IS Forum
Forum Index Register Members List Events Mark Forums Read Help

Go Back   International Skeptics Forum » General Topics » Conspiracies and Conspiracy Theories » 9/11 Conspiracy Theories
 


Welcome to the International Skeptics Forum, where we discuss skepticism, critical thinking, the paranormal and science in a friendly but lively way. You are currently viewing the forum as a guest, which means you are missing out on discussing matters that are of interest to you. Please consider registering so you can gain full use of the forum features and interact with other Members. Registration is simple, fast and free! Click here to register today.
Reply
Old 18th March 2011, 05:53 PM   #1
dflynn
New Blood
 
Join Date: Mar 2011
Posts: 2
The towers were designed to survive a plane impact

Hi, I frequent other forums which have conspiracy sections and this pops up a lot, that the towers were designed to survive a plane impact.

A cursory search online points more to the fact they designed the building and somewhere along the line someone said hey this is really tall what if a plane hits it, so they had a chat about the possibility around a coffee and talked themselves into believing it would survive.

This is a far cry from being specifically designed to survive and all the considerations to materials , supports, fire prefention etc, that would entail.

I am sure this has been brought up a lot so apologies, the amount of threads upon searching was unreal.

Just looking for a simple yes or no with thanks to 'were they specifically designed to survive an impact by a large jet plane'

merci
dflynn is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th March 2011, 05:54 PM   #2
Thunder
Banned
 
Join Date: Nov 2006
Posts: 34,918
they did survive. long enough to get the vast majority of the personnel out.
Thunder is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th March 2011, 06:03 PM   #3
Lenbrazil
Muse
 
Join Date: Mar 2008
Posts: 974
I guess you missed it but there is a link at the top of each page to search the forum which makes it easy to find threads and posts were topics were previously discussed.
Lenbrazil is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th March 2011, 06:10 PM   #4
Justin39640
Illuminator
 
Justin39640's Avatar
 
Join Date: May 2009
Posts: 4,202
Originally Posted by dflynn View Post
Hi, I frequent other forums which have conspiracy sections and this pops up a lot, that the towers were designed to survive a plane impact.

A cursory search online points more to the fact they designed the building and somewhere along the line someone said hey this is really tall what if a plane hits it, so they had a chat about the possibility around a coffee and talked themselves into believing it would survive.

This is a far cry from being specifically designed to survive and all the considerations to materials , supports, fire prefention etc, that would entail.

I am sure this has been brought up a lot so apologies, the amount of threads upon searching was unreal.

Just looking for a simple yes or no with thanks to 'were they specifically designed to survive an impact by a large jet plane'

merci
Welcome to the forums!

Yes. It was assumed the plane (a 707) would be lost in the fog or low on fuel and looking to land at one of the local airports. They assume it would be going slow based on that. They also didn't consider fuel load and the fires that such an accident would cause.

They also determined the collapse mechanism. According to Les Robertson, the guy who designed them, they fell as they theorized they would.

Like Thunder said they did survive the impacts. Many people credit the engineering for saving lives in that respect. On the other hand, many believe the design and placement of the stairwells was one of the main causes of loss of life above the impact zone.
__________________
"I joined this forum to learn about the people who think that 9/11 was an inside job. I've learned that they believe nutty things and are not very good at explaining them." - FineWine
"The agencies involved with studying the WTC collapse no more needed to consider explosives than the police need to consider brain cancer in a shooting death." - ElMondoHummus
Justin39640 is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th March 2011, 06:12 PM   #5
ElMondoHummus
0.25 short of being half-witted
 
ElMondoHummus's Avatar
 
Join Date: Oct 2006
Location: Somewhere north of the South Pole
Posts: 12,279
Thunder is right. The bottom line is that one of the designers is on record as saying that the example they were thinking of was a 707, low on fuel, and lost in the fog on landing approach, therefore flying slowly. Not a 757/767 with a pretty decent fuel load going in excess of 400 knots.

Furthermore, fuel loads were not taken into consideration. The subsequent fires were initially thought to be small, limited, and controllable enough by the sprinkler systems to allow for further firefighting to take place.

And lastly, modeling was simply not as rigorous in the 60's as it can be nowadays. Computerization has allowed for very good advances in structural modeling, and issues that were not easily considered in decades past can now be studied in simulation. But the point is that the design didn't have the benefit of this computerization back then.

In spite of that, the towers stood long enough for a substantial evacuation to take place. Many of the people who were trapped were on floors above the impact/fire zones, and if there was some escape route for them, it's definitely plausible that they would've had time to evacuate too. That, in fact, is the topic of one of the subreports of the famous NIST report: "Occupant Behavior" and "Egress".

Do a forum search for the terms "Robinson" (that's Leslie Robinson, the chief structural engineer during the constructoin of the towers), "low fuel" and "707", and you'll come up with the relevant threads.
__________________
"AND ZEPPELINS!!! We haven't even begun to talk about Zeppelins yet! Marauding inflatable Teutonic johnsons waggling their way across the sky! Indecent and flammable all at once."
ElMondoHummus is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th March 2011, 06:15 PM   #6
beachnut
Penultimate Amazing
 
beachnut's Avatar
 
Join Date: Oct 2006
Location: Dog House
Posts: 25,939
Originally Posted by dflynn View Post
Hi, I frequent other forums which have conspiracy sections and this pops up a lot, that the towers were designed to survive a plane impact.

A cursory search online points more to the fact they designed the building and somewhere along the line someone said hey this is really tall what if a plane hits it, so they had a chat about the possibility around a coffee and talked themselves into believing it would survive.

This is a far cry from being specifically designed to survive and all the considerations to materials , supports, fire prefention etc, that would entail.

I am sure this has been brought up a lot so apologies, the amount of threads upon searching was unreal.

Just looking for a simple yes or no with thanks to 'were they specifically designed to survive an impact by a large jet plane'

merci
Robertson designed them to survive an impact at 180 mph, low on fuel, lost in the fog trying to land. This is the most likely accident to plan for.

