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

[Christophera]

He has proven there are steel columns in the core through his series of pictures Christophera, however, you have not proven there is a concrete core within, based on your one smoke obscured pic. You are the one claiming there is a concrete core, so it is up to you to prove it. That picture does not.

As far as I know I've explained how the construction photos are misinterpreted and those explanations are consistent with the demolition images.

No one has offered a reasonable explanation for what this is if it is not a tubular concrete core. Something thing that must be done before any conclusion can be made.

You do realize there was a core do you not?

 

[Christophera]

Christophera,
Do you now agree that what you've been calling "3" rebar on 4' centers" is not that at all, but huge steel columns where you believed a concrete core to be?

This must be 3" REBAR ON 4' CENTERS because the spire is a 20 inch box column at the same distance 1 second before. The concrete was behind the spire and when the spire fell the rebar at the corner of the concrete core remained standing.

 

[Brainache]

This must be 3" REBAR ON 4' CENTERS because the spire is a 20 inch box column at the same distance 1 second before. The concrete was behind the spire and when the spire fell the rebar at the corner of the concrete core remained standing.

I must be missing something here because that picture you keep saying is 3" rebar on 4' centers has been shown to be the central steel support beams teetering momentarily before collapsing.
What makes you say it is 3" rebar?
I'm not an engineer so I guess its possible I just don't get it, but it really does seem to me that you are just lying to avoid admitting an error.
Is ignoring all contrary evidence and restating an invalid argument over and over again a strategy that works for you?
Are you just waiting for everyone to get bored with you so you can claim victory when noone will bother debating anymore?

 

[Alareth]

Repeating an action expecting a different result every time is the definition of insanity.

 

[Architect]

I'm not an engineer so I guess its possible I just don't get it, but it really does seem to me that you are just lying to avoid admitting an error.

I'm an architect who works on tall buildings and I do get it. It's steel and linings, not concrete.

Chris, if you're that sure it's concrete then you'll have no problem providing evidence rather than ambiguous (I'm being kind) photographs and the odd dubious text on a CT site. Go and find articles written when it was built, people who worked on the site. Check the building warrant (permit, or whatever you call them in America) drawings. Go and speeak to retired members of the design team and ask.

Oh, ah, no. Wait a minute. That would involve real investigation, not just googling....l

 

[Architect]

whether the collapse is 8.4 seconds
or 15 seconds, I would like to have proper explanations. The pancake collapse is IMO impossible.

<snip>

In physics a theory should be tested and be reproducable, think about your pancakes and test your theory.

Welcome, Eisteen, from a fellow newbie.

Any building is only designed to accommodate credible loads; for example here in the UK, we would take account of wind loads and fire risk, but pay little attention to earthquakes - in stark contrast to, say, California or Japan.

Until 911, or 11-9 as we prefer to call it in the UK, aircraft hitting buildings was not considered a credible risk. There is no requirement in building regulations/codes, nor is there an accepted way of modelling the problem.

Nevertheless the designers of WTC took account - at some level - of a low moving 707 bitting them. What we don't have are the calculations or any detailed breakdown of the assumptions made. It may be (and probably is) well wide of the mark in comparison to the events of 911.

I know you haven't mentioned this, but I give it as an example of how we really design buildings. Here's why:

Collapse of the upper superstructure onto a lower floor was not considered a credible load. Typically there are 3 ways of controlling fire in any building:

1. Automatic firefighting - In-house suppression systems such as sprinklers.

2. Manual firefighting - firemen and hosereels, in other words.

3. Passive or structural fire proofing.


Now in the case of the towers, (1) was knocked out by the explosion and (2) was more or less impossible because of access difficulties. (3) was severely compromised because (a) much of the structure was damaged and (b) fireproofing was dislodged by the explosion.

We therefore had a building which was failing at an accelerated rate.

Now, I'd like you to consider whether any designer would have ever worked on the assumption that the huge mass above was going to impact on the lower structure at an acceleration of 10ms-2 (give or take)?

Would it even be possible to design to resist such loadings?

The simple answer is no, and the CTers typically show their poor understanding of design and structural issues when they harp on about this point.

Yes, the intermediate floors offered nominal resistance. But we're talking milliseconds, not seconds. And that's why the collapse happens at something near free fall speeds.

But it isn't free fall, is it? Because if we watch the videos, we see that columns and pieces of the facade are falling faster than the main collapse.

Progressive structural collapse is physically possible, and is supported by the evidence.

 

[Gravy]

This must be 3" REBAR ON 4' CENTERS because the spire is a 20 inch box column at the same distance 1 second before. The concrete was behind the spire and when the spire fell the rebar at the corner of the concrete core remained standing.

