TINSLEY VIADUCT STRENGTHENING, SHEFFIELD Tinsley Viaduct emerged as the winner in its category in a very strong field partly due to the sheer tenacity of all those involved - from the client - the Highways Agency - to the hundreds who worked long hours in the confined recesses of the huge, yet delicate, structure.
The notorious double-deck viaduct across the Don Valley, once the great steel manufacturing heart of Sheffield's industry, is the epitome of bold 1960s engineering - an assembly of thin steel plate-box girders pushing the limits of what was possible. 'A very fine, elegant and honest structure, ' was the conclusion of the strengthening team after living with it day after day for three years.
Unfortunately, at the crucial construction stage, sister structures from designer Freeman Fox & Partners at Yarra, Australia, and Milford Haven;
and from German engineers at Koblenz, showed that there were limits. The collapse of these three bridges prompted a major review of all steel boxgirder designs, which at Tinsley was resolved with years of remedial work to add relieving struts and ties to the slender trestles and cantilevered decks.
Massive increases in traffic density and lorry weights prompted further investigations and work at Tinsley, of which the latest project is hoped to be the last for many decades.
The chosen two-stage design-and-build strengthening contract involved extensive research and the addition of precisely machined steel Vee blocks welded into the structure at critical loading points. It was completed safely, using an innovative suspended access platform, to programme and below budget.
For building and civil engineering projects valued at over £50 million.
Sponsored by the Health & Safety Executive THE TEAM Client:
Highways Agency Cost £82.7 million Principal designer Owen Williams Consultants Contractor Edmund Nuttall Other firms Cleveland Bridge UK; Flint & Neill