By Aileen Robertson

THE OPERATORS of the Forth Road Bridge have warned that replacing or reinforcing the 44-year-old structure’s main cables could cost the Scottish economy £1 billion and put thousands of jobs at risk.

Fife would be worst hit if the project went ahead, said Forth Estuary Transport Authority.

It has been estimated that fixing the cables, which support the bridge deck, would take between seven and nine years and cost between £91 million and £122 million, at last year’s prices.

The impact on traffic, and businesses, would be devastating.

However FETA’s most worrying statistic, from a feasibility study carried out by WA Fairhurst, is that 3200 jobs could be lost as a result of long-term maintenance work.

The bridge’s structural problems have been well documented. Corrosion in the main cables has caused the wires inside to snap. Each time a wire snaps it is recorded by an acoustic monitoring system.

In December, the Scottish Government announced that a new bridge would be built at Queensferry, but it will open no earlier than 2016.

At first it was feared the existing Forth Road Bridge would have to be closed to heavy lorries in 2013, but after the announcement that a new bridge is on its way, it looks unlikely that will happen.

Despite this, central Scotland’s roads could still be plunged into chaos if a cable replacement project got under way before the new bridge is up and running.

FETA have invested millions in a dehumidification system to dry out the insides of the cables, but engineers will have to wait until at least 2011 to find out if it has worked.

If it fails, FETA can either replace the cables or introduce an additional cable alongside or above the existing ones to share the load.

Each option would require significant periods of lane closures and contraflows during peak hours, as well as various closures at night and at weekends.

In his report to the FETA board, who meet on February 22, chief engineer and bridgemaster Barry Colford said, “Major maintenance works on Forth Road Bridge over a sustained period...would potentially result in economic output falling to a level in the order of £1 billion below that anticipated were the bridge to be operating normally, a drop in turnover in excess of £1.3 billion below that anticipated were the bridge to be operating normally, and a loss of around 3200 jobs, some of which may turn out to be permanent.

“These figures are obviously very substantial and the effects on business would be most strongly felt in Fife as would the negative effect on employment.”

Councillor Tony Martin, FETA convener, said, “These new figures reinforce what we already thought—replacing or augmenting the cables without an alternative crossing in place is something to be avoided if at all possible.

“It should be remembered, however, that cable replacement will only be necessary if current work to dry out the cables fails to prevent further deterioration.

“We’re optimistic that this will succeed, but we’ve said all along that there is no guarantee. That’s why we commissioned this study. It gives us a head start in the worst-case scenario that current work fails.”