Why?Partial pull in from one side would not lead to buckling of the entire perimeter
Why?Partial pull in from one side would not lead to buckling of the entire perimeter
first of all it would only "pull in" opposite the core... corners would / could not be pulled in Do you think pull in on one short or long side would cause the entire perimeter to then buckle?Why?
Maybe. If the wall buckled Why do you think it can't?Do you think pull in on one short or long side would cause the entire perimeter to then buckle?
not enough axial capacity would be lost.Maybe. If the wall buckled Why do you think it can't?
not enough axial capacity would be lost.
13,227 pounds of explosives were used to demolish the Mina Plaza in UAE:
Source: https://www.youtube.com/watch?v=5ceXT5PYTGI
https://interestingengineering.com/...zas-demolished-in-abu-dhabi-within-10-seconds
And of course, they were also "smartly placed" by demolition professionals. But for this:
Eh, 75 pounds should suffice.
I did: steel.You didn't even say what the pipe was made of.
Go with NIST's back-of-the-envelope calculation. Make each floor able to carry the weight of 11 additional floors.You didn't specify the strength of the floor connections or the weight of the floor systems.
Ok, let me whip out my finite element software to model the propensity to buckle of an arbitrarily large and thick steel pipe that is impossible to construct and has no relevance to this conversation. Please just wait till I'm done to comment further. This may take a while.I did: steel.
Go with NIST's back-of-the-envelope calculation. Make each floor able to carry the weight of 11 additional floors.
13,227 pounds of explosives were used to demolish the Mina Plaza in UAE:
Source: https://www.youtube.com/watch?v=5ceXT5PYTGI
Well, the Wiki page doesn't specify, but from looking at videos of the demolition I'm going to take a wild guess that a lot of the 364 pounds of explosives were used to cut all or most of the main vertical columns near the base of the building. There's tiny explosions running along the entire height of the tower, but at 0:17 you can clearly see the huge blast at the bottom which actually causes the building to start falling:What now? Which evasion will you try now? How else will you reword your bare, uneducated, uncomprehending incredulity?
The lower half of where the original brick and granite building stood was removed, and after four months of preparation, the building was demolished by controlled explosive implosion on March 18, 2006, at 7:40 AM.
No further "off-topic" than most of the discussion. BUT a new theme. I made what to me was - still is - the obvious response:Well, I just mean replicating the minimum required lethal damage you believe the buildings suffered, but with targeted explosives. If a plane impact and fires can destroy the South Tower in a mere 56 minutes, it should be trivial to replicate the damage with demolition charges.
Henkka did not see the significance of my comment.Of course causing collapse by explosives is trivial. .......
...."replicating the damage" i.e. mimicking the actual collapses is a more challenging task.
So, since the discussion was heading into a more complex and off topic debate I said:Why would it be challenging? Just use explosives to do the same amount of damage you believe the plane impact and fires did. Or I mean, do only the amount of damage that was necessary to collapse the building. How much explosives would you need?
@Henkka has not taken that advice. BUT starts to drift into his new sort of unformed "hypothesis":OK. So OP the thread making that claim and let's see if you and I can work through the reasoning.
I (correctly I think) spotted the coming derail. And stated the problem concisely:It seems absurd that the WTC towers could be reduced to a smouldering pile of rubble in a few seconds, by a relatively tiny amount of explosives directly targeting the floor trusses on a few floors. But it follows logically from thinking that a plane hitting the building did the same thing. What one finds absurd is subjective though, so it's more like something to think about than some kind of QED argument.
henkka has since committed more fully to his "Drop the Towers by explosively initiating ROOSD".You need to drop the Top Block first.
Maybe cutting all the trusses would take hundreds of charges, but you wouldn't need that much explosive material in each charge, since the trusses were pretty flimsy.
You are not the only sinner. I've been less than rigorous myself on this thread as it gradually drifted of my OP which was response to your question:Sorry about it drifting so far off-topic… I saw you recommended I make a new thread, but the last time I did that it didn’t go well for me, so I’m a bit timid about starting threads now.
A comprehensive response to that question of necessity requires an understanding of the actual collapse mechanisms. And some drift of topic into explaining the actual mechanisms has been necessary because of the limited understanding some members have of those real events.(Is it your position that the WTC towers could have collapsed from fire alone, without plane impact?)
It wouldn't take any explosives because debris did it as shown in this graphic first posted in Nov 2007.So you could do a controlled demolition of the tower just by attacking these flimsy little things with explosives?
That doesn't look like it would take a powerful explosive to take out the connection. Cut the trusses on a couple floors to get the unstoppable cascade going, columns lose lateral support, and it's RIP World Trade Center. Doable?
