Failure mode in WTC towers

[Max Photon]

I'd like my upper block with anchovies please.

Max notes:



That is because you are a smart dude.

In your case let's not consider what I wrote as a contradiction but just as a description of the phenomena observed.

But doesn´t what you wrote beg the following questions:

Since the upper "block" was leaning over the east facade of the lower section, how did it get all the way inside there?

How does that correspond the the "dust" ejections observed: The first 2 more powerful horizontal rows skipping a few floors?

The bizarre ejection patterns seen along the northeast corner? Note that some of these ejections skipped floors along this corner and LATER, after the leading edge of the "collapse" front has passed, you see ejections along the corner on the very floors skipped.

Max, to my knowledge only Norseman even attempted to explain how the upper "block" perimeter sections "sheared" the floors from the lower "block" perimeter along this facade.

Of course this seems inconsistent with the "piston effect" that will be needed to explain the forceful ejections seen leading the way in the observed "collapse" wave. For that the idea of pancaking will need to be introduced by someone who believes in the OCT.

Norseman, since you put much work into your previous explanation, if you wish to simply "cut and paste" it here for the others to see rather than retyping it, such a reply would work for me.

(bold mine)


Major Tom,

Again, I'm not sure I see any contradiction.

The upper block rotated significantly around a hinge until the hinge failed. On the east face the direction of the rotation ensured that the columns of the east face of the upper block went behind (inside of) the columns of the lower block.

It appears from videos that once the east face of the upper block got behind the lower block, the slope of the upper's panels wedged the lower's panels outward as the upper block fell. Some video show beautifully the panels of the east face of the lower block falling away after appearing to swallow the upper block as a gull would swallow a fish.

Maxwell Livingston

 

[Max Photon]

Newton's Bit, realcddeal, and column moment

Is this the sum of truther knowledge? Can you really not understand the difference between a FEM of a simple concept and a collapse model?

Heiwa and Realcddeal can't figure out how a load applied to the face of a column produces a moment. You can't figure out what a model is.

Talk about taking things out of context. I said the moment would be removed from the column due to an opposing force and counteracting moment from the adjacent beams.

Okay.

Correction to my post above, Realcddeal doesn't understand what a fixed connection in a frame means and thus doesn't understand this problem.

Newtons Bit,

To my eye it looks like you are taking things out of context.

I believe realcddeal is discussing core columns.

With respect to your diagram, again, isn't N7-N8 more representative of what realcddeal is describing than column N1-N2?

The very simple point is that core columns would be pinned or fixed by floors and by horizontal core members - in other words, by a system of horizontal beams attached to all four faces of a core column - and that this horizontal system of beams produces counteracting forces that resist any deflection of the column from true, which results in a core column that experiences negligible internal moment.


Max

 

[Heiwa]

Why does it get wet then?

Tipping floors and flowing rubble? You are getting more ridiculous by the minute and, as I said earlier, spoiling these threads

Reason why it gets wet is that this happens after the (compressed) air has disappeared from the action.

So you suggest that no floors tipped and that no rubble flowed in the WTC collapses?

Just clean breaks everywhere and orderly piles of parts on the ground?

 

[Major_Tom]

NB notes:

Is this the sum of truther knowledge? Can you really not understand the difference between a FEM of a simple concept and a collapse model?

Were you planning to to apply your FEM to the WTC towers and the specific "collapses" witnessed at some point? If not, what good is it?

I am listing observed phenomena. In so far as your FEM can be shown to match observed phenomena, it is useful.

If not, it will remain a product of your own imagination.

WTC 2, east face, floors 81 to, say 70. You have floors, perimeter and core. Not brain surgery. Only 3 general objects.

Pencil sketches, anything. Use a freakin' crayon, I really don´t care.

If you can´t commit to some collapse initiation and progression mechanism in this very limited region which matches observed phenomena then your act of hiding behind ambiguity will be seen to be wearing pretty thin.

The ability to match observed phenomena is the basis of putting any explanation or model to the test.

Why are you introducing your FEM in the first place? Is it not to try to explain core column-to-column weld breakage? Isn´t weld breakage just another witnessed occurance?

So you have no problem ignoring many other witnessed occurances in order to "explain" weld breakage, which is just another witnessed occurance?

What if I were to introduce a demo model which will adequately take down the twin towers, though it has nothing to do with anything that was observed on 9-11 (like Christophera, for example), wouldn´t you quckly point out the contradiction and think I was a freakin´nutcase?

Why wouldn´t the same apply to you?

Max wonders:

The very simple point is that core columns would be pinned or fixed by floors and by horizontal core members - in other words, by a system of horizontal beams attached to all four faces of a core column - and that this horizontal system of beams produces counteracting forces that resist any deflection of the column from true, which results in a core column that experiences negligible internal moment.