The impact at 180 mph is equal to about 187 pounds of TNT.

Impacts on 911 were at 470mph and 590mph, equal in kinetic energy to 1300 and 2093 pounds of TNT.
7 and 11 times greater than the design.!!!

A study after 911 confirms an impact of 200mph would not damage the WTC towers significantly.

There was a white paper, a marketing tool for the WTC, which said 600 mph. The white paper was not from engineers, it was a marketing tool; no engineering. Robertson did the numbers, it was 180 mph, that number was confirmed after 911.
beachnut is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th March 2011, 06:21 PM   #7
dflynn
New Blood
 
Join Date: Mar 2011
Posts: 2
Originally Posted by Justin39640 View Post
Welcome to the forums!

Yes. It was assumed the plane ...
Thanks a lot, so it was assumed they would survive the impact but not that they would not subsequently collapse .

Usually I see they were designed to survive ie not fall ie explosive demolition.

Lenbrazil point taken, yes it was very rude of me to first post a question before looking through all the threads.
dflynn is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th March 2011, 06:33 PM   #8
Grizzly Bear
このマスクによっ
 
Grizzly Bear's Avatar
 
Join Date: May 2008
Posts: 7,864
If the recent earthquake in Japan is any indication, you can design for the things that you can anticipate, but there's no way to account for every conceivable combination of events that takes place at a given moment. As much as I hate to use that as an example it is a case in point that is applicable to the twin towers.

In the earthquake situation, the powerplant was designed for a 7.0 on the Richter scale, the reactors were designed to shut down, while backup coolers were designed to keep them stable. The tsunami along with a series of problems have led to a catastrophe that is still unfolding as we speak. Much like the WTC were designed with the idea that a plane may severely cripple the structure; they did not account for the deficiencies that such an impact would have on fire suppression. They can bring it up that the air collisions were considered as part of the equation, they wouldn't be necessarily wrong, but "first time in history" seems to be their catch all criteria rather than design anyway so I don't see their point in citing it particuarly when designing for the aircraft impact did not guarantee in of itself that the towers would have survived the combination of things that came together.
__________________

Last edited by Grizzly Bear; 18th March 2011 at 06:35 PM.
Grizzly Bear is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th March 2011, 07:14 PM   #9
Dave Rogers
Bandaged ice that stampedes inexpensively through a scribbled morning waving necessary ankles
 
Dave Rogers's Avatar
 
Join Date: Jan 2007
Location: Cair Paravel, according to XKCD
Posts: 32,744
Originally Posted by ElMondoHummus View Post
And lastly, modeling was simply not as rigorous in the 60's as it can be nowadays. Computerization has allowed for very good advances in structural modeling, and issues that were not easily considered in decades past can now be studied in simulation. But the point is that the design didn't have the benefit of this computerization back then.
This point is worth emphasising. If I recall correctly, Leslie Robertson claimed to have carried out three pages' worth of longhand calculations to analyse whether the buildings would collapse as a result of an airliner hitting them (although these three pages have not been found). Three pages of manual calculations could be carried out in a fraction of a second by a spreadsheet application on an average powered computer these days, whereas NIST's calculations required long run times on high specification workstations. And yet truthers prefer to accept the result of the former as more rigorous than the latter, despite the fact that the opposite is clearly true. A classic case of confirmation bias.

Dave
__________________
There is truth and there are lies.

- President Joseph R. Biden, January 20th, 2021
Dave Rogers is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th March 2011, 08:39 PM   #10
ergo
Illuminator
 
ergo's Avatar
 
Join Date: Aug 2010
Posts: 4,339
http://community.seattletimes.nwsour...7&slug=1687698

Quote:
"We looked at every possible thing we could think of that could happen to the buildings, even to the extent of an airplane hitting the side," said John Skilling, head structural engineer....

Skilling, based in Seattle, is among the world's top structural engineers. He is responsible for much of Seattle's downtown skyline and for several of the world's tallest structures, including the Trade Center.

Concerned because of a case where an airplane hit the Empire State Building, Skilling's people did an analysis that showed the towers would withstand the impact of a Boeing 707...

Skilling - a recognized expert in tall buildings - doesn't think a single 200-pound car bomb would topple or do major structural damage to a Trade Center tower. The supporting columns are closely spaced and even if several were disabled, the others would carry the load.

http://911research.wtc7.net/wtc/analysis/design.html

Quote:
Frank A. Demartini, on-site construction manager for the World Trade Center, spoke of the resilience of the towers in an interview recorded on January 25, 2001:

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 jetliners because this structure is like the mosquito netting on your screen door -- this intense grid -- and the jet plane is just a pencil puncturing that screen netting. It really does nothing to the screen netting.

Demartini, who had an office on the 88th floor of the North Tower, has been missing since the 9/11/01 attack, having remained in the North Tower to assist in the evacuation. Demartini had first worked at World Trade Center when Leslie E. Robertson Associates hired him to assess damage from the truck bombing in 1993.
__________________
“Much of the 9/11 story has not been told to the public" - Steven Badger, attorney for insurance litigators affected by the WTC disaster.
ergo is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th March 2011, 09:17 PM   #11
beachnut
Penultimate Amazing
 
beachnut's Avatar
 
Join Date: Oct 2006
Location: Dog House
Posts: 25,939
The chief structural engineer is the prime source; Physics Required

Quote:
Leslie E. Robertson, The lead structural engineer reflects on the rise and fall of the World Trade Center towers, spring 2002 wrote: "It appears that about 25,000 people safely exited the buildings, almost all of them from below the impact floors; almost everyone above the impact floors perished, either from the impact and fire or from the subsequent collapse. The structures of the buildings were heroic in some ways but less so in others. The buildings survived the impact of the Boeing 767 aircraft, an impact very much greater than had been contemplated in our design (a slow-flying Boeing 707 lost in the fog and seeking a landing field). Therefore, the robustness of the towers was exemplary. At the same time, the fires raging in the inner reaches of the buildings undermined their strength. In time, the unimaginable happened . . . wounded by the impact of the aircraft and bleeding from the fires, both of the towers of the World Trade Center collapsed."
http://www.nae.edu/Publications/Brid...adeCenter.aspx
http://www.nae.edu/Publications/Brid...dSecurity.aspx
Chief of the structural design for the WTC, makes all the cherry picking, quote mining truthers, outright knowledge free failures.




