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Regarding live loads etc, I think each floor assembly was rated to take something like ten times its own weight, static. John Goss said eleven. But in the more conservative case, WTC1, there were at least ten floor assemblies, plus the top mechanical floor (heavier than a standard floor assembly), plus the hat truss, plus the roof, and all the contents, which included heavy stuff like elevator winches etc. Oh, and there’s an aircraft in there too. That lot has to come to more than eleven times the weight of a floor assembly, so even if we gently lowered it onto the highest floor assembly below the damaged zone, it’s too much, the floor’s going to go. The floor is only four inch concrete on one inch bar joists, no way it can hold that lot. And it wasn’t gently lowered; it was dropped 3.7 metre at 2/3g. No way. Not worth calculating. It’s not going to hold, and the next floor down is even worse of course. Collapse ensues.
Second attempt (first submitted 23.04.20 at 02:28)
Thank you, Clark
Clark September 5, 2019 at 15:03 https://www.craigmurray.org.uk/forums/topic/engineering-prof-releases-draft-report-on-9-11-collapse-of-wtc-bldg-7-in-nyc/#post-46875
“Chandler’s “Downward Acceleration of WTC1” theory applies only to a contiguous block of material, not to a lattice of steel supporting thousands of tonnes of concrete in a structure that was over 90% empty space.”
Chandler’s observations rely on Newton’s laws, the law of conservation of energy etc., and logic. Could you please substantiate your above statement?
Clark April 21, 2020 at 14:38
“If the paper is right, the thermitic material presumably came from somewhere else. It would seem more likely that it was deliberately added to the dust; a psi-op to help protect the Saudi-jihadi-NATO collaboration.
What do you mean by “came from somewhere else”? Who would deliberately add it “to the dust”, and how?
What do you think about my remarks with regard to your calculations?
Thanks, mod.
Clark I’ll try to reply later today to your points still outstanding.
Thanks
Chandler’s Downward Acceleration predicts that no structure can undergo top-down accelerating collapse.
When I realised that I knew there had to be something wrong with it; it must be possible to contrive a structure that can. Then I realised the problem; his model is one dimensional. The diagram is two dimensional, but only one dimension appears in the maths; the vertical. Nothing can go past anything else on the way down; the material above is forced to go through the material beneath by this limitation of the model.
Chandler’s model can be applied in three dimensions, but there must be no variation in the structure in the two vertical dimensions. It applies to a block, and indeed Chandler refers to the sections above and below the damaged zones as blocks, but they are not, they are mostly empty apart from air.
So I immediately wondered what would happen if the vertical frame members got displaced laterally ie. they got out of line, and that starting point eventually led me to understanding the way the collapses proceeded.
– “What do you mean by “came from somewhere else”? Who would deliberately add it “to the dust”, and how?”
Oh, the CIA probably. By “any means necessary” of course!
– “What do you think about my remarks with regard to your calculations?”
Do you mean your April 21 03:51 comment #52251?
Yes, I took the load bearing capacity as zero since I couldn’t calculate it, and because the truss ends and truss seats look like almost nothing compared with the perimeter and core columns:
http://cryptome.org/info/wtc-punch/pict55.jpg
Instead, I did the momentum transfer calcs, or rather I guestimated them and Nikko’s spreadsheet did it more thoroughly, and then I went back to ensure there was enough energy dissipated in inelastic collision momentum transfer to tear out the truss connections. There’s enough spare energy throughout collapse; not a huge excess at first, but the initial part of the collapse was the slowest anyway. Once the collapse accumulates mass and velocity there’s loads of spare energy, and momentum transfer becomes the main thing holding it back.
This is what I meant a few comments above: April 23, 02:20 #52343
Part of my justification for delaying examination of mechanical resistance is that it doesn’t have to be the truss seats that failed. If we imagine a falling pile of rubble between perimeter and core, rather than a regular pancaking/stacking of whole floor slabs, it’s the centre of the long floor spans that are most vulnerable; the rubble would smash through rather than decoupling floor assemblies from the vertical core and perimeter columns at the truss seat connections.
