Acceleration of the falling top blocks.

[ergo]

No, it's not at all evident. You claim that the core should be self-supporting. The core itself is nothing but a series of tall columns. How are these columns supposed to be self-supporting? They have nothing to stabilize them laterally.

OMG. Not going to bother.

 

[DGM]

If the core alone had been built, it would have blown over in the first serious gale. It was not "self-supporting" in any useful, real-world sense. Also the exterior columns contributed significantly to carrying gravity loads. The floors connected to the exterior, so those walls had no choice but to bear gravity loads.

I doubt it would take even that. A light breeze could have easily set-up a collapse

(see Tacoma Narrows bridge)

 

[000063]

So you're just making an amateur guess? That's fine, as long as you acknowledge this, and acknowledge that your amateur guess is not part of an engineering peer review...

"Moon-sized field of rubble".

This is nonsensical. Do you understand what you're saying?

I don't think you understand your own argument.

Ergo, I've noticed that you never explain how people don't understand their own argument. You just say they do. I suspect you're projecting your inability to understand it. Oddly enough, I have never seen you make these claims of a Truther, no matter how nonsensical the argument. Why is that?

You don't ask the questions here, DGM. You answer them. Here's where you can begin. K?

So nobody but Debunkers are actually beholden to actually answer questions about their position? Odd.

No. Read the thread. Stop trying to get on the other side of the table. Defend your stupid theory or stop posting.

Ergo, why do you not want to defend your claim?

What part of this don't you understand?

I hear Dodge makes good trucks.

 

[000063]

This pretty much sums up how I feel every time ergo posts something....

[qimg]http://i1094.photobucket.com/albums/i442/zerxsdctbghv/DEzsn.gif[/qimg]

As the macho man would say; "Yeah!"

How unfortunate.



I have to "prove" to you what is common knowledge about the floors? Why?

If it's "common knowledge", why are you so reluctant to prove it? It's common knowledge dogs bark. All I have to do to prove it is find a dog. Or find a video of a dog on Youtube. Or open up Wikipedia to Dog. Or call a local vet, or open an encyclopedia, or any one of a tonne of readily available sources.

Of course, it's not common knowledge, except among people who have studied the plans. The only person claiming it is common knowledge is you.

I'm not sure it's worth the time to find the "proof" for you, DGM. I have photos that I would have to upload, and then find some written documentation explaining the floor assembly. Why should I do this? Do you doubt there were bridging trusses? Am I wrong about that?

I can see you're backpedalling, without even having to check. You made a specific claim about the nature of the trusses, not their existence.

What do you think they do?

Dodge noted, attempt to shift the discussion away from your beliefs about the truss strength.

I look forward to your answer to the above question.

Quote-mine noted.

?

I sincerely hope this isn't DGM's way of avoiding my question.

Probably not, seeing as you just quoted Brass.

But one bedunker's as good as another, eh?

Why does nobody know exactly what happened? Why should this be mysterious for structural engineers for a gravity collapse of a steel-framed highrise? Aren't you folks always saying how "obvious" the collapse was? Why is this difficult for you?

If a guy gets shot in the chest and dies, I can tell the bullet killed him without knowing its exact path through his chest. Appeal to impossible precision. The scanners on the Enterprise--any model--would probably have difficulty tracking everything going on in the collapse. However, they would have no problem with enough detail to ascertain what happened.

And please tell us more how the floors were ripped from the columns, how that occurred at the average rate of 0.16 of a second per floor through 287 floor-to-column connections, and how all that ripping of connections (and concomitant pulverization of all building contents) only took an extra 0.047 of a second to occur per floor than if each floor fell through air. I'd be fascinated to hear this story.

You're trying to drive the thread away from the question of your old claims, while providing nothing more to support your new claims than incredulity.

 

[A W Smith]

Actually, what we've seen is a spammed image that shows the floors under construction. An image that also seems to want to give the impression that the floors were precariously flimsy and that the steel cabling in the trusses is something in the order of less than an inch thick. What isn't shown in that spammed image are the bridging trusses and the complete assembly that secures the floor panels to the columns.

Excuse me. "cabling" ??????? Cannot find one word mentioning "cable" in this fema document.

http://www.fema.gov/pdf/library/fema403_ch2.pdf

Did you maybe mean "Bar" as in "Bar joist"??


http://en.wikipedia.org/wiki/Open_web_steel_joist

The main function of an OWSJ is to provide direct support for roof or floor deck and to transfer the load imposed on the deck to the structural frame i.e. beam and columnhttp://en.wikipedia.org/wiki/Column.

Not vice versa.

 

[GlennB]

It was self supporting in a very useful, real world sense. What height of stand-alone structure are you envisioning here that it would "blow over"?

A WTC1 or 2 height.

Well, duh.

So, we're OK then? The WTC cores were not "self-supporting" alone. They needed the exterior walls to become, as a unit, self-supporting.