911 truth can't do physics, they have no clue what kinetic energy is, or why 10 times more kinetic energy is significant.
Which part of "low on fuel" does 911 truth have a problem with?

Last edited by beachnut; 18th March 2011 at 09:22 PM.
beachnut is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th March 2011, 11:51 PM   #12
TruthersLie
This space for rent.
 
TruthersLie's Avatar
 
Join Date: Jun 2009
Posts: 3,715
Originally Posted by ergo View Post
Please keep in mind that good ole Ergo here doesn't know the difference between
into vs onto
essentially vs actually
a debris field the "size of the moon" and center of mass
about
exponentially
and thinks that a buildings footprint includes buildings across the street and even the ROOF of an adjacent building.

So it is fully understandable that he only datamines but doesn't read for comprehension.

P.s. Hey ergo.... about explosions... you know the caracas tower fire (where you really stepped ONTO your dick, and INTO a pile of fail) it had multiple reported explosions. Did the NWO cause those? Have you figured out why it remained standing yet?
__________________
"There are submissions to the Journal of 9/11 Studies, but that's about as convincing as submissions to the Journal of Intelligent Design Studies." –Noam Chomsky (and this can be said of ANY and all twoof papers)
TruthersLie is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 12:07 AM   #13
dc1971
Banned
 
Join Date: Oct 2009
Posts: 3,021
Originally Posted by ergo View Post
...and the jet plane is just a pencil puncturing that screen netting. It really does nothing to the screen netting.
Nothing other than poking a hole in the screen netting.
dc1971 is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 12:17 AM   #14
ozeco41
Philosopher
 
ozeco41's Avatar
 
Join Date: Mar 2009
Location: Moss Vale, NSW, Australia
Posts: 7,577
Originally Posted by dc1971 View Post
Nothing other than poking a hole in the screen netting.
That comment by Frank A. Demartini must rank as one of the all time poor analogies:
Quote:
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 jetliners because this structure is like the mosquito netting on your screen door -- this intense grid -- and the jet plane is just a pencil puncturing that screen netting. It really does nothing to the screen netting.
It would certainly have returned to haunt him except, sadly, he appears to have been one of the victims of 9/11.

As for the "pencil puncturing" we know that the full silhouette - fuselage and wings - cut through the outer walls of both Twin Towers. Something that I as a structural engineer would not have predicted before 9/11 even tho' it is easy to understand in hindsight.
ozeco41 is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 01:28 AM   #15
Quad4_72
AI-EE-YAH!
 
Quad4_72's Avatar
 
Join Date: Nov 2006
Posts: 6,354
Originally Posted by ergo View Post
Facts and research done after the collapses are of little concern to ergo. He would rather go off of someones guess before the attacks even happened as opposed to an actual engineering report completed in hindsight. We keep him around just for kicks
__________________
Looks like the one on top has a magazine, thus needs less reloading. Also, the muzzle shroud makes it less likely for a spree killer to burn his hands. The pistol grip makes it more comfortable for the spree killer to shoot. thaiboxerken
Quad4_72 is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 02:39 AM   #16
randman
Illuminator
 
Join Date: Mar 2011
Posts: 3,677
Well, I don't normally wade into these debates on this topic but jet fuel does not burn at a temperature sufficient to melt steel, at least the kind they built the Twin Towers with.
randman is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 02:50 AM   #17
Scott Sommers
Illuminator
 
Scott Sommers's Avatar
 
Join Date: Jul 2009
Posts: 3,859
Originally Posted by randman View Post
Well, I don't normally wade into these debates on this topic but jet fuel does not burn at a temperature sufficient to melt steel, at least the kind they built the Twin Towers with.
I'm glad I can be the first person to thank you for taking the time to ask this question. This is so smart. I have never thought of this one. And it's just obvious. Like I've been saying, common sense is so much better than reading.

Come on all you JREF smarty-pants. Just because you've an engineer and have built all those big buildings doesn't mean a little come sense can't put you in your place! What's the answer to this one?
__________________
See my blog,
Wonders of the Invisible World

Last edited by Scott Sommers; 19th March 2011 at 02:52 AM.
Scott Sommers is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 02:56 AM   #18
brazenlilraisin
...tart
 
brazenlilraisin's Avatar
 
Join Date: Nov 2010
Posts: 660
Don't normally wade in...? I wonder if you've ever even seen the ocean! I'll stipulate that burning jet fuel won't melt steel...do you think steel has to be in a liquid state before it loses its ability to bear loads? Were there other contents burning in the towers that could burn hotter and longer than jet fuel? This is Twin Towers 101 stuff, dude.
__________________
"LMAO! pure intelligets, have you read my posts?"--superlogicalthinker
brazenlilraisin is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 03:11 AM   #19
randman
Illuminator
 
Join Date: Mar 2011
Posts: 3,677
Originally Posted by brazenlilraisin View Post
Don't normally wade in...? I wonder if you've ever even seen the ocean! I'll stipulate that burning jet fuel won't melt steel...do you think steel has to be in a liquid state before it loses its ability to bear loads? Were there other contents burning in the towers that could burn hotter and longer than jet fuel? This is Twin Towers 101 stuff, dude.
I don't see how office stuff would burn sufficiently hot. From the press reports, the claim is the steel softened due to the heat. That did not likely happen.
randman is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 03:24 AM   #20
Scott Sommers
Illuminator
 
