Another Question for Heiwa : Amazing Fireproof Steel

[Architect]

The problem is that he wholly fails to understand how the structure works:

There are no "spandrels" between the outer envelope and the inner core, but rather a series of relatively lightweight girder trusses. These suport the floors, which comprise approx. 3" concrete on permanent steel shuttering.

Now in the event of a collapse, a number of things can happen. The concrete and shuttering will serve to spread loads but - as the imposed load will exceed design capacity - the floor and trusses fail. Alternatively, the floor fails however because of the shuttering damage to the girder trusses is.....yup, you guessed it......inevitable. His analogy about it "punching through" is simply fantasy.

But even this analogy is flawed because, as everyone is pointing out, we're not talking about a few point loadings but rather the wholesale collapse of the upper structure which - the more observant (i.e. everyone) will have noticed - occupies the same floorplate.

Laugh? I nearly died....

 

[X]

??? Please, learn to spell.

I apologize for my spelling. Mozilla does not have a spellcheck built in, and sometimes my typing gets ahead of my fingers.

The columns are in principal free standing and interconnected by horizontal spandrels (wall columns) and horizontal beams (core columns) in all directions at regular interwalls. This structure keeps the whole tower in place!

Spandrels? Odd, I would not have expected those to be present in the WTC, unless there were arches.
I would think that wall and core columns would be vertical, not horizontal. I'll assume you meant that the columns were interconnected by horizontal members.

On these columns floors are hanging. Like pictures on a wall. No big deal!

If the hook of the picture breaks, the picture drops down.

Not the whole structure holding the hook.

Hanging?
Even if your analogy is accurate, the floor will collapes onto the floor below it, and so on and so forth. And a great many other things will be breaking, bending, and flexing. It's not a pretty thing, and very destructive.

What is your age? 10? Excellent! You can read? Read http://heiwaco.tripod.com/nist.htm .

I expect you to apologize for that.

 

[Architect]

X, mate, it's apologise........

 

[tsig]

Westprog:

Glad to see someone recognize that my questions were indeed ON TOPIC!

I would say that the RATE of expenditure of the PE is the important factor to consider. The average collapse POWER during the first second of collapse of a WTC tower was about 2000 MW and this energy was directed into a collapse zone consisting of about 4000 tonnes of material.

Still confusing PE with KE I see. It's a common mistake for those without engineering training. At least on Earth.

 

[Architect]

Hey! Children! Stop bickering!

Mum and Dad are trying to concentrate!!!

 

[X]

X, mate, it's apologise........

<---- Canadian.

We use British English that's been slightly corrupted by America.

 

[Architect]

I have been to Canada. They spelled everyfing like wot we do, as far as I can remember*.......you're clearly just a NWO Shill pretending to be Canadian. Why, I bet you really are a sabreur!



ETA: * Mais n'est pas les Quebecois, je pense........

 

[X]

Only for fun, and Je n'est pas parle Francais.

On a more appropriate note, that you might be able to answer for me, are floors actually "hung" the was Heiwa descibes?
If not, how are they attached?
(referring to large, steel-framed high-rises, that is).

 

[Architect]

C'est un des sujects obligitoire dans tous les ecoles ecossaise, mai malheuresement je cannae remember how tae spell pas.

No, per my note above the floors rested on girder trusses.

 

[Apollo20]

Just to clarify, I am not Canadien, merci mon ami, .....

Anyway, it is clearly tsig who is confused..... Everyone knows that PE is energy possessed by virtue of an object's POSITION in an energy field, be it gravitational, electrical, magnetic, etc. The "energy" of the towers, expressed as a capacity to do work, starts as POTENTIAL ENERGY and, what is more, the kinetic energy not only starts at zero, it is also zero at the end of the collapse. The release of the PE stored in the collapsing towers delivers 500 Joules per kg to the impact zone.

 

[Heiwa]

There are no "spandrels" between the outer envelope and the inner core, but rather a series of relatively lightweight girder trusses. These suport the floors, which comprise approx. 3" concrete on permanent steel shuttering.

And who has suggested that there are spandrels between the perimeter walls and the core?

The perimeter walls (columns + horizontal spandrels at regular intervals) are selfsupporting. Like the core columns assembly with its spandrels (horizontal beams). Totally selfsupporting. No spandrels between the outer walls and the core!

The floors are then just hanging between these two separate structures.

Overload a floor and you get one failure point! Either at the outer wall or at the inner core (the support bolt shears off) or somewhere in between (to high stress in truss flange). It can only fail at one location! And it cannot damage any column! And then the load distribution of the failed floor changes = the load is removed from the failed floor! Evidently a failed floor cannot carry any load!

