twinstead
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Are you implying that the videos of the obvious buckling of the exterior columns in the last few minutes before the collapse are faked?
I need all debunkers I can get!
- Thread starter Lennart Hyland
- Start date
Are you implying that the videos of the obvious buckling of the exterior columns in the last few minutes before the collapse are faked?
I think he's also implying that compression is the only force acting on the columns.
twinstead
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Oh. It seemed to me that the obvious bowing occurred before the collapse started and any compression was available to act on them, but I'm no expert; I'm sure I barely know what compression means in this context
To me those images go a long way to explaining to this non expert what happened. We had a bird's-eye front row seat to the exact instant the building failed, and exactly at the location where it failed. Just inward bowing and the release of a massive portion of the building suddenly upon the part below the failure.
GStan
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Oh. It seemed to me that the obvious bowing occurred before the collapse started and any compression was available to act on them, but I'm no expert; I'm sure I barely know what compression means in this context
To me those images go a long way to explaining to this non expert what happened. We had a bird's-eye front row seat to the exact instant the building failed, and exactly at the location where it failed. Just inward bowing and the release of a massive portion of the building suddenly upon the part below the failure.
Compression (i.e. gravity) is the vertical force of the building's weight pushing downward on the columns. The columns are also subjected to the lateral force of the heated, sagging floor trusses pulling the columns inward. As many have mentioned, this inward bowing is clearly visible in many photos and videos that captured the last few minutes before the collapse. It is patently absurd to believe that all of the images showing it are fake.
twinstead
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Thanks. That made sense even to me.
So it all comes back to instead of him adjusting his theory in light of the visual evidence, he just claims the visual evidence is faked.
That's the first time I've ever seen a conspiracy theorist do that...
You seem quite ignorant of the very visible fact of exterior columns buckling, which you claim to be photoshopped if present. Why is that?
These generally provide a good read;
http://www.debunking911.com/sag.htm
http://www.debunking911.com/collapse.htm
Collapse Initiation
•The inward bowing of the East wall induced column instability, which progressed rapidly horizontally across the entire East face.
•The East wall unloaded and tried to redistribute the loads via the hat truss to the weakened core and via the spandrels to the adjacent North and South walls.
•The entire section of the building above the impact zone began tilting as a rigid block (all four faces; not only the bowed and buckled East face) to the East (about 7ºto 8º) and South (about 3ºto 4º) as column instability progressed rapidly from the East wall along the adjacent North and South walls. The building section above impact continued to rotate to the East as it began to fall downward, and rotated to at least 20 to 25 degrees.
•The change in potential energy due to downward movement of building mass above the buckled columns exceeded the strain energy that could be absorbed by the structure. Global collapse then ensued.
South Face of WTC1
(here you can see WTC1 suffering from fires as low as the 92nd floor up to the 112th floor, 113th-114th too if you look at the upper left corner.
http://wtc.nist.gov/pubs/Media_Public_Briefing_040505_final.pdf
NISTNCSTAR1CollapseofTowers.pdf
*NISTNCSTAR1-1.pdf More detail here: http://wtc.nist.gov/oct05NCSTAR1-1index.htm
*NISTNCSTAR1-2.pdf More detail here: http://wtc.nist.gov/oct05NCSTAR1-2index.htm
*NISTNCSTAR1-3.pdf More detail here: http://wtc.nist.gov/oct05NCSTAR1-3index.htm
*NISTNCSTAR1-4.pdf More detail here: http://wtc.nist.gov/oct05NCSTAR1-4index.htm
*NISTNCSTAR1-5.pdf More detail here: http://wtc.nist.gov/oct05NCSTAR1-5index.htm
*NISTNCSTAR1-6.pdf More detail here: http://wtc.nist.gov/oct05NCSTAR1-6index.htm
*NISTNCSTAR1-7.pdf More detail here: http://wtc.nist.gov/oct05NCSTAR1-7index.htm
*NISTNCSTAR1-8.pdf More detail here: http://wtc.nist.gov/oct05NCSTAR1-8index.htm
http://wtc.nist.gov/reports_october05.htm
Why do you suggest I am ignorant? No, I see no exterior columns buckling or instability. No, the East wall cannot bow inward ... it is too strong and not instable at all. The stresses in the East wall are very low.