Pinned relative to the building structure, not to the earth as your foundation comment suggests.

 

[Major_Tom]

Corsair 115 comments:

It seems rather silly to me to label that an explosion given that the building is already in the process of collapsing. Furthermore, if that was an explosion, it was not a very powerful one. Look how little disruption there is in the smoke, and notice how there is no sign of shrapnel departing from the building at high speed.

The following clip shows some known examples of controlled demolition.

I´d like you to look at the 2 examples between :15 and :30 and at 1:15

Do you see shrapnel? The WTC towers have more forceful ejections than these. Do you see high-speed forceful ejections in the 2 examples cited?

No one was hiding a demo in these examples.

http://www.youtube.com/watch?v=pbL165QM9wo

 

[Major_Tom]

Max, no contradiction is the portion you put in bold print.

Now lets combine the idea with the ejection patterns observed.

Skipping a few floors would be contradiction number 1, ejection patterns along the northeast corner can be considered contradiction number 2. Video references reproduced below.

9/11: South Tower NBC Closeups. The camera is fixed on the north and east facades. The editor crops and uses slow motion and repetition to reveal the ejection patterns along these 2 faces during collapse initiation and progression.
http://www.youtube.com/watch?v=xtpWu-XZ7kM


9/11: South Tower NBC Closeups Version 2. Same as above using some different editing.
http://www.youtube.com/watch?v=COpfvXj_BVo


9/11: History Channel South Tower. From the northwest. Wonderful compliment to the two previous clips. Collapse initiation and ejection patterns with slow motion editing.
http://www.youtube.com/watch?v=AXak_...eature=related

 

[Myriad]

The following clip shows some known examples of controlled demolition.

I´d like you to look at the 2 examples between :15 and :30 and at 1:15

Do you see shrapnel?

It appears that someone removed the window glass in those two examples, and probably most of the building contents as well. (Do you think they demolished them with desks, computers, filing cabinets, light fixtures, etc. still in place?) Among other benefits, this would minimize flying shrapnel.

If demolition charges were set off in the towers or in 7 on 9/11, I wouldn't necessarily expect to see the shrapnel in photographs, especially not in video. It would be moving too fast. I would, however, expect to see it in the bodies of numerous shrapnel casualties over a quarter of a mile away.

ETA: Please, don't take my word for it. Contact a demolition engineer and ask what would happen if demolition charges were set off in a building with its furnishings and exterior window glass still intact.

Respectfully,
Myriad

 

[Myriad]

I don't see any calculations in your post. If you're quite good at this, then show me your calculation of the peak dynamic load that 33,000 tons of water dropped, say, 3 meters onto a wtc tower floor would exert, and then show me your calculation of how much force the floor can resist, so that I can see that the first number is less than or equal to the second.

It doesn't work like that! The water does not impact the hard surface (or vice versa). Air (not a very rigid body) is trapped between the hard surface and the water and compressed to say 10 bar and then the air 'explodes' - that is the observed impact - and the water splashes in all directions. I have measured the pressures involved! If there is no impact, the water is just pushed to the side.

Comparing the upper block to 33,000 tons of falling water was your idea. All I said was that the moving water would exert a dynamic load on the floor below. Obviously you agree, because you speak of pressurized air being trapped between the water and the surface, and that pressure is a force exerted on the surface (as well as on the water), which is a dynamic load.

What I still don't see are your calculations showing that the load on the floor resulting from the 33,000 tons of water is less than what the floor can withstand.

What happens when a lot of rubble (many material parts and bodies of various stiffness) impacts onto a wtc tower floor from above is another matter. I assume the rubble compacts, but it must also be pushed to the side. Both effects take time and consume energy and cannot be regarded as an instant impact that overloads the floor.

Rather a fast build-up of rubble takes place on the wtc tower floor that might be overloaded. The floor will then break in one location; at the side or in the middle, and become sloping and the rubble will flow along the slope, e.g. out of the building or through a hole in the floor and probably get stucked there = the collapse is arrested.

All that mass, changing direction from falling downward to flowing down a slope out of the building, exerts a force in doing so. (Changing direction is acceleration, and you're familiar with Newton's Second Law, right?) You have calculations that the partly damaged sloping floor can withstand that force, rather than just continuing to be crushed by the falling mass of rubble, right? Please show them.

All these ideas that a rigid mass suddenly impacts an initiation zone in the wtcs and creates a crush zone is just fantasy. Rubble do not behave like that.

You're welcome to present your own model, in which the status of the upper and lower blocks and the movement of the rubble are more precisely accounted for along the way, rather than being abstracted into "zones" for modeling convenience. Let's see your calculations.

If you want to model the rubble as a fluid, that might not be a bad approach. I assume the flow will be turbulent. What value do you have for the Reynolds Number for such a model, and how did you determine it? That would be a useful initial step, since just about all other fluid dynamics calculations depend on that value.

