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Post by ktesibios on Oct 20, 2005 9:48:16 GMT -4
Preparing a building for explosive demolition means placing charges directly on structural members, not stashing them here and there in janitor closets and suchlike. Gaining access to these members means tearing up interior walls, floors, etc. at multiple locations distributed through the building.
These are changes which the most clueless stuffed suit in the corporate universe couldn't fail to notice, and yet we haven't any reports of them being observed prior to the attacks.
Claims that the preparatory work could have been done in a working office building and remain completely unobserved are a cartload of horse patooties.
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Bob B.
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Post by Bob B. on Oct 20, 2005 9:58:45 GMT -4
Claims that the preparatory work could have been done in a working office building and remain completely unobserved are a cartload of horse patooties. I couldn't agreed more. This is to me the strongest and most undeniable evidence the buildings were not rigged for demolition. The demolition theory should be flushed down the crapper where it belongs.
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Post by JayUtah on Oct 20, 2005 10:29:20 GMT -4
Turbonium, we discussed this. Buildings demolished by mechanical means can, in some cases, be said to have been "pulled". This is because this type of demolition is done by companies that descended from construction companies, using the same kinds of heavy equipment. Buildings demolished by explosive means are said to have been "shot", not "pulled". This is because this type of demolition is done by companies that descended from mining companies, using the same kinds of explosives. Their jargon goes back to their roots. I checked.
This is not a discussion being engaged in entirely by laymen. As I said, i contacted a member of Controlled Demolition directly and asked the specific question. He clarified the terminology. All you have is a second- or third-hand story about another Controlled Demolition employee simply having used the word "pull" in its generic context.
Spokesmen for Larry Silverstein have disavowed that he was involved in any conspiracy to demolish WTC 7 on Sept. 11. The original proponent of the interpretation of Silverstein's remarks has withdrawn his claim due to lack of foundation.
It's quite irritating, Turbonium, when you return to the same old points you made weeks ago as if none of the intervening discussion had taken place. As I said, if you wish not to be characterized as a conspiracy theorist, then the onus is on you to stop fitting the definition.
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lenbrazil
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Post by lenbrazil on Oct 20, 2005 11:03:18 GMT -4
The infamous Silverstein quote if anything make the CT less likely. What are we to assume the quote means, that the fire department demolished WTC - 7 ? Can you give us the exact quote in context?
1] If the FDNY were 'in' on the conspiracy why did they send so many men into WTCs 1 & 2? Or are we to assume that they only were involved in demolishing WTC 7 and didn't "smell a rat" when the towers collapsed? Why would they cooperate with, instead of denouncing someone responsible for the death of so many of their colleges
2] When are we to assume WTC 7 was rigged, before or after the planes struck. If it was rigged before, why would Silverstein have said he told the fire department to "pull it"? Hadn't the decision already been made? Or are we to assume he rigged the building and took a "wait and see" attitude and under certain circumstances might have decided to not demolish it? and then sent in people to remove the explosives if he decided not to demolish it? Of course in controlled demo normally holes are drilled and parts of the support structure are cut, how would he have covered that up? How was it 'preped' without anybody noticing?
That raises another question regarding the towers how were they prepared for demolition without anybody noticing?
Another possibility is that they decided at the time to "pull" WTC-7, who then went into the burning building to prep it? You said no one was in WTC-7, how did they get in and out without anybody noticing? Why would they have prepared the towers ahead of time and only decided to demolish WTC-7 in the last minute?
3] If the demolition of WTC-7 was part of some plot why on Earth would Silverstein "admit" this in an interview? He is a very shrewd character and not prone to slips of the tounge. Casting doubt of the official version not only would threaten his insurance settlement [his supposed motive] but could subject him to arrest on charges for which he would face the death penalty [if he didn't die in a mysterious accident first].
You say the official explanation which is universally accepted by experts doesn't make sense, yours makes far less.
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Post by JayUtah on Oct 20, 2005 11:07:04 GMT -4
1. It seems to me that the WTC structures would be much weaker on the side that the planes crashed into. They would have taken more structural damage, had more fireproofing knocked away from the frame, and would have burned for slightly longer. Wouldn't this have caused the buildings to collapse on that side much faster?
Well, maybe. Structural mechanics is a complicated science. The principles are not that complicated, but the ways they are applied to actual structures can be complicated because the structures themselves interact in complex ways. The collapse will not necessarily initiate where the most visible damage is.
I'll try an example.
