WTC 1 & 2. What happened after collapse initiation?

[Heiwa]

Could you re-run your analysis and include a lateral load of 4 kips per column and include P-Delta? (That'd be P little delta btw, we'll neglect big delta).

Let's first agree the basics, i.e. the columns first slice the floors apart locally where columns/floors are in contact and that the floors hinges down in all directions on top of each other and rub against one another = friction.

Evidently some of this friction will be transmitted to the lower structure columns laterally via the remaining intact bolted connections but I assume the spandrels and horizontal beams will take care of that.

Actually the friction between damaged, slooping floors rubbing against each other producing a lateral force on the columns is quite similar to the wind acting on the intact structure in storm.

But let's face it! Most friction energy is consumed at the rubbing contact point floor/floor. Any remaining lateral force applied to the column will just produce a reaction force in the spandrels and the columns are not really affected.

 

[Grizzly Bear]

And the locally damaged floors hinge down on and rub against one another and FRICTION stops further destruction. The global collapse should have been arrested very quickly according my observations that NIST ignores and censures 100%. Friction? Not mentioned in the NIST report. Reason is that NIST does not know anything about damage structure analysis. NIST only knows a little about how to design and build structures. Not how to destroy them.

With all do respect I am having trouble understanding your logic here. Before I respond further I'd like to confirm with you if this model represents your conclusion. I'll decide the appropriate response once I know for sure

http://heiwaco.tripod.com/WTC1slicea.GIF

 

[Heiwa]

Heiwa, I am going to spell this out in giant bold letters.

Large sections of the core; 40 stories of WTC 2 (south tower), and 60 stories of WTC 1 (north tower) initially survived the collapse. Your local controlled demolition theory is debunked by that alone

But by all means... if you have an explanation for the cores still standing despite the interior blasts you claim are proven by the so called 'squibs' fire away...

Evidently the criminals did not LCD the lowest part of the core to complete the destructions. It would have been to obvious. Your observation in fact supports my hypothesis of LCD. Thanks. But OT of course. T is what happened just after initiation 70-90 floors higher up.

 

[Grizzly Bear]

Evidently the criminals did not LCD the lowest part of the core to complete the destructions. It would have been to obvious. Your observation in fact supports my hypothesis of LCD. Thanks. But OT of course. T is what happened just after initiation 70-90 floors higher up.

huh.... babysteps... baaaabysteps.... *Must stay patient since I'm talking to a brick wall and everything needs to be spelled out*

Evidently the criminals did not LCD the lowest part of the core to complete the destructions.

Kind sir, you have implicated that they 'LCD'd' floors below the impact region, at intervals of four to six floors. Would you mind clarifying why more than half of the core height standing between the impact regions and ground level is still standing after the floors and perimeter columns had collapsed below it? Could you please kindly explain how 60 stories, and 40 stories, respectively represent the very bottom of the tower?

Or are you inept at reading and find joy in misconstruing my words?

It would have been to obvious.

As if it wouldn't have been obvious detonating them anywhere else

Your observation in fact supports my hypothesis of LCD. Thanks.

No, that sounded like some weird fantasy coming from you seriously misreading my response. Do I need to talk you through this and bold in red every point I am making?

But OT of course. T is what happened just after initiation 70-90 floors higher up.

Of course, I was asking why 40 to 60 stories of either core was standing despite your highly speculative fantasy LCD's having gone off on several floors well below the impact regions. Since you claim that these explosions went off every 4 to 6 floors, why is the core still standing for 15 to 25 seconds after the collapse, if they were supposed to be compromised to bring the building down in its entirety?

ETA, and just where the hell did I imply anything happening at the base of the core?

 

[Heiwa]

With all do respect I am having trouble understanding your logic here. Before I respond further I'd like to confirm with you if this model represents your conclusion. I'll decide the appropriate response once I know for sure

http://heiwaco.tripod.com/WTC1slicea.GIF

Yes, the figure evidently represents the various stages of events/further local failures after initiation due to gravity and how the destruction would be arrested mainly due to released energy being absorbed when causing these new failures and friction between partly damaged parts rubbing against each other and explanations are given in the articles. There is another figure showing an alternative sequence that also is being arrested.
The message is evidently that the lower structure would always destroy the upper block structure after initiation and all energy released would be absorbed in the process = no global collapse would ensue due to gravity only as proposed by NIST.
The strain energy built into the lower structure hardly comes into action at all! Only the top part of the lower structure is affected after initiation. Etc, etc.

