Why did the WTC columns pull in?

[BenBurch]

I've pointed that out myself numerous times, including in my post one before Max's.

However, the hole created by the impact is almost invariant. It's the internal damage that's dependent on lots of minor contributing factors. The NWO would conclude that the big ventilating hole was not something they needed to worry about.

Also, as Max will tell you, thermite needs no external oxygen source.

Well, I was specifically thinking of the non-impact case. I should have been more clear but the dogs were bugging me to go out and I wasn't ignoring them very well...

Since the goal should be to make buildings safer under "ordinary" fire circumstances as we likely cannot ever prevent a terrorist for repeating the attack, I have wondered about the case where the only air movement was from the HVAC system and any glass that the fire can break.

If we assume an un-fought class-A office fire in a building just like WTC 1/2, is there a likelihood of a global collapse? If the answer is yes, then we need to seriously consider what sort of large buildings we allow in the future.

 

[R.Mackey]

If we assume an un-fought class-A office fire in a building just like WTC 1/2, is there a likelihood of a global collapse? If the answer is yes, then we need to seriously consider what sort of large buildings we allow in the future.

Yup. Hence the $64,000 question. As I wrote above, the answer is "yes," according to Dr. Quintiere. How likely we don't know yet; his opinion appears to be the upper bound of a somewhat loose consensus.

It's also interesting to review Arthur Scheuerman's hypothesis for WTC 7 (he sent me an update this morning). Both WTC 7 and WTC 1 and 2 appear to be governed by the caternary behavior of long-span supports, with special emphasis on thermal contraction after burnout. (NIST reports on the long-span factor for WTC 1 and 2, but we still don't know what they'll say about 7.) If his hypothesis holds up, then we may have a common mode failure bewteen all three buildings. This is about as close to a "smoking gun" as we're likely to see, at least in the real world.

 

[AZCat]

If we assume an un-fought class-A office fire in a building just like WTC 1/2, is there a likelihood of a global collapse? If the answer is yes, then we need to seriously consider what sort of large buildings we allow in the future.

By "un-fought" do you mean that the sprinkler systems are disabled? The 1975 WTC fire is a good example of a non-sprinklered fire. My reference book (High Rise: Fire and Life Safety by O'Hagan) is at home so I can't quote from it, but he essentially says that if the response to the fire had been delayed by an hour there might have been structural failure of one or more columns. Would that have caused collapse? Probably not, depending on how many columns were damaged.

 

[BenBurch]

Well, AZCat, as I understand it, WTC 1 & 2 had essentially no sprinkler systems except in the "core" to protect exit routes.

 

[funk de fino]

That is the $64,000 question. I spend about 20 pages on this in my whitepaper.

Opinions vary. NIST says no. Purdue says maybe. Arup says probably. Dr. Quinitere says yes.

It's also difficult to answer because the impact and fire are not truly separable. If you don't have the perimeter column damage, you probably don't have the massive window and floor breakage, either, and your fire is likely to be smaller and poorly ventilated. You also probably don't have the extensive fireproofing damage. It may be that the answer is "yes," but such a combination is so unlikely that it can be disregarded.

This is real questioning of the NIST Report -- not bogus nonsense about explosives and thermite. It's important to future building design. Several excellent teams are trying to answer this as we speak.

Thanks for the reply.

I went back and read the relevant parts of NIST and seen that they did apparently conclude that it would not have collapsed without the combination of fire and damage.

 

[AZCat]

Well, AZCat, as I understand it, WTC 1 & 2 had essentially no sprinkler systems except in the "core" to protect exit routes.

This is going to have to wait until I can get out from under a couple of deadlines, but I have a stack of magazines with articles about fire protection in the WTC. I'll go back and check them, unless you have another source handy. I thought that the WTC towers were fully sprinkled, but I could be wrong.

 

[BenBurch]

This is going to have to wait until I can get out from under a couple of deadlines, but I have a stack of magazines with articles about fire protection in the WTC. I'll go back and check them, unless you have another source handy. I thought that the WTC towers were fully sprinkled, but I could be wrong.

From; http://wtc.nist.gov/pubs/factsheets/faqs_8_2006.htm

8. We know that the sprinkler systems were activated because survivors reported water in the stairwells. If the sprinklers were working, how could there be a 'raging inferno' in the WTC towers?

Both the NIST calculations and interviews with survivors and firefighters indicated that the aircraft impacts severed the water pipes that carried the water to the sprinkler systems. The sprinklers were not operating on the principal fire floors.

However, there were ample sources of the water in the stairwells. The water pipes ran vertically within the stairwells. Moreover, there would have been copious water from the broken restroom supply lines and from the water tanks that supplied the initial water for the sprinklers. Thus, it is not surprising that evacuating occupants encountered a lot of water.

Even if the automatic sprinklers had been operational, the sprinkler systems—which were installed in accordance with the prevailing fire safety code—were designed to suppress a fire that covered as much as 1,500 square feet on a given floor. This amount of coverage is capable of controlling almost all fires that are likely to occur in an office building. On Sept. 11, 2001, the jet-fuel ignited fires quickly spread over most of the 40,000 square feet on several floors in each tower. This created infernos that could not have been suppressed even by an undamaged sprinkler system, much less one that had been appreciably degraded.