Quite basic actually but it seems they do not teach that at US universities.

No total collapse will follow if you overload a floor.

 

[Architect]

And who has suggested that there are spandrels between the perimeter walls and the core?

You did .

The perimeter walls (columns + horizontal spandrels at regular intervals) are selfsupporting. Like the core columns assembly with its spandrels (horizontal beams). Totally selfsupporting. No spandrels between the outer walls and the core!

Rubbish. You're suggesting that the envelope and the core both stand as independent structures 100 stories tall. This is just plain wrong.

The floors are then just hanging between these two separate structures.

Wrong. Try looking at the construction diagrams and details in the NIST report.

Overload a floor and you get one failure point! Either at the outer wall or at the inner core (the support bolt shears off) or somewhere in between (to high stress in truss flange). It can only fail at one location!

Wrong. You've completely ignored how the floor is constructed, in particular the manner in which a in-situ reinforced slab redistributes loads and ditto the impact of the permanenet steel shuttering.

And it cannot damage any column! And then the load distribution of the failed floor changes = the load is removed from the failed floor! Evidently a failed floor cannot carry any load!

1. The girder trusses act as part of a composite structure to restrain the outer facade, hence damage thereto compromises the overall stability.

2. And where does the load from the failed load magically go in your little fantasy?

Quite basic actually but it seems they do not teach that at US universities.

One of us is a chartered architect - in the UK, as you are well aware - speciailising in the design and construction of tall buildings. And the other is a naval architect - purportedly - who has shown no grasp of basic structures or undertaken any research into the design of the WTC.

Hmm. I'm sure that readers will draw their own conclusions, and that you will not like them.

No total collapse will follow if you overload a floor.

That depends on the structural design. You simply can't make a competent sweeping generalisation like that.


You know that old phrase about giving a man enough rope? You're the embodiement. We don't need to debunk you, for you're doing it yourself.

 

[einsteen]

1. You are sitting in a space capsule of mass M orbiting the earth at a velocity v. The capsule clearly has kinetic energy 1/2Mv^2, but what is its potential energy? Your distinction between KE and PE suggests that the PE is zero,.... but is this correct?

It seems that none of the big mouthers is able to solve this high-school problem...

v is related with the distance R of the orbit. Solve for R and that gives the potential energy (of course not MgR) but the integral Mg(r)=GM*M_earth/r^2 over the distance

 

[tsig]

Hey! Children! Stop bickering!

Mum and Dad are trying to concentrate!!!

You got it. No more from me.

Sorry about the derail.

 

[Architect]

By all means keep discussing it with Frank, but this is the "hold Heiwa's keech ideas up to the light of proper scrutiny" thread......

 

[Apollo20]

And here's a couple of questions for Heiwa:

The release of the PE stored in the collapsing towers delivered 500 Joules per kg to the impact zone. That is ten times the elastic strain energy capacity of structural steel.

Where did all that energy go? Is it possible that some column welds fractured?

 

[einsteen]

I'm sure Heiwa can answer for himself, but I'm sure he knows it seems energetically possible, however I'm not sure how he thinks the collapse will continue once there is sufficient movement. I think the point he wants to make is that the initiation could never happen under the known conditions and therefore the after question is not relevant for him.

 

[westprog]

And here's a couple of questions for Heiwa:

The release of the PE stored in the collapsing towers delivered 500 Joules per kg to the impact zone. That is ten times the elastic strain energy capacity of structural steel.

Where did all that energy go? Is it possible that some column welds fractured?

Heiwa hasn't done the PE calculation, beyond claiming that it's negligible. I don't think that he's likely to worry about it now.

 

[westprog]

Westprog:

Glad to see someone recognize that my questions were indeed ON TOPIC!

I would say that the RATE of expenditure of the PE is the important factor to consider. The average collapse POWER during the first second of collapse of a WTC tower was about 2000 MW and this energy was directed into a collapse zone consisting of about 4000 tonnes of material.

It's interesting that one of the objections to the observed collapses of the towers is that they fell too fast - where of course the rate of expenditure of PE is directly correlated with the speed of collapse.

 

[Apollo20]

Einsteen:

We all saw the perimeter columns in the fire-affected impact zones bow-in and fail.

Some questions:

What caused this?
Could it have been from aircraft impact damage and subsequent heating of the structure?
With the perimeter columns compromised in this way, could the (damaged) core still support the building?