Some Misunderstandings Related to WTC Collapse Analysis

[Tony Szamboti]

[

QUOTE=Jeffrey Orling;73836]Can't have a one story column disappearance... it would be 3 and the core above would drop causing more than 6 floors to break free and drop and no I don't think it would arrest.

A three story collapse at one time would have been impossible. The columns are supported by beams at every floor.

And no I don't think the tower would stand with one floor of columns instantly vaporized. And yes a floor can support one or two as additional floors slabs as static load...dynamic... not so sure.

Well you need to explain how the column energy absorption can be by-passed. So far all I have seen you and like minded individuals who don't accept demolition as the cause for collapse do is a hand wave that they missed each other. You have no load or mechanism to cause that condition.

Each floor was capable of supporting a significant number of additional floors (much more than one or two. NIST even acknowledged this in one of their FAQs. There would be no chance of developing a dynamic load to equal that static load when just one floor falls onto the one below. ROOSD cannot work right away in the early stages of the collapse. It needs a significant number of floor to have been broken loose.

[Albert Doyle]

The perimeter would be pulled inward and fail causing the upper section to descend and impact the next story down and arrest. A one or two story fall does not produce enough kinetic energy to continue the collapse as it is significantly less than the column energy absorption.

Jeffrey thinks his ROOSD can begin right away but it can't as the floors could take 29 million lbs. of force, which is a static load of about five additional full floors with their live load. The dynamic load of one floor assembly would be nowhere near 5g's so ROOSD needs to wait until a sufficient number of floors have broken loose and gained momentum.

But this is a deficient model. In your model the flange effect caused by the perimeter frame being pulled in would then cause the falling section to wedge the lower section's perimeter frame outward. As it did this it would pull the fasteners for the floor pads to the inner core outward causing, once again, a misalignment of the core columns causing instant load failure. As I've repeated in several posts your model is fatally flawed because it fails to involve the necessary lateral forces that would necessarily be involved by physical design.

But that isn't what happened in my opinion. As I said, the pneumatic blast pressure from the falling concrete floor pads exited both outward and inward driving the floor pads off their mounts and downward in an accelerated dynamic that undercut the static resistance of the core columns as it progressed in a wave just ahead of that static resistance form.

Uh, I thought 12 floors fell above the collapse zone in the North Tower?

[Tony Szamboti]

Not if you correlate it to the actual conditions in the tower. The damage area in the tower was from floor 93 to floor 99. This would easily cover all the splices in the drop area. Plus the actual dynamic involves the antenna dropping, so the entire 12 floors were having a catastrophic failure that would involve all relevant members from the roof line to the 93rd floor. You have to understand the totality of the event as it corresponds to everything involved. The floor pads flanged the perimeter skirt just enough to drive the top section like a wedge down the shaft of the outer frame.

This is so completely incorrect it is hard to know where to start. The main thing I would say is that it does not work the way you say because only one exterior wall was damaged in the North Tower and your theory needs them all to be equally damaged. Your logic is also circular. We are trying to discern why the upper section fell apart and you are simply assuming it did with no reason given for it.

That's exactly what they were. If they were explosives charges where was the residue? Explosives are made of identifiable chemicals. For the third time, where were the detonation flashes seen in all other controlled demolitions? The tower had glass windows on all sides. You have an Ashley Banfield sound analysis for the blasts in Building 7. Where is that analysis for these very prominent timed demo charges? You can't tell me demo blasts seen so prominently on the collapse video made no such recordable sound? Time you gave an answer for that. As I've explained in detail, the compressed air pressure blasts would occur with each floor pad as it collapsed on the one beneath it. Funny how that's exactly what you see in your video. The pressure would escape out the point of least resistance - which is exactly what you see with those jets escaping out the windows.

In the meantime a second escape point would be inward and into the inner core column. Your thinking is somewhat 2 dimensional. Unfortunately this is a three dimensional problem best shown by animated illustration of the key dynamics involved as they occurred. As each pad crashed it created the pressure blast jets you see. The relevant dynamic is that of each blast as it occurs in a split second and drives the outer frame outward and inner core inward. You don't seem to fathom that the tower design was an inadvertent self destruct design as the pneumatic blast from each pad destroyed the column supports as its force was aimed horizontally. At the point of those jets the force driving the pads was the mass of all the debris above it shooting down the shaft. You fail to understand that the dust jets you cite on video are those very blasts appearing right in the right place at the right time as this phenomenon occurred. If your theory of CD initiating the collapse were true those dust jets are far too late into the process and are not seen earlier on the upper floors.

There is no way for a collapsing floor to produce a focused jet coming out of just one area and your theory does not explain the focused jets on the corner of the building. The gain on microphones are not intended for long range. The Ashley Banfield audio was low but when combined with her actions became obvious as to what her reaction concerned. David Chandler explains this in his video about it.

[Tony Szamboti]

The perimeter would be pulled inward and fail causing the upper section to descend and impact the next story down and arrest. A one or two story fall does not produce enough kinetic energy to continue the collapse as it is significantly less than the column energy absorption.

Jeffrey thinks his ROOSD can begin right away but it can't as the floors could take 29 million lbs. of force, which is a static load of about five additional full floors with their live load. The dynamic load of one floor assembly would be nowhere near 5g's so ROOSD needs to wait until a sufficient number of floors have broken loose and gained momentum.

But this is a deficient model. In your model the flange effect caused by the perimeter frame being pulled in would then cause the falling section to wedge the lower section's perimeter frame outward. As it did this it would pull the fasteners for the floor pads to the inner core outward causing, once again, a misalignment of the core columns causing instant load failure. As I've repeated in several posts your model is fatally flawed because it fails to involve the necessary lateral forces that would necessarily be involved by physical design.