I thought it did? why do you think it didn't?Sorry about it drifting so far off-topic… I saw you recommended I make a new thread, but the last time I did that it didn’t go well for me, so I’m a bit timid about starting threads now.
Scaling down does not work, because some properties scale linear, some quadratic, and some cubic.Scale it down so it's inches rather than feet. Or go all out and make it centimeters. It's now a 10m pipe-in-pipe. Could you get it to ROOSD? The answer now is "of course not!" because of the scaling problem that we're familiar with.
I'm asking whether the full-scale version (of something we all know wouldn't be susceptible to ROOSD) might be susceptible to ROOSD.
And, please remember that I'm only saying this to formalize my "incredulity" as something you can (literally) poke holes in. Why is it you think the mesh is so much weaker than the single pipe?
WTC1 was 1360 ft tall, 208×208 ft = 43264 ft²I'm not even sure that your one-foot thick, 200 feet wide, 1000 feet tall pipe wouldn't collapse on itself, or how thin you'd need to make its wall to insure collapse in a moderate breeze.
Pretty sure your pipe would collapse if made from 3" steel.Fire Technology, doi:10.1007/s10694-012-0285-6.
Overview of the Structural Design of World Trade Center 1, 2, and 7 Buildings
Each column on floor 10 to 107 was fabricated by welding four steel plates to form a tall box, nominally 0.36 m (14 in) on a side. The space between the steel columns was 0.66 m (26 in), with a framed plate glass window in each gap. Adjacent columns were connected at each floor by steel spandrel plates, 1.3 m (52 in) high. The upper parts of the buildings had less wind load and building mass to support. Thus, on higher floors, the thickness of the steel plates making up the columns decreased, becoming as thin as 6 mm (¼ in) near the top down from as thick as 76 mm (3 in) at the lower floors. There were 10 grades of steel used for the columns and spandrels, with yield strengths ranging from 248 MPa (36 ksi) to 690 MPa (100 ksi). The grade of steel used in each location was dictated by the calculated stresses due to the gravity and wind loads. All the exterior columns and spandrels were prefabricated into welded panels, three stories tall and three columns wide. The panels, each numbered to identify its location in the tower, were then bolted to adjacent units to form the walls (Figure 4). Field panels were staggered so that every third panel was spliced at each floor level. The use of identically shaped prefabricated elements was an innovation that enabled rapid construction.
@Jeffrey Orling also has some credibly plausible alternate explanations but all of them are far from supported by hypotheses.You have s false impression of the tower being pulled in from all sides. In reality, only one wall was pulled in. Refer to NCSTAR 1-6D Executive Summary
I like the idea of using the actual thickness of the perimeter columns. On my math, the actual WTC columns could probably stand (alone) about 300-400 feet before needing lateral bracing. (I'm not deeply committed to any particular height but the textbook example with a 1/10" steel tube can reach over 200 feet.) They got their lateral bracing at each floor (every 12' or so) from the spandrel plates and, ultimately, the corner connections to the perpendicular facade.Pretty sure your pipe would collapse if made from 3" steel.
I like this too. But keep the core columns in mind. The "hole" is a square donut.Oh, and you can drop a square lid into a square hole, but you can't drop a round lid into a round hole. That impacts your "impalement" scenario.
Well, the Wiki page doesn't specify, but from looking at videos of the demolition I'm going to take a wild guess that a lot of the 364 pounds of explosives were used to cut all or most of the main vertical columns near the base of the building. There's tiny explosions running along the entire height of the tower, but at 0:17 you can clearly see the huge blast at the bottom which actually causes the building to start falling:
Source: https://www.youtube.com/watch?v=79sJ1bMR6VQ
So, it's basically a classic CD implosion. There's also this:
So this was a professional demolition, with months of prep work, where explosives were used to cut the supports at the bottom, of a much smaller building. What you're proposing to do is quite different, where 75 pounds of explosives would be used on a bunch of horizontal floor supports near the top of the tower, instead of on vertical columns near the base... So just to recap, you think you could demolish a building over three times larger than this, with a quarter of the explosives, by attacking horizontal beams at the top, and obviously without months of prep work since there was no such work done on the WTC towers prior to 9/11. All I can say is, good luck with that.
Yes. And so predictable.Thanks for fulfilling my prophecy that you would merely reword your bare incredulity.
Yes!Still no argument.
Begging the reality that is has nothing to do with the actual 9/11 collapses.Yes, 364 pounds, much of which to cut [columns] that carry like 27 floors above them. Of course it would take far less to take out truss chords that bear a much smaller load.