 

[000063]

Still not answering the question.

The floor system, which exists in both upper and lower building assemblies, is not tasked with arresting the collapse. The column structure, which exists in both upper and lower building assemblies, is.

No, the "cabling" I'm referring to is not the sway dampers, DGM.

Then why not say what you are referring to? Why do you have time to hang around and ask pointless questions instead of backing up your actual claims? And how does something that's "common knowledge" suddenly require such a strenuous effort to find?

Yes. It's intuitive.

If I went to my nephew and asked him about telling the time by sun position, I think he'd be able to wrap his head around the concept. One you seem to have a problem with. Given that, you can understand why I'm loathe to trust your judgement about the level of comprehension required for, oh, anything.

Some truss pics for DGM. Because he seems a little confused about the bridging trusses.

[qimg]http://i889.photobucket.com/albums/ac91/jaswinder_bucket/WTC/633_insulated_trusses.jpg[/qimg]

[qimg]http://i889.photobucket.com/albums/ac91/jaswinder_bucket/WTC/trussassembly.png[/qimg]


http://whatreallyhappened.com/IMAGES/bridging_truss.jpg

Edited by LashL: 

Changed hotlink (breach of Rule 5) to regular link.

That's nice. What relevance do these have to your specific claim about the nature of said trusses? DGM has explicitly stated he does not discount their existence, only the capabilities you claim for them.

And why did you have time to look up those pictures but not to prove the trusses could do what you claim?

You also didn't understand the transverse trusses....

An intellectually honest person might take this chance to clarify what they mean instead of trying to prove their alleged superiority.

...Wrong about what?

Quite a lot, as it happens.

No, that's incorrect. The core was self-supporting. It had to carry the gravity loads. Where are you getting this information from?

First, provide evidence for your assertion of the self supporting core. And that evidence about the trusses you found such a strain to look up earlier.

Of course they are. The whole building is a structural system. Nothing new about that. But the core isn't going to crumble with the loss of a few floors.

So the whole building is a structural system, yet the core is self-supporting?

...
And what was it that you originally took issue with in my description of the floor assembly?

Wait, so you said that it would take a lot of your time to back up your claim, yet now you pretend to want to know exactly what DGM was talking about? How would you know what he wanted you to prove would take a while to find out if you didn't already know what he wanted? Are you just spinning your wheels to avoid having to admit your claim was wrong?

PS: (see what I mean by time wasting?)

I certainly do.

No, that's clearly not what I'm saying, which is evident in several of my posts above. I guess this strawman signals your exit from this discussion?

So, what were you actually saying? It should be easy to summarize.

OMG. Not going to bother.

Incredulity and evasion, we're familiar.

 

[wheunis]

Good. Then you should be able to wrap your mind around just how strongly built the WTC was and realize any falling floors would have been slowed by the steel framework of the building. Not that floors fell, of course. By the time they started falling, they were not floors anymore. They were bits and pieces of floor material, which doesn't give a solid jolt.

Drop foam a dozen feet. It doesn't produce a very big jolt. That's what happened. Foam fell. Not floors.

What you're trying to sell, it would appear, is that a 200lb man falling on you is less painful than 2x 100lb men?
And for that matter 100x 2lb babies?

You are right on one thing... the lower floors, once impacted by the incoming mass from above, were not floors for very long after the impact.

But you are wrong to think at any point, that any amount of "vaporization" or "dustification" or "wave your magic wand over this and it falls slower -ification" took place.

You have tried to make the point yourself in here, about how strong you believe the steel structures to be.
If your "floors were dustificated" theory is to hold, why aren't all the support columns still standing? (Just like good, hearty, honest, and hardworking supermansteel beams should?)

You're grasping at straws. You claim that dust/foam/powder and like substances cannot have momentum, or terminal velocity, or speed, or impact equal to that of the same mass in a solid state.
This is just not true.
Please just stop.
There is no conspiracy. There is no inconsistency. For some reason you have concocted this need to blame someone larger to fit the scope of the incident.
Big things are not always the doing of big people...

War of the Worlds was just a fictional radio show!

Dammit, Janet! Do not go through that door!

 

[Animal]

No, that's incorrect. The core was self-supporting. It had to carry the gravity loads. Where are you getting this information from?

And you are wrong. The core required the floor system for lateral support, just as the outer ring of columns did.

 

[Animal]

OMG. Not going to bother.

Because you don't have a clue.

 

[Gamolon]

Do you understand he difference between "building load" and "individual floor load"?

yes.

You say that you understand the difference yet you post this garbage.

The 1st floor was strong enough to hold 109 upper floors. The 2nd floor was strong enough to hold 108 upper floors.

You obviously DON'T understand the difference.

 

[000063]

Almost as if he's saying whatever it takes to prop up his position for a few more posts without caring about whether its logical or not.

The funny thing is that even if he was right, in the strange Bizarro world where physics are different, the upper block impacted with several times the mass of the entire building, well out of any given floor's weight class, even his bottom one.

