Engineers usually gain valuable knowledge from failures, but seldom as much overseas business as those close to the collapse of vast concrete cooling towers at Ferrybridge coal fired power station in 1965 and at Fiddlers Ferry 19 years later. The only real public civils disaster in the power sector allowed British consultants and CEGB engineers to offer improved cooling tower designs to most overseas countries that still rely on coal fired plants.
The three, 114m tall towers at Ferrybridge collapsed dramatically during a gale. Turbulence, back currents and updrafts broke apart upper sections of the towers lifting them well clear of the remainder.
An aged design, involving a single layer of reinforcement within 125mm thick walls, had created inherent weaknesses and resultant tests on some 360 cooling towers led to more than a third of them being strengthened.
'I was horrified to discover that the widely used design specification had just evolved from a 1920s Dutch development and that, in practice, nobody had been designing the towers from scratch,' recalls Bill Hannah, CEGB's then investigating board secretary. 'We discovered other towers throughout the country in a much weaker state than the ones that collapsed.'
The design review led to wall thickness nearly doubling and reinforcement increasing to two layers.
The subsequent collapse of a single tower at Fiddlers Ferry in 1984, due to a flaw in the construction of its concrete side, led to further improved construction techniques and helped create a corps of engineers able to export their world leading technology.