WTC collapses - Layman's terms again

Any guesses as to how long it will be before Heiwa spits in Dr. Greenings face with his usual hand wave?

Dr. Greening:
I just want to say that I appreciated your post and I am also sure that many interested lurkers questions were addressed. Heiwa on the other hand is a conspiracy theorist first, engineer second that will not give your effort a second look (if he reads it at all).
 
Pomeroo and DGM:

Thank you!

I agree, Heiwa will probably press on regardless ....

Why should I care?

I write mainly to convince myself, the toughest, most sceptical critic I know.

Hidden agenda, my foot!
 
From the answers I've received, I think it's safe to conclude that Mark Roberts wasn't telling the truth about holding the molten material flowing out of WTC2 in his hands.
 
tanabear said:
From the answers I've received, I think it's safe to conclude that Mark Roberts wasn't telling the truth about holding the molten material flowing out of WTC2 in his hands.
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I, on the other hand, think it's safe to assume that everything Mark Roberts says about the events of 9/11/01 is completely accurate. He, like the fantasy movement, has a track record.
 
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Sagging floors and bowing perimeter columns, that speaks pretty hard against 3.7m free fall.
 
Apollo20:

Thanks for reply in message #617

Apollo20:

First of all let me tell you that I HAVE looked at ship collisions. I even have a copy of Minorsky’s classic (1959!) paper and I have played around with Minorsky’s KE equation by making various estimates of his resistance factor, Rt, as it might apply to the Twin Towers. If you take Rt to be ~ 18 m^3 you arrive at an energy loss for the impact of a 30,000 tonne “ship” of about 900 MJ which is of similar magnitude to my quantity E1. However, the important difference between ship collisions and the WTC collapse is that GRAVITY is not a factor in ship collisions while it is THE key factor in the collapse of WTC 1, 2 & 7.

Very good! In a ship collision or grounding we have initial momentum + forces that produce structural damage. The forces involved are the propulsive force of the striking ship and of course the reaction forces incl. friction. In grounding gravity is an important factor. In the WTC 1 case gravity force, reaction forces when parts contact and fail and friction between various parts are the key factors.

Apollo20:

But let’s look at your specific points of criticism of my (and other similar) collapse calculations. Here I have to begin by saying that the supports of the upper block did NOT “suddenly disappear” as you claim. How could they? Instead, as many collapse videos and photos show, the perimeter columns first bowed inwards over a vertical height of several floors. Eventually it appears that the A325 bolts at the column splices failed in shear – on the south face of WTC 1, and the east face of WTC 2. This type of failure, although it started along one wall and rapidly spread to other walls, caused the upper block to tilt several degrees from the vertical in the direction of the failed wall. Then, very quickly, the hinged wall also failed allowing the entire upper section to break free and essentially “free fall” onto the lower structure.

The specific points of criticism regarding the initiation of global collapse are:

1. All supports of WTC 1 suddenly disappear below the upper block.
2. The upper block near free falls 3.7 meters.
3. The upper block impacts a lower structure with perfect alignment.
4. The upper block is still intact.

Prior to this it is suggested that some perimeter columns bowed inwards over a height of several storeys, i.e. serious local failures. What would have caused that in WTC 1 south wall? Heat, fire? Anyway, bowing inward and, I assume, followed by bending/buckling would produce a layer of failed structural parts that would dampen any following downwards displacements of parts above. As the failures apparently spread to the east and west walls, same failures would happen there assuming that 100's of bolts sheared off at the floors connections. In my view such a scenario is very unlikely and not seen on any videos; no floors are seen falling down at this point. But let's assume two or three floors fall down and that the east and west walls also bow and buckle bend inwards. The result would be 2000 m² of buckle bent south, east and west walls (columns) would form a layer of failed parts between the upper block and the lower structure. Those failed parts would definitely arrest any further failures. I will include that in the picture in my article! Thanks for the idea.

You on the other hand suggest that the entire upper section breaks free! How? From the failed columns below that has buckle bent?

I my opinion the upper block would still be connected to the failed columns all the time and there would never be any free fall or impact. All potential energy released at this time would be consumed to produce the layer of failed parts between the upper block and the lower structure. The upper block should therefore have remained on top of the lower structure.

Apollo20:

Now, because the initial drop involved some tilting motion, the upper section would obviously NOT be perfectly aligned with the lower section at the moment of impact. So, Heiwa, I have never made such an assumption, nor is perfect alignment of the upper and lower sections of the towers critical to my model!