Scott Sommers's Avatar
 
Join Date: Jul 2009
Posts: 3,859
Originally Posted by randman View Post
I don't see how office stuff would burn sufficiently hot. From the press reports, the claim is the steel softened due to the heat. That did not likely happen.
Absolutely. The likelihood that a fire could soften steel is ridiculous.
I've never heard such a silly thing.
__________________
See my blog,
Wonders of the Invisible World
Scott Sommers is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 03:29 AM   #21
randman
Illuminator
 
Join Date: Mar 2011
Posts: 3,677
Originally Posted by Scott Sommers View Post
Absolutely. The likelihood that a fire could soften steel is ridiculous.
I've never heard such a silly thing.
Well, keep in mind a hot enough fire could. You can melt steel in a furnace but this steel was designed to withstand fire for this exact reason.
randman is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 03:36 AM   #22
Scott Sommers
Illuminator
 
Scott Sommers's Avatar
 
Join Date: Jul 2009
Posts: 3,859
Originally Posted by randman View Post
Well, keep in mind a hot enough fire could. You can melt steel in a furnace but this steel was designed to withstand fire for this exact reason.
Exactly. This is what I meant. I doubt anyone here has heard this argument before. It's absolutely brand new to this forum. I'm really waiting to see what kind of answers you get.
__________________
See my blog,
Wonders of the Invisible World
Scott Sommers is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 03:45 AM   #23
tfk
Illuminator
 
Join Date: Oct 2006
Posts: 3,454
dflynn,

"The towers were built to withstand a jet impact" is a myth. An urban legend.

It is false.

Yeah, I know perfectly well that it gets repeated over & over. Famously by Frank DeMartini, the building manager in 2001.

As in THIS VIDEO.

Mr. DeMartini was a bona fide hero of 9/11, who gave his life that day trying to save others, while knowing the risks. And deserves all the respect in the world for those actions.

But he was a building manager. His job was to deal with the day to day running of an already constructed office complex. This means dealing with unions, project scheduling, & city hall. He didn't know diddly about Structural Engineering, as proven by his "pencil & screen netting" comment. I invite any one of you to show me some "structural" screen netting, loaded in high levels of compression. The answer is "the screen netting is unaffected by the pencil poke precisely because it is weak & flexible & in tension, not compression." Things that are weak & flexible & loaded in tension are singularly useless at holding up buildings.

Notice that the author of this video has "promoted" Mr. DeMartini to "Designer of the Twin Towers". Great. I guess John Skilling decided to hire a grammar school kid in 1963 to design the tallest building in the world, eh?

This is precisely the type of false, unverified, uncritical stories that underlie all of the truth movement's nonsense.

Listen to one of the real design engineers of the towers, Leslie Robertson, in an interview after 9/11/2001.

"We should not and can not design buildings and structures to resist the impact of these aircraft. Instead, we must concentrate our efforts on keeping aircraft away from our tall buildings, sports stadiums, symbolic buildings, atomic plants, and other potential targets"
Leslie Robertson, Structural Engineer, WTC
http://www.nae.edu/Publications/TheB...adeCenter.aspx

Did you catch that? "We should not and can not design buildings and structures to resist the impact of these aircraft."

So, what happened between 1964 & 2002? Did we lose the ability to design buildings to withstand aircraft impacts? No. The answer is, we never had it. And we still don't really have it today. (Engineers can make buildings much safer against this form of attack. They CAN NOT design any building - other than windowless 10-foot thick domes, like nuclear reactor containment domes - to withstand airplane impacts.

In order to come close, it takes supercomputers & FEA software, neither of which existed in 1964. They didn't have electronic calculators. They had slide rules. There is no way on earth to do that sort of a calculation with slide rules.
___

OK, the back-story behind "the towers were built to withstand jet impacts"...

What it would take to do this analysis:

Scientists & engineers are pretty damn clever. But there are serious limitations to the calculations that we could make about "real world" parts, prior to 1970s & '80s. That is, prior to the availability of Finite Element Analysis programs. The very first of these programs (NASTRAN) became available in the 1970s & 80s.

The memo that NIST is quoting was dated Feb 3, 1964, prepared by Malcom Levy, the head of planning & construction for the PANYNJ. So there is zero possibility that those software tools were used.

So, where did the myth originate? James Glanz's book "City in the Sky" has the story.

No one knows who started the calculation, but it was apparently carried out by some un-named engineers working for the PANYNJ, under the direction of Levy.

Here's an except from Glanz's book:

*****

"The first part of the calculation would have been quite simple. The towers had been designed to withstand the forces of windstorms with gusts of at least 120 miles an hour. Specifically, they were supposed to hold up against at Least forty-five pounds of lateral force on every square foot without shearing off and toppling. Each tower would be about 1,350 feet tall and 209 feet across on each face: 282,150 square feet. So if a wind sufficient to exert forty-five pounds per square foot of force was blowing directly against one of the faces. that would be about 13 million pounds. all told. And the tower should stand, with a standard safety margin of perhaps 30 to 40 percent to spare.

To figure out if the plane had a chance of tipping the tower over. Mal Levy’s engineers needed to estimate how much force the collision might produce. A Boeing 707 made a B-25 look like an insect in comparison. With a tip-to-tip wingspan of 131 feet and a fuel capacity of more than twenty thousand gallons. a fully loaded 707 can weigh 300,000 pounds on takeoff, and its cruising speed is about 600 miles per hour. The engineers knew that parts of the little B-25 flew all the way through the limestone-encased Empire State Building and out the other side. So it might have been reasonable to assume that the bigger. faster 707. after plowing into the much more compliant facade of a World Trade Center tower, would not come to a complete stop before it reached the opposite side of the floor, 209 feet away. It is a complicated problem to figure out precisely how hard the plane might push on the tower during a collision, but given the plane’s known weight. initial speed, and stopping distance, any freshman engineering student could come up with a rough estimate. The number turns out to be 17 million pounds, probably within the safety margin.

Levy’s engineers had discovered that not even a speeding 707 would shear off one of the towers."

