Originally posted by scrapple

There is only so much energy in a given system. We can have pulverized concrete, snapped mechanical connections or bent columns, but not all from the force of the top section.

Without doing the math, the above conclusion is only speculation on your part. It may very well be correct. I don't know.

But the concrete being pulverized is making more and more sense to me. Shredded may be a better description. The steel grid making up the trusses of the above floor, along with the mass and the acceleration due to gravity would cause the concrete slabs to be shredded, much in the same way the steel beams in the Pentagon shredded FL 77 as it went through the building.

Any ideas of the mass of each tower?

Originally posted by Griff

Originally posted by nick7261
The accelerating mass of the upper floors was too much force for the steel beams to withstand.

Problem is. What caused the floors above to accelerate down when steel in fire deforms and bends? What I mean is that steel doesn't just give way under heat at one instance. It bends and deflects and becomes malliable. So, what would cause the upper cap to "drop" in the first place rather than deform and bend more slowly?

So in other words you think the building should just slowly collapse. It simply doesn't work that way.

If you were to take your chair leg and slowly hack away at it, is it just going to slowly fall, or at some point if the chair going to just fall over? With the fire it weakens the steal which reduces it's strenth. There is a point at which the weight above is great enough to overcome to strength of the steel. At which point the supports give way. They don't just slowly fold down. It's basic physics.

So at a certain point the heated steel is too week to support the weight. That point does not give, the weight is transfered to the remaining supports. Once the weight is greater than the remaining supports can hold, the whole thing comes down. The floor below can in no way withstand the force of an entire floor in momentum (for example, hold a 40lb weight. Then try catching a 40lb weight dropped form 12 feet above). Then each floor below has to take on the weight f the building above adding an additional floor worth of weight and momentum with each floor. This is called a progressive collapse.


I know everyone means well, but it's kinda silly seeing a whole bunch of us with no expertise what so ever trying to convince ourselves that we are structural engineers. Just because YOU don't understand how collapses work does not prove a conspiracy. it only proves you are not a structural engineer.

And of course all this has been well documented by hundreds of engineers and scientists and tested. As well as viewable by every structral engineer in the world. So again, not understanding the engineering does not make the engineering wrong.

Huh snoopy.....

It just happens that Griff is a structural engineer.....

So has anyone mentioned the requirements to be listed as an expert on the web site which is the subject of this thread? It's quite telling.

All you have to do is submit the forum and enter your information. There is no verification process what so ever. Anyone on this forum can sign up and say they are an engineer or architect and you will be listed as an expert on the web site.

This is what you call fraud.

Just wait until Griff comes back if he has the patience to deal with the invasion of trolls on ats lately, then I'm sure he will prove to you what he is...

Edit: I meant that he was expressing not being sure if ats is worth it anymore in another post.

This was not directed at you in anyway snoopy.

[edit on 31-5-2007 by selfless]

Originally posted by selfless
Huh snoopy.....

It just happens that Griff is a structural engineer.....

And what I am saying is that he isn't. If he was, he would not be asking questions the way he is asking them. But I guess since he is listed as a civil engineer on a web site that has no verification process at all, it must be true.

You're telling me that a civil engineer is suggesting that a it's odd that a failed support on a building could cause a sudden collapse instead of slowly falling? I mean that alone should be a red light for you.

Originally posted by selfless
Just wait until Griff comes back if he has the patience to deal with the invasion of trolls on ats lately, then I'm sure he will prove to you what he is...

And by trolls you mean anyone who disagrees with you. Nice.

Gosh yeah I am so out there for being skeptical of a web site that allows anyone to say they are an engineer or an architect. That's just a center of honesty there in that web site. What a troll I am for pointing out a fraudulent web site.

So hopefully Griff will clear things up for us. But one thing he can't clear up is that the web site is a fraud.

But hey, I could tell you I'm a civil engineer too. Am I now somehow credible? Of course not, because I am not telling you there's a conspiracy. If any structural engineer came on here and didn't tell you there was a conspiracy, you would call them a troll.

Please stay on topic, discuss the facts or lack there of, but not other members.

Originally posted by snoopy

Originally posted by selfless
Huh snoopy.....

It just happens that Griff is a structural engineer.....

And what I am saying is that he isn't. If he was, he would not be asking questions the way he is asking them. But I guess since he is listed as a civil engineer on a web site that has no verification process at all, it must be true.

At least give Griff the benefit of the doubt.

Structural engineers are not robots, they can ask questions just like anyone else.

Originally posted by selfless


At least give Griff the benefit of the doubt.

Structural engineers are not robots, they can ask questions just like anyone else.

Did you read the post that was a response to his? Until today I had given him the benefit of the doubt. But more importantly I was talking about the web site, not Griff. Remeber the topic of the post that we all have gotten off track from? It's about a web site that lists a lot of architects and engineers who all support the conspiracy theory.

Only problem is that anyone and their mother can say they are an engineer or architect and instantly be added to the list. Hence the web site being a fraud.