Imagine you have a heavy beam held up by three posts -- one on each end and one in the middle. Now let's say the middle post catches on fire and is completely destroyed. What are your possible failure modes? Well, you could believe that the beam might sag and fail in the middle, having lost its central support. Or you may consider that one of the end posts -- now having to bear more load than intended -- may buckle and fail. So where you see the collapse initiate may not necessarily be where the structure was first compromised.
2. Is it true that there were drills simulating attacks in NYC and Washington shortly before the real attacks?
Not to my knowledge. I'm aware of various regional readiness exercises (in other U.S. regions) based around the scenario of a hijacked airliner. But these never translated into national policy or protocol.
3. Seeing as how WTC 7 was only hit by debris from the WTC collapse, does it seem odd that the building collapsed as well?
No. The early estimates of how much of WTC 7 was damaged or destroyed by tower debris underestimated the actual damage. Further, WTC 7 was damaged by fire that burned for 7-8 hours in the region of the transfer trusses that formed a critical part of the building's overall structure.
What do you think of the owner's comment about pulling the building?
He never spoke about pulling the building. Exactly what he was talking about and what he meant by the phrase "pull it" is a matter of some debate. However, since he was talking to the fire chief and "pull it" does not refer to explosive demolition, it does not seem defensible that he was referring to demolishing WTC 7 intentionally. A spokesman for Silverstein has denied that interpretation.
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Post by nomuse on Oct 20, 2005 13:05:22 GMT -4
"Pull it" and "pull" were said by Larry Silverstein, the WTC owner, who is not a member of said professions, either, as far as I am aware. So why can one layman not validly opine on what another layman meant when he said this? Both sides of the argument have been made by laymen. So, the average man on the street, if told to "Pull it!" would immediately run to the nearest building and begin wiring it with explosives? Apparently Mr. Silverstein does speak the technical language of a subculture. He, and whoever he was actually giving the order to, both spoke fluent conspiracy-believer.
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Post by Fnord Fred on Oct 20, 2005 13:27:09 GMT -4
1. It seems to me that the WTC structures would be much weaker on the side that the planes crashed into. They would have taken more structural damage, had more fireproofing knocked away from the frame, and would have burned for slightly longer. Wouldn't this have caused the buildings to collapse on that side much faster?Well, maybe. Structural mechanics is a complicated science. The principles are not that complicated, but the ways they are applied to actual structures can be complicated because the structures themselves interact in complex ways. The collapse will not necessarily initiate where the most visible damage is. I'll try an example. Imagine you have a heavy beam held up by three posts -- one on each end and one in the middle. Now let's say the middle post catches on fire and is completely destroyed. What are your possible failure modes? Well, you could believe that the beam might sag and fail in the middle, having lost its central support. Or you may consider that one of the end posts -- now having to bear more load than intended -- may buckle and fail. So where you see the collapse initiate may not necessarily be where the structure was first compromised. Makes sense. Basically the failures of the columns on one side would cause extra load on the others, causing them to fail - right? I guess I was expecting there to be some sort of rotational acceleration - not sure why though, come to think of it. I'll have to find what I was reading earlier then. I'll check turbo's link first - it might be a similar article to the one I was reading. It seems like he would have said 'pull out' instead of 'pull it', but then again technical terms don't always (or even usually) make sense if heard by laymen. I'd like to focus on Question #2 for now, I'll take a look and see if I can find what I was reading about it earlier.
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Bob B.
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Post by Bob B. on Oct 20, 2005 13:30:22 GMT -4
Consider the following model:
Let’s say we have a building with three rows of columns, A, B and C. Row A is along the north face of the building, row B is through the middle, and C row is along the south face. Let’s assume the columns in row A are either destroyed or severely damaged. The load previously supported by these columns will be transferred to rows B and C. These columns may still be able to support the building, but they are now overloaded. If their strength is weakened further, say by heating due to a fire, they may fail.
Let’s say the load bearing capacity of the columns in row B has diminished to such point they buckle and fail. You might think that the top of the building will rotate to the north and the structure will topple over sideways. But for this to happen, the columns in row C must continue to hold up the south side of the building as the north side falls. This won’t happen. As soon as row B fails, row C becomes extremely overloaded. Furthermore, the slightest sideways motion causes the row C columns to lose their verticality. As soon as row B fails, the columns of row C will likewise buckle and collapse almost immediately. The top of the building will fall almost straight down.
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Post by Fnord Fred on Oct 20, 2005 13:31:01 GMT -4
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Post by nomuse on Oct 20, 2005 13:31:40 GMT -4
I'm afraid I can't construct a proper truth table that explains a demolitions of WTC7.
We may first assume that the building was to be made unusable so as to defraud insurance and recover the valuable real estate under it. Further, we may assume that whatever caused the collapse of the two tallest structures in the WTC complex, this was a predicted event known to whoever wanted WTC7 destroyed.