The figures in your latest paper to be published in the ASCE journal show perfect alignment.

Apollo20:

Simple geometrical considerations show that a block that drops by column failure at one face, while remaining hinged at the opposite face, would strike the floor below when the tilt angle reaches about 3.3 degrees. Furthermore, the perimeter columns on the face that is falling would strike the row of columns immediately below the upper block along a line located about 10 cm INSIDE their vertical axis. Such collisions would be more of a series of glancing blows than the “head-on” impact of a drop hammer you imagine. The columns below the upper block would thus be pushed aside like skittles hit by a bowling ball rather than compressed like pistons or springs. Thus the structure below the upper block was destroyed by successive splice (weld or bolt) shear failures all the way down the tower.

You conveniently forget the enormous amounts of failed perimeter wall columns inside the initiation zone + a couple of failed floors that act as an effective damping device. The forces and momentum now applied from above must evidently pass through these failed parts and then down to the uppermost intact floor of the lower structure, through the 500+ bolts there to be applied to the columns below.

You cannot assume that the forces/momentum from above are directly applied to the columns of the structure below; they have to pass the damping device, the intact top floor of the lower structure and the bolts.

If this unlikely event would take place, I would assume the bolts would shear off and there would be no bowling ball hitting the intact columns below like skittles.

When the bolts of the uppermost floor shear off more failed parts are added to the damping device already formed above.

Apollo20:

Now I admit that none of this detail is explicitly treated in my one-dimensional collapse calculation; but after just a few lower floors were obliterated in the way I have described, the fine detail of each subsequent floor failure has hardly any effect on the overall collapse kinetics which is now dominated by momentum transfer in a gravity field.

So you assume that the upper block remains intact and that failed parts in the initiation zone do not produce any resistance or consume any energy! In my opinion the local collapse would have been arrested at this time, many times over. But now the following is supposed to happen:

5. The upper block (mostly air) assisted by gravity only destroys the columns of the lower structure below (the columns break every 10-12 meters like spaghetti).
6. The upper block lands intact on a heap of rubble after a successful push-down of the tower
7. The upper block finally selfdestructs in a push-up of the rubble.

Apollo20:

So, Heiwa, you are making the same mistake that Ace Baker and others of his ilk have made before; you are assuming that a model must follow every nuance of the process under investigation to be valid. This is simply not true, and is probably not possible for a chaotic event such as the destruction of the Twin Towers. But worse yet, you are also assuming that if a mathematical model of the collapse of a WTC tower has obvious inaccuracies and errors of detail, these flaws somehow PROVE that the collapse was a CD.

I admit my model calculation is very crude, but it shows that a gravity-driven collapse of WTC 1 & 2 was physically possible without the help of explosives! My model may not “see” everything that happened; you, on the other hand, see things that never happened ……

Mistake? I quote your latest article (to be published?) in the ASCE journal (June?, July?) and query some basic assumptions in it, e.g. points 1-7 above. Your mathematical model is another matter. It doesn't prove anything. I just propose that collapse arrest is the most likely outcome of local structural failures due heat/fire in a steel structure. No free fall, no impact.

Your model and mathematical calculations are very crude and do not show that a gravity only driven collapse is physically possible unless you make fancy assumptions that cannot be supported by real observations and physics and, of course, experience gained from analysing ship collisions/groundings where much bigger energies and forces are involved.

I suggest again that you do not publish the article or at least take away your name as co-author.

kind regards

Heiwa
 
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MRC_Hans said:
Wow! 16 pages and still at square 1.

Hans
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Of course thanks to DC but now Apollo20 has taken off so it starts to get interesting. Maybe I should start another thread just with Apollo20:s highflying ideas?
 
Maybe you should attempt to answer just one technical question in relation to any of the various ridiculous statements you've made in your attempt to support your "theory".
 
Reading comprehension does not appear to be one of Heiwa's strong points.
 
Apollo20 said:
Heiwa:

Instead, as many collapse videos and photos show, the perimeter columns first bowed inwards over a vertical height of several floors. Eventually it appears that the A325 bolts at the column splices failed in shear – on the south face of WTC 1, and the east face of WTC 2. This type of failure, although it started along one wall and rapidly spread to other walls, caused the upper block to tilt several degrees from the vertical in the direction of the failed wall. Then, very quickly, the hinged wall also failed allowing the entire upper section to break free and essentially “free fall” onto the lower structure.
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Assume the WTC1 south wall fails due to all bolts shearing off at three floors and that the wall locally bucklebends inwards and breaks in one location(not seen on any videos of course). Very bad local failure.

