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The WTC1 and WTC2 were designed to withstand multiple 707 impacts?

Minadin

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Minadin
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In order to not pollute the original thread by delving into a specific sub-topic with a number of replies by non-conspiracists, I am starting a new thread.

In the thread "Twoofers Only:", Jhunter asks Conspiracy Theorists to list some of the things about which they believe Gravy is demonstrably wrong. The first reply included this:

StickMan2008 said:
The debunkers love to focus on the speculations and divert attention away from smoking gun facts.

For instance, they love to focus on how it's speculation if whether a 707 could do comparable damage to a 767 (although if you have a fundamental grasp of science you could figure this out with a kinetic energy formula. That and the fact that the building was designed to take SEVERAL 707s which is more than comparable to a single 767)
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(bolding mine)

I've not heard this particular assertion before now, and I'm wondering where it originates. Does anyone know where this idea comes from?

Most of the information I've read is from Les Robertson and seems to indicate that the energy from the combustion of the fuel was not considered, and that the impact they considered was of a 707 lost in fog and traveling at near landing speed, rather than full throttle such as on Sept. 11, 2001. Figures below are from his article in the Bridge magazine:







Which seems to confirm what I had initially thought. I don't see any references to multiple aircraft impacts there; I can't even fathom why you would try to design for it. A single airliner crash is rare and catastrophic enough as it is.

Does anyone know what StickMan is talking about?
 
I'm just going from memory here, but I think someone said that the structure of the Towers was such that an aircraft striking it would be like poking a hole in a screen door.

I also recall that Robertson said they had no way in the mid-60s to model the damage caused by the fuel an aircraft would be carrying, so they basically ignored it for their calculations.
 
I think he basically stated that in the article I linked above. "Poking a hole in a screen door" sounds like someting a conspiracy theorist would say, not an engineer. Reminds me of the "Rabbit Cage of Doom" experiment on You-Tube.
 
1. If the World Trade Center (WTC) towers were designed to withstand multiple impacts by Boeing 707 aircraft, why did the impact of individual 767s cause so much damage?

As stated in Section 5.3.2 of NIST NCSTAR 1, a document from the Port Authority of New York and New Jersey (PANYNJ) indicated that the impact of a [single, not multiple] Boeing 707 aircraft was analyzed during the design stage of the WTC towers. However, NIST investigators were unable to locate any documentation of the criteria and method used in the impact analysis and, therefore, were unable to verify the assertion that “… such collision would result in only local damage which could not cause collapse or substantial damage to the building.…”

The capability to conduct rigorous simulations of the aircraft impact, the growth and spread of the ensuing fires, and the effects of fires on the structure is a recent development. Since the approach to structural modeling was developed for the NIST WTC investigation, the technical capability available to the PANYNJ and its consultants and contactors to perform such analyses in the 1960s would have been quite limited in comparison to the capabilities brought to bear in the NIST investigation.

The damage from the impact of a Boeing 767 aircraft (which is about 20 percent bigger than a Boeing 707) into each tower is well documented in NCSTAR 1-2. The massive damage was caused by the large mass of the aircraft, their high speed and momentum, which severed the relatively light steel of the exterior columns on the impact floors. The results of the NIST impact analyses matched well with observations (from photos and videos and analysis of recovered WTC steel) of exterior damage and of the amount and location of debris exiting from the buildings. This agreement supports the premise that the structural damage to the towers was due to the aircraft impact and not to any alternative forces.
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http://wtc.nist.gov/pubs/factsheets/faqs_8_2006.htm

Btw, the comment about the "mosquito netting on your screen door" was made by Frank Demartini.
 
A couple of small question: Why would anyone in the 1960s design a building to withstand the impact of more than one jet? Would it have seemed like a likely scenario?
 
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Port Authority Construction and Project Manager Frank DeMartini (who was not involved in the towers' design) made the "multiple 707" statement during an interview. He was incorrect: there was no such design requirement, and I've not seen any engineer who has studied the towers' construction who agrees with him. Also, DeMartini didn't mention what he thought would happen as a result of the fires that would result from such collisions.

DeMartini died in the north tower on 9/11. He had radioed about the possibility that the express elevators could fall (some already had), and he later asked for any available structural inspectors to come up to inspect the 78th floor: part of its drywall covering had been knocked off and the columns exposed, and he was apparently oncerned about the structural integrity.
 
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Also, 'multiple' is a somewhat flippant term to use, probably made to alleviate layperson concerns over the performance of the tower should one plane strike it, but in the expectation that the tower would never be hit by any aircraft and so the claim would never be tested.