 

[Heiwa]

huh.... babysteps... baaaabysteps.... *Must stay patient since I'm talking to a brick wall and everything needs to be spelled out*



Kind sir, you have implicated that they 'LCD'd' floors below the impact region, at intervals of four to six floors. Would you mind clarifying why more than half of the core height standing between the impact regions and ground level is still standing after the floors and perimeter columns had collapsed below it? Could you please kindly explain how 60 stories, and 40 stories, respectively represent the very bottom of the tower?

Or are you inept at reading and find joy in misconstruing my words?



As if it wouldn't have been obvious detonating them anywhere else



No, that sounded like some weird fantasy coming from you seriously misreading my response. Do I need to talk you through this and bold in red every point I am making?


Of course, I was asking why 40 to 60 stories of either core was standing despite your highly speculative fantasy LCD's having gone off on several floors well below the impact regions. Since you claim that these explosions went off every 4 to 6 floors, why is the core still standing for 15 to 25 seconds after the collapse, if they were supposed to be compromised to bring the building down in its entirety?

ETA, and just where the hell did I imply anything happening at the base of the core?

You are right that I am just speculating about the LCD as according my analysis the destruction due to gravity would have been arrested after say 1 or 2 seconds. Gravity alone could not cause the destruction seen on all videos. Reason is that many interested parties wonder what could have caused the rapid destruction lasting for 10 seconds or more and LCD = external energy brought in to assist is my guess. The details of that is beyond my expertize and should be investigated by qualified experts.

 

[Grizzly Bear]

Yes, the figure evidently represents the various stages of events/further local failures after initiation due to gravity and how the destruction would be arrested mainly due to released energy being absorbed when causing these new failures and friction between partly damaged parts rubbing against each other and explanations are given in the articles.

Allow me to begin with the model I asked about first. Your analysis assumes that the entire top section should have been cut through by the core columns, and it should have slipped down inside of itself, while the perimeter columns rigidly hold firm and the interior floors arrest collapse via friction. There are several problems with assuming this:

• The tilting of the upper section as it begins to fall applies immense shear stresses against the perimeter columns. These shear stresses were far greater than any of the bolts connections were capable of arresting.
  
  I can corroborate this through examining two observations:
  
  - The planes were a mere 100-tons, and plowed through the perimeter columns with ease. The columns which were directly impacted by the place underwent intense shear stresses that exceeded what the connections were capable of resisting.
  
  - The perimeter columns were distorted just by the lateral loading imparted by the sagging floors in the impact regions. This was happening well before the collapse initiated. Newton's Bit did calculations on this Here, though I am certain you've seen it already.
  
  You're treating the perimeter columns as if they are so rigid they could contain a 15 to 30 story section of building without the individual parts yielding catastrophically. What the pre-collapse buckling demonstrates is that the individual exterior columns are not as rigid as your model would suggest. They were deforming under 6 Kips of lateral shear. The upper section was roughly 100,000 - 150,000 tons.
  
  That appears to me to be the biggest weakness in your argument.

 

[pomeroo]

Yes, the figure evidently represents the various stages of events/further local failures after initiation due to gravity and how the destruction would be arrested mainly due to released energy being absorbed when causing these new failures and friction between partly damaged parts rubbing against each other and explanations are given in the articles. There is another figure showing an alternative sequence that also is being arrested.
The message is evidently that the lower structure would always destroy the upper block structure after initiation and all energy released would be absorbed in the process = no global collapse would ensue due to gravity only as proposed by NIST.
The strain energy built into the lower structure hardly comes into action at all! Only the top part of the lower structure is affected after initiation. Etc, etc.

You ran away in disgrace after you committed yourself (hmmm, there's a good idea) to maintaining that dropping the top third of a building onto the bottom two-thirds from a height of two miles does no damage to the bottom part. We all understand that the bottom part gets completely destroyed.

How could make such an egregious error and when will you acknowledge that you were spectacularly wrong?

