Moderated Continuation - Why a one-way Crush down is not possible

[Newtons Bit]

I generally just scroll past your ignorant repetitive posts. but this caught my eye.



Yet you have claimed in hundreds of previous posts. That these very same floors which you now say are too fragile to support the core. Were somehow strong enough to arrest this collapse due to entanglement?

I love Heiwa's "evidently" statements. He just throws out a couple hundred years of engineering theory, makes a wild assumption and leaps to a completely invalid conclusion based on that assumption.

 

[BigAl]

AA. In principle yes. The core is self-supporting and so are also the four walls of perimeter columns/spandrels assemblies just bolted together around the core. The pre-fab floors are simply hanging on angle bars between core and perimeter and fixed by bolts. All described in my papers.

Is he speaking of WTC1 and 2? It doesn't sound like it.

 

[tfk]

NIST seems to have missed the angle bars/bolts that connect the pre-fab floor assemblies to the perimeter columns and the core beams. Without them the floors would simply drop down.
Evidently these floors - read bolts - do not provide lateral support of the core that is self-supporting.

.
Thanks, guys, for showing me this...



.
.
.
OK, Anders.

Would you mind excusing the rest of us for a bit. We've got some things to talk about...

Thanks.

Tom

 

[BadBoy]

 

[BadBoy]

.
Tim,

Now you've impressed me.

It doesn't matter that others have suggested this before. You came up with it yourself.

I think "absolutely". People have compared this to records dropping on a spindle.

And I think that components in the floors that were toughest were the rebar in the concrete. That rebar, interwoven & tied together, is incredibly tough stuff. The cross trusses too, of course.

But those concrete floors were incredibly thin.

As a very interesting exercise, go out into a football field some day with 3 of your buddies. Pace off a square about 200' (67 yards) on a side. (Just approximately) Now imagine a slab of concrete stretching between all of you, with the rectangular core cut-out, just 5.5" thick (with 1.5" deep Vee channels).

Now stack 110 of them on top of each other...

To me, what is amazing about that building is not "what is there". It is how much they were able to pare it back to the absolute essentials, and still have a terrific, robust building that took as much punishment as it did.

Tom.

 

[Heiwa]

.
Thanks, guys, for showing me this...



.
.
.
OK, Anders.

Would you mind excusing the rest of us for a bit. We've got some things to talk about...

Thanks.

Tom

Just carry on. Don't forget your rubble compacting rubbish destroying anything paper/theory to be published. I assume you talk about it. Any progress?

 

[A W Smith]

Have you got rocks in your head?

Just carry on. Don't forget your rubble compacting rubbish destroying anything paper/theory to be published. I assume you talk about it. Any progress?

Resolve your rubble theory with this Anders

Originally Posted by Heiwa
NIST seems to have missed the angle bars/bolts that connect the pre-fab floor assemblies to the perimeter columns and the core beams. Without them the floors would simply drop down.
Evidently these floors - read bolts - do not provide lateral support of the core that is self-supporting.

Yet you expect these same floors that you assert through profound ignorance are too fragile to laterally support the core. To support 15 floors of accelerating gravity driven "rubble"?

 

[tfk]

Is he gone?

Good.

OK. A typical Floor Plan for the towers. I suspect the mechanical floors might have been beefed up a bit.

​

In mechanics, the geometric property that defines the ability of any member to resist bending is (improperly, but casually) called the moment of inertia. (It's correctly identified as the "2nd moment of area").

Numerically, in a rectangular beam, it given by:

I = b h³/12.
Where b = width of beam
h = thickness of beam
​

This shows that the stiffness of the beam goes as the cube of the thickness and only linearly with the width. So, if you double the thickness of a beam, it gets 8 times stiffer. If you double its width, it gets only 2 times stiffer.

​

In the picture above, (if these were diving boards) you're looking at the thickness of the beams. The width runs into the page.

Diving boards are intentionally made thin, because you want them to flex.

The point is that, when the diving board above bends, as with someone standing on it, the material fibers along the top of the board have to elongate. They go into tension. The fibers along the bottom side of the board have to shorten. They go into compression. There is a plane of fibers half way between the top & bottom that stays the same length (as when straight). This is called the Neutral Axis, and it undergoes no stress. The distribution of stress goes linearly from max tension at the top fibers to zero stress to max compression at the bottom of the board.

The fibers that are along the top & bottom are doing the maximum amount of work. The fibers near the neutral axis are doing almost none. That is exactly why, in order to get the stiffest beam possible for the least amount of material, you move as much material as possible as far away from the neutral axis as possible. When you do this, you end up with an "I" beam. Very efficient for resisting gravity loads in bridges. Turn the beam sideways, in the form of an "H" and it will be not nearly as stiff against vertical bending loads.

You can see these beams, and their orientation in the Floor Framing Diagram above. Note that the four corner beams (and one in the center) are all oriented to make an "H". All the rest of the beams are oriented to make an "I".