The hat truss has nothing to do with this ... it is 15 floors above. Why would the East wall 'try' to use the roof for assistance ... to the core? The stresses in the East wall are still too low.
How can you suggest that the entire WTC1 building above the impact zone can tilt as a rigid block? It is not rigid at all. It is mostly air, there is a lot of SAND mixed with cement to form concrete in the floors (70% of the total remaining mass up there - most SAND/4-5% of the volume) and very little steel to support all this sand (1% of the volume). It is not rigid! The floors (mostly sand fixed by cement on a thin steel plate) is just bolted to the outer walls and inner columns.
The top part of WTC1 is of course the lightest part of the whole building.
So it is also the weakest part of WTC1 - the top. OK, 33 000 tons total but volume wise (a big volume) not heavier than a solid bale of cotton. And apart from air ... most sand in the floors .... and then some little steel in walls and columns.
I cannot see this bale of cotton/sand/steel rotate 20-25 degrees. And why would it do that? It is fixed to the structure below. Did the whole tower below rotate or was the top suddenly 100% free to rotate = not connected to the structure below. How could that happen?
And then this: The change in potential energy due to downward movement of building mass above the buckled columns exceeded the strain energy that could be absorbed by the structure. Global collapse then ensued.
What is global collapse? That a bale of cotton rotates? And falls down? Of course the strain energy of the strong structure below could absorb that little mass. The structure below was much stronger than the little weight up top.
So sorry. I do not follow. Read my simple observations at http://heiwaco.tripod.com/nist.htm again and look at the picture at the end of the article.
Simply speaking. Before any 'global collapse ensued' up top something else happened up above the initiation zone. The whole top part disintegrates. Sand in the floors is blown upwards, steel parts in the walls are thrown sideways - it is like a fountain of sand blowing UP. Like fire works? Look at the first 1/2 second of the 'collapse'. And, you need extra energy for that. Not little potential energy falling down in 1/2 second.
It is quite clear from the photo of the 'global collapse' taken one second after it started. Most of the mass above is blown 100 meters sideways in all directions and cannot put any strain on the structure below = no global collapse
The structure below? It is apparently disinitegrated by the same effects that happened above at the initiation zone. Whatever that could be?
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JimBenArm
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Must resist straight line...
Pulling me in...
Too strong... can't talk in complete sentences...
I can't let it pass!
Because you are! You prove it with every bit of nonsense you post here!
Ah, sweet release...
twinstead
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So you think the many videos of that exact thing happening are faked? You mean to tell me that you don't see any buckling or instability at all in this clip?
http://video.google.com/videoplay?docid=2873871255585611926#1m10s
I'm no expert. Perhaps you can explain in small words what it is I am seeing in the above video, because to me it looks like some major bowing.
But dear Heiwa, you need not tell me you didn't see exterior columns buckling, you need to tell me that you did since that is what I showed you in my post and links.
It is not negatable, you need to move on and give your alternative version of why they did buckle and what it ment for the buildings stability.
You're thinking volume-wise, not weight-wise.
Erhm, everything from the 95th floor and above is in this case the tilting part, is this part the lightest part? Only if you compare this formention section with the rest of the building.
It sure wasn't lighter than say the 94th or 93rd floor.
First you invision the aformentioned section to not be heavier than a solid bale of cotton of the same volume (remember this does not denote weight), then you proceed to argue about a "bale of cotton" and how this supposedly means the top must have been completely dismembered from the rest of the building??
You're not arguing on what I've written you nor on the links provided, that's for sure.
Here's the final report on the Twin Towers Collapse, by NIST.
http://wtc.nist.gov/NISTNCSTAR1CollapseofTowers.pdf
(The Account for WTC1 is on page 69, figures-pictures are listed before that, referenced in the given chapter).
Final Reports of the Federal Building and Fire Investigation of the World Trade Center Disaster.
In 0.7 seconds, 35 exterior columns were severed, whereas 2 were heavily damaged. 6 core columns were immedietaly severed, whereas 3 were heavily damaged.
43 of 47 core columns stripped of insulation on one or more floors.
Insulation stripped from trusses covering 60,000 ft2 of floor area.
While you're going through the NIST-reports, if you have the time I'd recommend you read the following paper at the same time;
Mechanics of Progressive Collapse: Learning from World Trade Center and Building Demolitions.
