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Mention the Tay Bridge disaster today and the result is likely to be a smirk: its strongest association is famously the worst poem, by the worst poet, published in English. Written — perpetrated might be a better word — by William Topaz McGonnagall, it begins:
“Beautiful railway bridge of the silv’ry Tay
Alas! I am very sorry to say
That ninety lives have been taken away
On the last sabbath day of 1879
Which shall be remembered for a very long time.”
and goes sharply downhill from there.
So far, so amusing: bring out the comedy Scottish accent and get orating. But a look back into the Engineer archives will quickly banish the smiles. The disaster was horrible and unprecedented: at the height of the Victorian age of heroic engineering, in the crucible of the industrial revolution and the homeland of the steam railway, a showpiece of engineering collapsed while a train was crossing it. Nobody survived; there were sixty known victims, but only 46 bodies were ever recovered. It’s now believed that as many as 75 people died (McGonnagall’s fact-checking was a bad as his poetry).
The Engineer’s report on the disaster shows a publication in shock. ‘The daily newspapers have told the world all that is known abou the circumstances of the catastrophe; and we have no intention of again going over the harrowing details,’ it says. ‘It is our province… to consider how and why the bridge fell.’
Even this ultra-rationalist magazine admits its unease over the collapse of the bridge. ‘Its fall is beyond any question in some way a reproach to the engineering science of Great Britain,’ it says. ‘Our only comfort is that nothing of the kind has ever happened before.’
The report details the construction of the bridge; the way its iron supporting towers were supported on brick pillars (which, in fact, still survive alongside the bridge that replaced the ill-fated structure); and the changes that were made to the design by chief engineer Thomas Bouch as the bridge was built. It seems to discount the idea that the winds blowing directly against the side of the bridge on the night of the disaster, with gusts now estimated to be as high as 80mph (129km/hr), could have caused the central section of the bridge to topple. ‘There can be no doubt that the wind blew with the force of a hurricane,’ it says. ‘We shall assume that it exerted the, in this country, almost unparalleled pressure of 60lb on the square foot.’ But the girders were well cross-braced and even this force should not have been enough to break them, it concludes.
The report also discounts the idea that the train was blown off the rails and struck the inside of the box-girder construction above the train line; it was travelling too slowly, it says. In fact, nothing in its analysis shows up any obvious engineering weakness; the report concludes that it awaits the result of the enquiry.
When the enquiry finally reported, it concluded that the bridge had been ‘badly built and badly maintained.’ The cast iron in the structure was not strong enough, owing to problems at the foundry that had supplied it; moreover, the cross-bracing in which The Engineer had so much faith was inadequate to stand up to repeated stress of high storms, and had been weakened in the years before the collapse. Bouch never worked again, and his previous designs were condemned: he died in October 1880. His obituary in The Engineer, mentions his “rough rule-of-thumb modes of procedure and reasons for “putting a bit on and taking a bit off”.’
Going back to the lamentable McGonnagall, although his poem is dreadful, the ending is something that no engineer could deny:
“For the stronger we our houses build
The less chance we have of being killed”
Nothing to add to opinions on engineering….but I forever marvel at the wonderous skill and talent of the engravers of the period, how they achieve such a variety of tones and effect
“The lighter blades also make it possible to design new wind turbines that have lighter and less expensive components, such as the drive shaft, tower, and foundation. Instead of a 24-ton rotor, you might have a 15-ton rotor. That’s a substantial weight to save on the end of a long cantilevered tower,”- David Cripps, senior technical manager at Blade Dynamics.
http://www.technologyreview.com/news/510031/the-quest-for-the-monster-wind-turbine-blade/
Talk about a dumb quest. The bigger the turbine the higher the nacelle AND the higher the side loading. The taller tower will need to be stronger and have a heavier foundation. This factor is doubly important for the stability of floating turbines, which would cost a fraction to install.
The tower is a cantilever in respect to side loads, not gravity.
For both the ETI and the wind industry as a whole, logical reasoning is notable for its absence. Nowhere more so than in ignoring the need for energy storage. (They say it’s not their responsibility!!)
In the 19th. century, poor Thomas Bouch was presumably unaware of the lateral loads. What excuse can there be in the 21st. century?
Allowing some sympathy for Bouch, it has to be said that the old Tay Bridge looks wrong – the width of the base, relative to its height. As a “rule-of-thumb”. . . .