*****

I believe that Glanz has this just slightly wrong. "Shearing" implies that the building slides off of its base. This is a silly, unrealistic failure mode. Structural engineers would recognize this. The proper failure mode would be "tipping", in which the building fractures at the highest stress point (i.e., right at ground level) and tips over. It is trivial to go from shear to moment calculations, and I believe that this slight variation from the one that Glanz describes is the calculation they would have done.

Notice that the wind shear load was 13 million pounds, and the calculated plane impact shear load was 17 million. And they concluded that this was "probably within the safety margin".

THIS is the level of accuracy that the "design for impact" analysis provided.

The second calculation imagined that a number of the beams on one side of the building, equivalent to the wingspan of the plane, were "surgically removed". As if you just took a Sawzall & cut them out. Absolutely no other damage to any part of the building. No fires, no damaged core columns, no damaged floors, etc.

The question asked: Would the building fall over under this condition.

They found out that it would not.

Clearly, neither one of these very unrealistic & very crude calculations comes anywhere CLOSE to a rigorous analysis upon which one could make the assertion that the building "was designed to withstand a jet impact".

____

So, how did the myth arise?

Intrigue, back-stabbing, bluff & bluster, and sloppy, self-serving interpretations of crude calculations.

Lawrence Wien, the "King" of Manhattan Real Estate was the owner of the Empire State Building (and a bunch of other commercial real estate properties in NYC). He, and several others were desperate to stop the WTC project. They didn't want the competition. Wien knew all about the plane that had hit his building (before he bought it). Wien had read the report on the fire damage & response of the ESB.

In Febuary 13, 1964, "... Wien called reporters to his office high above Forty-second Street, where the elegant silhouette of his most prized possession—the Empire State Building—was framed perfectly in his picture window. ... The twin towers, he claimed, would be dangerously unstable and prone to catastrophe, especially in a large fire or an explosion, when they could collapse."

The PANYNJ was not going to let Wien derail their project.

"What the real estate people did not know was that Levy already had his script prepared. Nor could they have known how far the Port Authority was willing to go to protect its project. On February 14, the day after Wien made his allegations. Lee Jaffe summoned reporters for a briefing at Port Authority headquarters. She distributed a three-page telegram sent that day from Richard Roth, one of the partners at Emery Roth & Sons, the New York architectural firm that had been assigned to work with Yamasaki on the trade center. Under the prestigious imprimatur of his firm, Roth had sent in an urgent rebuttal of Wien’s claims. The telegram “authoritatively refutes the false allegations of ‘real estate figures’ published in THE NEW YORK TIMES today,” Jaffe snarled in the memo she gave to one of those reporters. The telegram was impressive and detailed—pointing out, for example, that for the World Trade Center design.

THE STRUCTURAL ANALYSIS CARRIED OUT BY THE FIRM OF WORTHINGTON SKILLING, HELLE & JACKSON IS THE MOST COMPLETE AND DETAILED OF ANY EVER MADE FOR ANY BUILDING STRUCTURE. THE PRELIMINARY CALCULATIONS ALONE COVER 1,200 PAGES AND INVOLVE OVER 100 DETAILED DRAWINGS.

Point number three on the list of design features was this:

3. THE BUILDINGS HAVE BEEN INVESTIGATED AND FOUND TO BE SAFE IN AN ASSUMED COLLISION WITH A LARGE JET AIRLINER TRAVELING AT 600 MILES PER HOUR. ANALYSIS INDICATES

There was no elaboration on that assurance, but after a lengthy list of endorsements supposedly given by other architects and engineer, the telegram ended on this note:

11. THE TOWERS MAY BE SAID TO BE THE FIRST BUILDINGS OF THE 21ST CENTURY AND THE DESIGN CONCEPTS WHICH THEY EMBODY WILL BE INCORPORATED IN SOME MEASURE IN EVERY FUTURE HIGH RISE BUILDING EVER BUILT.

RICHARD ROTH
EMERY ROTH & SONS


Mal Levy, Lee Jaffe. and the Port Authority’s engineers had bested the great Lawrence Wien."

The newspaper reporters ran wild with the story.

And an urban myth was born.

That is the story behind the "design to withstand a jet impact".

A bunch of horse-pucky, fed to reporters, who were not competent enough, or skeptical enough, to do their homework.
___

You can read all about this episode HERE. Do a search for "Levy", and read pages 131 thru about 139. It's a fascinating little vignette of the PANYNJ project managers bluffing a businessman and the press. And getting away with it.

BTW, Robertson apparently did some later studies (after the towers were built, IIRC). But nobody has ever been able to find those reports, and the limitations on computers & FEA software in the late 1970s imposes the same limitations on the conclusions of that study as well.

By the time the later studies came along, the myth was already well entrenched.

Anyone who says that "The towers were designed to withstand jet impacts" - and there are LOTS of people who do say this - is parroting an urban myth that they do not understand.


Tom

Last edited by tfk; 19th March 2011 at 03:50 AM.
tfk is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 04:58 AM   #24
progge
Thinker
 
Join Date: Feb 2009
Posts: 171
For the sake of completeness, let me point out that PANY construction supervisor Guy F. Tozzoli commented on this issue, too.
Quote:
Wir haben damals eine Studie gemacht und ausgerechnet, was passieren würde, wenn das größte Flugzeug, eine 707, einen Turm trifft. Wir sind davon ausgegangen, dass Flugzeuge über New York ihre Geschwindigkeit auf 200 Meilen pro Stunde drosseln müssen. Und dass sie auch nicht voll getankt sein würden, sondern sich im Landeanflug befänden.
This is from a Nov. 2002 interview in a German daily newpaper. My translation:
Quote:
Back then we conducted a study about what would happen if the biggest plane, a 707, would hit one tower. We assumed that planes across New York would have to reduce their speed to 200 mph. And that they wouldn´t be loaded with maximum fuel, but would approach for a landing.
progge is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 05:26 AM   #25
kookbreaker
Evil Fokker
 
kookbreaker's Avatar
 
Join Date: Aug 2001
Posts: 13,635
Originally Posted by Scott Sommers View Post
Exactly. This is what I meant. I doubt anyone here has heard this argument before. It's absolutely brand new to this forum. I'm really waiting to see what kind of answers you get.
You're a cruel man, Scott.
__________________
www.spectrum-scientifics.com <- My store of science toys, instruments and general fun!

