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TWO STEPS FORWARD, ONE STEP BACK
Milestones along the path of engineering failure
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In 1981, two suspended walkways, fully occupied by guests, collapsed onto a packed lobby at a tea dance at the Hyatt Regency Hotel in Kansas City. The structural design had been altered and the changed design implemented due to a series of management and communication errors during construction. This failure of organization has been much studied as providing a deadly example of how a design and construction team should not operate.
photo : via CommandSafety.com
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Let's begin as we hope never to go on, with what was - until the destruction of the World Trade Center in New York - the deadliest structural collapse in US history. The Hyatt Regency Hotel walkway disaster in Kansas City in 1981 resulted in the death of 114 people and the injury of 216 more. Among any number of popular reports and academic analyses of what went wrong, CommandSafety.com, the website of veteran US firefighter and rescue expert Christopher Naum, provides a concise but detailed and readable analysis. Naum argues that the tragedy proved to be an important driver in the developing field of Urban Heavy Rescue, much relied upon in urban disasters today.
An equally readable but longer analysis, aimed at the layman, may be found in Henry Petroski's excellently titled, "The Engineer Is Human: the role of failure in successful design", in which the Hyatt Regency disaster features prominently.
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This is the crucial design modification that the fabricator made to the Hyatt Regency walkways without written clearance from the engineer. Even if that part of the story appears straightforward - and this is a necessarily simplified version! - it is made less so by subsequent analyses showing that even the original design was not up to state code for Kansas. The devil is indeed in the detail.
photo : via CommandSafety.com
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The legacy of the Hyatt Regency bridge collapse is also felt in the fields of risk assessment and forensic engineering, and involved several prominent experts in these relatively young disciplines at the time. These included structural engineering innovator Lev Zetlin, whose designs for the New York World's Fair featured in the January 2017 issue of this newsletter. After selling his engineering firm in 1972 to the company that was to become Thornton Tomasetti, Zetlin increasingly devoted himself and his consultancy to the analysis of structural failure. He died in 1992 and his life is remembered here, in The New York Times.
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MANY RIVERS TO CROSS
Among famous bridge collapses, the Tay Rail Bridge disaster in 1879 stands as one of the UK's own worst structural engineering failures. At the time, the two-mile bridge was the longest in the world and had been completed less than two years before it fell. The account on engineering-timelines includes details of the original bridge's successors up to the present day.
To delve more deeply, there may be no more carefully detailed source than the dedicated Tay Bridge Disaster site run by mathematician and former British Steel employee, Tom Martin. His Open University web pages on the subject include a nice short video that concludes with the retelling of an eye-witness account of the disaster. History is barely a generation away...
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DON'T LET THE SUSPENSE KILL YOU
Thankfully, there were in fact no humans killed by the spectacular Tacoma Narrows Bridge collapse, captured below - although sadly, a dog that was too scared to leave an abandoned vehicle on the bridge did perish when the deck finally fell.
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Journalist and photographer Howard Clifford seems ready to die for his art in this picture of him leaving the Tacoma Narrows Bridge a little late for most people's comfort. The owner of the image - the Tacoma Narrows Bridge collection at the University of Washington - provides excellent information about the bridge and a host of players involved in its construction and collapse. This particular account indicates that engineer Charles E. Andrew was not to be blamed for the faulty design.
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Thomas Telford's bridge over the Menai Strait, opened to the public in 1826, was the first major example in what became a massive boom in suspension bridge building.
By 1940, when the Tacoma Narrows Bridge opened in Washington State, USA, it was the third longest suspension bridge in the world after San Francisco's Golden Gate Bridge and the George Washington Bridge between New York City and New Jersey. Nick-named "Galloping Gertie", the bridge lasted a mere four months until its famous undulating collapse in high winds.
You can watch it - with salient facts given by the (apparently) near-contemporary commentary - in an unattributed video posted by nuclear physicist Simon Lespérance on YouTube. The "professor of engineering" seen walking on the bridge is F. Bert Farquharson of the University of Washington. From the account on the Washington State Department of Transportation's excellent dedicated web pages (complete with "weird facts", weird fact fans should note), it seems a surprising number of people were keen to get on the bridge that night! More recent reports suggest that the often-reproduced live footage may have been accelerated for dramatic effect. Worth watching, though.
