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Recent Engineering Debacles 7
- Thread starter hidalgoe
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Twoballcane
Mechanical
How was Katrina an engineering degacle? That was a Catogory 5 storm (extreme conditions). Where as the epoxy plug used for the concrete ceilng pannes was just a dum design (plain old gravity caused this failure).
Tobalcane
"If you avoid failure, you also avoid success."
Tobalcane
"If you avoid failure, you also avoid success."
Yes, if hurrincanes were engineered, Katrina would be a crowning jewel of engineering success, a perfect storm!. The levy designs were not engineering debacle. They were not designed for Category 5 storms or resulting surges and was well known.
In fact the existence of New Orleans city is awed engineering feat. Without the continuously running pumping system it would not exist.
Rafiq Bulsara
In fact the existence of New Orleans city is awed engineering feat. Without the continuously running pumping system it would not exist.
Rafiq Bulsara
Here are the examples of "debacles":
Rafiq Bulsara
Rafiq Bulsara
MikeHalloran
Mechanical
More political than technical.
The 'local' levees were not designed to withstand impact from barges, of which there are many.
No one seems to have authority or budget to seize and secure or dispose of derelict barges.
Some landowners would not allow access to the dry side for maintenance. Yeah, I'd have thought eminent domain would take care of that, but in Louisiana, apparently it doesn't.
There was disagreement about who was responsible for maintenance.
There was no money for maintenance.
The only strictly technical failing that I see is a lack of structural redundancy in the levees. The "I-walls" are constructed in segments, basically like tilt-up panels, with water seals but no structural linkage between them. A barge hit tilts just one of them, producing two notch weirs, between the tilted panel and its neighbors.
The barge owner of course doesn't report an allision, and the landowner doesn't have money available for excavating the water side mud and re-erecting the panel, nor authority to do it. Those secondary levees were designed by USACE, which then assumed that maintenance would be conducted by local authorities, of which there are many. .. and the finger- pointing goes round and round and nothing gets fixed.
Mike Halloran
Pembroke Pines, FL, USA
The 'local' levees were not designed to withstand impact from barges, of which there are many.
No one seems to have authority or budget to seize and secure or dispose of derelict barges.
Some landowners would not allow access to the dry side for maintenance. Yeah, I'd have thought eminent domain would take care of that, but in Louisiana, apparently it doesn't.
There was disagreement about who was responsible for maintenance.
There was no money for maintenance.
The only strictly technical failing that I see is a lack of structural redundancy in the levees. The "I-walls" are constructed in segments, basically like tilt-up panels, with water seals but no structural linkage between them. A barge hit tilts just one of them, producing two notch weirs, between the tilted panel and its neighbors.
The barge owner of course doesn't report an allision, and the landowner doesn't have money available for excavating the water side mud and re-erecting the panel, nor authority to do it. Those secondary levees were designed by USACE, which then assumed that maintenance would be conducted by local authorities, of which there are many. .. and the finger- pointing goes round and round and nothing gets fixed.
Mike Halloran
Pembroke Pines, FL, USA
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- #9
I think most "debacles" occur when accountants, MBAs and Clients disregard what engineers are trying to do and, for the sake of making better business decisions and improving schedule, go and do whatever they want and bully the engineers into agreeing with them under the threat of losing business - or your job - if you don't.
Regards,
SNORGY.
Regards,
SNORGY.
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- #10
Many failures of engineered systems (buildings, bridges, products, etc.) occur; however, few are caused by engineering failures. Most are caused by construction deficiencies or operational issues (poor maintenance, overloading/over-use, environmental deterioration, aging, etc). Should engineering be done so as to countermand these possibilities or even inevitabilities? No. In general, some of that is balanced in the design (we design structures for say a 50-year life and pavements for 20 years, etc.); however, things don't last forever. That's one reason most states have a statute of repose that negates an engineer's liability for design after a period of time, usually 10 or 15 years.
msquared48
Structural
"Most are caused by construction deficiencies or operational issues (poor maintenance, overloading..."
The perfect example of this scenario is the Hyatt Regency Walkway failure back in the early 80's. It was due in part to overloading and crowd resonance (too many people plus dancing to a beat), but mainly due to a connection design modification that doubled the stress on the connection - contractor wanted something simpler and more buildable - $$$ for him - and the reviewers (engineers) missed it.
Unfortunately for us, there are many others. It was immediately after this failure though that structural engineers' libility insurance premiums went through the roof.
Mike McCann
MMC Engineering
The perfect example of this scenario is the Hyatt Regency Walkway failure back in the early 80's. It was due in part to overloading and crowd resonance (too many people plus dancing to a beat), but mainly due to a connection design modification that doubled the stress on the connection - contractor wanted something simpler and more buildable - $$$ for him - and the reviewers (engineers) missed it.