I have asked 'truthers' in the past to provide their upper limit on 'multiple'...is it 4? 10? 20? But strangely all are unwilling to do so. 'Multiple' is good enough for them, though reality has a different idea.
 
It is a travesty that the Troofers use DeMartini this way; he's one of the true heroes of 9-11, who saved more lives than the overhyped Willie Rod.
 
Brainster said:
It is a travesty that the Troofers use DeMartini this way; he's one of the true heroes of 9-11, who saved more lives than the overhyped Willie Rod.
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On July 28, 1945, the Empire State Building was struck by a B-25 bomber on its way to Newark Airport

It left a hole 18 feet wide and 20 feet high.

But the building did not collapse.

It was for this reason, that the WTC Towers were built to sustain impacts from several jet airliners.


"The building was designed to have a fully loaded 707 crash into it. That was the largest plane at the time. I believe that the building probably could sustain multiple impacts of jet liners because this structure is like the mosquito netting on your screen door, this intense grid. And the jet plane is just a pencil puncturing the screen netting, it really does nothing to the screen netting.”
Frank A. DeMartini
Manager, WTC Construction & Project Management
1/25/01

Died in the 9/11 attacks



Im pretty sure Frank is a tin foil head too right?
 
StickMan2008 said:
It wouldn't matter.

The fact that it could sustain more than one makes the OS a joke.

LMAO @ that ridiculous chart of kinetic energy where the 707 barely registers.
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No, it matters greatly, as does your avoidance of having to consider it.

Do you think the tower could have withstood the impact of five passenger aircraft?
 
One of the posters here (I believe it was R. Mackey) calculated that the greater mass of the 767, traveling at much more than the 180 mph assigned to the 707, imparted a force to the towers that was 36 times greater than that of the putative 707. Given that, the surprise is that the buildings stood as long as they did.

Got any calculations to show why the building should have stood, Stick?
 
The towers did withstand the impact.....coupled with the intense fires, however, it soon collapsed.
 
StickMan2008 said:
On July 28, 1945, the Empire State Building was struck by a B-25 bomber on its way to Newark Airport

It left a hole 18 feet wide and 20 feet high.

But the building did not collapse.
Click to expand...

If you can't see why you are comparing apples to oranges here, you surely haven't learned anything in the past 6 years.

ESB = concrete facade, concrete core
WTC - steel framed construction; majority GLASS window exterior, STEEL core.

Gee, I wonder why the ESB didn't collapse.

what have firefighters have expressed in the years of fighting fires concerning steel structures?

go look it up
 
StickMan2008 said:
On July 28, 1945, the Empire State Building was struck by a B-25 bomber on its way to Newark Airport

It left a hole 18 feet wide and 20 feet high.

But the building did not collapse.

It was for this reason, that the WTC Towers were built to sustain impacts from several jet airliners.
Click to expand...

That's your assertion, not proven fact, and it's a breathtaking non sequitur.


StickMan2008 said:
"The building was designed to have a fully loaded 707 crash into it. That was the largest plane at the time. I believe that the building probably could sustain multiple impacts of jet liners because this structure is like the mosquito netting on your screen door, this intense grid. And the jet plane is just a pencil puncturing the screen netting, it really does nothing to the screen netting.”
Frank A. DeMartini
Manager, WTC Construction & Project Management
1/25/01
Click to expand...

My bolding.

First of all, DeMartini's first sentence contradicts your statement; he's clearly using the singular.

Secondly, he says nothing about the speed of the 707. KE = 1/2mv^2, as I hope you know, so if it was designed to cope with a 180mph impact then a 400+mph impact would be roughly equivalent to five 707's hitting it in the same place.

Thirdly, the multiple impact statement is a project manager's opinion. Sometimes I wish I lived in a world where every piece of engineering performed as well as the project manager liked to think it did.

Put aside the usual conspiracy theorist's false dichotomy that DeMartini was either correct or lying. He stated an opinion. Events showed that opinion to be erroneous.

Dave
 
Stickman - the building did withstand the impact of the jet crash.
 
jhunter1163 said:
I'm just going from memory here, but I think someone said that the structure of the Towers was such that an aircraft striking it would be like poking a hole in a screen door.

I also recall that Robertson said they had no way in the mid-60s to model the damage caused by the fuel an aircraft would be carrying, so they basically ignored it for their calculations.
Click to expand...

I remember seeing that video where that person used that analogy. I thought that it was a poor analogy.

The screen on a screen door is not a support structure. The frame of the door is. The spandrel columns were part of the support structure on the towers.
 
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