BOSSES at the Forth Road Bridge today said they were working to “minimise” traffic disruption despite announcing a £5 million project to replace nearly 1000 heavy-duty bolts.
The repair scheme was unveiled after inspections revealed cracks in 28 steel nuts holding up the structure, prompting the decision to fit new components instead.
Forth Estuary Transport Authority (FETA) said gantries on wheels would be moved on to the bridge to allow engineers to fit new nuts and bolts as they go along, removing the need for regular closures. The programme is being fast-tracked to save time on the urgent redesign of these parts, with work to get under way by early autumn and finish a year later.
Officials said the decision to replace all 944 of the nut and bolt assemblies, which hold the vertical hanger ropes to the main suspension cables, will lead to less disruption than continuing to carry out rolling repairs on cracked parts. The replacement programme was today welcomed by motoring groups as the “most sensible option”.
Neil Greig, of the Institute of Advanced Motorists’ Motoring Trust, said: “Replacing them as part of an ongoing programme seems to be the most sensible option.”
The fast-tracking of the redesign process is set to be discussed by FETA next week. The need for replacements has been deemed “sufficiently urgent” that a “negotiated procedure” is to be used. This means FETA will negotiate a contract directly with a preferred supplier rather than putting a contract out to tender.
Barry Colford, chief engineer and bridgemaster, said: “Until we have replaced all of these bolt assemblies, it is quite possible that further emergency repairs will have to be carried out at short notice, requiring weekend traffic restrictions.
“So far we have been able to limit the disruption, but this would become increasingly difficult if failures occur during the winter when light and fair weather are in shorter supply.
“The bridge remains perfectly safe to use – the risk we are trying to prevent is the need for longer-term lane closures that would cause unprecedented disruption.”
FEARS were first raised in 2007 when bridge inspectors discovered a number of cracked nuts on the cable bands that hold the vertical hanger ropes to the main suspension cables.
The cracked nuts were replaced and £530,000 set aside to replace all of them. Inspections this year revealed a further 17 cracked nuts.
The “most critical location” has already been repaired.
The cost of redesigning and replacing all of the cable band nuts and bolts has been estimated at £5m.