Tragedy at the Riverside

I hope that the disaster in Durham where tragically two people were killed because the inflatable took off, was not another of these low-level wind phenomena that are best known for the bridge collapse at Tacoma Narrows.

Some of these structures are stable in high winds, but start to vibrate when the wind is at just the right level. At Tocoma Narrows, the bridge collapsed with a wind speed of about 40 mph. Not particularly high.

We nearly had another tragedy in this country, when it was proposed to build a suspension bridge across the Mersey between Runcorn and Widnes. The design was shown to the ICI Scientific Society on Merseyside and according to the tale, ICI's vibration expert got up and proved that due to the nearness of the railway bridge, the suspension bridge would vibrate and might fail. It was not a good day for the designers, but it would have been even worse if they'd built the bridge.

There are vague references to this on the Internet, but nothing that would capture the apparent dramatic confrontation in the ICI Scientific Society.

It all goes to show, that if you build anything like the inflatable at the Riverside, it must be fully wind tunnel tested.