Video stills taken during the storms which illustrate how much the lighting columns bent in the wind
The work was contracted by the Highways Agency following exceptional storms which caused the collapse of a dozen lighting columns. Ninety more had to be cut down when it was revealed that they showed signs of storm damage. The winds to which they had been subjected were only about half the UK design speed for such columns. But unlike most UK storms this one blew for three days non-stop.
Amateur video of the columns, shot during the gales, clearly shows that deflections of up to 2m were endured by some of the 12m, 16m and 18m high posts. After several hours, columns sited where the storm was worst had failed at the shoulder where the column diameter changes.
'Clearly there was a need for the standards to be improved to prevent this and the Highways Agency retained TWI to discover the reason and propose new rules' Highways Agency principal engineer John Wyatt said 'The failures were due to fatigue.'
Thirty-six sample lighting columns were randomly selected from various makers for investigation at Abington. They were fatigue tested and several failures occurred at the shoulder, base and at the door opening corners.
As a direct result of this work the 1994 rules in BD 26 are now to be modified to be consistent with the results obtained ruing work by TWI. It is proposed that the same requirement will be included in the current revision of European Standard EN 40.