I don't understand. Where in relation to the structure in my photo do you believe the concrete core and rebar were?

 

[Belz...]

Congratulations,

You have found the only piece of evidence that MIGHT be misinterpreted to support that the WTC towers had steel core columns.

Well, we've seen plenty that HAVE been misinterpreted to support that the WTC towers had a concrete core.

The 2 columns toppeling have a base pivot point that can be projected downward at an angle to the lower left to show they are a part of the row of interior box columns on the left that have separated and are falling inward. What you confusingly refer to as hallways are simply rectangular spaces formed by the interior box columns and floor beams on the panel of columns we see that were the inner wall of the outer tube of the "Tube in a tube" construction.

If those columns were inside the core area, at that height, caught falling at that angle, they would be much further to the right and we would see more of them approximately parallel as they topple. With 47 , 1300 foot steel columns toppling in whatever directions, they would be a prominent feature in the images of the towers coming down. As it is this, is the only image that can me even misinterpreted to show "core columns" from the demolition.

Niice try Gravy.

I'd think that image is simply the same as yours, just better showing that structure, and I'd also think this is from the outside of the WTC, not the core.

 

[T.A.M.]

As far as I know I've explained how the construction photos are misinterpreted and those explanations are consistent with the demolition images.

No one has offered a reasonable explanation for what this is if it is not a tubular concrete core. Something thing that must be done before any conclusion can be made.

You do realize there was a core do you not?

Not sufficient Christophera...you see:

If a friend comes over to my house and says to me:

"There is life on mars."

The responsibility is his to prove this is true, If I am to believe it. If he is an expert in astronomy, or astrophysics, or astrobiology (not sure if that is even a science yet) than his opinion might carry extra weight, but if not, he better find me some good articles written by such experts to prove it to me, or else he better have a martian standing behind him.

It is not enough for him, as a layman, to take out a telescope, find mars, then let me look while saying..."now you see those tracks...those are aquaducts...where there are aquaducts there are living creatures." It just doesnt work that way...

TAM

 

[Belz...]

Based on real collapses of steel and concrete structures. Which, by the way, never collapse all the way to the ground. The conservation of energy has them slowing, then deflecting.

When's the last time you saw 32 storeys of a building fall on the rest of it ? For all we know, it DID slow down, but the force coming down on the undamaged WTC was simply too great. Don't forget that, with each successive floor, the falling mass increased.

It is convienent to say that WTC 2 was damaged more but it is well known that the right engine went entirely through the building and most of the fuel did too.

Irrelevant. The point is that the plane hit a corner, damaging the structure, and at a lower point than the first tower.

If the damage was worse then it would be because the core corner was taken out which would mean that the tower would fall to the south east, or more south as the perimeter wall was damaged on the south side.

Since neither you nor I know exactly which columns or sections of the interior of WTC2 were damaged, I don't see how you can make this statement.

Your argument is self defeatng.

Yours is circular. Wanna dance ?

 

[Belz...]

Yea, tell me about it. We need an explanation of why the top of WTC 1 fell south when it was hit on the north side. the school kids will lose all confidence in science if you try to explain with your logic.

I wasn't trying to explain anything. I simply said that this wasn't a grade-school level problem, while you're trying to make it exceedingly simple. I would dare say, "common-sense" simple.

I only expected to see the 47 1300 foot steel columns if they existed, which they did not.

I can't even read what's written on the truck in the foreground. I don't know how you could expect to see individual columns on a section that's 30 pixels wide.

I expect you to be able to come up with images of some of the 47, 1300 foot columns clearly in the core area doing something. 72 pages and not one image that clearly shows this. Pretty bad,

If you'd care to stop labeling them "box columns" you would've seen them by now.

 

[Belz...]

IMO there is a kind of fighting ongoing between the people who believe in the official theory
and people who believe in the alternative theories, I think that's the wrong way.

Welcom einsteen. That's a very bad way to start a post, though, as if JREFers don't use facts. Have you read this thread ?

The pancake collapse is IMO impossible.

I'd like to hear read why.

I don't believe in paranormal stuff, I even don't believe in God, but I also don't believe in a pancake
collapse

That's amazing, considering it's happened before.

Do you believe in gravity ?

calls me a conspiracy nutter or something like that because the pancake theory is also just a theory.

Like evolution, right ?

In physics a theory should be tested and be reproducable, think about your pancakes and test your theory.

<smacks himself on the forehead> OF COURSE!! Gravy! Get me some steel! Huntsman! Get me some concrete trucks, please. Delphi! I'll need some office furniture. Steal it if you have to. Shrinker! Cables and electricity, if you will. Pardalis! I need two 767s ready to roll. I'll get some cranes. Bob_kark... just keep counting those socks, man.