I would then assume that the south wall above drops down a little, all the bolts of the floors above shear off, and that the complete south wall of the upper block drops to the ground. Serious local failure - but not global collapse.
The floors previously attached to the south wall above would be hanging on the core. No tilting.

Same goes for the east and west wall if the floor bolts shear off and their is local buckling. The walls would drop down and the floors would be hanging on the core. No tilting.

Now of course someone will suggest that the outer walls didn't fall down because they were hanging on the roof hat trusses and that all the loads of the walls (not supported by the columns below) and all the floors attached to them above the buckle area were transmitted via the hat trusses to the core that in turn was overloaded.

So the hat trusses could transfer the load of 60 metres of walls/floors. Any evidence for that?

But let's assume it. Now also the core bucklebends if it is overstressed. Where? apparently at the top just below the hat trusses, where the core columns were weakest.

So now the core buckles up at the top just below the roof. The walls are still hanging on the roof. What happens then? Tilting? Maybe.

Free fall and impact? No.

Well - we would see the roof moving down. And we see that. We should then focus what happens 60 metres down. Are the walls in the initiation zone bowing and bucklebending inwards? Maybe.

So we have two areas of local failures - one is the floors 94, 95 and 96 that have dropped down and the walls there are bowing inwards and another is up top the core is collapsing just below the hat trusses on which the outer walls of the upper block are hanging.

What happens then? Well it would appear that any further collapse would continue up in the core just below the hat trusses. By gravity. But the core gets stronger further down. It is possible that local failures are arrested where the core gets stronger. There is neither free fall or impacts in the scenario. Just transfer of loads to the core where the parts are deformed.

But let's assume the core fails completely in the upper block.

So in this scenario the upper block disintegrates in the core starting from top. That is why the upper block is getting shorter. It telescopes down into itself. No further local failures at the other failed area.

When the parts of the upper block now is mowing down due to local failures in the core starting up top, two walls of the upper block would surely be outside the lower structure and shear off and drop down to ground.

Many things may happen. But one thing is certain. The upper block is partly destroyed in this phase. Any theory assuming that the upper block remains solid, rigid, intact, indestructible in any later phase of failures is WRONG.
 
Heiwa said:
Assume the WTC1 south wall fails due to all bolts shearing off at three floors and that the wall locally bucklebends inwards and breaks in one location(not seen on any videos of course). Very bad local failure.

I would then assume that the south wall above drops down a little, all the bolts of the floors above shear off, and that the complete south wall of the upper block drops to the ground. Serious local failure - but not global collapse.
The floors previously attached to the south wall above would be hanging on the core. No tilting.
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Wrong wrong wrong.

The outer walls are the loadbearing element. The floors are not capable of a cantilever such as you describe, indeed DC has a seperate thread going at the moment regarding the connections from which it is abundantly clear that such a scenario is wholly impossible.


Same goes for the east and west wall if the floor bolts shear off and their is local buckling. The walls would drop down and the floors would be hanging on the core. No tilting.
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Previously we had a garden table analogy. Now you're moving on to a Christmas tree, as far as I can tell.

Now of course someone will suggest that the outer walls didn't fall down because they were hanging on the roof hat trusses and that all the loads of the walls (not supported by the columns below) and all the floors attached to them above the buckle area were transmitted via the hat trusses to the core that in turn was overloaded.
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The accepted hypothesis based on the evidence is that initially localised failures were transmitted to adjacent panels but that, as the failure progressed, these significantly exceeded their capacity and instead loads were transmitted via the hat trusses to the core. These were not designed to carry such loads and consequently failure occurred.

So the hat trusses could transfer the load of 60 metres of walls/floors. Any evidence for that?
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As I said, reading comprehension.

But let's assume it. Now also the core bucklebends if it is overstressed. Where? apparently at the top just below the hat trusses, where the core columns were weakest.

So now the core buckles up at the top just below the roof. The walls are still hanging on the roof. What happens then? Tilting? Maybe.
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Incomplete technical appraisal based upon a strawman argument. No change in your usual MO, Heiwa. The rest of your post is similarly error-ridden.
 
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Heiwa said:
See my previous message to Frank. I do not ignore that gravity (or any force involved) may add energy. Topic is what energy is available at the collision and where it is applied to cause failures and what happens then.
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You say that you do not ignore the gravitational potential energy, then you proceed to ignore it.