 

[Heiwa]

Allow me to begin with the model I asked about first. Your analysis assumes that the entire top section should have been cut through by the core columns, and it should have slipped down inside of itself, while the perimeter columns rigidly hold firm and the interior floors arrest collapse via friction. There are several problems with assuming this:

• The tilting of the upper section as it begins to fall applies immense shear stresses against the perimeter columns. These shear stresses were far greater than any of the bolts connections were capable of arresting.
  
  I can corroborate this through examining two observations:
  
  - The planes were a mere 100-tons, and plowed through the perimeter columns with ease. The columns which were directly impacted by the place underwent intense shear stresses that exceeded what the connections were capable of resisting.
  
  - The perimeter columns were distorted just by the lateral loading imparted by the sagging floors in the impact regions. This was happening well before the collapse initiated. Newton's Bit did calculations on this Here, though I am certain you've seen it already.
  
  You're treating the perimeter columns as if they are so rigid they could contain a 15 to 30 story section of building without the individual parts yielding catastrophically. What the pre-collapse buckling demonstrates is that the individual exterior columns are not as rigid as your model would suggest. They were deforming under 6 Kips of lateral shear. The upper section was roughly 100,000 - 150,000 tons.
  
  That appears to me to be the biggest weakness in your argument.

You have misunderstood. NIST & Co assume that the upper block is completely intact during the complete destruction. The upper block lowest floor is never damaged and acts as a piston top compressing air below and crushing down floors and columns below, inspite of the fact that there are big holes in the floors for lifts, cables, piping, stairwells, etc.
It is quite ridiculous and not seen on any videos. The upper block is the first to be destroyed as seen on all videos. It cannot then crush down anything.

I, using clear thinking when checking the NIST & Co scenario, suggest that the stronger structural parts, the columns, damage the weaker structural parts, the floors, when in contact with each other after initiation. As only floors are damaged locally at one edge, they are assumed to hinge down at the other edge and then drop down on the floor below and rub against it there. Friction develops ... and arrest further destruction very soon.
NIST & Co ignores friction as an important factor to arrest gravity driven local failures.

If you look at my figures and read my articles you will see that, e.g. no vertical loads are imposed on the perimeter wall columns as 50% of them are outside the action and the other 50% are damaging floors. No big shear can be imposed on the columns after that; the friction forces on the slooping floors between damaged floors are evidently transmitted to the columns via the intact bolted connections but that connection is so weak compared with the column so it will shear off first. The bolts have 1/1000 the strength of the columns.

Evidently the lower columns at say floor 30 could contain all the masses of the 78 floors above without any problem. Compressive column stresses were <0.3 yield everywhere when structure was intact.

But my scenario does not take place. The upper block disappears when the lower structure is still intact. And then the lower structure is destroyed by LCD as proposed earlier.

The serious error by NIST & Co is that they ignore external FRICTION as the main energy absorption factor after structural failures of composites (concrete/steel) occur. Only the 'internal friction' of a part represented by its strain energy is assumed to absorb energy but it only works when the part is initially deformed or cut apart. Their explanation of the cause of a gravity only driven collapse is therefore not valid.

Back to the drawing table!

 

[Pardalis]

The upper block disappears

It disappears in a cloud of dust, how are you able to determine how the upper block is through that thick cloud?

Besides, "disappear" doesn't mean its mass disappeared as well does it? It disappeared from sight.

 

[Heiwa]

It disappears in a cloud of dust, how are you able to determine how the upper block is through that thick cloud?

Besides, "disappear" doesn't mean its mass disappeared as well does it? It disappeared from sight.

Well, it seems to telescope into itself or shrink 50%, which is possible as it is 95% volume wise air, so you wonder what LCD causes that? An implosion! It happens before initiation of damages lower down. Read my article!

Its mass ... or rather its masses, because the upper block consists of many different parts, i.e. masses, cannot be as originally connected but rather separated, so they can hardly produce any damages below.

Actually the WTC1 upper part (33 000 tons) is only 17% steel (100's of separate columns/floor plates parts). 70% is concrete and the rest glass, gypsym, wood, etc. Very flimsy all together. Like a crystal glass. Not solid.

Only a fool believes that all that loose scrap/dust can destroy an intact steel structure below. I wonder why NIST insists on that. Potential energy (of dust) exceeding strain energy (of steel) = global collapse. ??? Funny sectarian physics.