Lower on drama but higher on clear explanation are a series of short Open University videos delving into the collapse of the Silver Bridge across the Ohio River in 1967. This, tragically, resulted in the deaths of 46 people. The failure was attributed to poor maintenance as well as insufficient redundancy in the design: unlike its famous collapsing predecessors, the bridge was 39 years old at the time. Subsequently-built suspension bridges were already using safer designs with greater redundancy in case any single element should fail.
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Dr William (Bill) Brown, designer of the innovative streamlined deck adopted for the Severn Bridge in the 1960s, was a considerable contributor to long span suspension bridge design. Brown realized the full importance of aerodynamics in his field, and with his company Brown Beech (B2) worked to develop aerodynamic tests for different models. The model wind tunnel pictured here at the ICE in London was developed in 1988. It may generate better bridge design, but is there not still something menacing about that giant radiator in the distance?
photo : copyright www.engineering-timelines.com
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"THE CONCRETE AND THE CLAY BENEATH MY FEET BEGINS TO CRUMBLE..."
The jaunty refrain of 60s beat band, Unit 4 + 2, would have rung hollow indeed to contractors Balfour Beatty - or anyone else involved - following the collapse during construction of part of the new Heathrow Express tunnel in 1994. Almost miraculously, no-one was hurt, but the accident has been called the UK's worst civil engineering disaster in the last quarter-century. It caused severe delays to programme, cost Balfour Beatty a fine of £1.2million, and revealed a level of risk that is truly awe-inspiring.
For those unfamiliar with the details, the BBC report of the judgement provides a summary. The report of the Heath & Safety Executive has been reproduced by the Temporary Works Forum here.
It seems there are lessons that have to be learned more than once, unfortunately. The HSE report pin-points the over-arching cause as "a cultural mind-set focused on attention to the apparent economies and the need for production rather than the particular risks." Does that sound a bit like "cutting costs and rushing the job"?
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Above, one part of the aftermath of London's Heathrow Express tunnel collapse in 1994. No-one was hurt but the impact on cost and construction was huge and far-reaching. If you happen to be a subscriber to New Civil Engineer, you can read this informed commentary by the editorial team.
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From the point of view of technological progress, it is disappointing when organizational failure leads to misuse of new techniques. Two hundred years ago, in very different times, the Brunels were under no illusions about the dangers of their innovations in tunnelling technology under the Thames, but pressed on regardless, putting their own lives on the line.
After the Heathrow Express tunnel collapse, the tunneling method used - the New Austrian Tunneling Method, or NATM - came under immediate scrutiny. "New or unfamiliar technologies require rigorous understanding and assessment before they are adopted," the HSE report notes. A special HSE report focusing exclusively on NATM was commissioned, and work on all NATM tunnels under construction in London ceased, awaiting the result. You can read that result here.
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DAM DISASTERS
For most high-profile engineering failures, the threat to human life is at least limited to the site of the accident. But then there are those in a special category of consequence, reaching far beyond the location of the original fault...
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The front page of the Los Angeles Times on Wednesday March 14th, 1928, reports on the disaster that began under three minutes before midnight on March 12th (put down your mobile and take a moment to reflect on that time lag between the event and the news!). The Smithsonian Magazine offers a an account of the disaster that considers in particular the rise and fall of the dam's engineer, William Mulholland.
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The St Francis Dam disaster in 1928 resulted in the loss of between 430 and 450 lives. As well as questions about design, risk and engineering professionalism, its story is part of a highly political and continuing narrative about how and where cities get their water. From an engineering point of view, readers might light to take a look at the St Francis Dam case study page of the American damfailures.org. In fact, the whole site is worth a browse for anyone with an interest in this area.
Fast forward the best part of a century to Russia's Sayano-Shushenskaya dam and power plant disaster in 2009, which, with 75 dead, claimed more lives than any Russian industrial disaster bar Chernobyl. The hydro-electric plant is Russia's largest power station and the implications of the loss of power involved added a further dimension to the catastrophe.
Unsurprisingly, the event has been analysed with interest by other economies reliant on high proportions of hydro-electric power. American writer Joe P. Hasler - not an engineer himself, but a frequent contributor to the "What Went Wrong?" pages of PopularMechanics.com - offers an interesting account.