Thanks for helping me win Best Toys in Philly Voter in 2011,2012, and 2014! We won' be discussing the disappointment that was 2013.
kookbreaker is online now   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 05:31 AM   #26
Scott Sommers
Illuminator
 
Scott Sommers's Avatar
 
Join Date: Jul 2009
Posts: 3,859
Originally Posted by kookbreaker View Post
You're a cruel man, Scott.
This is such a unique and powerful argument. I'd like to know where it came from. Did he make it up himself? Or read it somewhere then cut & paste it on to the forum. I'm just dieing to know what creative forces gave birth to this genius. I hope I haven't scared him away with my curiosity.
__________________
See my blog,
Wonders of the Invisible World
Scott Sommers is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 06:20 AM   #27
triforcharity
Banned
 
Join Date: Jun 2009
Posts: 13,961
Originally Posted by randman View Post
I don't see how office stuff would burn sufficiently hot. From the press reports, ENGINEERING REPORTS, the claim is the steel softened due to the heat. That did not likely happen. [IN MY OPINION]
Fixed that for you.

Hey, have you seen the data on the Carbington Fire Tests?

It's pretty cool. They built a large scale office building with steel. They set it on fire.

Guess what happened?

Lots of the steel failed. Lots of temperatures above 1800 deg. F.

Would you like the data and reports on that?

(For all your veteran's here, our old friend Psikehacker pointed to the Cardington Fire Tests as proof that steel wouldn't fail in a fire, and a typical fire wouldn't reach 1800 deg. F.

Yeah, he pulled an Ergo and stepped into a whole pile of fail! )
triforcharity is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 06:36 AM   #28
ElMondoHummus
0.25 short of being half-witted
 
ElMondoHummus's Avatar
 
Join Date: Oct 2006
Location: Somewhere north of the South Pole
Posts: 12,279
Did I just see someone try to whip out the "jet fuel doesn't burn hot enough to melt steel" myth again?



From http://wtc.nist.gov/pubs/factsheets/faqs_8_2006.htm:
Quote:
Based on this comprehensive investigation, NIST concluded that the WTC towers collapsed because: (1) the impact of the planes severed and damaged support columns, dislodged fireproofing insulation coating the steel floor trusses and steel columns, and widely dispersed jet fuel over multiple floors; and (2) the subsequent unusually large jet-fuel ignited multi-floor fires (which reached temperatures as high as 1,000 degrees Celsius) significantly weakened the floors and columns with dislodged fireproofing to the point where floors sagged and pulled inward on the perimeter columns. This led to the inward bowing of the perimeter columns and failure of the south face of WTC 1 and the east face of WTC 2, initiating the collapse of each of the towers. Both photographic and video evidence—as well as accounts from the New York Police Department aviation unit during a half-hour period prior to collapse—support this sequence for each tower.
From http://www.popularmechanics.com/tech...e-center#steel:
Quote:
FACT: Jet fuel burns at 800° to 1500°F, not hot enough to melt steel (2750°F). However, experts agree that for the towers to collapse, their steel frames didn't need to melt, they just had to lose some of their structural strength—and that required exposure to much less heat. "I have never seen melted steel in a building fire," says retired New York deputy fire chief Vincent Dunn, author of The Collapse Of Burning Buildings: A Guide To Fireground Safety. "But I've seen a lot of twisted, warped, bent and sagging steel. What happens is that the steel tries to expand at both ends, but when it can no longer expand, it sags and the surrounding concrete cracks."

"Steel loses about 50 percent of its strength at 1100°F," notes senior engineer Farid Alfawak-hiri of the American Institute of Steel Construction. "And at 1800° it is probably at less than 10 percent." NIST also believes that a great deal of the spray-on fireproofing insulation was likely knocked off the steel beams that were in the path of the crashing jets, leaving the metal more vulnerable to the heat.

But jet fuel wasn't the only thing burning, notes Forman Williams, a professor of engineering at the University of California, San Diego, and one of seven structural engineers and fire experts that PM consulted. He says that while the jet fuel was the catalyst for the WTC fires, the resulting inferno was intensified by the combustible material inside the buildings, including rugs, curtains, furniture and paper. NIST reports that pockets of fire hit 1832°F.

"The jet fuel was the ignition source," Williams tells PM. "It burned for maybe 10 minutes, and [the towers] were still standing in 10 minutes. It was the rest of the stuff burning afterward that was responsible for the heat transfer that eventually brought them down."
A previous thread where this was discussed; note the date on it is March 2006!Another set, from 2007 - 2009:There's the argument. Now, regarding:
Originally Posted by randman View Post
I don't see how office stuff would burn sufficiently hot. From the press reports, the claim is the steel softened due to the heat. That did not likely happen.
That is incorrect. As noted by one of the firefighters on this forum, even common structural fires can easily exceed 1,000oF just through the normal growth cycle alone. Much less the massive acre-wide, multifloor ones in the Twin Towers.

That is all the information needed to put this myth to rest. I suggest that if any further discussion occurs that it be split into one of the prior threads on this topic.

We're done with this here.
__________________
"AND ZEPPELINS!!! We haven't even begun to talk about Zeppelins yet! Marauding inflatable Teutonic johnsons waggling their way across the sky! Indecent and flammable all at once."
ElMondoHummus is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 06:43 AM   #29
Sunstealer
Illuminator
 
Sunstealer's Avatar
 
Join Date: Oct 2007
Posts: 3,128
Originally Posted by randman View Post
I don't see how office stuff would burn sufficiently hot. From the press reports, the claim is the steel softened due to the heat. That did not likely happen.
Wow we seem to have a professional metallurgist in our midst.