True! This current diversion started as an answer to @Henkka 's question how much explosives it would take to simulate the actual collapses. My proposition assumes that what really happened was "fires heat trusses over some floors -> trusses sag -> sagging trusses tug wall inward -> wall buckles -> top tilts and comes down -> collapse". A way to make trusses sag and thus to start a collapse sequence similar to the above, all you have to do is cut enough bottom chords. I suggested on all trusses over 3 floors, which would make the walls 16 times more vulnerable to buckling and likely cave in. I estimate 75 pounds of well-placed high explosives could do that jobBegging the reality that is has nothing to do with the actual 9/11 collapses.
I think there has to be a misunderstanding somewhere here for you to say this… The whole point of the question was that if you wanted to make the building collapse in a way that resembled the actual 9/11 collapse, but do it with explosives instead of a plane,(3) The resulting collapse would in no way resemble the actual 9/11 collapses.
It started referring to "actual collapses"True! This current diversion started as an answer to @Henkka 's question how much explosives it would take to simulate the actual collapses.
Hence my comment - because back in circa 2009 2010 that was the approach I took when, on two separate occasions, I offered to help a couple of serious truthers formulate pro-CD hypotheses.My proposition assumes that what really happened was "fires heat trusses over some floors -> trusses sag -> sagging trusses tug wall inward -> wall buckles -> top tilts and comes down -> collapse". A way to make trusses sag and thus to start a collapse sequence similar to the above, all you have to do is cut enough bottom chords.
I've been following the debate - but I miss the peak activity due to Time Zone issues. And four or five theme trails, all off-topic - is too much for me to attempt commenting on.I suggested on all trusses over 3 floors, which would make the walls 16 times more vulnerable to buckling and likely cave in. I estimate 75 pounds of well-placed high explosives could do that job
Henkka believed that far more explosives would be needed - without hinting what for.
Welcome to the Club. You are not the only one whose efforts are being ignored. Try counting the offers of explanation and help that I have extended to both @Henkka and @Thomas B .Henkka has failed to address my claim that there are about 150 trusses spanning between one wall and the core over three floors
Henkka has failed to address the claim that 75 pounds might suffice to cut 150 bottom chords
Henkka has failed to address my assertion that cutting bottom cords makes trusses sag and pull in on the walls.
Henkka has failed to either acknowledge or doubt that removing lateral support over 4 floors makes the walls 16 times more vulnerable to buckling
Henkka has failed to address the assertion that one wall would buckle in the scenario I outlined.
Henkka has failed to say anything about the suggestion that failure of one wall woul make the top tilt and come down and result in runaway collapse.
Hence my offers to help. Both you and I are competent teachers of these topics.My benevolent interpretation for all these failures, for Henkka's TOTAL FAILURE to address a single aspect of my argument, is that he is crassly out of his depth.
Definitely the work of genius.Henkka fails to see the gift I am giving him: a Truther theory for explosive demolition that could be squared with the extant evidence: you see, it takes so little to cut the chords. And no one really looked at the trusses much, for those got badly mangled and torn etc in the collapses. Would anyone actually report a severed truss chord? It could be done with steel-melting incendiaties even! Triggered by the heat of fires! It all makes sense! And no evidence for it - that's how clever the plan was, the perfect crime! 9/11 solved!
And totally loses the plot which is to mimic the actual 9/11 collapses.But no, Henkka insists on dozens, perhaps hundreds of tons of explosives.
But don’t you see the difference… Between what is a sort of classical bottom-up implosion of a tower, and what you’re proposing? Nobody, in the history of planet earth, has ever looked at a tall steel building and thought to themselves: ”Hmm yes, we’ll demolish it by removing some floor supports near the top of the tower!” That’s not a thing. If you wanted to replicate what happened to the Landmark tower on the WTC, I guess you would be cutting the core and perimeter columns near the base. Not sure how much explosives you would need, but I’m guessing way more than 75 or 364 pounds.Still no argument.
Yes, 364 pounds, much of which to cut colums that carry like 27 floors above them. Of course it would take far less to take out truss chords that bear a much smaller load.
Wanna bet???I think there has to be a misunderstanding somewhere here for you to say this…
EXACTLY - resemble the ACTUAL 9/11 collapse. Which actual collapses started with "Top Block" dropping THEN transitioned into ROOSD. IF you trigger it with ROOSD - and I think it is technically feasible - THEN No Top Block dropping to START the collapse. So it doesn't achieve the goal of "in a way that resembled the actual".The whole point of the question was that if you wanted to make the building collapse in a way that resembled the actual 9/11 collapse,
Yes. And I've offered to discuss THAT hypothesis in another thread because it is way off-topic here.but do it with explosives instead of a plane,
1) How much explosives would you need?
2) Where would the explosives be placed?
I think there has to be a misunderstanding somewhere here for you to say this… The whole point of the question was that if you wanted to make the building collapse in a way that resembled the actual 9/11 collapse, but do it with explosives instead of a plane,
1) How much explosives would you need?
