WTC Collapse - A Question of Fairness.

No steel-frame building, before or after the WTC buildings, has ever collapsed due to fire.

In light of the above statement is it fair to ask? . . .

1) Has any steel-frame building, before or after the WTC buildings, ever had a jet airliner fly into it?

2) Has any steel-frame building, before or after the WTC buildings, ever been hit with such lateral force?

3) Has any steel-frame building, before or after the WTC buildings, ever sustained itself after the resulting impact of a jet airliner, explosion and burning of 11,000 gallons of fuel?

4) Has any steel-frame building, before or after the WTC buildings, ever sustained itself after the resulting impact of a jet airliner, explosion and burning of 23,500 gallons of fuel?

No steel-frame building, before or after the WTC buildings, has ever collapsed due to fire.

In light of the answers to the 4 questions, is the above statement fair?

Originally posted by FEMA

No steel-frame building, before or after the WTC buildings, has ever collapsed due to fire.

In light of the answers to the 4 questions, is the above statement fair?

FEMA, in my view, yes.

Please understand that I am offering no opinion about what happened to the WTC. What I am answering is your direct question.

If we can agree that the statement is true:

No steel-frame building, before or after the WTC buildings, has ever collapsed due to fire.

..it is a fair question to ask, if you scientifically find it difficult to definitely conclude that the combination of being struck by "such lateral force" and the resulting fire were sufficient to have brought the structure down.

There is some evidence, however minimal, that suggests the combination was not sufficient.

I do not see making such a statement, or exploring the matter further, unreasonable.

As to my own position on the broader matter....I simply remain undecided.




[edit on 6-1-2006 by loam]

Hello Loamster!, good to have you aboard this thread.

I too will withhold opinion on the collapse because, as you correctly observed, the question simply asks about the fairness of this statement: "No steel-frame building, before or after the WTC buildings, has ever collapsed due to fire."

The question in this thread is one of that statement being a fair one when a person considers it was indeed made within the context of the WTCs, but without consideration to the fact no steel-frame buildings, before or after the WTC buildings, have ever had a jet airliner fly into them.

Perhaps a turn of phrase might shed more light on the point in question.

"No steel-frame building, before or after the WTC buildings, has ever collapsed due to a jet airliner impact."

Originally posted by FEMA

"No steel-frame building, before or after the WTC buildings, has ever collapsed due to a jet airliner impact."

I would equally have no concerns regarding such a statement.

I would say both statements are equally true. Also, you could add that no steel frame structure before or after 9/11 has ever collapsed from both jet airliner collision and fire. These statements are really comparing apples to oranges though. That is, until the next airliner smacks into another steel skyscraper. Which I hope never happens again.

Something else worth bearing in mind, is that even though a lot of teh fuel supposedly burnt off fairly early, it did mean that entire floors were ignited instantly, whereas in a 'normal' fire the progression would be much slower.
The impact, even if it did not sufficently enough damage the structure as some argue, also dislodged the fireproofing and most likely damaged the sprinkler systems.

But the key point, again, in my opinon is that the fires became widespread and capable of reaching significant temperatures in a manner of seconds.
I doubt many other steel structures that have been exposed to fires could really compare in that respect.

On another board I was browsing earlier which is populated by civil engineers, I noticed several comment that no-one would ever likely know the exact causes because there are too many variables and it is such a complex science.

[edit on 6-1-2006 by AgentSmith]

Does it count that the steel framed portions of the Windsor Tower in Madrid collapsed due to fire, while the concrete framed portion of the structure did not?

On another board I was browsing earlier which is populated by civil engineers, I noticed several comment that no-one would ever likely know the exact causes because there are too many variables and it is such a complex science.

Thanks for bringing that up AgentSmith. Certainly, on the one building that sustained a direct hit on center-side, one can't be sure just how much damage the central core took. So it comes back to the fairness of this statement: "No steel-frame building, before or after the WTC buildings, has ever collapsed due to fire."

To take it a step further, one could accurately state: "No 110-story steel-frame building, before or after the WTC buildings, has ever had such a fire."

OR

"No 110-story steel-frame buildings, before or after the WTC buildings, have ever collapsed."