These assumptions simplify our truth-table markedly.
The first element is, do the other collapses sufficiently damage the building in question? If they do, then our explosives were not used, and stand a chance of being discovered in the debris. If the debris and fire loading was too small, we would not be able to convince insurance investigators et al that that made our building fall -- we'll have to go back in and take out our explosives. (We can't simply leave them there and hope to fire them at some other excuse; all those engineers prowling around seeing to the structural integrity of the remaining WTC complex would discover them).
So we are left with third case; enough debris hits our building to convince trained investigators (okay, allows them to write a conving report to their superiors then go on vacation in the Bahamas with our payoff), but not so much debris hits as to prematurely collapse it, or reveal the explosives, or damage any of the firing systems.
At this point I must go out on a limb here. I can't think of any rational reason to delay firing the explosives, other than the simple fact that Mr. Silverstein had no way of knowing how closely WTC7 adhered to the Goldilocks condition, above. Delaying, however, only puts the explosives in more danger of being discovered either promptly, through fire setting them off prematurely, or through their eventual discovery in the collapsed rubble. The only answer, therefor, is that the building is in addition wired with thousands of sensors, rigged to a dynamic real-time simulation that Mr. Silverstein has minute-by-minute access to.
There is, however, still a simpler solution. We are already paying off the inspectors and insurance investigators and engineers (who would otherwise quickly discover that our building was in no danger of collapsing before we set off explosives inside it). Why not let the building stand, smoulder and only slightly damaged, then bribe a much smaller pool of investigators to say it has lost sufficient structural integrity to be uneconomical to repair -- it is then placed on the list to be demolished along with the other half-standing ruins of the WTC.
This satisfies our original goals with much less danger of discovery.
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Bob B.
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Post by Bob B. on Oct 20, 2005 14:20:33 GMT -4
Nomuse, you are mistakenly looking for the simplest answer. A tenet of conspiracism is that you must look for the most improbably and convoluted explanation.
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lenbrazil
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Post by lenbrazil on Oct 20, 2005 15:16:10 GMT -4
I quote wikipedia too, but one must be careful when depending on it as a reliable source of information - because literally anyone can edit it. Looking at the discussion page can be helpful. If I doubt anything I see there I check for confirmation.
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Post by JayUtah on Oct 20, 2005 16:07:59 GMT -4
Makes sense. Basically the failures of the columns on one side would cause extra load on the others, causing them to fail - right?
In a simplistic sense, yes. Remember that we're talking about buildings that survived an initial wound and then failed later from a combination of effects. The key is to understand how loads are transfered in both intact and compromised structures, and that's different for each individual structure. When you throw in thermal problems, you have to look at how all those effects might combine.
As with most technical problems, any individual example of structural failure with fit a pattern to some extent, and exhibit individual characteristics to some extent. You have to approach the investigation with a firm understanding of the individual behaviors, as well as a good theory for how they will interact.
I guess I was expecting there to be some sort of rotational acceleration - not sure why though, come to think of it.
That's the intuitive way to think about it, and not altogether an incorrect way. Go back to my post and beam example. Let's say the beam has enough margin to bear its load with only the two end columns, but the columns' critical load is exceeded; they are expected to fail by buckling.
One will probably fail first. What happens then? The remaining post becomes a pivot against which the beam will rotate; the now-free end of the beam begins to rotate downward. Intuitively we expect the remaining post to stay up and the free end of the beam to hit the ground after rotating, and then perhaps the column will tip over because it bears an eccentric load instead of an axial load, or perhaps the beam will break in the middle from dynamic loading as its free end hits. It all depends on the exact geometry and materials properties of the problem.
But a slightly more complicated problem considers that the beam is attached to the top of the post, and by rotating downward applies a bending moment to the post. It's not a "pivot" in the full sense of the word. Now with an eccentric load, even after the beam has rotated only a little bit, the second column may immediately fail. At this point the beam is no longer horizontal, and may still possess a very small angular momentum, but it is essentially unsupported and simply falls straight down.
This is actually what happened in the WTC south tower. The perimeter columns had been damaged on either side of one of the corner structures. The internal flooring, which braces both the perimeter and the core, had been destroyed either in the collision or had "hogged" (i.e., sagged) from the heat. The damage to the core would have been more extensive in this collision too, since the second airplane didn't have as far to travel from exterior to core. Thus an inordinate amount of load was transferred to that corner structure by the relatively intact structure above it.