Yet Griff claims to be a civil engineer and everyone thinks that what he says is the law. yet all the other engineers in the world must clearly all be wrong and incompetent. And by that what I am pointing out is that peoples opinion here as to whether someone is legitimate or not is if they support a conspiracy or not.


Hey, let' bring up another topic of issue brought up in the thread (even though it's not on subject either). This claim that the core columns telescoped into each other. Are we to believe that every core column was bigger than the column above? And that they came straight down into the one below? Maybe I missed it, but can someone show me the findings where this happened? Are there pictures of the columns all sitting inside of each other? I've missed plenty of things in the past, so maybe this is another one.

Talking about Griff is not off topic since he is on the list of engineers that this threads is discussing.

Originally posted by snoopy
Yet Griff claims to be a civil engineer and everyone thinks that what he says is the law. yet all the other engineers in the world must clearly all be wrong and incompetent. And by that what I am pointing out is that peoples opinion here as to whether someone is legitimate or not is if they support a conspiracy or not.

I always see engineers who are tied with corporations and the government claim that 911 was caused by plane crashes.

I See the independent engineers say otherwise.

That's just how it goes.

Originally posted by selfless

I always see engineers who are tied with corporations and the government claim that 911 was caused by plane crashes.

I See the independent engineers say otherwise.

That's just how it goes.

OK, so the engineers who don't think there is a conspiracy are linked to the government and the ones who do are independent?

I think thats more of how you see it than it goes. No offense meant, but honestly. Does that really seem like a fair assessment? The majority of scientists who worked on NIST were independent. And I have hardly seen any that say otherwise. We certainly can't go by the list on the web site this topic is about.

And of course we can say that the majority of the world body of engineers are independent. yet where's this big outcry? They all see everything that we have all seen. And they know more than us. Yet they don't speak out. I mean if they all say otherwise, where are they saying otherwise?

Originally posted by scrapple

Ask oneself, how does an "intact" top of the tower portion fall through 'undamaged' core structure below? One must eliminate core in the lower structure being hit to dice the concrete - right?

So why didnt we end up with an intact 10+story tower head falling onto the helpless streets of NYC that day like a giant lawn Jart?

Good question. Here's what I would suggest...

The steel framing of the upper levels diced the concrete slabs of the lower levels as explained in the previous posts. And likewise, the steel framing of the lower levels diced the concrete slabs of the floors falling onto them. This destroyed the upper concrete slabs, while at the same time the force of the upper levels accelerating downward was too much for the steel supports below to bear.

Conceptually this seems like it might be possible. At this point it's hard to determine what actually happened with the limited data available.

But you also must realize that a CD theory raises many of the same questions. If there was a CD, what caused the collapse from the top down? And if there were beams cut out from beneath the top floors, what was providing and resistance or force to cause the top floors to disintegrate on the way down? If there were CDs in the base of the towers, they would have fallen from the bottom like WTC7.

Originally posted by selfless

The fire was not even hot enough to burn a person that was standing in the big hole of the building and yet it collapsed in 1 hour....

If the fires weren't hot in the towers then why were dozens of people leaping to their deaths from the buildings? Were they just suicidal to begin with, or did they too misjudge the intensity of the fires in the WTCs?

Really, for someone who claims to be "open-minded" you're really struggling with the concept that the woman standing in the "big hole" was obviously standing on the opposite side of the building from the fires.

Originally posted by snoopy
What force is going to move the top of the building an entire city block over and onto the street next to the building?

This is an excellent point that has been overlooked by most people who claim that the towers falling into their own footprint is evidence of some sort of CD. You're exactly right -there are no external horizontal forces that would push the towers at all along the x-axis. The only evidence of any horizontal force was the result of WTC2's rotational momentum which initiated the entire WTC2 collapse.

Originally posted by snoopy

Someone already gave you an example using the bowling ball on a glass example. How about we try another one:

I grasp the dynamics of glass, muscle, watermelons, and bowling balls as irresistible when conceptualizing the resistant forces inherent to mechanical and chemical bonds of steel and concrete. But I feel human stacked on human isn’t really a competitive representation of tower structure.

The answer to what stops the bowling ball from crashing through glass – is nothing - depending on the right ball mass, velocity and material properties of glass. What is more troubling in this example is not the finger strength of the cheerleaders holding the glass pane but the steel reinforced football helmet the table it resting on - as its central core.

Undamaged I bet this system withstands the ball.

Relative to the core of the twin towers imagine a core stack of self supporting football helmets. Think they are going to just give up when a few already stacked on top are dropped from a distance?

I ask this not in jest. Is there a comparable NIST/FEMA/USGov test which attempts to simulate tower collapse combining both fire and structural damage? There is, and ONE of its tests resulted in a simulated tower collapse ala 911!

Want to know what scenario the scientists and engineers applied to precipitate full tower collapse? Simple - it required the catastrophic structural failure of the towers’ internal core structure "immediately" upon impact of the planes.

We all saw the struck buildings stand for a time, so relative to this post I think it behooves us all to check the credentials of the construction professionals as well as their employers when addressing this issue.