Engineers learn from experience and build for posterity, if only accountants would let them.
Greedy men calculate their cost/benefit analyses without a moral compass. The Wormit foundry wasn’t prosecuted for culpable homicide.
I guess the iconic Forth Rail Bridge was an expensive over-reaction to the Tay Bridge disaster, but surely that’s not a bad thing. 125 years later it looks like good value for money.
“Painting of the Forth Rail Bridge is now complete following a 10-year, £130M refurbishment and repainting project, delivered by Network Rail.” Why doesn’t the train company pay for it?
“The new paint is a specialist glass flake epoxy paint, similar to that used in the offshore oil industry. It is designed to last 25 years, but is expected to last much longer.” Could be good for another 125 years?
The Forth Road Bridge was opened in 1964. Errors in QC and construction have left a legacy of higher maintenance costs and shortened its useful life-span to 50 years.
“The corrosion problems in the cables mean that it is currently estimated that the bridge will be closed to HGV traffic by 2013. The construction of a supplementary cable-stayed bridge to the west of the current site was proposed in 2007, at a minimum potential cost of £3.2 billion.”
The legacy from poor construction, QC and maintenance in the States is an astronomical bill.
http://www.infrastructurereportcard.org/fact-sheet/bridges
“built to last 50 years” is not an intelligent design parameter. There can be no doubt, it’s a stupid false economy. And one of the solutions is, – “Increase (federal/state) funding for long-term research.”
Should we design offshore wind farms to be scrapped every 20-25 years, or serviced, refurbished and recycled for ever? When will intelligent governance deliver on industrial R&D?
Why was all the blame put on poor Thomas Bouch. He only designed the bridge, he did not build it. The blame I think lies with the Wormit Foundry for using Beaumount egg in the building of the bridge. No wonder the bridge fell down.
Fellow Bloggers may enjoy a short piece from a book I have written: which also describes that famous (should that be infamous) bridge.
Chapter heading: Education is what survives when all that has been learned has been forgotten.
B F Skinner
All Engineering undergraduates at St. Andrews were required to attend a lecture by the Dean on the first day of their first term. Professor Dick, an unfortunate name for 18 year old students to ponder, started with a short history of the subject and our new profession, gave warnings about the need to work hard, and then invited the entire class to accompany him down to the River Tay, which conveniently ran close to the University. There, in the water was the final part of his lecture: the rusting remains of the original Tay Railway bridge.
“Gentlemen,” he said, even though there was one girl in our class, “Gentlemen, never throughout your careers, nor your practice of the great profession that you are soon to commence, forget that any attempt to defy any of the Laws of Nature will result in both immediate detection and punishment. And if not for you personally, certainly for those who will have had the misfortune to use your skills. Which will have been shown to be wanting.” Splendid words, worthy of the Institution that he served, and the ideals that should unite all Engineers. Indeed should unite all professionals in whatever sphere of science and technology, whose role in life is solely to direct
“the great forces of Nature to the benefit of mankind.”
MJB
Decided to read the whole poem and it’s worse than those of Paula Nancy Millstone Jennings (one for the hitch hiker fans).
Working in failure mode analysis, I was wondering what an enquiry would make of the disaster today, would they have the same conclusions etc.
Wonder if today the train would have been halted till the winds dropped from 80mph before crossing. From the picture, the train looks as though it must have been the contributing factor as the other parts of the bridge look as though they survived intact.
With the recent Genoa road bridge collapse, perhaps a timely reminder that no matter how skilled we think we are, like the Tay our designs and builds are still fallible.
As they say about bridge designs ‘good designs survive the bad ones eliminate themselves ‘.
Another factors in the Tay collapse –
1. the bottom of the hollow cast iron columns were filled with concrete in summer; in the cold of winter, the cast iron columns shrank tightly onto the concrete core & many cracked & split vertically (as can be seen in this photo) http://www.open.edu/openlearn/ocw/pluginfile.php/75947/mod_oucontent/oucontent/648/3f53f892/648ee63d/tay_1_040i.tif.jpg .
2. The joint between the high spans that fell & the rest of the spans was grossly inadequate
for any side loads ( https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQQ806RuYYUavpwl1BvVuUavPNvZXyLhr_AzZzizydCmxA6Sc_5 )
The original lower truss girders are still in everyday use in the replacement bridge… 139yrs later.
https://i.ytimg.com/vi/ZylivFIrIVE/maxresdefault.jpg