How was WTC foundation failure achieved?

For this too happen there would have to be another force acting on it other than gravity.

The only thing that would have to have failed in order to eliminate or reduce and resistance from the floors would be the connectors at either the perimeter or core.
When these failed there was no resistance from them. The floor trusses were basically the bracing system that gave the towers their stability. Any time one end of a brace is lost all stability of that brace is lost and it no longer functions as a brace of any kind.

Being a rigid structure with factors for wind load and sway, how far out of plumb would the perimeter or core have to be before the connections failed?

You can see this happening in the collapse. The perimeter walls are peeling away from the structure and this is the reason that for the steel to be mostly outside the footprint and not that it was 'ejected' by some explosives.

At least we've gotten past that 'into its own footprint BS'

Originally posted by Vushta
The floor trusses were basically the bracing system that gave the towers their stability.

No... the core provided it's own stability. If the bracing were to fail, you would be adding no load to the core, you would be reducing the stresses on it... Maybe the concret slabs and outter lattice falls, but the core was TRIPLE redundant and LOSING load ad the collapse ensued.

Originally posted by Vushta
Being a rigid structure with factors for wind load and sway, how far out of plumb would the perimeter or core have to be before the connections failed?

Pretty far as the buildings sway in the wind all the time. They are DESIGNED to sway in HURRICANE FORCE winds. Ever been in the top of a 100 story building and taken a leak? Notice the water in the toilet swaying side to side?

Originally posted by Vushta
You can see this happening in the collapse. The perimeter walls are peeling away from the structure and this is the reason that for the steel to be mostly outside the footprint and not that it was 'ejected' by some explosives.

Conjecture. OR the core is dropping pulling in the trusses and outter lattice.

Originally posted by Vushta
At least we've gotten past that 'into its own footprint BS'

We all know it did not fall 100% into it's own foot print. When we say that, we nmean it went straight down and as much into it's own foot print as one would expect a 100+ story building to do in a CD. That is the goal od CD and these three buildings would have been considered HIGHLY SUCCESSFUL CDs based on this fact.

Originally posted by Vushta
The only thing that would have to have failed in order to eliminate or reduce and resistance from the floors would be the connectors at either the perimeter or core.
When these failed there was no resistance from them. The floor trusses were

OK for one pls explain how the connectors failed on floors that were undamaged and not on fire. We have already proved your pancake theory is wrong, concrete turned to dust etc...And no if one conector fails they won't all fail.
Second it was not a rigid structure, no high-rise is. They are designed to move and sway in the wind, so that they don't fail from stress. Witnesses have said the buildings swayed no more than they do in the wind from the impacts.

And thirdly if your analogy was correct and the floors pancaked down you would see interior columns still sticking up after the floors collapsed. If the floors became disconnected from the columns what caused the columns to come down with them?

And fourthly, no we haven't got passed the 'in their own footprint', especially building 7. And towers 1 & 2 fell as close to in their own footprint as you could get, especially if as you claim it was not a controlled demo. The building fell symmetrically straight down, the only reason debris spread outside it's footprint was just from the force of the debris hitting the ground, and as you say the columns that were balsted away from the sides. Like dropping gravel from high up, it's going to spread out.

If this is not in it's own footprint, what do you call it?

Originally posted by ANOK
OK for one pls explain how the connectors failed on floors that were undamaged and not on fire.

You had three main forces acting on the truss to column connections.

1) The downward sheering action from the tons of debris falling downward.

2) The outward movment of the exterior columns as they buckled and were pushed out by the falling debris from above.

3) The inward pull of the trusses as the debris hitting the middle of the floors bowed the floors downward.

Originally posted by ANOK
We have already proved your pancake theory is wrong, concrete turned to dust etc...

I don’t think you have proved squat.

Originally posted by ANOK
Second it was not a rigid structure, no high-rise is. They are designed to move and sway in the wind, so that they don't fail from stress. Witnesses have said the buildings swayed no more than they do in the wind from the impacts.

Wrong again.

I continued on to the west side near my office. I was fairly near the windows talking with two or three people, including especially Bobby Coll. I was looking him in the eye having a conversation with him when at apparently 9:03 -- I didn't check my watch -- the second plane hit the south side of our building at approximately the 78th, 79th, and 80th floors. Our room fell apart at that moment, a complete destruction without an explosion -- very strange things. The lights went out, but we were near the window so there was daylight. Again, there was this sort of thump, this explosion without fire and flame, a very strange sensation.

There was a twist, if you like, to the building when it got hit, and therefore the plane's hitting explained some things to me later, like why the ceiling fell apart. The ceiling tiles and some of the brackets and so on fell; some air conditioning ducts, speakers, cables, and things like that that were in the ceiling fell. I seem to have a sense that some of the floor tiles even buckled a bit or were moved. Some of the walls, I recall vaguely, were actually torn in a jagged direction rather then up and down. Again perhaps explained by the torque, some of the door frames popped out of the wall and partially fell or fully fell.