In the case of the towers, swaying motion of the towers at the top was one of the biggest problems that they faced. People were getting sick in initial testing. (Done secretly in a Seattle dentist's office..!!)

Tying the core to the outer walls of the tower increased it thickness by a factors of 1.5 and 2.4, in the two directions. To a reasonable approximation, this increased the stiffness of the tower by a factor of 3.4 & 13 in the two directions.

Let's have a show of hands... How many people think that Skilling & Robertson would NOT have securely tied the core columns to the peripheral columns and taken advantage of this increased resistance to swaying & projectile vomiting on the upper floors of their buildings?? OK, I see two: Heiwa & Bill Smith.

OK, how many people think that, if the core columns were, in fact, securely tied to the peripheral columns thru the flooring system, that the flooring system would NOT provided lateral support for the core columns? What a coincidence... Two hands again.

Hopefully, I've made my point.

Tom

 

[BadBoy]

Is he gone?

Good.

OK. A typical Floor Plan for the towers. I suspect the mechanical floors might have been beefed up a bit.

[qimg]http://www.internationalskeptics.com/forums/picture.php?albumid=176&pictureid=1423[/qimg]
​

In mechanics, the geometric property that defines the ability of any member to resist bending is (improperly, but casually) called the moment of inertia. (It's correctly identified as the "2nd moment of area").

Numerically, in a rectangular beam, it given by:

I = b h³/12.
Where b = width of beam
h = thickness of beam
​

This shows that the stiffness of the beam goes as the cube of the thickness and only linearly with the width. So, if you double the thickness of a beam, it gets 8 times stiffer. If you double its width, it gets only 2 times stiffer.

[qimg]http://www.internationalskeptics.com/forums/picture.php?albumid=176&pictureid=1416[/qimg]
​

In the picture above, (if these were diving boards) you're looking at the thickness of the beams. The width runs into the page.

Diving boards are intentionally made thin, because you want them to flex.

The point is that, when the diving board above bends, as with someone standing on it, the material fibers along the top of the board have to elongate. They go into tension. The fibers along the bottom side of the board have to shorten. They go into compression. There is a plane of fibers half way between the top & bottom that stays the same length (as when straight). This is called the Neutral Axis, and it undergoes no stress. The distribution of stress goes linearly from max tension at the top fibers to zero stress to max compression at the bottom of the board.

The fibers that are along the top & bottom are doing the maximum amount of work. The fibers near the neutral axis are doing almost none. That is exactly why, in order to get the stiffest beam possible for the least amount of material, you move as much material as possible as far away from the neutral axis as possible. When you do this, you end up with an "I" beam. Very efficient for resisting gravity loads in bridges. Turn the beam sideways, in the form of an "H" and it will be not nearly as stiff against vertical bending loads.

You can see these beams, and their orientation in the Floor Framing Diagram above. Note that the four corner beams (and one in the center) are all oriented to make an "H". All the rest of the beams are oriented to make an "I".

In the case of the towers, swaying motion of the towers at the top was one of the biggest problems that they faced. People were getting sick in initial testing. (Done secretly in a Seattle dentist's office..!!)

Tying the core to the outer walls of the tower increased it thickness by a factors of 1.5 and 2.4, in the two directions. To a reasonable approximation, this increased the stiffness of the tower by a factor of 3.4 & 13 in the two directions.

Let's have a show of hands... How many people think that Skilling & Robertson would NOT have securely tied the core columns to the peripheral columns and taken advantage of this increased resistance to swaying & projectile vomiting on the upper floors of their buildings?? OK, I see two: Heiwa & Bill Smith.

OK, how many people think that, if the core columns were, in fact, securely tied to the peripheral columns thru the flooring system, that the flooring system would NOT provided lateral support for the core columns? What a coincidence... Two hands again.

Hopefully, I've made my point.

Tom

er, you got my vote. Thanks, even I can understand that.

I got confused there for a second when Heiwa suggested the floors were just "hung" between the core and peripheral columns.

What would happen in a strong wind, if the core and peripheral columns were not secured to each other via the floor framing and the floors where kind of dangled between the inner core and the outer columns? (apart from the building flopping around a lot). Wouldn't the outside potentially move more than the inner core, or try to? I guess it would depend on how securly they were attached?

 

[BadBoy]

er, you got my vote. Thanks, even I can understand that.

I got confused there for a second when Heiwa suggested the floors were just "hung" between the core and peripheral columns.

What would happen in a strong wind, if the core and peripheral columns were not secured to each other via the floor framing and the floors where kind of dangled between the inner core and the outer columns? (apart from the building flopping around a lot). Wouldn't the outside potentially move more than the inner core, or try to? I guess it would depend on how securly they were attached?

Can the floors could be "hung" between the inner and outer columns such that they didnt provide lateral support such, but would transmit movement from the outside columns to the inside columns as Heiwa seems to suggest?

