(03-21-2021, 06:24 AM)Gointocarlton date Wrote:Not the one I was looking for but the statement about the the designers not expecting 90,000L of jet fuel on one floor was what I remember, Ill keep looking though for the what I was looking for. Some other pertinent points are made about why the buildings fell straight down.

https://www.tms.org/pubs/journals/JOM/0112/Eagar/Eagar-0112.html

Quote:To handle these immense forces, the engineers "designed the World Trade Center essentially as a large beam section," explained another panel member, Robert McNamara, president of the engineering firm McNamara and Salvia.

Newspapers and TV newscasts reported that the twin towers had been designed to withstand a collision with a Boeing 707. The events of September 11th show that this was indeed the case. "However, the World Trade Center was never designed for the massive explosions nor the intense jet fuel fires that came next a key design omission," stated Eduardo Kausel, another M.I.T. professor of civil and environmental engineering and panel member. The towers collapsed only after the kerosene fuel fire compromised the integrity of their structural tubes: One WTC lasted for 105 minutes, whereas Two WTC remained standing for 47 minutes. "It was designed for the type of fire you'd expect in an office building paper, desks, drapes," McNamara said. The aviation fuel fires that broke out burned at a much hotter temperature than the typical contents of an office. "At about 800 degrees Fahrenheit structural steel starts to lose its strength; at 1,500 degrees F, all bets are off as steel members become significantly weakened," he explained.

(03-21-2021, 08:19 AM)LP link Wrote:No not all all.

You know the math can't lie, you could halve all the figures from the actual and the resulting energies are still way beyond anything a building could resist. That is how back of the envelope calculations like this work, you don't end up an order of magnitude out.

For example; Looking 1/2 Mass(5% of WTC 1 or 2), 1/2 Gravity(reduced acceleration), 1/2 fall height
E = 22,500,000 x 4.9 x 5
E = 551,250,000 Newtons

F = E/g
F = 551,250,000 / 9.8
F = 56,250,000kg

Nothing we build today can withstand even that, it's at least an order of magnitude too high for any building to withstand and transmit that energy down through the structure to the foundations like a shockwave.

For comparative reference, the recent Beirut fertilizer blast was about 1/10th the collapse energy of just one WTC.

Ockham's Razor at work, I think I've read that somewhere before!

(03-21-2021, 08:48 AM)kruddler date Wrote:So 1 order of magnitude....
Get rid of your 5m, that is saying that 1.5m of floors were essentially not there.
10% (reduced to 5%) may be the height, but the base is more dense than the top, as the weight distribution may make it even less than that. 1/2 of gravity is still a hell of a lot of accelaration to happen all at once. Change those figures and there goes your order of magnitude before we even try.

Still....this assumes a uniform, whole collapse at once which is simply not practical.

(03-21-2021, 08:34 AM)LP link Wrote:[member=160]Gointocarlton[/member]‍  https://www.scientificamerican.com/article/when-the-twin-towers-fell/

Quote:Though the Boeing 767s airliners that hit the towers were somewhat larger than the Boeing 707 (maximum takeoff weights: 395,000 pounds versus 336,000 pounds) the structures were designed to resist, the planes carried a similarly sized fuel load as the older modelabout 24,000 gallons versus 23,000 gallons, according to Kausel.

(03-21-2021, 08:57 AM)LP link Wrote:1.5m high floors, really?

You're so far from reality, one minute you want to claim WTC7 collapses under free fall proves a deliberate implosion, even though that facts show it fell for a total of 1.4s slower than a free fall speed. Then you want the WTC towers to fall at 1/10th of the real world rate for 1/6th the distance collapse height. I don't know a building that has 1.5m high floors clear span floors, they just don't exist. A heated and buckled structural member functionally presents no resistance at all.

The weight of collapse goes up as the floors pancake, the total collapsing energy and mass doesn't decrease or stay static, it accumulates as it goes until it hits solid earth or compacted rubble.

(03-21-2021, 08:27 AM)cookie2 link Wrote:But undeterred.....................

(03-21-2021, 09:02 AM)kruddler date Wrote:Typo. 1.5x floors. As in 1 and a half floors that your numbers are stating simply weren't there.

(03-21-2021, 09:08 AM)LP link Wrote:I can only report what the phone calls from the WTC reported, that several floors had collapsed entirely preventing any escape. I've no basis to ever question that, each floor is about 3m.

I'm not sure anyone can refute those reports,

(03-21-2021, 09:08 AM)LP link Wrote:a bit like the suggestion made by some the that people calling their families from the plane that crashed in to the Pentagon weren't really there at all!

I mean it isn't just absurd, it's basically offensive sort of rubbish Daesh would come up with!

(03-21-2021, 09:28 AM)kruddler date Wrote:You are confusing yourself. You said 3 floors or 10m. Fine. I pointed out that those floors don't instantaneously vanish, so you halved it. So, 1.5 floors rather than 3. I pointed out that you are still 'vanishing' floors. This means your numbers don't work.

Then you talk about people making phone calls about floors collapsing. Which is fine, i believe that to be true. But you tell me, is it the floors collapsing that caused the whole thing to fall down? Or is it some floors, then they made phone calls. Then other floors? I can tell you that they certainly didn't have time to make a phone call once it started collapsing completely.

Also, by that link, they can;t agree on how exactly it failed either. They have some theories, but are not 100% certain. Which is fine.
There are other theories on how they came down which also fit the bill. There is theories which can be equally as plausible....but are scoffed at by blokes like you who (unlike me) refuse to look at the other side of things.
Nobody has commented about phone calls and the pentagon.

Only thing that i've said is the manouvre required could not be done with the precision it was by a novice pilot.
and
If there was a plane crash, you usually see evidence of the plane that crashed....and/or footage of the plane itself.