Unfortunately for us, there are many others. It was immediately after this failure though that structural engineers' libility insurance premiums went through the roof.
Mike McCann
MMC Engineering
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- #12
That's a matter of perspective.
One could rationally argue that it was an engineering debacle because the designers instantiated something that was difficult to implement and repair, and would be likely subject to a field modification, which turned out to be case. Had the original designers instantiated something that met the aesthetics and was relatively easy to construct, the problem might have never occurred. Bear in mind that the original design was not even conducive to an structural repairs, since it might have required the entire structure to be dismantled to just get to the middle sections.
TTFN
FAQ731-376
One could rationally argue that it was an engineering debacle because the designers instantiated something that was difficult to implement and repair, and would be likely subject to a field modification, which turned out to be case. Had the original designers instantiated something that met the aesthetics and was relatively easy to construct, the problem might have never occurred. Bear in mind that the original design was not even conducive to an structural repairs, since it might have required the entire structure to be dismantled to just get to the middle sections.
TTFN
FAQ731-376
Seeds of debacles are sewn when an owner selects an engineering firm based on "price" or worse through an architect! Eventually, the unlucky ones pay the price and the "rewards" and lucky ones escape.
Add to this all non-technical people making project related decision and you have a mess at your hands.
Engineers themselves are not blameless either. Most large A/E firm cannot retain good engineers, some good engineers are turned into bad managers. After their stellar marketing team secures a project, their "designers" go to work. The results are usually sad, unfortunately not all come to light in time, of ever.
Rafiq Bulsara
Add to this all non-technical people making project related decision and you have a mess at your hands.
Engineers themselves are not blameless either. Most large A/E firm cannot retain good engineers, some good engineers are turned into bad managers. After their stellar marketing team secures a project, their "designers" go to work. The results are usually sad, unfortunately not all come to light in time, of ever.
Rafiq Bulsara
patprimmer
New member
If greed, corruption or ignorance take over at any level, a debacle can result.
In my limited experience in construction, it is often at the contractor level. In automotive it has been mainly engineering being over ruled by marketing or styling or both.
If an engineer signs of on an unsound design because he will otherwise lose a job, that can be considered greed and corruption as he did sign off for profit.
Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &
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In my limited experience in construction, it is often at the contractor level. In automotive it has been mainly engineering being over ruled by marketing or styling or both.
If an engineer signs of on an unsound design because he will otherwise lose a job, that can be considered greed and corruption as he did sign off for profit.
Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &
for site rules
MacGyverS2000
Electrical
Mike,msquared48 said:
Are you sure about the overloading and resonance part? It has been quite a while since I've seen/read anything on the subject, but I thought the overload was mentioned as it related to the changed design (inferior side-by-side rods design). And from what I recall of the video one guest was taking at the time of the incident, no one one the walkway was dancing, they were just standing around talking to each other. Unfortunately, the guy decided to change his camera's battery about a minute before the walkway actually collapsed, so there's no video of the actual collapse.
Dan - Owner
msquared48
Structural
Yes, as there were a LOT of people on both walkways watching some event, and the music was playing, causing people to move in unison, increasing the load further in a cyclical manner. The connection change was the Main problemn as you say, but the loading situation did not help.
Mike McCann
MMC Engineering
Mike McCann
MMC Engineering
In addition to the awkward construction, which led to the field modification by the contractor, the original system was underdesigned, and with the modification, there was basically no margin left. If the original design had the appropriate design margins, the modifications might have survived the heavy loading.
TTFN
FAQ731-376
TTFN
FAQ731-376
Usually an attempt to solve a natural problem includes unintended consequences. Controlling the flow path of the Mississipi river is good for ship and barge traffic. However the navigational solutions affect the normal silt in the river delta. No silt and the land sinks. Also, we engineer short-term solutions. Nature has longer term consequences.
msquared48
Structural
JAE:
The people were watching a dance contest, so there was music, and could have been incidental rythmical movement from the crowd due to the music.
I am not saying that there was harmonic motion that could have incited a fundamental mode of the walkway. What I asm saying is that the harmonics of the crowd could have caused a sinusoidal variance in the gravity load of the crowd on the walkway, cyclically amplifying the live load to the connection, already doubled in stress over the original design.
Kind of the straw that broke the camel's back situation.
Mike McCann
MMC Engineering
The people were watching a dance contest, so there was music, and could have been incidental rythmical movement from the crowd due to the music.
I am not saying that there was harmonic motion that could have incited a fundamental mode of the walkway. What I asm saying is that the harmonics of the crowd could have caused a sinusoidal variance in the gravity load of the crowd on the walkway, cyclically amplifying the live load to the connection, already doubled in stress over the original design.
Kind of the straw that broke the camel's back situation.
Mike McCann
MMC Engineering
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