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The Sayano-Shushenskaya dam and hydropower station in full working order, as depicted on Russian travel blog, Russiatrek.org. At time of posting in 2014, complete repair and return to full operation were imminent. The power station - Russia's largest - is back up and running today.
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POWER TALK
Who said, "With great power comes great responsibility?" Before you reach for Google, it was not a Greek philosopher or a Renaissance thinker - it was a character in Spiderman. Some might argue that the inspiration of classic comic creator, Stan Lee, should not necessarily be used as a basis for making decisions about the public good. And yet, as we contemplate the the potential scale of nuclear power-related disaster over the last half-century, the sentiment holds true.
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The world held its breath in March 2011 as Japan struggled to contain the escalating effects of flooding by tsunami at Fukushima nuclear power station. The hydrogen explosion pictured above, although dramatic in appearance, was far from the most serious problem faced during the melt-down. The U.S. Goverment's report on the disaster is concisely summarised by opensourceinvestigations.com.
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The potentially massive radioactive fall-out from the Fukushima nuclear power station disaster in 2011 has thankfully been limited and largely contained. Fall-out in other areas, however - economic, social, environmental and on the nuclear industry worldwide - is monumental and as yet unquantifiable.
Among literally hundreds of books, articles, reports and other commentary, former president of ICE, Mark Whitby, has distilled the story of the disaster into a gripping one-hour lecture, occasionally updated and repeated around the UK. If you've missed him in person - most recently at an ICE event in Ipswich - you can listen to the version he gave in London earlier this year. It certainly makes an hour of ironing, or filing, or sorting the VAT receipts, fly by.
Of the longer accounts, Whitby recommends Ryusho Kuroda's On The Brink, accessible for readers of all levels of expertise. "You can lend it to your parents," he says at the start of his recorded lecture, "And they'll probably wonder why you became an engineer!"
For a rather drier but technically clear account written at the time of the disaster, try bravenewclimate.com's post harvested from the work of MIT- affiliated engineering systems expert, Josef Oehmen.
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FOUNDED ON SAFE GROUND?
The origin of Fukushima's troubles was an earthquake, generating not one but two tsunamis - only the second of which overpowered the protective systems in place around the reactors. Unsurprisingly perhaps, seismic activity has been behind a fair number of history's most famous structural collapses, a dozen of which are listed by weburbanist.com.
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It is perhaps unfair to list the Leaning Tower of Pisa as an engineering failure - its survival could equally be considered a massive success. Certainly, as a tourist attraction it is considered one of the wonders of the world, and as an advertisement for why geotechnical engineering is an important specialism, it is second to none.
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The Leaning Tower of Pisa is a rare example of an engineering failure that has been of greater note than any success could have been. How many other 14th Century bell towers can you name straight off the cuff? Madrid Engineering Group has kindly provided a succinct online case study of its history and the problems that made it famous.
Professor of Engineering John Burland worked on a 1990 project to preserve the tower, which of course included retaining its famous tilt. But to what degree? Scienceinschool.org produced this highly comprehensible report on the project as part of a personal profile on Burland, making extensive use of his own words.
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Pisa's not the only leaning tower with profile, in seems... Failed structural demolitions have their own special cohort of online fans, although this example from Providence, Rhode Island had already garnered a whole host of local followers when the world wide web was little more than a twinkle in Tim Berners-Lee's eye. The fantastically-titled artinruins.com provides a forum for contemporary reports of the failure. And many YouTube compilations prove that this instance of demolition failure was far from unique.
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AND SO IT FALLS DOWN
To round off our sombre theme on a somewhat lighter note, we invite our readers to kick back and join thousands of viewers in the simple pleasure of watching demolitions... backwards. If it only construction were that easy in real life.
Regular readers of engineering-timelines newsletter may be wondering... where are the women in this issue? Have there simply been no female engineers involved in disasters of any kind? Your questions and many others may be answered at the Institution of Engineering & Technology's (IET's) one-day conference on Monday 27 November: The History of Women in Engineering in the UK. There's still time to register.
Finally, while it's not quite on our subject of failure and collapse, Historic England's current search for notable sites of loss and destruction is thematically close enough to warrant a mention here. Intrigued? Visit the dedicated webpage to learn more...
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