But that isn't what happened in my opinion. As I said, the pneumatic blast pressure from the falling concrete floor pads exited both outward and inward driving the floor pads off their mounts and downward in an accelerated dynamic that undercut the static resistance of the core columns as it progressed in a wave just ahead of that static resistance form.

Uh, I thought 12 floors fell above the collapse zone in the North Tower?

12 floors did not immediately fall onto one floor. Jeffrey is talking about floors assemblies falling onto each other when he usues the term ROOSD (runaway outside office space destruction).

[Albert Doyle]

This is incorrect and you are just doing a giant incoherent hand wave here.

You can't get away that easily. If the antenna dropped first then the core beneath it gave way. That means the core throughout that 12 storey section failed. The source of that failure had to be at the damage area 12 floors below. That means the core failed in the damage area and the weight of the antenna caused it to fail. This 12 storey section then piled into the remaining tower below.

There is no way for a collapsing floor to produce a focused jet coming out of just one area and your theory does not explain the focused jets on the corner of the building. The gain on microphones are not intended for long range. The Ashley Banfield audio was low but when combined with her actions became obvious as to what her reaction concerned. david Chandler explains this in his video about it.

That's just you saying that. However the floor itself is comprised of a reinforced concrete pad and steel pouring platform. When it fell it was backed by a huge solid pile of debris from the falling section above it. You have a very limited understanding of this process to the point - I'm sorry to say - of incompetence. I'm sorry but your answers above are very weak and show less than genuine reasoning since the Building 7 collapse was at considerable distance from Ms Banfield. If you recall there were media people with identical microphones very close to the North Tower when it fell. Speaking of incoherent. In short you can't explain why there was no such captured recording of your very prominent CD explosions. Nor did you bother to answer the explosive residue point. Very weak Mr Szamboti. Get back to me when you can explain the lack of detonation flashes in the falling tower.

When the floor pad hit the one below it there was a very focused area of pneumatic escape. I don't know why you are having trouble realizing that as a trained engineer.


I must have missed your answer. Where were the dust jets for the original controlled demolition charges that caused the collapse at the upper floors?

[Lauren Johnson]

A three story collapse at one time would have been impossible. The columns are supported by beams at every floor.

Jeffrey, Tony, Thanks for your responses.

Tony, unless I am missing something, the three story collapse came from my thought experiment. Jeffrey pointed out that the columns were actually three stories tall. And to make matters clearer, I was supposing in my thought experiment that the entire support structure, columns, and all the cross bracing instantly vanished. The entire core structure is severed instantly and completely.

Tony, you said the initiation of a ROOSD would require five floors of core columns and their support structure to vanish to provide the sufficient force. I believe Jeffrey, said it would require only one floor.

That is helpful.

[Albert Doyle]

Uh, I thought 12 floors fell above the collapse zone in the North Tower?

12 floors did not immediately fall onto one floor. Jeffrey is talking about floors assemblies falling onto each other when he usues the term ROOSD (runaway outside office space destruction).

Funny that's what I see in the video.


Once again, you have an annoying tendency to not answer the point. You said it would take 5 storeys of falling mass to break the static resistance of the structure below. I pointed-out that the video clearly shows the 12 storeys of the top section falling into the building below. Sorry, but when I view the video I see a 12 storey section immediately falling into the top floor of the building below:



http://www.youtube.com/watch?v=6fg1jmr3n6w

[Lauren Johnson]

Once again, you have an annoying tendency to not answer the point. You said it would take 5 storeys of falling mass to break the static resistance of the structure below. I pointed-out that the video clearly shows the 12 storeys of the top section falling into the building below. Sorry, but when I view the video I see a 12 storey section immediately falling into the top floor of the building below:

Albert, calm yourself. Tony gave the number 5 based on my thought experiment of n number of floors of core support instantly vanishing. By the way, what are your credentials in this area again?

[Albert Doyle]

[

Tony, you said the initiation of a ROOSD would require five floors of core columns and their support structure to vanish to provide the sufficient force. I believe Jeffrey, said it would require only one floor.

That is helpful.

If I read it correctly Tony said it would take the mass of a 5 storey section to break the static resistance of the intact building below it. What static resistance means is simply the structural strength of the building below in its total state or stasis. When I pointed-out to him that a 12 storey section clearly fell on the rest of the building in the North Tower he failed to give a straight answer.

[Jeffrey Orling]

[quote=Lauren Johnson][QUOTE]

Tony, you said the initiation of a ROOSD would require five floors of core columns and their support structure to vanish to provide the sufficient force. I believe Jeffrey, said it would require only one floor.

[/QUOTE]

I said that a twin tower floor could support perhaps an additional one or two floors applied as a static load. I think as a dynmic load the applied forced could be 10x or more than a static load and so this may be able to fracture the floor this came down on and kick off the ROOSD process or prgressive unstopppable floor collapse.

Albert's point is that the move of the antenna strongly suggests that the entire core area may have come undone and the ALL the floors bove 98 were free and falling... inside the facade and the 12 story facade was pulled downward by those 12 floors as rhey came free from the core and were plunging down. Unfortunately we can see inside past the facade and have to use the movements telegraphed through it and to it. There defintely was subtle movement of the top which suggests the frame was under extreme stress and experiencing individual and aggregate column strength loss before the visible release and downward motion of the facade and the flash over and expulsion of material.