span allowing 65m clearance for the international shipping lane below. Rail traffic will be carried by two 8km long, twin bore tunnels reaching some 78m below sea bed. Four of the most advanced tunnel boring machines ever made are to be used to bore the 7.7m diameter tunnels. It is hoped that by using machines of this sophistication there will be no need to work under compressed air. Bridge piers for the 6.7km precast concrete bridge will be founded on concrete caissons sunk using seawater as ballast. The 6000 tonne caisson and deck sections will be positioned from an enormous floating pontoon bridge. The completed link should be ready by 1996. (TRRL)