Also, have you come up with any examples of large ships hulls made of 22-gauge steel and four inches of concrete? It sounds like a very economical way to build large ships, so it should be common. Unless, of course, there's some reason why ships' hulls aren't built that way. Can you tell me what that reason might be,?

Respectfully,
Myriad

 

[Newtons Bit]

Were you planning to to apply your FEM to the WTC towers and the specific "collapses" witnessed at some point? If not, what good is it?

You still don't get it do you? All the FEM is there is to illustrate the CONCEPT of eccentric shear connectors inducing bending moments in columns. This subject was brought discussed over several pages.

It applies to a single failure mode I listed in early in this thread in which columns that fail compressively will break at their weld-planes. It is a single failure mode that occurred and there were many. Do you have a problem with the concept that different columns failed in different ways?

 

[Heiwa]

Comparing the upper block to 33,000 tons of falling water was your idea. All I said was that the moving water would exert a dynamic load on the floor below. Obviously you agree, because you speak of pressurized air being trapped between the water and the surface, and that pressure is a force exerted on the surface (as well as on the water), which is a dynamic load.

What I still don't see are your calculations showing that the load on the floor resulting from the 33,000 tons of water is less than what the floor can withstand.

Respectfully,
Myriad

We are a little OT but it should be clear that an 'impact' is not scientifically defined by, e.g. FEMA, NIST, Bazant, Seffen & Co. When an object like a ship's hull in a seaway hits a water surface at high speed from above or horisontally, it would appear that compressed air, say 10 bar, between water/hull initiates the 'impact', i.e. the energy of the compressed air is of interest. What happens to this energy/pressure? The pressure is applied during a very short time to the water/hull. Both parts are affected! The hull plate may be plastically deformed due to high pressure (seen afterwards) and the water is pushed back to splash away as is observed (I have watched this thing in model/full scale many times) and the 'impact' energy is consumed.

End of 'impact'. No collapse ... except for the water!

 

[Heiwa]

All that mass, changing direction from falling downward to flowing down a slope out of the building, exerts a force in doing so. (Changing direction is acceleration, and you're familiar with Newton's Second Law, right?) You have calculations that the partly damaged sloping floor can withstand that force, rather than just continuing to be crushed by the falling mass of rubble, right? Please show them.
Respectfully,
Myriad

So what happen after the 'impact' (undefined) - we are not talking hull/water anymore but an alleged solid upper block of WTC and an upper floor in the still undamaged structure below?

Well, the upper block is not solid, rigid, stiff and it is only it bottom part that has 'impacted'. What is this bottom part? 280+ columns and the bottom floors of the upper block? Whatever, it has just overpressurized (overloaded) the top floor of the structure below. Newton's Second Law applies.

Why not ask NIST to clarify what happens? They just suggest in two lines in its 10000 pages report that the potential energy, PE, of the total upper block exceeds the strain energy of, I assume, the total undamaged, unheated lower block below, and that such an unscientific statement implies that 'global collapse ensues'.

In my view no such dramatic thing would happen. More realistically the energy of the 'impact' would just be consumed by local destruction, deformations and throwing lose part outside the building. The structure below may elastically compress and the upper block would remain on top of it, with its lower part locally damaged.

 

[Heiwa]

You're welcome to present your own model, in which the status of the upper and lower blocks and the movement of the rubble are more precisely accounted for along the way, rather than being abstracted into "zones" for modeling convenience. Let's see your calculations.

Respectfully,
Myriad

Why not ask NIST for its calculations about release of potential energy and the lack of strain energy of the structure below and a clear explanation what happens to the rubble? Nothing about those important subjects in their reports.

I have never experienced that a strong steel structure building collapses from top down due to lose structure dropping down from above. NIST should clarify! Or, as they have compromized themselves, a new independent investigation of ALL aspects of the collapses.

 

[Heiwa]

Also, have you come up with any examples of large ships hulls made of 22-gauge steel and four inches of concrete? It sounds like a very economical way to build large ships, so it should be common. Unless, of course, there's some reason why ships' hulls aren't built that way. Can you tell me what that reason might be,?

Respectfully,
Myriad

Ships are built only of steel and the WTCs could probably have been done like that too. I always wonder why they poured so much concrete (4 inches) on the floors! Any ideas?

 

[beachnut]

Ships are built only of steel and the WTCs could probably have been done like that too. I always wonder why they poured so much concrete (4 inches) on the floors! Any ideas?

No real idea why they wanted floors. escapes me?

This is indicative of people who do not understand 9/11 and how a building can fall due to massive impacts, mammoth out of control fires, and gravity.

 

[Furcifer]

Ships are built only of steel and the WTCs could probably have been done like that too. I always wonder why they poured so much concrete (4 inches) on the floors! Any ideas?