Okay. We should have two brand-new WTCs in just a few years. Then we can test the theory.

 

[Belz...]

- the whole frame then became weak because floor i (i=1,...,N) is strong enough to carry all other N-i stories and so on.

That doesn't need to happen. All you need is to bring the 78th floor (WTC2) to the point where it CAN'T handle the weight of 32 floors above it. Once the collapse starts, as someone said, the load that comes down on 77th will be 20-100 times greater than what it was designed to handle.

The firemen who made it a few blocks can tell you if there was any damage at the bottom.

They couldn't get to the impact floors. They can't tell us anything.

If one assumes all floors are as strong as the first floor (by symmetry in the construction) then I would expect that the upper block that is going to fall between the whole building will probably break one floor and then stops.

Read my comment above. This assertion of yours stems from ignorance of the scale of the collapse.

- A pancake collapse could probably happen if you ignore the core and the walls (isn't that what NIST did?) , but why does a floor become weak after 50 minutes when the whole area went from hot to cold (you can see people standing there, that's no spoof)

Maybe not directly in the impact hole, but you can clearly see several floors on fire above the impact point. WTC1 was basically on fire from the impact point to the top. That can't be good for structural steel.

- what is the initial starting point of the collapse, if you think about a domino effect what caused the first stone to fall, what about those strange explosions at the top ?

Look at them again. Dust and debris don't explode, they flow from the building. That's not an explosive charge.

- By the assumption of a domino-effect collapse there can be no transfer of information faster than free-fall. This is by definition impossible.

What's this "faster than free-fall" you're talking about. Free fall isn't a speed.

- And what about Ockham's razor, you must make your sophisticated pancake theory very complex, some explosives would make the theory easier..

Occam's razor isn't about simplicity, per se. It's about the theory that explains best while making the least assumptions. Presumably, the collapse of a 110-storey building will be a complex event.

 

[T.A.M.]

Belz:

Your description of Occam's Razor is by far the more accurate one, but for the majority who use it, it has often been "simplfied" or "modified" to mean..

"given two answers or solutions to a problem or scenario, the simplest one is the more likely to be correct, all other factors being equal."

This is the definition most go by, but your definition is actually a more accurate description of "Occam's Razor".

 

[WildCat]

I only expected to see the 47 1300 foot steel columns if they existed, which they did not.

Are you under the impression that each steel column was one piece of 1300 ft. long steel?

 

[Mancman]

Bolding mine. http://wtc.nist.gov/pubs/NCSTAR1-6ExecutiveSummary.pdf

About this quote you posted:

Finding 32: The building section above the impact and fire area tilted to the east and south at the onset of structural collapse. The tilt occurred toward the east side with the long span floors. Estimates made from photographs indicate that there was approximately a 3 degree to 4 degree tilt to the south, and a 7 to 8 degree tilt to the east, prior to significant downward movement of the upper portion of the building.

Bolding mine. This is interesting, as NIST also state that the North Tower top section also leant by 8 degrees before it began to move downward. Was an 8 degree lean the maximum strain that the columns on the other side of the building could withstand? Perhaps someone with more knowledge on this than myself (ie. any of you) can shed some more light on this.

 

[Christophera]

Give Us Your "Impressions"

Are you under the impression that each steel column was one piece of 1300 ft. long steel?

Maybe you don't have the experience to know that the word "column" implies one piece. The word "core" goes further with that assertion.

In the documentary it was stated that the "interior box columns" (not core columns) were butt welded with 100% weld making them virtually "one piece".

The concrete core was one piece and intended to resist torsion applied through the "flying" action of the tower faces in high wind.

Are you under the impression that columns that are assembled as segments can resist torsion? Are you under the impression that a 1300 foot steel member that is "assembled" can resist torsion. Are you under the impression that a 1300 foot piece of steel called a column can resist torsion better than 4 steel perimeter shear walls in a box shape?

 

[WildCat]

The concrete core

You think that dark section is only 17 feet wide? How big does that make the buildings in the foreground?

 

[Gravy]

Repeat for Chris:

I don't understand. Where in relation to the structure in my photo do you believe the concrete core and rebar were?

 

[Belz...]

Maybe you don't have the experince to know that the word "column" implies one piece. The word "core" goes further with that assertion.

Uh-huh. One piece core. Was it prefab ?

In the documentary it was stated that the "interior box columns" (not core columns) were butt welded with 100% weld making them virtually "one piece".

I assume you're again referring to that non-existent documentary.