Complex fluted concrete columns for the Verrieres £24M viaduct on the new central France motorway give a hint of the drama to come when the A75 autoroute hits the plunging Millau Valley.
A record breaking 2.5km long Sir Norman Foster-designed structure will carry the dual three lane road south 247m above the valley floor (NCE 26 November 1998). But construction and the private finance concession are yet to be decided.
Meanwhile, attention is on the 720m long Verrieres viaduct, one of two smaller valley crossings north of Millau. It has tapering columns up to 140m high designed by architect Mascarella of Marseilles, and a lightweight steel lattice deck being launched by Belgium firm Victor Buyck - part of a joint venture led by Spie Batignolles, and German owned firm Razel.
Concreting has been complex, with the firm consulting extensively with Austrian formwork supplier Doka on design of adjustable self-climbing forms. These had to handle a parabolic taper curve on the two highest of five piers, as well as the indented profile. Four consortia are in the running for the 30-50 year franchise to operate the route and a decision is expected shortly.