A THREATENED cross-Forth lorry ban has been averted following new checks on the Forth Road Bridge's main cable corrosion, The Scotsman has learned.
A predicted lorry ban as early as 2013 because of the weakening cable is now expected to be put back to nearer 2020.
That means lorries would be able to switch in time to the planned replacement bridge, which should be complete in 2016, even if w
ork to halt the corrosion fails.
A report into the latest inspection of the 2ft-thick cable, due to be published today, is understood to show "positive" findings.
These have enabled engineers to predict the cable's remaining lifespan with much more accuracy than before.
This is because they have been able to compare the results of February's cable inspection with those from 2004 – the only previous time it has been checked.
Following the 2004 check, experts estimated a lorry ban might have to be imposed some time between 2013 and 2020 if the corrosion was not halted. Closure of the bridge to all vehicles could follow as early as 2019.
The new results are expected to show the corroded cables still threaten the bridge's long-term future, but they effectively provide a greater breathing space.
The Scottish Government has given the go-ahead to a replacement bridge just west of the crossing, costing up to £4.2 billion, because of the threat.
The Forth Estuary Transport Authority has started to blow air into the cable in an attempt to halt the corrosion, caused by water seeping inside.
However, it will not be known for another three years whether this has been successful.
The latest inspection of the cable involved unwrapping its cover to check the 11,618 pencil-thin wires inside. The worst-corroded section found in 2004 was selected for the check.
Corrosion and wire breaks in the cable have already cut the bridge's strength by 8 to 10 per cent, and a further 10 per cent loss would force a lorry ban.
Business leaders were last night keeping their fingers crossed.
Ron Hewitt, the chief executive of Edinburgh Chamber of Commerce, said: "Business would welcome any lengthening of the life of the existing bridge, as current projections have threatened that a new crossing would not be ready before long vehicles would have to be banned.
"Early closure does not bear contemplating and so we hope the results will prove optimistic."
A Scottish Government spokeswoman said: "The Scottish Government will not know if the dehumidification work on the cables has worked until 2011.
"The year 2011 would be impossibly late to start the work which will protect cross-Forth travel, and the compelling case for proceeding with the Forth road crossing remains."
The full article contains 465 words and appears in The Scotsman newspaper.