As usual this is backwards. This is unusually thin due to the large span and truss system. Please read up more on construction methods and the WTC.

 

[DGM]

Ships are built only of steel and the WTCs could probably have been done like that too. I always wonder why they poured so much concrete (4 inches) on the floors! Any ideas?

Least expensive way to achieve a rigid floor.

 

[Max Photon]

On ejections skipping floors

Max, no contradiction is the portion you put in bold print.

Now lets combine the idea with the ejection patterns observed.

Skipping a few floors would be contradiction number 1, ejection patterns along the northeast corner can be considered contradiction number 2. Video references reproduced below.

As for Contraction 1: Ejections skipping floors...

Isn't the "skipped floor" because the MER had open floors?

 

[Newtons Bit]

Least expensive way to achieve a rigid floor.

Oi. That's the definition of ignorance. He writes papers (for children?) on why the WTC can't collapse, but can't figure out why we use concrete floors in buildings.

 

[Norseman]

As Max Photon correctly pointed out to you, the reason why it looks like the dust and smoke ejections are "skipping" a floor is the fact that the mechanical equipment room on floor 75 and 76 was one 28 feet high room around the core area. Therefore the collapsing floor from above had to move down further to build up enough pressure to forcefully start ejecting dust and debris compared with an ordinary 12 feet floor. This is consistent with the dust being ejected from the floor 75 level. (For readers unfamiliar with the details of this discussion, the mechanical equipment room is the two story high dark grey band seen going around the towers, easy to see on WTC 1 on the right in the screen shots above. The floors are framed by the two horizontal red lines in Major Tom's video frames above.)

Behind the perimeter columns on floor 75 and 76 there was a 4 feet deep plenum space in front of a wall containing ventilation louvers. See NIST NCSTAR 1-5A Appendix A. This is also visible in the blueprints. I would expect this wall to also have played a role in delaying the dust ejections depending on its construction.

I have to remind you again Major Tom of the fact that the dust and smoke ejections, as seen in the video frames you posted above, are lining up perfectly with the upper blocks rotation and progress down inside the lower block.

And then there was this tiny little problem about the missing sound of detonations in all the WTC collapse videos. The sound that we can clearly hear in every other controlled building implosion video.

 

[Major_Tom]

Max asks:

As for Contraction 1: Ejections skipping floors...

Isn't the "skipped floor" because the MER had open floors?

The second row of ejections are coming from these very open floors.

The ejections are skipping the upper escalator floor 77.

Norseman notes:

Behind the perimeter columns on floor 75 and 76 there was a 4 feet deep plenum space in front of a wall containing ventilation louvers. See NIST NCSTAR 1-5A Appendix A. This is also visible in the blueprints. I would expect this wall to also have played a role in delaying the dust ejections depending on its construction.

But the ejections were "delayed" on the floor above. The second horizontal row came from this very place.

The first ejections are from 79, 78. The second from 75, 76.

Also note that in the first row of ejections we see a strong ejection from the northeast corner, east face clearly FOLLOWING the long row of ejections along the central portion of this face. Piston?

Max, equally fascinating is the northeast corner during this process. Please notice how ejections from the north face along this corner lead ejections along the east face. Notice how well after the east face central region ejections and north face corner ejections lead the way, regions along the east face corner are relatively untouched. After the leading "collapse" edge clearly passes, we then see strong ejections leaving the east face corner after the rest of the floor has been destroyed. Piston?

Please watch how the corner is "worked", Max. This forced the OCT into floor failure "piston" theory. In the very corners?

Now please recall curioso number 3, how the perimeter of the lower portion falls largely as a single sheet. Splitting the corners is important in this process. The corners become vitally important.

Thanks for participating in the discussion, Norseman.

I recall your previous explanation for ejections here had to do with the upper perimeter sliding behind the lower perimeter and severing floors from the perimeter, is that true?

If this is true and the outside edges of the floor along the perimeter along the east face are the first to be hit and pushed down, the more interior portions of the floor following, you are closing off the east edge of the piston BEFORE the interior portion of the piston has a chance to act. If you try to apply piston theory with the east edge of the piston pushing down before the central part of the piston, then why the strong ejections eastward?

You are sealing the east edge of your system before the even before the pressure of your system has a sufficient chance to build up.

Could you be a bit more specific as to how the pressure is built up floor by floor considering that the east edge of your piston is clearly leading the way.

I´m looking for someone who believes in the OCT to COMMIT to either the explanation in the last sentence or pancaking floors which act as a "piston".

From the OCT point of view, these seem to be the only 2 choices. Is there a third choice from the OCT point of view I am missing?

I am addressing Norseman because he seems to be one of the only people daring enough to go into specifics.

Once again, a most sincere thanks for your participation.