For seven to ten seconds there was this enormous sway in the building. It was one way, and I just felt in my heart, Oh my gosh, we are going over. That's what it felt like. Now, on windy days prior to that there was a little bit of a sway to the building. You got used to it; you didn't notice it. The window blinds would go clack clack as they swung. As I said, for a good seven to ten seconds I thought it was over -- horrible feeling -- but then the building righted itself. It didn't sway back and forth; it just went one way, it seemed, and then back, and we were stable again.

www.pbs.org...

Please show me the buckling that caused collapse initiation (ie, ENOUGH buckling).

From NIST column safety factor figures, more than half of all columns on a single floor could fail before that floor would collapse, as one would expect of any skyscraper, since they are all over-engineered for safety.

Can you show something equivalent to more than half of all the columns completely failing on a single floor? Can you show anything other than those pathetic photos of only a small handful of buckled columns, across multiple floors?

If you can't, then I see no reason for you to believe any floor should have began to collapse in the first place.







[edit on 29-7-2006 by bsbray11]

Howie, do you realize that there were 47 7 inch core columns in the buildings design?

9/11 doesn't make any sense with what we're told.

www.freespeechwar.com...

This is a very good speech to watch. 9/11 Errors and Omissions.

Originally posted by whokilledthekennedys
Howie, do you realize that there were 47 7 inch core columns in the buildings design?

When you can tell me how many of the core columns on the impact floors were box columns and hom many were I beams and what percentage of the total building loads each column carried (all of this info is available in the NIST reports) then we will discuss this issue.

until then, I am going to assume that you don't know much about the building design.

Hey Howard --

I think you're missing all my posts.

I'm asking to see enough buckling on a single floor to show that it should have totally collapsed.

Lets start with the basics, bsbray,

1. Will you agree with me that the buckling evident in those photographs did not occur as a direct result of the plane impacts?
   
   That is, the buckling in those photographs occured later after the fires had been burning for some time.
   
   
2. will you agree with me that if the floors were intact that they would have resisted the buckling?
   
   

Originally posted by HowardRoark

1. Will you agree with me that the buckling evident in those photographs did not occur as a direct result of the plane impacts?
   
   That is, the buckling in those photographs occured later after the fires had been burning for some time.

No, as I have not seen sufficient information in this regard. I have also not seen sufficient evidence to conclude that the buckling was due solely to heat from sagging trusses.

But, I can discuss this hypothetically, so go on anyway.

1. will you agree with me that if the floors were intact that they would have resisted the buckling?

If floors were totally intact, perimeter columns would not buckle. I agree with that.


Showing me sufficient buckling, pre-collapse, on a single floor, to justify the total collapse of that floor, should not be that complicated. Either you can show me the buckling, or you cannot.

If the collapses initiated from immense amounts of structural integrity being lost due to buckling, then there should have been immense amounts of buckling. If you cannot show immense amounts of buckling before each collapse began, then you cannot support your theory.

"Buckling" after collapses are already underway does not establish a cause, but an effect of structural failures, which demolitions could just as easily produce.

Originally posted by bsbray11

Originally posted by HowardRoark

1. Will you agree with me that the buckling evident in those photographs did not occur as a direct result of the plane impacts?
   
   That is, the buckling in those photographs occured later after the fires had been burning for some time.

No, as I have not seen sufficient information in this regard. I have also not seen sufficient evidence to conclude that the buckling was due solely to heat from sagging trusses.

But, I can discuss this hypothetically, so go on anyway.

There are a number of photographs from earlier in the fires that do not show this buckling. If you want, I’ll dig them up. I really don’t feel like it now. Anyway.

1. will you agree with me that if the floors were intact that they would have resisted the buckling?

If floors were totally intact, perimeter columns would not buckle. I agree with that.

Good, then the photographs of the inward buckling of the exterior walls on the WTC towers clearly indicates that the structural integrity of the floor slabs were compromised in those locations.

Showing me sufficient buckling, pre-collapse, on a single floor, to justify the total collapse of that floor, should not be that complicated. Either you can show me the buckling, or you cannot.

You are still thinking on a floor by floor approach. The structure components can not be broken out floor by floor. The exterior walls, the core and the floor slabs were all separate, but interdependent parts.

Too many people seem to want to think of the building as a stack of floors piled up on each other. That is the wrong way to think of it. It was a hollow tube with the core and the floor slabs providing the necessary rigidity to the exterior wall system.

If the collapses initiated from immense amounts of structural integrity being lost due to buckling, then there should have been immense amounts of buckling. If you cannot show immense amounts of buckling before each collapse began, then you cannot support your theory.

The key question is this: how fast will the buckles propagate. As the exterior wall buckled inward, the buckled portion lost its ability to carry the loads it was designed to carry. Those loads transferred to the adjacent columns. As the buckle started to grow, those columns subsequently lost their ability to carry their original loads and the loads imposed upon them from the adjacent buckle area. This might start slowly, with the extent of the buckle being quite visible in the pictures.

Eventually, however, the accumulation of the loads and the rate of failure will reach a runaway point. (I am assuming that the rate of speed of the progression of the failure will increases exponentially.)

Unless you had a high speed camera trained on the building at that point, you would not be able to see the progression of the failure. It would look instantaneous.

The fact is, there is buckling in evidence prior to the collapse. At some point, that buckling caused the structural failure that brought down the building.

