Steelwork contractors are claiming that a quiet revolution has taken place in the short span highway overbridges market over the past five years.
These structures - with spans under 25m - would traditionally have been built in concrete.
But now statistics produced for Corus suggest that steel has captured about 20% of the market.
The turn in the material's fortunes was clearly seen on the M6 Toll where all the overbridges - 46 - were steel.
Price could be a reason.
Concrete construction prices have risen by 20% more in real terms than steel over the past 10 years, even after the recent rise in steel prices.
Structural steelwork is now only the same in real terms as in 1995. 'Steel price rises have left the competitive position unchanged, ' says Dr Peter Lloyd, managing director of steelwork contractor Fairfield Mabey. 'Concrete bridges also use a lot of steel and rebar prices have risen even more than the steel plate which we use in bridges.'
The Highways Agency has now reduced the headroom requirement for weathering steel girders over roads to 5.3m, the same as for concrete. One of the first projects to use weathering steel at the new headroom height is the recently opened £38.5M Chieveley A34/M4 junction improvement contract. This was also one of the first contracts where the Highways Agency assigned a monetary value to speed of construction in assessing tenders.