 

[Max Photon]

Well, Purdue took a shot at that, and they've run numerous computer trials. The things that forces you to make so many computer trials are the simplifications -- can you treat steel with a simple stress-strain curve, or do you need a detailed one? Treat all steel the same or not? What's the average strength of office furnishings? etc. All things that the NWO would also have to estimate.

Purdue is finding that these assumptions make a pretty significant difference with respect to the impact damage. However, they also find that they don't make a significant difference with respect to the final outcome -- they conclude that the fire can finish off the building for all of the various impact results.

Models are, of course, imprecise and limited to their assumptions. But if we accept the Purdue results as representative, we conclude that the likelihood of an impact leading to a total collapse is ~90+%. It will not be 100%, of course. Survival is possible, it merely appears to be rare. Whether it's 10% "rare" or < 1% "rare" we may never know.

So I would agree with you, up to a point. If there was a shadowy NWO cabal, they probably would conclude that collapse was likely but not guaranteed. If collapse was absolutely required, they probably would hit it with a little something extra.

Where I disagree is what they would choose to do with this knowledge. I think they'd choose to hit the structures with 747's and wipe them out at once. Cheaper, simpler, faster, safer. Same outcome. I would never in a million years expect them to try to mitigate a potential risk, that the 767's wouldn't be enough, by introducing the phenomenal risk of radical and complicated incendiaries. That's just silly. Either they're risk averse, or they're not. Your hypothesis requires that they're both.

Why didn't the hijillers fly 747's into the towers?

 

[aggle-rithm]

Why didn't the hijillers fly 747's into the towers?

They weren't on 747's.

 

[BenBurch]

Why didn't the hijillers fly 747's into the towers?

Ask them?

 

[R.Mackey]

Why didn't the hijillers fly 747's into the towers?

I don't know. The best guess I can come up with is that 747's tend to be international flights, and these were perceived to be a greater security risk.

Cost may also have been a factor. These are concerns that would not apply to the NWO.

Doesn't matter. I recall bin Laden himself didn't know if the structures would actually collapse. Surely they had no hope of totally destroying the Pentagon, so I don't imagine total destruction of any target was a mission requirement.

 

[BenBurch]

I'd say Bin Laden just wanted to have two damaged buildings blotting the NY skyline for the YEARS it would take to repair or dismantle them.

That they fell was a problem for him as I believe it caused many more nations to engage him in Afghanistan than otherwise would have been the case.

 

[Max Photon]

Why not 747s?

I don't know. The best guess I can come up with is that 747's tend to be international flights, and these were perceived to be a greater security risk.

Cost may also have been a factor. These are concerns that would not apply to the NWO.

Doesn't matter. I recall bin Laden himself didn't know if the structures would actually collapse. Surely they had no hope of totally destroying the Pentagon, so I don't imagine total destruction of any target was a mission requirement.

Um, Ryan, I thought the Evil Varmint were trying to knock the towers down. Remember? 1993?

And aren't they smart enough to figure out that a 747 would be more likely result in total collapse - or are you smarter than them?

So perhaps the reason Al-Sorta didn't use 747s is the same reason MILDEC didn't use 747s.

 

[Mr X]

Why did the columns bow in? There’s been quite a bit of speculation and misinformed opinion about the mechanics of the structure that caused that, so I hope to do a little bit of enlightenment. The first thing that needs to be looked at is the problem. Figure 1 shows a typical building section through a building such as the WTC towers.

etc

.

Hey Newtons Bit,

Thanks dude for trying to explain this to us. Though I have to say I'm having a little bit of trouble.
Let me ask you, was there only one severed column per floor?
Let me know soon.

 

[Newtons Bit]

Hey Newtons Bit,

Thanks dude for trying to explain this to us. Though I have to say I'm having a little bit of trouble.
Let me ask you, was there only one severed column per floor?
Let me know soon.

No, there were multiple severed core columns. NIST explains why and where. My pictures are just trying to outline the problem/concept, not directly represent it.

 

[Mr X]

No, there were multiple severed core columns. NIST explains why and where. My pictures are just trying to outline the problem/concept, not directly represent it.

Christ!...... you don't waste time.

How accurately do you feel your diagram reflcets/represents what actually happend?
Oh and by the way, are you representing what happend in the North tower or the South tower?

Mr X

 

[Newtons Bit]

Christ!...... you don't waste time.

How accurately do you feel your diagram reflcets/represents what actually happend?
Oh and by the way, are you representing what happend in the North tower or the South tower?

Mr X

It accurately represents the CONCEPT. NIST etimates the pull-in force, I use this force to show that the columns would pull-in until they fail (at temperature).

 

[Mr X]

It accurately represents the CONCEPT. NIST etimates the pull-in force, I use this force to show that the columns would pull-in until they fail (at temperature).

Funny.. cos when NIST did a real live test of this scenario, nothing pulled in and failled. Does that bother you in any way?


Mr X

 

[Newtons Bit]

Please provide link/source to this test. I've heard of no such thing.

 

[R.Mackey]

Funny.. cos when NIST did a real live test of this scenario, nothing pulled in and failled. Does that bother you in any way?


Mr X

Welcome to the Forums.

NIST did not do a "real live test" of this situation. You are probably referring to the certification test NCSTAR1-6B, which is not in any way similar, nor do the results of that test conflict with NIST's pull-in theory.

If you go to Page 2 of this very thread, you will see where I provide a paper by Dr. James Quintiere, who did do a real live test of this scenario, and confirmed that it happens. He even matches the expected timing.

As a result, we are not particularly bothered.