OR

"Nothing like the WTC buildings clamity, has ever happened before or after."

If you've noticed, the statements become pretty mundane - nothing turns on them. While being all true, they really serve no point. The question I'm asking is, was the inclusion of the word fire in that statement entirely fair when there were so many other circumstances to be considered. Here is a turn of phrase to illustrate the point.

"Many steel-frame buildings, before and after the WTC buildings, have collapsed vertically into their footprint through gravity." This statement is also 100% true and there is significant documentation to substantiate the statement.

As some engineers pointed out above

" . . . no-one would ever likely know the exact causes because there are too many variables and it is such a complex science.

This quote seems to be fair in that it considers all the variables.

It's the Roarkinator!

Thanks for posting Howard.

In a word, the answer to your question is, "Yes."

Shortly, you'll see where I'm going with this.

Setting watch: "Click."

See here the shortest ever complete rebuttal of a widely held misconception: WTC7

2) Has any steel-frame building, before or after the WTC buildings, ever been hit with such lateral force?

The wind force the Towers were built to withstand was greater than the force caused by those airplanes.
(An Aerospace Defence technician gave me a calcuation for this, although I didn't understand it being I am not a physicist.)

WTC Bldg = 208 ft x 1360 ft = 282,000 ft2
Windspeed = 140 miles/hour
Windspeed ft/s = (5280 ft/mile)( 1 hour/ 3600 sec)(140 miles/hour) = 205.4 ft/s

Find: Applied force acting on WTC:

Solution: Force lbf = Cd Q S
Cd = Coefficient of Drag = 1.0 for a flat plate.
Q = Dynamic Pressure lb/ft2 = 1/2 q V2 where:
q = air density @ sea level in slugs ft3 = .00237 lbf-s2/ft4, and;
V = Windspeed in ft/s = 205.4 ft/s
V2 = (205.4ft/s)(205.4 ft/s) = 42,189 ft2/s2
S = x-sectional area bldg = 282,000 ft2

Applied Force lbf = (1)(.5)(.00237 lbf-s2/ft4)(42,189 ft2/s2)(282,000 ft2) = 14,098,298 lbf acting at the center of the bldg.

The bending moment due to this force is: (14,098,298 lbf)(1365 ft)(1/2) = 9,622,088,474 ft-lbf. or 9.622 billion ft-lbf acting at the base.

And consider this: the engineers would have at least a factor of safety of 2 or more for this bending moment!

He didn't want me to disclose his name.

3) Has any steel-frame building, before or after the WTC buildings, ever sustained itself after the resulting impact of a jet airliner, explosion and burning of 11,000 gallons of fuel?

No, however according to official reports the jet fuel only served as an ignition. They believe the collapse was mainly because of the burning of office furniture and other such things.

Put into context the amount of damage done before the fires supposedly brought the towers down.

There was less than 15% total column damage in either tower in all likelihood. I say "in all likelihood" because no one went in to examine the core columns, but any common sense would dictate that after the initial impact into the steel perimeter columns, the planes' remains weren't going to have much strength to face the much thicker and wider-spread core columns, of which there were nearly 50 in either building. But the numbers for the perimeter columns were about 11% and 13% severed in the impacted region.

Now, according to NIST's own information regarding the safety ratings of the core and perimeter columns, the buildings would have to have an average of a 75% total column failure on any given floor to cause a whole floor to collapse.

The impacts caused about 15% column failure, so the fires would have to cause over 60% column failure.

Look to ANY steel skyscraper fire, in the history of the world, and show me where any such fire has caused 60% column failure on any given floor!

Look at the Maracas Tower fire. That fire lasted much longer than the WTC fires - even when put together - and spanned even more floors. The inspectors went in expected to see a mess but found virtually no damage to the steel structure.

Now, the Maracas Tower also had fireproofing, and I don't know whether that aided the Maracas Tower in its fire, but I can tell you that the fireproofing was irrelevant as hell at the WTC, because the steel wasn't even freaking heated to above around 250 degrees Celsius according to all available info. NIST examined hundreds of samples of steel, both from the core and perimeter, and found NOTHING showing heating above around 250 Celsius. The core columns didn't even reach temps that high! And this is all in their published report.