When the core finally gave way, the gravity loads are transferred by the upper structure and the hat truss to the perimeter walls. Two adjacent perimeter walls were already unable to bear that load, and the thin corner between them was relatively intact, but highly overloaded. That's where we see the structure buckle in the videos. There are about two frames of video where the corner structure begins visibly to deform, and then in the next frame is completely deformed and steel is ejected from the area.
The south tower did indeed begin to rotate toward that initial failure. The pivot was not the core, but rather the diagonally opposite corner, which represented the strongest remaining section of the perimeter at that height. But as the rotation bent those columns, they could no longer bear the load and they gave way. At that point rotational acceleration stops, although whatever rotational velocity you accumulated up to that point is still with you.
This principle is used in controlled demolition. I explain this in the lengthy other thread. Briefly, large buildings have "shear walls" or planes of vertical separation that allow the building to flex without tearing the structure. These provide natural planes of separation between substructures. By taking out the columns on either side of the shear plane first, and then cutting the outer "pivot" columns a split second later, you can induce a rotation that causes the building to lean in a certain direction as it falls. In the most elegant demolitions that rotation rate can be seen all the way down.
I'll have to find what I was reading earlier then. I'll check turbo's link first - it might be a similar article to the one I was reading.
I haven't yet read his link, so I can't yet confirm whether these were the exercises I read about several years ago.
It seems like he would have said 'pull out' instead of 'pull it', but then again technical terms don't always (or even usually) make sense if heard by laymen.
True, but this isn't a technical term. If I say "gusset plate," for example, that's a technical term. It doesn't have a meaning outside engineering or construction. It doesn't for example, mean something different to a chemist, or necessary mean anything to a chemist.
But if I say "bug", that can have several different meanings depending on context. It has a common definition meaning an insect. To a computer scientist it means a defect or failure in a system (ironically derived from a literal insect caught in a relay). To a surveillance expert it means a listening device. To a car afficionado it means a certain model of Volkswagen. Which meaning is intended depends solely on context.
The word "pull" or the phrase "pull it" means different things in different context. To a construction team it can mean demolishing a building using heavy equipment. But it doesn't mean that to an explosives demolition team -- in that industry (which is not the same as the construction-type demolition industry) it has no special meaning; only the "common" one. The question is what it means to Silverstein talking to a fire chief.
We don't know what exact words Silverstein used in his phone conversation with the fire chief. The PBS program in which the phrase appears shows Silverstein recounting later what he had said. He used the term in the interview, not necessarily in his phone conversation with the fire chief.
It is important to keep in mind that the conspiracy theorists say WTC 7 was intentionally destroyed using the explosive implosion method, which is the only method that would even come close to duplicating the visible observation of the building's demise. When I was finally able to reach someone who worked for the leading firm in that industry, they confirmed that "pull it" was not their slang; they used a different word.
WTC 6, which was heavily damaged as well, was demolished using more traditional wrecking-ball techniques. Those workers used "pull" in connection with their demolition, but they're the construction types, not the explosives types. And their laborious method bears no resemblance to the manner in which WTC 7 collapsed.
I'd like to focus on Question #2 for now, I'll take a look and see if I can find what I was reading about it earlier.
There's a fair amount of somewhat relevant discussion in the marathon thread.
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Post by Fnord Fred on Oct 20, 2005 19:29:37 GMT -4
Oh, fine. I guess I'll start in on my new book then. Thanks for your work on #1 and #3 though. You've answered my questions on those and then some. And I probably shouldn't have said technical term - damn semantics.
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Post by JayUtah on Oct 20, 2005 19:48:49 GMT -4
I understood what you intended by "technical term". The issue is what Silverstein exactly meant by a phrase than can have many meanings. If I take a common word and use it in a way particular to my profession, it becomes a "technical term" too. I can say "knuckle" in the context of building a concrete and steel structure, and you'd have to know a thing or two about construction to know that this means a piece of steel that dips into the concrete in order to provide extra anchorage. It has a precise meaning in that context. If I said "knuckle" in the context of ship handling, you'd have to know about ship handling and hydrodynamics to know that I mean a localized zone of turbulence caused by the rapid turning of a ship. It's a technical term in that respect too.
It's useful to discuss the distinction between terms that are purely technical and terms that become technical in certain contexts so that you understand the number of possible meanings Silverstein's comments can have. If he had said something that could have only one possible meaning, like "inverse tachyon beam", then we wouldn't need this conversation. But he said something that can be variously interpreted. The conspiracists hand you only one of many possible interpretation and demand that it's the one that fits. But what evidence do they have that theirs is better than any other? They draw one ill-fitting comparison to demolition and call it good. Why? Because they went down that line of reasoning focused on controlled demolition from the very beginning.
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