 

[leftysergeant]

Let me bring it back to my original premise. The normal way of viewing the collapses is that the tops of the buildings did a pratfall on the lower, causing instant catastrophic destruction of joints at the point of impact, thus initiating a cascade of destruction. This concept may actually confuse some people because itis hard to understand how even a dynamic load would crush down the core columns.

What I see happening, rather, is that the top parts sort of sagged, putting strain on the core columns in ways that they were not designed to bear weight, forcing them apart. This same process, of course, also separates the top core columns from one another. This releases a lot of floor slabs to overload those below to cause a steady progressive collapse down the inside of the office areas and to force the perimeter columns outward.

That the crushing and wedging apart of the core columns would arrest is not really controversial. What is controversial, and it is a point on which we diverge from the twoofers, is that there are other forces at play. The lateral connections between many of the core columns at the top have now been deswtroyed and are standing there, shaking in the tumultuous upward stream of air and being pounds by collapsing floor slabs (which I think we can colclude spararted first fromm their outer connections. This has to have set up some serious vibrations or various sorts of resonnances to further stress the welds and joints.

The ability of a steel grid tower (as championed by ergo) depends on every part's moving and rebounding in unison. If there are columns of uneven lengths standing free at the top of that tower, this will not happen. Thus joints are strained even more, and the stress becomes greater as more joints at the top fail, allowing more chaotic and wider-ranging oscillations of the standing colmuns. We can see this in the final shot of the spires, as one column moves back and forth at least three times before falling. This is obviously inconsistant with CD, which requires simultaneous failure of all columns at any given level.

 

[WTC Dust]

I include the columns on the first floor to be a part of the first floor. Not just the "floor" itself, but the entire construction of the first floor. It was strong enough to hold the top 109 floors without a problem for 30+ years.

This is incorrect. The floors were only built to hold their own contents. NONE of the weight of the floors above them were held by the floors, that weight was all attached to the core and perimeter columns.

If the upper block started to fall, the only way it could be "caught" by the building below it is for the columns of the upper block to somehow remain perfectly aligned with the columns below, and land perfectly on top of them. This became impossible as soon as the upper block began to tilt.

 

[WTC Dust]

I said this "At the relatively low speeds that gravity alone would produce". I never said gravity was a speed, rather, that it would produce a speed. Get it right.

Do you understand scaleability? The square-cube law?




Gravity is a force, which causes acceleration -- not a speed.

If you drop an object from the top of our atmosphere, it would land (ignoring air resistance) at around ten kilometers per second velocity.

And although MV = MV, Ke = 1/2MV^2. That Ke goes up FAST as the distance fallen increases.



Okay, this is what you expect. That's fine; a lot of people have naive expectations about how objects and forces outside of their direct experience behave.

But you want to do science? You don't go with untested gut assumptions. YOU CALCULATE.

If you don't do the numbers and TEST how you think the behavior should happen, you aren't even doing cargo cult science. You just plain aren't doing it.

 

[WTC Dust]

Fire damage? Really? The previous fires in the WTC did not do this.

No fooling, the towers stood for 20 some years without gravity making them collapse.
Everyone knows it's the fire damage that caused the towers to collapse. It's simple physics.

 

[WTC Dust]

Responses in red.

QUOTE=000063;8237312]Advanced weaponry never used before or since in any known capacity, that produced effects comparable to no known weapons, which would've cost more to develop and use than any possible profit gained by the conspirators, which would require a massive logistical and support base.


Why do you say this?

And there have been examples of the top parts of buildings starting to fall and then making the building collapse under them.

Not like the WTC, they didn't.

Good idea.[/QUOTE]

 

[WTC Dust]

I'd like to know what you think broke apart all the steel columns. Not the floors. It's not like the floors went wackety wackety all the way down and the steel columns remained. They were broken apart.

I'm not citing any official model other than the design of the building. The floors were not attached to each other, they were only attached around their edges to the columns. The floors could not hold the whole building above them, this is a trivial fact. I know you've seen the pictures of the truss seats hundreds of times on this forum, do I really need to show them again?

It also shouldn't require an "official collapse model" for you to realize that if you break a column, the upper section can't hold up any load unless it's sitting on something that can hold just as much load. So it either has to land on top of the lower section again, or there needs to be something else it can land on that can hold it up. What do you propose could do that? Do you think the beams that horizontally stabilize the columns could bear that kind of vertical load? There isn't much of anything else the core columns could land on, and there's literally nothing else for the perimeter columns to land on.

 

[WTC Dust]

This is a silly concept. The mass of the upper floors did not increase at any point.

Someone did the math. The upper floors hit with about six times the mass of the entire tower. I don't know how you expect the lower section to withstand that.

 

[WTC Dust]

I'll jump in with an answer: Less than three seconds.

How long (in your mind) does the upper block remain intact once "collapse" begins?