In case you're wondering, 250 degrees Celsius does not cause any strength loss in steel (at least nothing approaching even 1% loss anyway). That means the initial >15% columns severed, stayed at >15% columns severed, until it is shown that steel anywhere in those buildings was heated beyond 250 degrees Celsius. That doesn't mean NIST coming up with handy computer sims, or experiments in their own conditions and under their own supervision, but actual samples from the WTC.

And yes, especially for WTC7, as someone brought up, is the statement "fair." More than fair, because the only times buildings have ever been destroyed like that were during demolitions and demolitions alone, plain and simple.

NIST examined hundreds of samples of steel, both from the core and perimeter, and found NOTHING showing heating above around 250 Celsius. The core columns didn't even reach temps that high! And this is all in their published report.

You would be referring to this quote:

Observations of paint cracking due to thermal expansion. Of the more than 170 areas examined on 16 perimeter column panels, only three columns had evidence that the steel reached temperatures above 250 ºC: east face, floor 98, inner web; east face, floor 92, inner web; and north face, floor 98, floor truss connector. Only two core column specimens had sufficient paint remaining to make such an analysis, and their temperatures did not reach 250 ºC. ... Using metallographic analysis, NIST determined that there was no evidence that any of the samples had reached temperatures above 600 ºC. (p 90/140)

NIST Draft Report

Page 142

wtc.nist.gov...

Just thought I would post that.

Originally posted by bsbray11
Look at the Maracas Tower fire. That fire lasted much longer than the WTC fires - even when put together - and spanned even more floors. The inspectors went in expected to see a mess but found virtually no damage to the steel structure.

Now, the Maracas Tower also had fireproofing, and I don't know whether that aided the Maracas Tower in its fire, but I can tell you that the fireproofing was irrelevant as hell at the WTC, because the steel wasn't even freaking heated to above around 250 degrees Celsius according to all available info. NIST examined hundreds of samples of steel, both from the core and perimeter, and found NOTHING showing heating above around 250 Celsius. The core columns didn't even reach temps that high! And this is all in their published report.

Uh, I think you mean the Parque Central tower in Caracas. You wouldn't want Dick Cheaney to think you're an agent or something.





The floor beams in the Parque Central. Notice the different between them and the WTC towers?

That's right, they aren't trusses.

In fact, the Parque Central tower uses an entirely different framing system, called a "Superframe."

The structure
Although NFPA was not officially invited to investigate the Parque Central fire, I visited the scene the day after the fire to interview Caracas’ fire chief, incident commander Colonel Rodolfo Briceño, who oversaw the incident, his commanders on the ground and other responding personnel, the designer of the building’s original sprinkler system, and building maintenance personnel. I also collected information from newspapers and walked through Parque Central’s West Tower, which is virtually identical to the East Tower.

The twin towers of the building were completed in 1982 as part of a 25-acre (10-hectare) complex known as Parque Central, which was built between 1970 and 1982. The complex also contains more than 1,100 retail stores, seven 40-story residential towers, and a 35-story hotel. The East Tower has 56 floors above ground and 4 underground, with a total height of 725 feet (221 meters). Each floor plate covers an area of 20,450 square feet (1,900 square meters) that includes eight elevator banks and two enclosed, remote fire exit stairwells (see floor plan).

The reinforced concrete structure consists of perimeter columns connected by post-tensioned concrete “macroslabs” that are each 10 feet (3 meters) deep and above the second–floor mezzanine, the 14th, 26th, 38th, and 49th floors. There’s no central core.

Individual floors between the macroslabs have a steel-deck floor supported by steel beams, all protected underneath with spray-on Cafco Blaze Shield DC/F mineral glass fiber wool with cement fireproofing. According to Cafco’s Manny Herrera, the floor was designed to meet U.S. standards for a two-hour fire resistance rating. However, the overall fire compartmentalization of each floor slab was decreased by the addition of several unrated floor panels to provide access to mechanical and plumbing systems.