Limiting your analysis only to the energy that is "available at the collision" by which you apparently mean only the kinetic energy generated after a drop of one floor, is like declaring how far a car can go based on ignoring the energy of the fuel in the gas tank.

The energy readily available, released by the simple process of mass dropping (whether or not it drops in "free fall" and whether or not it's structurally intact at the time), is hundreds to thousands of times the energy of the ship collisions you're familiar with.

Respectfully,
Myriad
 
Myriad said:
You say that you do not ignore the gravitational potential energy, then you proceed to ignore it.

Limiting your analysis only to the energy that is "available at the collision" by which you apparently mean only the kinetic energy generated after a drop of one floor, is like declaring how far a car can go based on ignoring the energy of the fuel in the gas tank.

The energy readily available, released by the simple process of mass dropping (whether or not it drops in "free fall" and whether or not it's structurally intact at the time), is hundreds to thousands of times the energy of the ship collisions you're familiar with.

Respectfully,
Myriad
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Sorry, I do not ignore gravity and its effects. I just focus on what gravitational energy is available at every step of the incident.

When the structure is intact the energy is stored in the parts (including the Earth) and only produces forces that produce stresses in the structure. You agree?

When local failures of parts occur and no displacement of attached parts occur no energy is released. Only forces are redirected to other parts, where stresses may be increased. You agree?

When any failed part is displaced downwards due to gravity it releases energy. In local failures, parts still attached to other parts, that energy is normally consumed causing local deformation of the failed part! You agree?

Of course, if a big loose weight on a failed part starts to drop free fall there is energy involved/released ... but then we have to analyse that;

What weight is it?
Why does it free fall?
Where does it start from and where does it end?
Etc.

A loose weight dropping outside the structure will evidently not damage the structure.

I have not been able to identify any loose weights in the WTC1 except for furniture, decorations and humans. Everything else, i.e. the structural parts, were connected to one another. Nothing free falls! Only local parts fail and all energy released is consumed to deform the parts. No free fall, no impact. Not even floor bolts sheared off at the walls, so that the walls could hinge down on the loose end. But even if some floor bolts shear off and the floor hinges down the energy involved is known and will be absorbed by the floor below. No ship collision where the momentums and forces are 100 times bigger than at WTC 1.

Sorry - you are 100% wrong in your analysis. Try again. I always look forward to your comments.

Kind regards

Heiwa
 
Heiwa said:
Minadin just asked for one. Let's start with that one. Take a difficult one. I want to impress my audience that I can answer it.
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How about the resistance of the floor structure to the gravitational acceleration of the top mass. You told me before you don't deal with this because you like to keep it simple. Impress us with your calculations!
 
Architect said:
The accepted hypothesis based on the evidence is that initially localised failures were transmitted to adjacent panels but that, as the failure progressed, these significantly exceeded their capacity and instead loads were transmitted via the hat trusses to the core. These were not designed to carry such loads and consequently failure occurred.
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I have difficulty to follow:

What localised failures are you talking about? The outer walls bucklebending inwards at around floor 96? Reason? The floor bolts sheared off at the walls and that the floors dropped down a little - still attached at the core, I assume. Ok, I can follow that.

But what adjacent panels are you talking about? The wall columns bucklebend locally and that means that the wall above will displace downwards. As the wall above is connected to the core via floors, the wall will try to pull the floors with it. The weakest link is the floor bolt but it will not shear off at this step because the wall is now hanging on the hat truss.

Is that what you mean? I cannot see any panels here - and failures transmitted to them.

So the wall is hanging on the hat truss and the hat truss transmits the load to the core. Very well.

If the hat truss doesn't fail and the wall drops down (and a piece of the hat truss), the forces involved will be transmitted to the core. No energy has been released so far. Only forces have been shifted around. You agree? This is what happens due local failures. Forces are shifted around.

So now extra forces are carried by the core and the stresses there increase.
You agree?

How much? So that the core columns start to buckle. Why not? Where? Of course where they are weakest = just below the hat truss.

So let's assume the core columns up top deform and the structure attached displace downwards and any potential energy released is consumed by the deformations in the core.

No free fall. No impact!

Actually it is very frequent when local failures occur for any reason (a columns is heated and buckles!) and forces are shifted about (the force in the column must move somewhere else!) that local failures occur at other locations (where the force is now applied).

Free falls and impacts are very rare. Never occur, actually (apart from loose furniture that slides to the side and out of a window).

Pls clarify what you actually mean. Adjacent panel?
 
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