Failure mode in WTC towers
- Thread starter GregoryUrich
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No it does not prove CD in any way. It is entirely consistent with fact that the collapse initiation started with the failure of the south exterior wall on floor 98. This caused the upper block to tilt south while the collapse initiation moved from column to column on its way to the north side on floor 98. In the video and in the presentation, you can see see the smoke ejections on floor 98 appearing first on the south end of the west exterior wall and then moving north. On the north exterior wall you can see them appearing first on the east end and then moving to the northwest corner, where the smoke ejections on floor 98 meet up. The fact that smoke ejections move in from the east on the north side first is an indication that the east wall gives way a bit faster the west wall. In the videos you can see the antenna starting to rotate southeast a bit in to the collapse and not only south as it does at the start of the collapse initiation.
bofors
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Why would an aircraft impact on the north side result in a collapse starting on the south side?
That is what we have said all the way. And if you take a look at NIST NCSTAR 1-6 you will find that NIST says the same thing. Of course we can not be 100% sure exactly on which floor the inward bowing south wall collapsed since that part was obscured in smoke and flames, but the collapse initiation spread around the tower on floor 98.
As you can see in the picture there is very hot fire burning on that floor.
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Corsair 115
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Would you call the fires seen in that photo large or small? Heiwa is of the opinion that the fires seen are small.
That's because the intensive fires on the south side heated up and weakened the structure on the south side more than what aircraft damage and fire together managed on the north side.
There are two factors that in my view considerably contributed to the very intensive fires on the south side.
The first is the fact that the aircraft struck the tower from the north. As the aircraft moved into the tower it would shovel combustible office material to the south side of the tower. In other words we should expect a lot of combustible material, both aircraft debris and office material to have been piled up against the exterior wall on the south side of the tower on the impact floors.
In addition the aircraft opened a large ventilation hole on the north side, broke down interior partition walls, broke windows and ripped out a exterior wall panel on the south side.
The first factor would allow long burning fires on the south side. The second factor allowed the northwesterly wind on that day to enter the tower on the north side and blow a large portion of the hot fire gases on a given floor out through the windows on the south side, thereby reinforcing the effect of any fire on the south side, while it supplied the fires on the south side with air.
As you can see in this photo the intensive fires are burning on several floors on the south side, pumping heat into the structure.
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As we have established, the piece in the photo below is shaped like a corner section
It seems to come from the 94th-92nd floors, northwest corner.
In the photo below we can see a large interconnected piece of the perimeter falling from the left (east) side of the building.
This piece fell off from the corner of the building, 97th to the 92nd floors.
According to the idea of gravitational collapse and buckled perimeter columns along the collapse initiation zone (floor 97), this falling piece should have buckled columns at least along it's top edge.
This piece doesn't seem folded up "like an accordian". It looks as if it just fell from the corner of the building without being crushed.
It seems to come from the 94th-92nd floors, northwest corner.
In the photo below we can see a large interconnected piece of the perimeter falling from the left (east) side of the building.
This piece fell off from the corner of the building, 97th to the 92nd floors.
According to the idea of gravitational collapse and buckled perimeter columns along the collapse initiation zone (floor 97), this falling piece should have buckled columns at least along it's top edge.
This piece doesn't seem folded up "like an accordian". It looks as if it just fell from the corner of the building without being crushed.
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Not necessarily, as should be evident from the parts of the core that remained standing for a very short time after the remainder of the towers had collapsed. The core columns need the bracing given to them by the floor beams and trusses to remain standing. As the mass of the upper block ripped off the floor connections on its way down the core columns became unstable and started to fail. And of course lots and lots of core columns were surely broken off directly by the falling debris due to off axial impacts or even mainly lateral impacts. Think of what happened when the floors of upper block of WTC 2 was speared by the core columns in the lower block and vice versa.
And of course we would expect the core columns to mainly break off in their weld connections, with the exception of the columns from the impact zone that had more complex damage due aircraft impact and heat weakening.
Regarding a core columns ability to remain standing unsupported, you can start building a column with the use of a magnetic erector set and see how high you can build, before it becomes unstable and collapse. This just to show the principle.
Major Tom, I have to remained you that you are making damage assessments based upon some heavily compressed low resolution photographs. It is not possible to see the kind of damage details that you can see in this photo:
From NIST NCSTAR 1-3C
You should take a close look at these two videos of the the collapse and study the exterior wall sections that is visible just after the upper block has disappeared into the lower block. One is a part of the north wall from below the east part of the impact hole pivoting out of the the smoke/dust. And the other is a part of the west wall standing for a moment before it collapses, the top of it is likely the floor 98 edge. Note that the sections on both sides of these two sections are already gone.
http://www.youtube.com/watch?v=nDGCFDoMmuA
http://www.youtube.com/watch?v=dfSAiDq15ys
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I am not sure what point you want make with this Major Tom, I have to point out that you at the moment are kicking in open doors with your posts about exterior panels peeling and breaking off etc. If it helps your understanding of how the towers collapsed please go ahead.
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Newtons Bit
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How many times has it been explained to you already?
We should not expect the columns to rotate significantly at plastic hinges. The splices will fail first.
Quit your jaqing off. It's getting old and you come across as a spoiled little troll.
Ignorance
I am a critical thinker who respects genuine experts, especially when they have the ability to communicate some their knowledge to people who lack technical backgrounds. I am a harsh critic of ineducable, willfully ignorant charlatans who deliberately distort quotes and peddle bogus science in the service of an evil cause.
Get off your lazy butt, stop pontificating about subjects you are incompetent to discuss, and learn something.
Don't you wish you had a point to make?
I have followed your antics with some amusement and much disgust. But you really are quite mad. Your thermite fantasy has been destroyed. Give it a rest.
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Along with the large corner perimeter piece seen falling as a 5 floor section from the northeast corner, in the photos below we can see a large perimeter section (at least 20 columns wide) falling from the west face and another large section falling from the north face.
Here you can see the corner section and another large section falling from the west face. There is another large section emerging from the dust on the north face barely visible.
It emerges in the photo below.
Here we see large sections from the north and west faces falling.
I postulate as follows: These large perimeter sections seen falling before all others are from the 92nd to 98th collapse initiation zones. They fall off the building as large perimeter pieces (spanning up to 5 or 6 floors) and do not appear noticably crushed, deformed or buckled.
We will get much higher quality photos and zoom in on these falling pieces.
Here you can see the corner section and another large section falling from the west face. There is another large section emerging from the dust on the north face barely visible.
It emerges in the photo below.
Here we see large sections from the north and west faces falling.
I postulate as follows: These large perimeter sections seen falling before all others are from the 92nd to 98th collapse initiation zones. They fall off the building as large perimeter pieces (spanning up to 5 or 6 floors) and do not appear noticably crushed, deformed or buckled.
We will get much higher quality photos and zoom in on these falling pieces.
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Gravy
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Do you ever plan on learning? Ever?