Luckily, where I live (France), all sects of any kind are forbidden by law. Religious (praying) associations are governed by a 1905 law, etc. and cannot do any other business. If you do not comply, you are a sect. The French society as such does not interfere besides that. The French republican values are quite clear - liberté, égalité, fraternité. You cannot beat those. In US they seem go have gone with the Homeland Security Act paving the way for, e.g. the new US physics and structures theories.

 

[pomeroo]

You have misunderstood. NIST & Co assume that the upper block is completely intact during the complete destruction. The upper block lowest floor is never damaged and acts as a piston top compressing air below and crushing down floors and columns below, inspite of the fact that there are big holes in the floors for lifts, cables, piping, stairwells, etc.
It is quite ridiculous and not seen on any videos. The upper block is the first to be destroyed as seen on all videos. It cannot then crush down anything.

I, using clear thinking when checking the NIST & Co scenario, suggest that the stronger structural parts, the columns, damage the weaker structural parts, the floors, when in contact with each other after initiation. As only floors are damaged locally at one edge, they are assumed to hinge down at the other edge and then drop down on the floor below and rub against it there. Friction develops ... and arrest further destruction very soon.
NIST & Co ignores friction as an important factor to arrest gravity driven local failures.

If you look at my figures and read my articles you will see that, e.g. no vertical loads are imposed on the perimeter wall columns as 50% of them are outside the action and the other 50% are damaging floors. No big shear can be imposed on the columns after that; the friction forces on the slooping floors between damaged floors are evidently transmitted to the columns via the intact bolted connections but that connection is so weak compared with the column so it will shear off first. The bolts have 1/1000 the strength of the columns.

Evidently the lower columns at say floor 30 could contain all the masses of the 78 floors above without any problem. Compressive column stresses were <0.3 yield everywhere when structure was intact.

But my scenario does not take place. The upper block disappears when the lower structure is still intact. And then the lower structure is destroyed by LCD as proposed earlier.

The serious error by NIST & Co is that they ignore external FRICTION as the main energy absorption factor after structural failures of composites (concrete/steel) occur. Only the 'internal friction' of a part represented by its strain energy is assumed to absorb energy but it only works when the part is initially deformed or cut apart. Their explanation of the cause of a gravity only driven collapse is therefore not valid.

Back to the drawing table!

NIST believes that you demonstrate no understanding of basic physics. The agency recommends reading an introductory text.

 

[pomeroo]

Well, it seems to telescope into itself or shrink 50%, which is possible as it is 95% volume wise air, so you wonder what LCD causes that? An implosion! It happens before initiation of damages lower down. Read my article!

Its mass ... or rather its masses, because the upper block consists of many different parts, i.e. masses, cannot be as originally connected but rather separated, so they can hardly produce any damages below.

Actually the WTC1 upper part (33 000 tons) is only 17% steel (100's of separate columns/floor plates parts). 70% is concrete and the rest glass, gypsym, wood, etc. Very flimsy all together. Like a crystal glass. Not solid.

Only a fool believes that all that loose scrap/dust can destroy an intact steel structure below. I wonder why NIST insists on that. Potential energy (of dust) exceeding strain energy (of steel) = global collapse. ??? Funny sectarian physics.

Luckily, where I live (France), all sects of any kind are forbidden by law. Religious (praying) associations are governed by a 1905 law, etc. and cannot do any other business. If you do not comply, you are a sect. The French society as such does not interfere besides that. The French republican values are quite clear - liberté, égalité, fraternité. You cannot beat those. In US they seem go have gone with the Homeland Security Act paving the way for, e.g. the new US physics and structures theories.

Enough deranged babble about sects. You claimed, insanely, that dropping the upper third of a building from a height of two miles onto the bottom two-thirds does no damage to the bottom part. You are fantastically, absurdly, ridiculously, spectacularly WRONG.

No engineer could possibly make such a preposterous claim. When will you acknoweldge your egregious error?

YOU CAN RUN, BUT YOU CAN'T HIDE.

 

[Grizzly Bear]

Well, it seems to telescope into itself or shrink 50%, which is possible as it is 95% volume wise air, so you wonder what LCD causes that? An implosion! It happens before initiation of damages lower down. Read my article!

Heiwa.... you are contradicting truth movement claims again! AE 911 claims that the towers collapsed into their own footprint AND spread debris over 16-acres...

