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Has Anyone Seen A Realistice Explanation For Free Fall Of The Towers?

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Independant Engineers Have Web Sites About The Concrete Core

kevin said:
2 1/4" rebar is the biggest in the standards.
http://www.sizes.com/materls/rebar.htm

it looks like for vertical walls rebar spacing doesn't typically exceed 24" on center (don't really have a link for this.)

BTW, the little BBC graphic is wrong about concrete. That image was first used by the BBC on 9/13/2001, 2 days after the collapse. I doubt very much they verified the accuracy. They reused the image in an article on October 4, 2001. However if you actually read the article you'll find it says "But the steel supports in the central cores supporting the towers were protected from fire by plaster that had been sprayed on to them." Plaster is not concrete and fire protection materials of any sort are not structurally supporting.

http://news.bbc.co.uk/1/hi/sci/tech/1579092.stm

Another article, from March 7, 2002, states "The drywall fireproofing surrounding the central columns was highly fire-resistant but not very strong." This matches what I remember from a Nova episode, that the steel central core was protected by fire-resistant drywall (two layers) that was blown off by the explosion exposing the steel.

http://news.bbc.co.uk/1/hi/sci/tech/1858491.stm
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http://www.unc.edu/courses/2001fall/plan/006e/001/engineering/

A Description of the World Trade Center

The twin towers of the World Trade Center were essentially two tubes, with the north tower (1,368 feet) six feet taller than the south tower (1,362 feet), and each were 110 stories tall. Each tube contained a concrete core, which supported only the load of the central bank of elevators and stairwells (Snoonian and Czarnecki 23).
 
Dave_46 said:
As the answer to my two questions are yes and yes, you need to correct the errors you have just acknowledged in the graphic on your website.
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i don't talk about the melting temperature on my site and the terms "column" and "beam" are always used properly by yours truly. Check your reading of my site, slow down some. My text presents a scan which is hosted on the bbc site.

http://news.bbc.co.uk/olmedia/1540000/images/_1540044_world_trade_structure300.gif

and THEIR information is in error, not mine. I point at their errors, not the ones you do however. A much bigger one. I point at the fact the core they show has no place for elevators and stairs inside it.
 
Gravy said:
I ask you again, Christophera, what's the recipe for invisible concrete?

Christophera's "Invisicrete" Core
[qimg]http://www.internationalskeptics.com/forums/imagehost/87904495b5c1ae08b.jpg[/qimg]

The Actual Tower Cores Were Of Steel

[qimg]http://www.internationalskeptics.com/forums/imagehost/87904495b879af0d4.jpg[/qimg]
[qimg]http://www.internationalskeptics.com/forums/imagehost/87904495b879cb1fb.jpg[/qimg]
[qimg]http://www.internationalskeptics.com/forums/imagehost/87904495b879ebd4b.jpg[/qimg]
​
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One is not of the twins or the light is so weird you cannot see the perimeter steel. The others are the TWIN towers but we are looking over the concrete core inside the steel framework below, the outer tube of the "tube in a tube" construction.

Get the original image urls up for us to look at.

I explain the hallways and light passing thru the core just as we see. http://concretecore.741.com).
 
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Hutch, I looked up the dimensions and got a slightly different outcome.

At 110 stories and approximately 1365' (an average between the two heights of the towers) each floor comes out, rounded off, to slightly more than 12' high. It has to be assumed that there was no gap in the concrete between floors, because that would defeat the entire purpose of having a concrete core. But to simplify the calculations I rounded it off to 12' per floor in order to lowball and to make up for the little bit of room the rebar would require.

The dimension of the short sides of the core were 88' and the long walls were 138'. That doesn't take into consideration that thickness of the concrete. But again, I'd rather lowball so the CTs don't think I'm making any kind of outrageous claim. Using those basics assumptions and round-offs, that means each story would require (in inches) the following amount of concrete:

1056 * 144 * 17 * 2 (short sides) + 1656 * 144 * 17 * 2 (long sides) = 13277952 cubic inches of concrete per story.

A cubic yard of concrete is 46656 cubic inches.

That means each floor required @ 285 cubic yards of concrete for the core at a minimum. Multiplied by 110 stories, that means the total concrete required for each tower would be 31350 cubic yards. Assuming each concrete truck carried about 9 cubic yards of concrete, which is what most of the concrete trucks I've used carry, that means that 3483 concrete trucks were required for each large tower to create a concrete core.
 
