Paris Air Terminal Collapse; $900 M dud?

http://www.helenair.com/articles/2004/05/24/national/a02052404_01.txt

I've stared at a few photos of the collapse at the Paris air terminal and to my eye, the structure looked to be too fragile. I'm predicting that they'll have to rip the whole thing down; it cost $900 million to build.

I thought it funny/sad that the day they were doing the final inspection and approvals, a light fell from the ceiling right in front of the inspectors. I hope they had insurance on it.
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Is it me or is there more building collapses recently.

France suffered with the walkway collapse to the Queen Mary 2 as well

http://news.bbc.co.uk/2/hi/europe/3713053.stm

Last week explosion at small plastics place in Glasgow destroyed building and killed 9

http://news.bbc.co.uk/2/hi/uk_news/scotland/3728701.stm

Near Edinburgh is the Forth Bridge, railway bridge that is least twice as strong as it needs to be, it was built a few years after a rail bridge collapse, Tay Bridge, about 40 miles up the coast.

Public faith in engineers needed restored, may be we are back there again.

Adam

New cracking noises heard in terminal

"PARIS (Reuters) - Construction workers heard new cracks Monday in the roof of a Paris airport terminal where part of the ceiling collapsed a day earlier, an airport spokesman said....

ADP Chairman Pierre Graff has said the entire terminal would be torn down if the building turned out to be unsafe."

Hello PhotonBoy,

I have noticed that as more advanced computer modeling is used for design work, the factors of safety are being reduced. This allows for less materials being used which keeps costs in order. The models are good, but it is difficult to model every condition.

An example is the composite industry. Years ago the standard design was wamped with a safety factor of 10. This made parts very heavy and thick. Now, in some applications, the safety factor has been reduced to 1.5. Note that if the safety factor goes below 1, the part breaks.

The interesting thing is that even with 10 safety factors, things broke. Now we have a better understanding of the forces at work, have better analytical tools, and years of historical data to draw from, and things still break.

Of course, a more efficient design requires careful attention to construction methods and materials.

I will be interesting to see what they come up with for the cause of the failure.

Tom

Tom, I agree with you on the safety factor issue.

I'm surprised at the extremely thin concrete that was used for the terminal. I read where they expected the structure to sag as much as 8 cm. after construction. I'm not sure that concrete was the best material to use in this application. The walls would also be continually stressed by barometric pressure differences, high winds, vibration by jet engine exhaust, thermal stress from sunlight, expansion and contraction due to day-night temperature differences, etc.

Even if the remaining structure is sound (which I doubt), they may still need to destroy it due to the loss of public confidence.

Another recent one

http://www.mosnews.com/news/2004/05/21/transvaal.shtml

Adam

I get goosebumps thinking that I passed through that terminal about 2 times in the last 4 months. Man ! you can bet I'll be looking at overhead ceilings as I RUN through these things in the future. Don't architects have a way to test the soundness of construction or plant sensors that monitor for worrisome shifts in modules or something?? CDG is a very Nice Airport otherwise- on my top 10 list.
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If you ask me it all seems like part of the lousy trend of reverse engineering an aesthetic conceptualization. What Tage Frid called "cold designing". He believed that engineering and aesthetic have to evolve together based on solid knowledge of the working characteristics of the materials involved. Lately it seems that designers just want things to match the aesthetic "vision" at all costs, even if that means throwing all practicality and known structural performance variables out the window. If you've ever had an architect throw a complete hissy at you because you told them their concept is understructured and dangerous, you'll know what I mean. Hell most times you can't even talk structure with the designers!

I'm not even gonna get into poor building practices perpetuated by ungodly production deadlines!

The Dilbert cartoon is a nice showing of engineers versus Marketing! (or designers in this case).

It is sad that that whole terminal will have to come down. Who will ever trust it now?

Form follows function

Creative types will argue against that maxim endlessly, and often skirt it when told otherwise by experts.

It's not surprising that creative types do that when aesthetic is their master - no more than it's surprising that engineers and the like often don't care what their product looks like so long as it fuctions.

...but it's rare that a well-designed - yet ugly - something killed someone due to lack of attention to aesthetics.

I don't know much about this but I thought they ran 'static loading calculations'. Is if possible that they did not put in all the number of the various loads when they did the modeling.

Or a brother of a brother provided the concrete perhaps....

There were reports of puffs of dust, so the concrete could be an issue. Imagine poorly set concrete with voids, cracks, improper mixing, tamping, etc. Under the tremendous compression it would be enduring, combined with continuously changing stresses due to expansion and vibration, it's possible to imagine cracks worsening in time, then letting go.

If I recall correctly, even Frank Lloyd Wright's designs were famous for their leaks and stress cracks.

-Bill

Odd, I recall hearing that Frank Lloyd Wright built robust buildings. The slender columns in the Johnson Wax building has a safety factor in excess of 10 under static load.

His Imperial Hotel in Tokyo survived a devestating earthquake not too long after its construction.

http://www.channelnewsasia.com/stories/afp_world/view/86861/1/.html

"The (terminal) was like a performance, at the very outer limit of the material. Everything was calculated and taken into account. But in this outer limit all you need is a piece of metal in the wrong place or a bad lot of concrete -- no-one can protect himself against that," said Paul Chemetov."The airport's operations director Hubert Fontanel said that temporary supports will be installed in the section of the terminal where the latest damage appeared. "It is important for the investigation to keep the structure in its actual state," he said.

...

"...The affected section is symmetrically opposite the part that was destroyed in Sunday's collapse. Both areas differ from the rest of the structure in containing access points to three boarding walkways, and there was speculation this may have been a factor in the disaster.