Hell Gage can't seem to decide between whether the towers 'exploded outward' or 'imploded on itself.'

And you just said a few posts back that you were speculating about the LCD's, which I've already pointed out has serious holes in it. Do we really need to go through with that again?

Its mass ... or rather its masses, because the upper block consists of many different parts, i.e. masses, cannot be as originally connected but rather separated, so they can hardly produce any damages below.

Your model contradicts the same principal however by ignoring that the perimeter columns would as well fail from lateral forces imparted by the dynamic loads in the collapse. The south tower collapse initiation and events leading up to to initiation for both towers demonstrated this quite nicely, as exterior columns were bowing inwards under simply the weight of the sagging floors...

Only a fool believes that all that loose scrap/dust can destroy an intact steel structure below. I wonder why NIST insists on that. Potential energy (of dust) exceeding strain energy (of steel) = global collapse. ???

Funny... it's as if you've completely rejected the existence of an ENTIRE section of building bearing down on a single floor all at once at collapse initiation. When you get out that world that assumes the entire upper section completely turned into dust, let me know.

Luckily, where I live (France), all sects of any kind are forbidden by law. Religious (praying) associations are governed by a 1905 law, etc. and cannot do any other business. If you do not comply, you are a sect. The French society as such does not interfere besides that. The French republican values are quite clear - liberté, égalité, fraternité. You cannot beat those. In US they seem go have gone with the Homeland Security Act paving the way for, e.g. the new US physics and structures theories.

Fallacy of ignoratio elenchi (irrelevant conclusion). I don't know what has you obsessed with sects in this thread, however it is irrelevant to the discussion. Stop trying to distract from the argument.

 

[tanabear]

Tilt happens first. There is no expectation of differential resistance once the collapse begins. Very simple.

However, whatever initial angular momentum the upper block gains before collapse, is likely to be sustained. But those are different concepts.

This is yet another question that is so confused that it beggars belief.

There is no way for the west wall only to survive collapse. The upper block blankets the entire footprint and will crush all sides of the lower structure. Even if this was not the case, the west wall cannot survive under its own weight if the rest of the structure is destroyed. There is no anomaly here at all.

So the upper block of the south tower tilts to the southeast then it falls 3.7 meters onto the lower block. If this is the case, then we shouldn't observe the destruction of the lower block and upper block until this 3.7 meter fall. So show me when this 3.7 meter drop occurs in one of the videos of the South Tower's collapse. If we notice the building being pulverized before this 3.7 meter drop occurs(i.e. while it is still tilting), then wouldn't this falsify Bazant's theory that this 3.7 meter drop is what supplied the necessary energy to destroy the tower?

For instance, in this picture we can see some of the upper and lower block starting to be pulverized.



Here we can see the tilt continue:



And continue:



So if the tilt comes first, then the 3.7 meter drop, why is the building being destroyed before this 3.7 meter fall occurs?

 

[Pardalis]

Well, it seems to telescope into itself or shrink 50%

You can't know that for sure, since we can't see a thing through that cloud of dust.

Luckily, where I live (France), all sects of any kind are forbidden by law. Religious (praying) associations are governed by a 1905 law, etc. and cannot do any other business. If you do not comply, you are a sect. The French society as such does not interfere besides that. The French republican values are quite clear - liberté, égalité, fraternité. You cannot beat those. In US they seem go have gone with the Homeland Security Act paving the way for, e.g. the new US physics and structures theories.

Well, that's quite... intriguing.

I'm sure a psychiatrist would have a field day with this.

 

[R.Mackey]

So the upper block of the south tower tilts to the southeast then it falls 3.7 meters onto the lower block. If this is the case, then we shouldn't observe the destruction of the lower block and upper block until this 3.7 meter fall. So show me when this 3.7 meter drop occurs in one of the videos of the South Tower's collapse. If we notice the building being pulverized before this 3.7 meter drop occurs(i.e. while it is still tilting), then wouldn't this falsify Bazant's theory that this 3.7 meter drop is what supplied the necessary energy to destroy the tower?

No. Tilting means the remaining columns at the collapse zone are buckling, and that means some destruction of the lower block. There is further destruction (of the "hinge") at the instant the upper block also begins to fall. There is a great deal more destruction after whole new floors are hit and destroyed later in the collapse, but whenever there is motion of any kind, there is some destruction.