Concrete Batch Plant Built At WTC Site.

Apollyon said:
Assuming each concrete truck carried about 9 cubic yards of concrete, which is what most of the concrete trucks I've used carry, that means that 3483 concrete trucks were required for each large tower to create a concrete core.
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There was a batch plant built at the WTC to produce the mass of concrete required. A high speed series of very well contained and distributed high explosives gets it all out from inside that steel where you can see it.

Here are the interior box columns silhouetted against concrete shear wall

Compare the volume of the basements to the volume of the concrete core towers here. SAND & GRAVEL.

I've done those calc's many times and there is way too much concrete onsite for the official towers.
 
Christophera said:
http://www.unc.edu/courses/2001fall/plan/006e/001/engineering/

A Description of the World Trade Center

The twin towers of the World Trade Center were essentially two tubes, with the north tower (1,368 feet) six feet taller than the south tower (1,362 feet), and each were 110 stories tall. Each tube contained a concrete core, which supported only the load of the central bank of elevators and stairwells (Snoonian and Czarnecki 23).
Click to expand...

same article:
Second, Yamasaki had to make sure the air pressure generated by the express elevators would not buckle the elevator shafts. The engineers of Otis Elevators came up with a solution to this problem. By using a drywall system fixed to the reinforced steel core, the shafts were strengthened enough that air pressure was not an issue.

Out of curiosity, a few questions. Since you cited the University of North Carolina course work as authorative, do you also stand by the findings published in that article that the buildings fell because of fire? If not, how did they get this one fact right and all others wrong?

Since the concrete core cited in the UNC article only supported elevators and stairwells, and not the building, what does the construction of the core have to do with how the buildings did or did not fall?
 
Christophera said:
http://www.unc.edu/courses/2001fall/plan/006e/001/engineering/

A Description of the World Trade Center

The twin towers of the World Trade Center were essentially two tubes, with the north tower (1,368 feet) six feet taller than the south tower (1,362 feet), and each were 110 stories tall. Each tube contained a concrete core, which supported only the load of the central bank of elevators and stairwells (Snoonian and Czarnecki 23).
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I'll see your link by students and raise you a link based on information from the structural engineer who actually built the towers:

http://www.newyorker.com/fact/content/?011119fa_FACT

What Skilling proposed was a pure tube structure. His design was consistent with the general principles at work in the new generation of high-rises, but he carried the concept of the tube building farther than it had ever been taken before. (Or since: the Sears Tower, in Chicago, which replaced the World Trade towers as the world's tallest building in 1973, is also a tube building, but it is actually a cluster of nine smaller tubes.) The Twin Towers would be perforated steel boxes surrounding a hollow steel core. The outer box would be two hundred and eight feet on each side, and made of fourteen-inch-wide steel columns that were spaced on forty-inch centers—much closer than the fifteen-to-thirty-foot spaces that separate most supporting columns in a building. Like the cast-iron buildings of the previous century, the exterior walls would be load-bearing; unlike most skyscrapers, which hide their supporting columns, the Twin Towers would proudly wear their structure on their sleeves. Because there were so many load-bearing columns around the perimeter of each building, the engineers could completely eliminate all columns within the office space. Joining the outside tube to the inner core were state-of-the-art lightweight floor trusses that spanned sixty feet from core to exterior walls on two sides, and thirty-five feet on the other two sides.
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Christophera said:
Compare the volume of the basements to the volume of the concrete core towers here.
I've done those calc's many times and there is way too much concrete onsite for the official towers.
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and did you include the concrete from 110 floors of 8" concrete slabs 208' x 208' each?

since you've done these calcs you wouldn't mind posting them here would you?
 
Christophera said:
There are 2 photos there. Right side is torch cut but left is explosive shear.
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"Explosive shear?"

OK. Then where's the plastic deformation one would expect from "explosive shear?" The heating and concusssion from an explosion large enough to slice such a beam would create some massive deformation. Where is it? I don't see it.
 
kevin said:
and did you include the concrete from 110 floors of 8" concrete slabs 208' x 208' each?

since you've done these calcs you wouldn't mind posting them here would you?
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I wouldn't mind if I could find them, but I can't so I won't. I do remember about a year ago I did parallel calc's with someone on a board and I think we came up with about 250,000 cu. yds. Above ground per tower.