So come on mister professional lets see you answer these questions because it's obvious that you know exactly what you are talking about and I need to be educated.

1. At what temperature does steel lose half of it's yield strength?

2. What temperatures can be achieved in office fires?

3. What is creep?

4. What is thermal expansion?

You'll also need to provide a reference for your answers.

Thanks.
Sunstealer is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 06:56 AM   #30
Scott Sommers
Illuminator
 
Scott Sommers's Avatar
 
Join Date: Jul 2009
Posts: 3,859
Originally Posted by triforcharity View Post
Fixed that for you.

Hey, have you seen the data on the Carbington Fire Tests?

It's pretty cool. They built a large scale office building with steel. They set it on fire.

Guess what happened?

Lots of the steel failed. Lots of temperatures above 1800 deg. F.

Would you like the data and reports on that?

(For all your veteran's here, our old friend Psikehacker pointed to the Cardington Fire Tests as proof that steel wouldn't fail in a fire, and a typical fire wouldn't reach 1800 deg. F.

Yeah, he pulled an Ergo and stepped into a whole pile of fail! )
I keep telling you guys, a little common sense goes way further than a pile of reading. Forget about all those PhDs. If you want to see a PhD in common sense, have a look at some of randman's other posts. He has a PhD in the common sense of evolution and another one in the common sense of property law and Freeman Science. He's a model of that expert Truther I keep talking about.

But for any of those reading-kind-a-folks who might be interested in those reports you talk about, they're all on the Internet here
http://www.civ.ed.ac.uk/research/fire/cardington.html
But where did reading ever get you, except in trouble with the teachers?
__________________
See my blog,
Wonders of the Invisible World

Last edited by Scott Sommers; 19th March 2011 at 07:59 AM.
Scott Sommers is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 07:00 AM   #31
triforcharity
Banned
 
Join Date: Jun 2009
Posts: 13,961
Scott,

You crack me up!!

Books? We don't need no stinkin BOOKS!!!
triforcharity is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 07:15 AM   #32
Justin39640
Illuminator
 
Justin39640's Avatar
 
Join Date: May 2009
Posts: 4,202
Originally Posted by randman View Post
I don't see how office stuff would burn sufficiently hot. From the press reports, the claim is the steel softened due to the heat. That did not likely happen.
Where were you 35 years ago? Think of all the money you could have saved them in not having to fireproof all the steel!
__________________
"I joined this forum to learn about the people who think that 9/11 was an inside job. I've learned that they believe nutty things and are not very good at explaining them." - FineWine
"The agencies involved with studying the WTC collapse no more needed to consider explosives than the police need to consider brain cancer in a shooting death." - ElMondoHummus
Justin39640 is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 07:24 AM   #33
gumboot
lorcutus.tolere
 
gumboot's Avatar
 
Join Date: Jun 2006
Posts: 25,327
The towers did survive the aircraft impact. What they didn't survive was large scale fires. At the time the towers were built it was impossible for anyone to model fires to any extent that could determine fire survivability.

If anyone tries to claim they designed the buildings to survive those fires, they're lying.
__________________

O xein', angellein Lakedaimoniois hoti têde
keimetha tois keinon rhémasi peithomenoi.


A fan of fantasy? Check out Project Dreamforge.
gumboot is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 07:29 AM   #34
ergo
Illuminator
 
ergo's Avatar
 
Join Date: Aug 2010
Posts: 4,339
Originally Posted by tfk View Post

Mr. DeMartini was a bona fide hero of 9/11, who gave his life that day trying to save others, while knowing the risks. And deserves all the respect in the world for those actions.

But he was a building manager. His job was to deal with the day to day running of an already constructed office complex. This means dealing with unions, project scheduling, & city hall. He didn't know diddly about Structural Engineering, as proven by his "pencil & screen netting" comment.

Quote:
Frank A. Demartini, on-site construction manager for the World Trade Center
..... had first worked at World Trade Center when Leslie E. Robertson Associates hired him to assess damage from the truck bombing in 1993.

John Skilling:

Quote:
John Skilling was a civil engineer and architect, best known for being the chief structural engineer of the World Trade Center...

Prominent constructions under his leadership include the World Trade Center, Rainier Bank Tower, the Seafirst Building, Seafirst Fifth Avenue Tower, Century Square, Columbia Seafirst Center and the Washington State Convention and Trade Center.

http://www.britannica.com/EBchecked/.../John-Skilling

Quote:
Skilling became a principal of the Witt firm in 1950. He led the evolution of a small, regionally oriented firm into the nationally acclaimed structural engineering organization that it became over the nearly 45 years of his direction. In 1955, the firm became Worthington & Skilling; in 1960 it became Worthington, Skilling, Helle & Jackson; in 1967, Skilling, Helle, Christiansen, Robertson; and in 1983, Skilling Ward Rogers Barkshire. Beginning in 1987 it became Skilling Ward Magnusson Barkshire until Skilling’s retirement in 1995, when the firm employed a staff of 72.
http://www.historylink.org/index.cfm...m&file_id=9632

Quote:
Leslie Earl Robertson (born 1928) was one of the chief structural engineers of the World Trade Center...as an "up-and-coming engineer", Robertson was contracted by Worthington, Skilling, Helle, and Jackson (WSHJ) to participate in the design of the World Trade Center Twin Towers (1966–1971), his first high rise construction

Engineering perspective of the collapse of WTC-I Irfanoglu, A., Hoffmann, C.M. 2008 Journal of Performance of Constructed Facilities 22 (1):

Quote:
That the World Trade Center Towers withstood the impact loads of commercial aircrafts on September 11, 2001, was not surprising for structural engineers. However, very few in the profession expected the collapse of the towers during the fires that followed.
__________________
“Much of the 9/11 story has not been told to the public" - Steven Badger, attorney for insurance litigators affected by the WTC disaster.

Last edited by ergo; 19th March 2011 at 07:36 AM.
ergo is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 07:51 AM   #35
TruthersLie
This space for rent.
 