If indeed the floor slabs were getting smashed through, that’s entirely within the realm of “deformation of materials”, which is where kinetic energy dissipates to when inelastic collisions occur. In this scenario, momentum transfer and overcoming mechanical resistance are pretty much the same thing.
Whichever failure demands least energy is the one that will occur quickest; a chain is only as strong as its weakest link.
Remember that we’re considering failure, but the ordered geometry of the building is its main source of strength, especially in structures that are as lightweight as possible like the Twin Towers were. Any event which disrupts that order weakens the structure. The second law of thermodynamics is on the side of collapse – disorder tends to increase.
Abstract: https://hal.archives-ouvertes.fr/hal-02004696
Full paper: https://hal.archives-ouvertes.fr/hal-02004696v3/document
[…] that 3 deep under-
ground nuclear explosions occurred on
September 11, 2001 under the World
Trade Center site, each of them at
least of 50 kt and more probably on
the order of 100 kt of TNT.[…]Stop tying yourselves in knots trying to deny this.
Pooh?
Pooh, Nikko presented some of his spreadsheet results here, regarding an idealised internal collapse of floor assemblies of WTC1:
– “The 10-storey section would take 0.88 s to fall the 3.8 meters before hitting the first floor below and in that time its velocity would increase from 0 m/s to 8.6 m/s. The collision with that floor (law of conservation of momentum) would reduce its velocity to 7.8m/s and the now 11-storey equivalent block would take 0.39 s to accelerate to 11.6m/s before again colliding with a floor, the impact of which would slow it down to 10.7 m/s. And so on and so on all the way to the ground through the remaining 98 floors, which it would hit after 11.7 seconds with a speed of 50 m/s.”
That’s well within the ~15 seconds of WTC1’s collapse.
My “back of a fag packet” momentum calculations are here. If you can face technical reading, the ROOSD collapse progression process is here. ROOSD is Rapid Open Office Space Destruction – cascade destruction of the floor assemblies, confined and thus channelled by the perimeter.
Evening, Clark
I haven’t been feeling too well, and my mind, if there is such an entity, has been elsewhere. Once I recover, I hope I’ll able to play a straight bat (no, not a white bat) to hit whatever you throw at me. 🙂
Thanks
Pooh, thanks for checking in. I have been on the thread under Craig’s latest post, frantically countering anti-lockdown rumours with evidence so we don’t end up inadvertently suffocating 400,000 old folk to death with no hospital care.
Sorry to hear you’ve been unwell. I hope it’s not the covid, which is known to sometimes produce neurological effects. Day ten is said to be critical; if you take a downturn around ten days after first noticing symptoms, get yourself checked over.
Get well soon; Love and Rage 🙂
Thanks, Clark. Nah, no virus has been able to penetrate my aura. Let’ say it’s an epiphany occasioned by loving and raging. We’ll soon lovingly rage forward and clash in the bright future of loving rage and set our encrypted event notes free to embrace and love-dance in the gravitational aftermath of our mutual rage-assisted free fall destruction. 🙂
Do good and take care.
Here’s what’s making me want to dance these days. Teardrop by Massive Attack is the love; can our teardrops quench the fire? I hear they played at Marble Arch, but there was so much going on, so many places to be at once.
For the rage, The Comet is Coming:
Imagine a culture that has, at its root
A more soulful connection to land and to loved ones
But I can hear the lie before you speak
There is nothing but progress to eat
And we are so fat and so hungry
Start Running:You think the complete collapse (disintegration of reinforced concrete and steel into dust) of both towers (110 stories high each) is elementary following the impact of two planes. Would your calculations need revising if there were only one or no planes? And what has your research revealed about the size of the planes and exact impact points?