Also, keep in mind that the upper block continues to rotate even after it begins to fall. It retains some angular momentum. This makes it very difficult to estimate exactly when it begins to fall. In your pictures, the fall is already underway, it's just hard to see because the sense of scale is so huge.

Finally, "the 3.7 meter drop is what supplied the necessary energy to destroy the tower" is wrong. There is additional gravitational energy injected all throughout the collapse. The 3.7 meter drop is only needed to begin destruction, i.e. enough energy to fail the second floor's worth of supports. And this is, indeed, enough energy to do so.

The rest of the structure consumes approximately 50% of the total gravitational energy during the collapse, much more than the initial kick after the upper block falls 3.7 meters.

 

[NobbyNobbs]

Example - a crystal glass is standing on a marble table, its foot shears off and the top part of the glass displaces downwards (free fall in this case) ... and guess what happens! Yes - the dropped glass part applies a force on the marble table and the marble table applies an equal force on the dropped part and kinetic energy is at play. In this case the marble table can easily absorb the energy released (and remains virtually intact) but the little glass part cannot ... and breaks.

I have a better example. Balance a brick on your head. No problem, right? No damage to you, none to the brick.

Now hold that brick two feet above your head and drop it.

Report back on your results.

It is not much to report. Nothing really happens. A normal steel (yield 23 kgs/mm²) column with slenderness ratio <35 and compressed to 0.3 yield (thus 7 kgs/mm² compressive stress) and heated to 500°C will not fail! It will compress/bulge a little but it is hardly noticeable.

Heiwa--

I decided to try your experiment. I spent the money, followed your instructions to the letter, and guess what? Catastrophic collapse.














Um...I don't actually have to prove I did the experiment, do I?

 

[X]

Heiwa:

I would like to see that calculations showing that your "exepriment" represents a valid scal model for the escenario being addressed.

Surely as a ship designer you have vast experience with the intricacies of scaling, and are well aware of the care needed to be taken when designing scale models for testing.

Please provide calculations validating the scaling used in your "experiment" design.

 

[Heiwa]

No. Tilting means the remaining columns at the collapse zone are buckling, and that means some destruction of the lower block. There is further destruction (of the "hinge") at the instant the upper block also begins to fall. There is a great deal more destruction after whole new floors are hit and destroyed later in the collapse, but whenever there is motion of any kind, there is some destruction.

Also, keep in mind that the upper block continues to rotate even after it begins to fall. It retains some angular momentum. This makes it very difficult to estimate exactly when it begins to fall. In your pictures, the fall is already underway, it's just hard to see because the sense of scale is so huge.

Finally, "the 3.7 meter drop is what supplied the necessary energy to destroy the tower" is wrong. There is additional gravitational energy injected all throughout the collapse. The 3.7 meter drop is only needed to begin destruction, i.e. enough energy to fail the second floor's worth of supports. And this is, indeed, enough energy to do so.

The rest of the structure consumes approximately 50% of the total gravitational energy during the collapse, much more than the initial kick after the upper block falls 3.7 meters.

1. Tilting means that the supporting columns did not fail simultaneously which in turn means that no real impact can occur later, e.g. one side drops first and the other sides a couple of seconds later = a very slow load/energy transfer.
2. Tilting also means that the mass is displaced outside the structure below and will not act on it, e.g. two of the four walls must be outside the structure at initiation and slide off. A lot of energy is lost due to tilting.
3. Tilting further means that it is the weaker structural parts of the upper block, the floors, that contact the stronger structural parts of the lower structure, the columns = the upper block should be destroyed first. Compare 1. This event takes a couple of seconds.
4. Evidently a lot of energy is absorbed as elastic deformation that would brake the downward movement and then bounce back the mass involved.
5. When the upper block is destroyed and energy is wasted, there is little else that can destroy the structure below due to gravity.
6. When parts contact and rub against one another, friction develops and further energy is wasted. Five partly damaged upper block floors rubbing against five partly damaged lower structure floors produce a lot of friction that would arrest any collapse. No more floors are hit and no more energy is supplied.
7. It is like a child jumping on a mattress. You bounce and if the springs fail you get entangled in the damaged mattress = no collapse.