Monitoring the Forth Road Bridge to spot potential faults like the one that closed it would have been an enormous task and probably not economically viable, MSPs heard today.
Peter Hill, general manager of the Humber Bridge - a suspension bridge like the Forth - was asked by an inquiry into December’s shutdown whether it could have been foreseen.
He told Holyrood’s infrastructure and capital investment committee that if a monitoring system had been installed, “it is possible with a very detailed analysis of every point of the structure”.
However, he added: “It would a huge exercise, especially the suspension area, which is a web of elements.
“It would be an enormous task to monitor and probably not economically viable.”
Mr Hill also praised the bridge’s staff, led by its former bridgemaster, who left last year.
He said: “I can only say, knowing the competencies of the team under Barry Colford, I can’t see that this incident could have been otherwise determined or pre-warned in any other practical way.
“As to the subsequent actions of the team that are now looking after the bridge and reacting to this emergency, it seems to have been entirely appropriate.”
The bridge was closed for two-and-a-half weeks after a steel pin was found to have seized in the “truss” support structure under the bridge’s southbound carriageway.
John Evans, a consultant with bridge engineers Flint & Neill, told the inquiry: “I don’t think you would have foreseen what the particular failure was but the idea of having contingency measures in place for when something catastrophic happens might be looked at in the future.”
Mr Evans said there had been no evidence of the creaking or groaning associated with the fault, which he said “resonates through the whole structure”.
Another engineering consultant, Richard Fish, told the MSPs: “The cause would have been very difficult to predict.
“The effect, as in the closure of the bridge, that was taken not as a light decision.
“I wouldn’t question that decision made by the engineers who are at the sharp end and faced with that sort of issue. The decision had to be taken around public safety.
“It’s ironic because Forth is one of the best-managed bridges in the UK.
“It would seem unlikely that something would be overlooked.”