What I calculated concerns only collapse progression ie. progressive collapse, not collapse initiation ie. structural failure.
Collapse progression is the part that Chandler claimed to have proven to be impossible in his “Downward Acceleration of WTC1” (link), which is the reason that demolition theorists so often cite Newton’s laws. The critical part is on page 9 of the link; it’s very simple and the physics is right which is why it has convinced so many people, but there’s only height in the equations, there’s no width or breadth, so it doesn’t apply in the real world. It “proves” that nothing can ever collapse, which is clearly absurd.
The collapses of the Twin Towers clearly proceeded from the aircraft impact zones downward, and that, and Chandler’s paper, are the reasons that demolition theorists have to postulate charges on every storey – a type of demolition never seen in the demolition industry, a massive amount of work and an absolute pig to synchronise and sequence – I’ve done a bit of theatrical pyrotechnics in my time, plus a few gas explosions; purely for entertainment. And if an aircraft had failed to arrive or hit they’d have had a very embarrassing pre-rigged skyscraper to explain.
The NIST reports don’t cover collapse progression; they only go as far as collapse initiation ie. structural failure, and then say that complete destruction was thereby assured, citing Bazǎnt, 2001. But Bazǎnt’s paper is entirely theoretical, and inspection of the wreckage proves that that isn’t the way the Towers collapsed. There’s been loads of hoo-ha over this but it’s entirely irrelevant to anything in the real world because the collapses proceeded by ROOSD (see my comment #52684 above) not Bazǎnt’s theory. My observations and calculations confirm ROOSD. I discovered ROOSD after I’d worked out the same thing myself.
Far more important is that NIST couldn’t make their proposal for structural failure work, and it appears to be wrong. NIST said that heat made the floors sag, pulling in on the perimeter causing the perimeter to buckle, but when they tried it with a full scale model it didn’t work. But you only have to watch the collapse videos to see that it’s wrong, because for WTC1 the antenna starts falling before the top section begins to descend, indicating that the core must have failed first not the perimeter.
My best guess about structural failure is that the buildings had become overloaded in the years since construction, and that’s what the cover-up is about. They were designed before there was any idea that everyone would have a computer on their desk, with a big old-fashioned glass monitor. Remember how heavy computers and monitors were in the 1990s? Plus loads of ancillaries had been installed; escalators between floors, all the massive screens of stock market trading rooms, whole rooms full of racks of what were effectively lorry batteries for uninterruptible power supplies for computer data centres… I reckon the Twin Towers were loaded beyond their design capacity, they were in an illegal state even before the aircraft hit, and that’s part of the reason that the victims’ and families’ compensation was settled out of court.
The Twin Towers were of an experimental design and wouldn’t have been permitted in any state of the US; they only got permission because the Port Authority of New York and New Jersey had an exemption from New York State building regulations. By 2001 they were loaded way beyond capacity I reckon and were disasters waiting to happen.
So a collapse progression followed a collapse initiation, but your calculations do not involve any study of the initiation, you just accept planes hit the towers, but you don’t their size, weight and where they hit the towers! Is this correct, if not please reference the information?
I accept the copious evidence that aircraft hit the Twin Towers, in such places as to cause the extensive damage and fire, all as indicated by countless videos, photographs witness testimony and debris. I expect they were the passenger flights as claimed because this would be almost impossible to distort, but I haven’t looked into it.
The calculations for the structural failures which initiated the collapses are beyond my expertise, and in any case the extent and disposition of internal damage can only be estimated.
So you can calculate and speculate about progressive collapse at considerable length, promoting an impressive “spontaneous combustion due to shock and sympathy collapse theory”, but freely admit you haven’t considered the initiation! Bit of an admission don’t you think?
? :/
Humans seem weird to me.
You are arguing a progression theory, but if planes hit the towers and unless they were exactly the same shape, size and weight, and unless they hit in exactly the same spot, then surely your back of the envelope calculations would need revising, and require an initiation theory?