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Newtons Bit
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Stop arguing from incredulity and using extremely poor and misleading analogies. I already did the math, the potential energy above can easily exceed the strain energy of the columns. The building will collapse and will not stop once started. Move on.
No, better to move back ... and check your calculations. As shown in my article being discussed (at the request of Lennart Hyland), it is shown that the compressive stresses in the relevant columns are very low ... even if some perimeter wall columns are missing and some core columns are assumed to be damaged (the tower still stands) and that heat cannot affect the still intact columns.
The stresses in the intact columns are still <40% of yield (assuming 500°C) and their slenderness ratio is/remains very small. This mean NO COLLAPSE can occur. The strain energy (strength) of the allegedly heated columns is still much bigger than any energy (or force) acting from above.
So no potential energy can be released.
But let's assume it does. Why would this energy then act on the structure below? The mass above - and its energy - is disconnected from the structure below! And regardless - the structure below is very strong and will just deflect any energy coming from above.
Any energy being released from above will of course take the path of least resistance below = through the air, and fall to the ground. This is what happens in every structure being overloaded and explains why no steel framed scyscraper suddenly collapses in 1000 000's of pieces.
Read again http://heiwaco.tripod.com/nist.htm . If you find any errors pls inform me.
Gravy
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Absolutely astonishing.
Why did this progressive collapse proceed to the ground? Why did the mass above not know to transport itself laterally, using no energy, so that it could take the "path of least resistance" through the air? What a stupid mass!
Jeebus, I have to get away from this insanity.
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Corsair 115
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Indeed. It would seem Heiwa is inventing entirely new laws of physics. Either that, or he is really bad at expressing his ideas clearly.
Newtons Bit
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I've asked you this already, what moments develop in a moment frame when one column in the frame is severed? What moments develop when a large row of columns are severed?
Compressive stress is not the only stress in the columns. There is bending stress (in two different directions) as well as shear. These are all additive. From basic mechanics :
Pu/Pn + 8/9(Mux/Mnx + Muy/Mny) + Vu/Vn < 1
Or the column fails. Which it did. Now then, what other stresses are developed in the column? What forces do the severed core columns put on the exterior columns? You've shown a grossly inaccurate way of calculating compressive stress vs strength (Pu/Pn), now calculate Mux/Mnx, Muy/Mny, and Vu/Vn.
I've already calculated the kinetic energy of the collapse as 2105MJ, the strain energy to buckle, develop plastic hinges and ultimately sever the columns on an entire floor near the collapse floor as 171MJ. The collapse continues.
The upper block doesn't bounce off or go sliding off because it penetrates through the floor slabs of the lower block. The columns in the upper block are like a hundred knives slicing through the slab of the lower block.
Stop making up fake engineering and do something real. Compressive forces are not the only forces acting on the columns. Forces do not follow the path of least resistance. Electrical currents follow the path of least resistance. Forces are not electrical currents. Bodies in motion will continue in the direction they were moving in until acted upon by a force. The upper block will not fall directly on top of the columns of the lower block. The upper block falls on the floor slabs of the lower block. The slabs of the lower block cannot apply a force on the moving upper body that is large enough to deflect it.
It cannot be any more simple.
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A W Smith
Philosopher
In auto accidents. Why don't cars morph around the utility poles they are hitting? I mean the energy path of least resistance is around the pole correct? so why doesn't the car just side-step the pole? AND you don't have that pesky gravity complication to contend with.
Heiwa my argument above makes just as much sense as yours. You have FAILED as an engineer.
Heiwa my argument above makes just as much sense as yours. You have FAILED as an engineer.
Attachments
I calculate the potential energy of the mass above (33 000 tons) after falling one floor (3.7 meters) at gravity (10 m/s²) as 339.17 kWh and that is not a lot. However, it assumes that all wall and core columns buckle/split simultaneously and that is not seen on any forensic records. The wall columns are not really heated at all (and do not buckle) and the core columns are according NIST not heated more than 500°C and can at that temperature not buckle due to mass above! They may compress and bulge, that's all. And it takes time. No potential energy will be released then!
No load of mass above can be transmitted from core to walls; the floor bolted connections the columns are too weak.
I doubt you have read my article.
Why should we read the work of an incompetent? You have no idea how often your errors have been corrected on this forum.
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