Static design loads with a 10x safety factor is pretty standard... And it is other problems (materials, construction tools and processes, settling, leaks/aging, non-standard designs and building techniques, etc.) that are also important.

For example, his famous Falling Water house had to have major structural work done:

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In 1994, our continued concerns about the structural integrity of the house led us to engage the engineering firm, to conduct a comprehensive analysis of the master terrace cantilever using non-destructive testing methods. The results of the study indicated that the master terrace could not function as an independent cantilever, and that it was transferring its load to the living room level. Furthermore, the study predicted the ultimate failure of the living room cantilevers if no remedial action was taken. The study recommended that the structure be repaired. In order to stop the deflections and provide a margin of safety, Western Pennsylvania Conservancy installed temporary shoring in 1997. A 1999 peer review approved the proposed plan for the structural repair, which will strengthen the living room using post-tensioning, and waterproofing the building.

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Another is the Marin County Civic Center. Here is a Grand Jury Report about ongoing maintenance problems:

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Although its design was conceived more than 40 years ago, the building even today has a futuristic look and feel thanks to Wright's distinctive style. Preservationists view the Civic Center as one of his finest public buildings. Nevertheless, the roof has leaked for years, leaving water stains on the ceiling and buckets in the hallways.
...
The Marin Center is fast approaching an advanced state of disrepair, and it presents hazards for workers as well as for visitors attending events. Recently, one of the sofas of the nine cantilevered canopies that ring the Exhibit Hall fell when two roofers were standing on it while inspecting for dry rot. (See photo in APPENDIX B - Not included in this web version). Fortunately, no one was hurt. The Grand Jury observed that all of the canopies are sagging and are currently held up by wooden 4 x 4s. The canopies sag to such a degree that the emergency exit doors cannot be fully opened. Repairs such as these are costly; and deferred maintenance only increases costs and presents unexpected and significant fiscal challenges.

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Much of these problems were the result of on-going leaks that nobody could fix. I remember my father talking about the leaks 30+ years ago.

Leaking Wright designs are legend in the construction trades:

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OCTOBER: WESTCON member Chris Nelson will give us some background and insight about the "Repair of the Frank Lloyd Wright Marin Civic Center". (Would you believe a Frank Lloyd Wright building that no longer leaks?)

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I am not trying to take away from the beauty of his designs--but they did tend to exceed the capabilities of the materials and construction trades available at the time.

Here is an article Frank Lloyd Wright is not God that quote:

[ QUOTE ]
All of these reflections are prompted by a good short piece in Wednesday's WSJ by Lee Rosenbaum about the campaign to repair one of Wright's most famous buildings, Fallingwater. That's the house in the Pennsylvania woods that seems to be all cantilevers and horizontals dangling out over a stream. It was completed in 1939 and is often cited as one of the great houses of the 20th century; some call it Wright's greatest work. Rosenbaum, who seems happy to accept the greatness of FLW, is nonetheless unsparing in his descriptions of how temperamental a house (or "house," given that it has so seldom managed to function as one) Fallingwater is. The bill for the repair work? $11.5 million.

A few excerpts from Rosenbaum's article:
<ul type="square">[*]Perilously perched over a western Pennsylvania waterfall, Fallingwater has been in constant danger of falling into water and has been persistently penetrated by falling water -- some 60 chronic leaks ...
[*]Structural engineer Robert Silman slammed Wright's stone-and-concrete masterpiece as "not safe from the day it was built ... One side of the living room had sagged almost seven inches ... "
[*]"Wright saw the exterior and interior as the same, flowing together. This makes a great aesthetic impression, but it's terrible for waterproofing," commented Ms. Jerome [of the company overseeing some of the work] ... [/list]

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And back to the topic of the thread--it seems that the airport building was not over stressed by passengers (only four or so killed) or weather. This seems to be more the result of an over-architectured design with few redundant structural elements (and/or large safety margins)--And when one element failed (for whatever reason), the rest of the structural unit failed catastrophically. Does not sound like a well engineered building. But we will have to await the results of the investigation to be sure what happened.

-Bill

PhotonBoy 05/24/04 11:08 AM: "The walls would also be continually stressed by barometric pressure differences, high winds, vibration by jet engine exhaust, thermal stress from sunlight, expansion and contraction due to day-night temperature differences, etc."

Weakened Concrete Is Cited in Collapse at Paris Airport

NY Times, July 7 (sic) 2004

"...The commission said it would consider how the materials might have settled over time and whether changing outside air temperatures caused the steel framework to expand and contract against the concrete, which was kept at a more stable temperature by air-conditioning inside. Such movement may have weakened the concrete at the points where it is joined to the framework by the steel struts, causing the struts to punch through the concrete shell...."

I predict they'll need to tear down the whole thing. Kiss $900 million good bye. The expanding/contracting exterior metal outer cover was supported by metal bars. These bars, under pressure, penetrated the concrete below which was held at a constant temperature by the heating/cooling system. I can't see any easy fix for the problem.

I guess they have anounced the reason for the collapse:

CDG To Rebuild Collapsed Terminal Roof

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An official report last month concluded that the terminal roof had been weakened by temperature changes that had caused the building's outer shell to shift by one or two centimetres daily and wore down the concrete roof.

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Hurry, you too can still invest in this important structure!

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The French government said last month it planned to press ahead with selling off shares in ADP, which helped build the terminal at a cost of EUR750 million (USD$973.2 million). It is designed to handle 10 million passengers a year.

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A longer article on the costs to rebuild the roof (they will leave the rest of the structure intact):

IHT

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Graff said the airport operator would start to take bids on demolition of the entire 650-meter roof of the boarding area "within weeks," and to take bids on rebuilding it "within a few months." The building's lower levels are considered safe and can remain in place.

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-Bill