2) Where would the explosives be placed?
Yes. And I've offered to discuss THAT hypothesis in another thread because it is way off-topic here.
What catastrophically confused thinking.But don’t you see the difference… Between what is a sort of classical bottom-up implosion of a tower, and what you’re proposing? Nobody, in the history of planet earth, has ever looked at a tall steel building and thought to themselves: ”Hmm yes, we’ll demolish it by removing some floor supports near the top of the tower!” That’s not a thing. If you wanted to replicate what happened to the Landmark tower on the WTC, I guess you would be cutting the core and perimeter columns near the base. Not sure how much explosives you would need, but I’m guessing way more than 75 or 364 pounds.
This is nonsene on too many levels than I have time to unravel at this time. For starters: you obviously have no concept of how many orders of magnitude more energy fires brought to the action than even the biggest explosive CD ever. You fail entirely to appreciate that fire can damage a structure in several way that explosives can't. And these unrealistic amounts of explosives are of course a problem for TRUTHERS ONLY!I think these are good questions. They address the OP by asking us to specify exactly what damage to the structure a fire would have had to do in order to bring about a 9/11-style collapse. It allows us to quantify the energy that a fire would have had to deliver by other means.
If it would take an unrealistic amount explosives (compared, say, to the volume of the floors that need to be rigged), or if they would need to be placed outside of the floors that were on fire on 9/11, then that would suggest the answer to the OP question is no.
I’m not proposing to trigger it with ROOSD… I’m not proposing anything. I’m asking you guys about what you believe happened. I’m asking you to set explosives in the building to cause the same amount of damage as you believe the plane impact and fires caused on 9/11. If it’s the same amount of damage, and that damage caused the building to collapse on 9/11, then you should get a similar collapse. Whether it’s ”top block first” or ”ROOSD first” doesn’t matter to me.EXACTLY - resemble the ACTUAL 9/11 collapse. Which actual collapses started with "Top Block" dropping THEN transitioned into ROOSD. IF you trigger it with ROOSD - and I think it is technically feasible - THEN No Top Block dropping to START the collapse. So it doesn't achieve the goal of "in a way that resembled the actual".
It would be great (and entirely on topic) if you could quantify this for us.you obviously have no concept of how many orders of magnitude more energy fires brought to the action than even the biggest explosive CD ever.
Either those are three blatant lies or you don't understand what you are posting.I’m not proposing to trigger it with ROOSD… I’m not proposing anything. I’m asking you guys about what you believe happened.
Blatant stupidity. "You should get a similar collapse even if it is totally different".then you should get a similar collapse. Whether it’s ”top block first” or ”ROOSD first” doesn’t matter to me.
Because the collapse initiation was triggered at a location where the fires focused sufficient heat. As I said - your thinking on that issue is backwards.Since the energy of the fire was not focused on the task of bringing down the building,
You can with great ease do this yourself. Or can you not? I showed you how 75 pounds of explosives suffice. The typical combustibles in an office (paper, plastic, wood) have something like 4 times the energy release of high explosives. So. 75 pounds of explosives equivalent to 20 pounds of wood or paper. I'll leave to you how much conbustibles there are on 5 floors of the WTC and divide.It would be great (and entirely on topic) if you could quantify this for us.
I assume we agree that most of the energy of the fire was "wasted", i.e., not "delivered" to the structural components that needed to fail.
Since the energy of the fire was not focused on the task of bringing down the building, it becomes a good question whether the total energy of the fire minus the wastage from its inefficient application to the collapse mechanism bring the "orders of magnitude" into closer agreement.
And then subtract the amount of times you've called us dishonest and stupid.Try counting the offers of explanation and help that I have extended to both @Henkka and @Thomas B .
That will be an easy bit of arithmetic. Why do you sink into personal attack in the face of a statement of simple fact?And then subtract the amount of times you've called us dishonest and stupid.
Sorry, I hadn't been following your debate with @Henkka in detail (I just liked those questions). I had to search to find it, but, yes, this is good:And my 75 pounds proposal.
This is where a load path diagram would really useful. Those chords seem awfully critical. More critical than I would have thought any engineer would have made them. But I guess it's possible. It's not obvious to me, anyway.One way to make the floor trusses sag would be to cut their bottom chords, which are steel rods no more than 1 inch thick, if memory serves. The top trusses would sag and pull in, having lost the trusses' internal stability. Do this on all trusses on one side of the tower over 3 floors or so, and I think you might initiate a collapse in a similar fashion as the fires did. I'd guess, wildly, that half a pound of explosives per chord would be plenty. We are talking about perhaps 150 trusses? So 75 pounds of explosives. You could even fire them without time coordination, or at random times, or triggered by the heat of fires, just cut onf after another until you have cut enough for collapse to initiate.