PS. Was that you sitting on the throne?
Any structural failure across the entire cross-section of the tower would cause the section above to begin descending, initiating progressive collapse. It doesn’t matter what causes the structural failure. If it occurred very high in the tower, the section above might be light enough that the structure beneath could arrest its descent. If it occurred low enough, the section beneath would suffer complete accelerating progressive collapse, but the top section might also topple; this partially happened to WTC2.
Christianity teaches that all should emulate Jesus. I think there’s great value in that, and I think the story of Jesus is profound, powerful and highly political – a man gave up all pursuit of wealth to become a travelling healer and a teacher of peace and comradeship. He taught that relationship with the divine is personal rather than the preserve of a privileged class, whom he called out as corrupt and hypocritical. He travelled to the capital city where he engaged in civil disobedience, overturning the tables in the temple and dispelling the traders. He foresaw his own end, and thus transformed the traditional ritual of his culture. He was betrayed to the authorities who put him on trial, but they could find no crime. But a rabble had been roused against him and so he was tortured to death in public.
An early chapter in The Master and Margarita by Mikhail Bulgakov fictionalises a meeting between Pontius Pilate and Jesus. I found it electrifying. But I do not call Jesus ‘Christ’ and I will not call myself a Christian, because I am not superstitious, I reject resurrection, and because Christ means ‘saviour’ and I don’t believe that anything or anyone was saved. On the contrary; since 9/11, it has seemed that all is lost, and the first thing lost was rationality, which I struggle to restore.
@ Clark
“Any structural failure across the entire cross-section of the tower would cause the section above to begin descending, initiating progressive collapse”.
So you’re accepting this happened, without any consideration of whether it was possible, by the means alleged?
No, and for WTC1 it looks like NIST’s proposal is wrong. From the video record, the antenna began descent before the perimeter failed, and the antenna was near the centre of the roof and thus over the core, so it looks like the core failed first, whereas NIST claim the perimeter failed first.
But I am sure that structural failure due to damage and fire was possible; NIST tested their proposal with a full-scale mock up, and it nearly worked; the floor systems sagged, but not enough to cause structural failure. Ultimately, anything can break, and it is likely to break in a way that hasn’t been thought of, and don’t trust any engineer who tells you otherwise; he’s over-confident. NIST made their mock up for the test, so it was brand new, whereas the Twin Towers had stood there for decades, suffering metal fatigue, rusting, modification and whatever else. And we can’t be sure it was ever constructed to full specification, or that the steel components didn’t have manufacturing weaknesses. And as I said before, the towers could have become overloaded with contents of excessive weight.
Failure is always possible, but the art of engineering is to make failure as unlikely as you can. But it ultimately comes down to thermodynamics – every structure suffers random changes over time, there are infinite ways that changes can cause failure, but theres’s only one way a structure can avoid failure which is not to change too much, so ultimately luck and time are against you. Your structure will fail eventually, even half of Stonehenge has fallen down. Smashing an aircraft into a structure and setting it on fire speed up the rate of change, and thus hasten failure.
Structural failure is proven, by the photographic and video record of gradual deformation of the buildings at the damaged zones prior to collapse, and by the wreckage, which includes some vertical column members bent double.
I rule out pre-rigging with explosive demolition systems as the initiator of structural failure because, in both cases, structural failure occurred at the damaged zone, but that’s where any pre-rigged system would have had to operate properly, despite aircraft impact damage and extensive fire.
I don’t rule out assistance by explosives placed in or near the damaged zone after impact of the aircraft, and here’s a little snippet you probably haven’t seen on Truther sites.
WTC2’s structural failure was almost certainly just the aircraft. NIST’s test was marginal, failure almost occurred. WTC2 was struck lower down, so there was over twice the load on the damaged zone, and it was struck off-centre, so the damage was less symmetrical – if you want to break a stick or a tube, start by cutting a notch in it, and then bend it about the point you weakened.