What is important is that we have images showing what can only be a concrete core.

Here is how it get's set to go away.

http://algoxy.com/psych/9-11scenario.html
 
Apollyon said:
Sorry, it doesn't work that way. You made the claim, you provide proof to back it up.
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What, didn't you see the low-res pic taken from a mile away showing a shadowy something obscured by smoke? Proooooooof!!!!!!!!!111
 
Christophera said:
I wouldn't mind if I could find them, but I can't so I won't. I do remember about a year ago I did parallel calc's with someone on a board and I think we came up with about 250,000 cu. yds. Above ground per tower.
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Ahh, I see the government is out to fool the people of the world and you're too busy to repeat some calculations that prove it. Nice fighting for justice attitude you have there. I'd like to try my own calculations, what did you use for the volume of the concrete core? What did you subtract out for floor pentrations?

What is important is that we have images showing what can only be a concrete core.
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That picture proves absolutely nothing. I have picture of a cloud that looks like a horse, doesn't mean I believe in flying horses.
 
kevin said:
ummm, i hate to point this out but the WTC was finished in 1972. 15 years before the last batch plant left the island. I wouldn't be surprised if they used an onsite plant to mix concrete. They did have to pour all those floors.
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Shhhh!

I was trying to use CT "facts" on him.
 
From the Florida Atlantic University Catalog:

Common Sense Analysis for Strength of Materials (EGM 3524) 3 credits
Prerequisite: EGM 3510
Concepts of stress and strain; mechanical properties of materials,
force, deformation and stress analysis of structural members;
stress and strain transformations; principal stresses; failure theories;
and concept of buckling. All course work is accomplished through the use of
common sense. No math or physics pre requisites needed.
 
Regnad Kcin said:
Mr. Brown:

Welcome back. I look forward to your answer to the following question, which I've asked you numerous times in this thread:

At what level (that is, between what stories) did each airplane strike each WTC tower?
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Christophera said:
WTC 1 94th to 96th, WTC 2 74th to 78th.
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Thank you for your answer.

According to Wikipedia, WTC 1 was hit between the 93rd and 99th floors and WTC 2 between the 77th and 85th floors. While your answer does not correspond exactly, there is a non-conflicting overlap, so all's fine so far.

Now, let's take your figures and divide them down the center for argument's sake and simplicity of calculation. That is, WTC 1's main floor hit will be the 95th floor. WTC 2 will be 76th floor. With me so far?

Furthermore, again at Wiki, "Flight 11 was traveling roughly 490 mph (790 km/h) when it crashed into the north tower, Flight 175 hit the south tower at about 590 mph (950 km/h)."

Now then, on your website, you have this to say:

Christopher A. Brown said:
TOWER FALL SEQUENCE

Excavator operators in clean up were amazed that they didn't have to use breakers to remove the foundations. The explosions were done with great efficiency in the base of the concrete core structure and exterior foundation. The detonations simply broke the foundation, and significant walls, moving relatively little material and were not explosively connected to travel upward. The gravity load of the tower lent its mass to the foundation breakage and divided the total seismic wave into 2 smaller events. The upper detonations and thermite initiation later were timed. If they were not timed and were remote, why would the second tower hit, least damaged, fall first? Human nature says that while conducting a ruse, those who have control to make it as perfect as ruse as possible, will do so. Meaning;

The pilot of the flight 11 hit the wrong tower.

There was no remote control over planes or detonations.

The fact that both towers fell almost identically and the tops fell in the wrong directions relating to the faces they were struck on are major factors that indicate the controlling aspects of the towers fall was completely separate from plane collisions and fires and that they were a demolition, controlled by timers.

Viewed from the east, here is the top of the north tower falling to the south when the tower was hit hard on the north side. Damage there logically causes a failure there having the tower fall to the north.

In addition to the above, it is completely illogical that this building, hit first, hit hardest, burnt worst, would fall last, without demolition's being involved.
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Bolding mine.

Aside from your error that that WTC 1 was "hit hardest" (and the corresponding mistake that it was the more damaged) do you see the error in your logic regarding the sequence of the collapses, or do I have to point it out to you?
 
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