The transition from “buckling on one face” to “total structural failure” would have been so quick that it would seem to be instantaneous.

Originally posted by HowardRoark
Good, then the photographs of the inward buckling of the exterior walls on the WTC towers clearly indicates that the structural integrity of the floor slabs were compromised in those locations.

You have failed to show this, and NIST has failed to show this, and I'd rather not make any assumptions from a lack of information. But again, I will be hypothetical.

You are still thinking on a floor by floor approach. The structure components can not be broken out floor by floor. The exterior walls, the core and the floor slabs were all separate, but interdependent parts.

Then show me enough perimeter column buckling across multiple floors to justify collapse initiation, keeping everything in proportion.

Too many people seem to want to think of the building as a stack of floors piled up on each other. That is the wrong way to think of it. It was a hollow tube with the core and the floor slabs providing the necessary rigidity to the exterior wall system.

Leave it to a pancake theorist to make the whole structure revolve around the trusses.

The key question is this: how fast will the buckles propagate.

Apparently you cannot show enough buckling to justify collapse in any photographs or video, and thus cannot logically justify your own theory. I say this because in each post, you fail to do this.

So your next retreat is that the necessary amount of failure all happened so rapidly that we just weren't able to observe it, before the global collapse was already underway!

Aside from using classic conspiracy theory logic, ie "it's true because you can't prove it", you also ignore the fact that columns had already buckled much earlier -- and this buckling did not propogate at all!


So in the same building, buckling columns apparently both do no propogate at all, and also propogate so rapidly that they cannot be seen in photos or on video, on the very same floors. This strikes me as ridiculously illogical.

Challenge failed, HowardRoark.

[edit on 31-7-2006 by bsbray11]

Howard, I have to go with BSBray on this one, unbiasedly, I haven't even seen any photos of any sort of noticeable buckling around the World Trade Centers 1 and 2 before they initiated collapse, not on any one side of the building.

Originally posted by Masisoar
Howard, I have to go with BSBray on this one, unbiasedly, I haven't even seen any photos of any sort of noticeable buckling around the World Trade Centers 1 and 2 before they initiated collapse, not on any one side of the building.

WTC 2




WTC 1

In this picture, the numbers indicate the extent of the inward buckling in inches. 55 inches is four and a half feet.

Basically, anything over a foot would have been greater than the width of the column, and would have meant that the column was not supporting its loads anymore.

Originally posted by ANOK
Point is the towers should hot have fallen all the way to the foundation to start with.

The damage was in the top portions of the buildings, floors approx 90 and up.

What caused the top to force the bottom to collapse in that way? 15 floors does not have more mass than 90 floors.

Theres was no resistance from undamaged floors as the building fell.
For this too happen there would have to be another force acting on it other than gravity.

How about a building designed to take a static load being overwelmed by a dynamic one? Figure the top 3rd of the building started to fall and its energy collapsed the floor below it and so on and so on. Each floor added its energy to collapsing the floor below it. The foundation caught the worst of it.

Howard, the point is that all of those columns could have been supporting 0 load and that still does not explain why the collapses began.

Now you're just ignoring the whole discussion we just had, to go right back to your flawed theories.

Originally posted by Slap Nuts
No... the core provided it's own stability. If the bracing were to fail, you would be adding no load to the core, you would be reducing the stresses on it.

Wrong.

The core had no lateral stability.

In a typical high-rise building, the core columns are braced like so:



The diagonals provide lateral stability to the structure. The WTC towers were different. The lateral stability was provided by the Vierendeel trusses formed by the exterior walls.

With a few exceptions*, the core area of the WTC towers looked like this:



Thus, without the lateral stability imparted to the core through the floor trusses from the exterior walls, the core columns would have been susceptible to failure like so:




*The exceptions being the two sets of mechanical floors, the hat truss, and the sub-plaza levels.

Originally posted by bsbray11
Howard, the point is that all of those columns could have been supporting 0 load and that still does not explain why the collapses began.

Now you're just ignoring the whole discussion we just had, to go right back to your flawed theories.

I totally lost you there. What do you mean that the columns could have been supporting 0 load?


They weren't supporting 0 load, they were supporting the building above them.

JimC, so the building fell progressively faster yet was losing mass at the same time.

Losing structural mass.. yet still manages to take down the rest of the 70+ something floors below it that were structurally sound. I know a large mass like that can cause significant damage, I'm not going to argue you there, but the whole building. No.

Originally posted by JIMC5499
Each floor added its energy to collapsing the floor below it.

Do you understand the fact that pulverizing concrete into a very fine powder takes a lot of energy? Or dissociating steel members?

Energy was not just added from floor to floor. That is about the farthest from what actually happened. Aside from massive amounts of energy being exerted by the falling floors for each additional floor destroyed, most of the mass was also falling over the sides of the buildings. Also, each floor was progressively taking more and more energy to destroy because of thicker columns towards the base, and floors that have already been destroyed do not destroy additional floors very efficiently. Imagine a destroyed floor falling. They were falling everywhere, in all directions -- in pieces.

Not just straight down, gaining momentum and mass and speed the whole time.