Five structural bays rest on four lines of columns in each direction supporting the steel deck. In effect, the concrete structure includes five stacked steel buildings, each supported by a macroslab. During the fire, two steel decks partially collapsed; other than that, there was no collapse inside the building. However, deflection in some steel beams was severe

s ource

Originally posted by HowardRoark
Uh, I think you mean the Parque Central tower in Caracas.

You wouldn't want Dick Cheaney to think you're an agent or something.

Hey, at least the Caracas Tower isn't the Vice President of the United States of America.

The floor beams in the Parque Central. Notice the different between them and the WTC towers?

Not made of steel?

[edit on 17-1-2006 by bsbray11]

Method of construction is just as significant as the materials used.
The steel parts of the Madrid tower collapsed (though again it was of different design to the WTC) so I'm curious how you would compare the Madrid building to the Caracas one? Was the Madrid tower damaged using explosives as well?

[edit on 17-1-2006 by AgentSmith]

Originally posted by AgentSmith
Method of construction is just as significant as the materials used.

Maybe with extremely temperate fires, but these weren't hot enough for the construction to matter! The steel wasn't even heated enough to result in any major damage, despite the comparative severity of the fire.

Again, steel must be heated to around 600 degrees Celsius before losing critical strength. Heating of 200 or 300 degrees Celsius, such as what was seen at the WTC, will NOT significantly affect the integrity of the steel.



Also keep in mind that the photos you see online of the inside of that tower are going to levitate around the areas of the most damage, as I would imagine they're coming mostly from media sources and common sense would dictate the media is going to report and show what's most interesting and relevant (or at least, that's how it's supposed to work).

The steel parts of the Madrid tower collapsed (though again it was of different design to the WTC) so I'm curious how you would compare the Madrid building to the Caracas one? Was the Madrid tower damaged using explosives as well?

I believe you are confused, because I have not mentioned the tower in Madrid on this thread, nor do I believe I have ever made any comparison of the Caracas and Windsor Building Towers.

Oh I'm not confused, I realise you havn't. That is why I'm asking you..
Have you any comments regarding a comparison between the Caracas building and the Madrid one? They both employed steel in their structure, but as the construction method appears to be irrelevant, I am curious as to how you can explain the partial collapse of one while the other stays intact?
I'm curious if you would explain that with explosives, or if there is an alternative explanation you would like to share with us...

[edit on 17-1-2006 by AgentSmith]

Originally posted by AgentSmith
Oh I'm not confused, I realise you havn't. That is why I'm asking you..
Have you any comments regarding a comparison between the Caracas building and the Madrid one? They both employed steel in their structure, but as the construction method appears to be irrelevant, I am curious as to how you can explain the partial collapse of one while the other stays intact? I'm curious if you would explain that with explosives, or if there is an alternative explanation you would like to share with us...

There was a role of concrete in the construction of the Windsor Building that was not present in the WTC, or, as far as I know, the Caracas Tower, and thus I refrain from referring to the Windsor Building.

I'm not familiar with the exact structure of the Windsor Building, but I understand that rather than having a steel frame, it was supported by concrete that was reinforced by steel. I would imagine that the failure was related to this more than the effect of the fire upon the steel, and thus you have no such failures from actual steel skyscrapers.

You'll notice that the building did not globally collapse upon itself into a pile of steel shards and conrete dust, too. What of it did collapse was very different than any part of the WTC collapse.

Originally posted by bsbray11

The floor beams in the Parque Central. Notice the different between them and the WTC towers?

Not made of steel?

[edit on 17-1-2006 by bsbray11]

This picture is a little clearer.

www.nfpa.org...

The floor truss beams in the Caracas tower were connected to intermediate beams that ran from column to column and the columns were much closer together than the WTC towers. Also, note that the fireproofing was still intact after the fire. The same could not be said for the WTC where the integrity of the fireproofing was questionable even before the planes hit.



Oh, and reinforced concrete plays a major role in the Caracas tower building. It is what is called a superframe building. The major load bearing elements are concrete, with steel beams and columns used to build out the infill floors. See the quote in my post above.


[edit on 17-1-2006 by HowardRoark]