TruthersLie's Avatar
 
Join Date: Jun 2009
Posts: 3,715
Originally Posted by ergo View Post
Thank you for completely supporting EVERYTHING TFK said.

REading for comprehension bites you in the ass again (The claim you BOLD is a bare assertion, without any support to back it up. )...but then again what else can we expect from someone who mixes up
essentially vs actually
into vs onto
a debris field the "size of the moon" vs center of mass
ABOUT
exponentially
who doesn't know about metaphorical speech
and thinks that EXPLOSIONS are all caused by EXPLOSIVES

It is funny though.
From your own citation
Quote:
Conclusions
Impact simulations indicate that the damage states of the WTC-I core structural elements are
very sensitive to analysis parameters and as such, it is not possible to suggest the exact state of
the core framing after the aircraft impact. Simulations indicate consistently that the worst
damage to the core structure was sustained in the 95th through 97th stories of the tower.
For both the intact and plausible compromised core states considered, it is estimated that a core
collapse mechanism could have been initiated in WTC-I if the tower core column temperatures
were elevated to approximately 700oC. As the aircraft debris went through several stories in the
tower, much of the thermal insulation on the core columns would have been scoured off. Under
such conditions, the ensuing fire would be sufficient to cause instability and initiate collapse.
From an engineering perspective, impact damage to the core structure had a negligible effect on
the critical thermal load required to initiate collapse in the core structure
.
So it wasn't the core, but the FIRE which brought the towers down. I'm glad you agree.
__________________
"There are submissions to the Journal of 9/11 Studies, but that's about as convincing as submissions to the Journal of Intelligent Design Studies." –Noam Chomsky (and this can be said of ANY and all twoof papers)

Last edited by TruthersLie; 19th March 2011 at 08:00 AM.
TruthersLie is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 07:56 AM   #36
gumboot
lorcutus.tolere
 
gumboot's Avatar
 
Join Date: Jun 2006
Posts: 25,327
Originally Posted by randman View Post
Well, I don't normally wade into these debates on this topic but jet fuel does not burn at a temperature sufficient to melt steel, at least the kind they built the Twin Towers with.
Wow. It's like my long-dead grandfather just came alive before my eyes.
__________________

O xein', angellein Lakedaimoniois hoti têde
keimetha tois keinon rhémasi peithomenoi.


A fan of fantasy? Check out Project Dreamforge.
gumboot is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 08:02 AM   #37
TruthersLie
This space for rent.
 
TruthersLie's Avatar
 
Join Date: Jun 2009
Posts: 3,715
And more for ergo to ignore as he datamines but then doesn't understand it... (like his stepping onto his dick over bazant and footprint)

From his same citation
Quote:
It is evident from observation and our simulations that the debris of the aircraft went through theWTC structure at stories 94 through 97. Much of the fire insulation would have been scoured off leaving the steel elements unprotected during the immediately following fire event. Experimental data for steel in that condition (Buchanan 2000) indicate that the metal temperature in all unprotected structural elements would have reached 700 oC in a typical office fire. That condition would suffice to initiate instability (e.g. Ali and O’Connor 2001, Wang and Davies 2003) even if all the girders were intact and the failure mechanism was limited to one story of the core
structure
.
so they AGREE with bazant... even though you say they don't. It is rather amusing...
__________________
"There are submissions to the Journal of 9/11 Studies, but that's about as convincing as submissions to the Journal of Intelligent Design Studies." –Noam Chomsky (and this can be said of ANY and all twoof papers)
TruthersLie is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 08:52 AM   #38
tfk
Illuminator
 
Join Date: Oct 2006
Posts: 3,454
Originally Posted by ergo View Post
John Skilling:

http://www.britannica.com/EBchecked/.../John-Skilling

http://www.historylink.org/index.cfm...m&file_id=9632

Engineering perspective of the collapse of WTC-I Irfanoglu, A., Hoffmann, C.M. 2008 Journal of Performance of Constructed Facilities 22 (1):
http://www.You_didn't_address_1_comment.com

http://www.You_didn't_negate_1_argument.com

http://www.Posting_links_without_arguments_is_FAIL.com

http://www.Don't_reply_to_Obvious_Brainless_Trolls.com
tfk is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 11:30 AM   #39
Brainster
Penultimate Amazing
 
Brainster's Avatar
 
Join Date: May 2006
Posts: 18,358
Originally Posted by Justin39640 View Post
Like Thunder said they did survive the impacts. Many people credit the engineering for saving lives in that respect. On the other hand, many believe the design and placement of the stairwells was one of the main causes of loss of life above the impact zone.
Most tall buildings are designed around a central core where the vertical penetrations (stairwells and elevator shafts) are located, for good reason: It optimizes the rentable area and window views. However, I suspect more buildings will have that central core reinforced with concrete, which might have saved some lives on 9-11 (and cost the lives of that group of trapped elevator passengers who were able to bust through the drywall and escape through a restroom).
__________________
My new blog: Recent Reads.
1960s Comic Book Nostalgia
Visit the Screw Loose Change blog.
Brainster is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 19th March 2011, 12:08 PM   #40
Grizzly Bear
このマスクによっ
 
Grizzly Bear's Avatar
 
Join Date: May 2008
Posts: 7,864
Originally Posted by tfk View Post
ergo keeps emphasizing professional titles for sole criteria as if people are supposed to be impressed. Maybe he needs to change hobbies.
__________________
Grizzly Bear is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Reply

International Skeptics Forum » General Topics » Conspiracies and Conspiracy Theories » 9/11 Conspiracy Theories

Bookmarks

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -7. The time now is 06:51 PM.
Powered by vBulletin. Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.

This forum began as part of the James Randi Education Foundation (JREF). However, the forum now exists as
an independent entity with no affiliation with or endorsement by the JREF, including the section in reference to "JREF" topics.

Disclaimer: Messages posted in the Forum are solely the opinion of their authors.