But it seems to me though that IS what lateral support is, is it not. I mean the inner and outer columns are either connected securely or not, and if they were not connected securely then wouldn't you get some problems when things start moving on the floor framing between the two?

 

[Heiwa]

What would happen in a strong wind, if the core and peripheral columns were not secured to each other via the floor framing and the floors where kind of dangled between the inner core and the outer columns? (apart from the building flopping around a lot). Wouldn't the outside potentially move more than the inner core, or try to? I guess it would depend on how securly they were attached?

Nothing really would happen. As the four perimeter walls are bolted together and thus self-supporting and one side is subject to wind load, they will deflect and maybe twist. The core - subject to no wind will just stay where it is.
Now - hang up the floors between perimeter/core and the structure will be more sturdid.

 

[Heiwa]

Hopefully, I've made my point.

Tom

Still waiting for your rubble compacting/rubbish one-way crushing theory. Simple diagrams with lines, triangles, circles, etc, may be useful.

 

[BadBoy]

Nothing really would happen. As the four perimeter walls are bolted together and thus self-supporting and one side is subject to wind load, they will deflect and maybe twist. The core - subject to no wind will just stay where it is.
Now - hang up the floors between perimeter/core and the structure will be more sturdid.

so, are you saying the whole structure wouldn't move (sway) with wind load, because if they did then the floors would get pushed into the inner core wouldnt they?

 

[Newtons Bit]

So Heiwa thinks a 1000 foot tall single column is self supporting now? What a loon.

 

[bill smith]

Is he gone?

Good.

OK. A typical Floor Plan for the towers. I suspect the mechanical floors might have been beefed up a bit.

[qimg]http://www.internationalskeptics.com/forums/picture.php?albumid=176&pictureid=1423[/qimg]
​

In mechanics, the geometric property that defines the ability of any member to resist bending is (improperly, but casually) called the moment of inertia. (It's correctly identified as the "2nd moment of area").

Numerically, in a rectangular beam, it given by:

I = b h³/12.
Where b = width of beam
h = thickness of beam
​

This shows that the stiffness of the beam goes as the cube of the thickness and only linearly with the width. So, if you double the thickness of a beam, it gets 8 times stiffer. If you double its width, it gets only 2 times stiffer.

[qimg]http://www.internationalskeptics.com/forums/picture.php?albumid=176&pictureid=1416[/qimg]
​

In the picture above, (if these were diving boards) you're looking at the thickness of the beams. The width runs into the page.

Diving boards are intentionally made thin, because you want them to flex.

The point is that, when the diving board above bends, as with someone standing on it, the material fibers along the top of the board have to elongate. They go into tension. The fibers along the bottom side of the board have to shorten. They go into compression. There is a plane of fibers half way between the top & bottom that stays the same length (as when straight). This is called the Neutral Axis, and it undergoes no stress. The distribution of stress goes linearly from max tension at the top fibers to zero stress to max compression at the bottom of the board.

The fibers that are along the top & bottom are doing the maximum amount of work. The fibers near the neutral axis are doing almost none. That is exactly why, in order to get the stiffest beam possible for the least amount of material, you move as much material as possible as far away from the neutral axis as possible. When you do this, you end up with an "I" beam. Very efficient for resisting gravity loads in bridges. Turn the beam sideways, in the form of an "H" and it will be not nearly as stiff against vertical bending loads.

You can see these beams, and their orientation in the Floor Framing Diagram above. Note that the four corner beams (and one in the center) are all oriented to make an "H". All the rest of the beams are oriented to make an "I".

In the case of the towers, swaying motion of the towers at the top was one of the biggest problems that they faced. People were getting sick in initial testing. (Done secretly in a Seattle dentist's office..!!)

Tying the core to the outer walls of the tower increased it thickness by a factors of 1.5 and 2.4, in the two directions. To a reasonable approximation, this increased the stiffness of the tower by a factor of 3.4 & 13 in the two directions.

Let's have a show of hands... How many people think that Skilling & Robertson would NOT have securely tied the core columns to the peripheral columns and taken advantage of this increased resistance to swaying & projectile vomiting on the upper floors of their buildings?? OK, I see two: Heiwa & Bill Smith.

OK, how many people think that, if the core columns were, in fact, securely tied to the peripheral columns thru the flooring system, that the flooring system would NOT provided lateral support for the core columns? What a coincidence... Two hands again.

Hopefully, I've made my point.

Tom

If you have a tall thick tree and you build a perimeter structure around and run beams to the tree all around attached n the same way as in the WTC you could say it provides lateral support to the tree. But you would also be aware that the tree did not actually need the support and was just being used as a convenient place to hang one end of the beam..

 

[A W Smith]

Keebler elf Bill smith jumps in with his ignorance

If you have a tall thick tree and you build a perimeter structure around and run beams to the tree all around attached n the same way as in the WTC you could say it provides lateral support to the tree. But you would also be aware that the tree did not actually need the support and was just being used as a convenient place to hang one end of the beam..

You are really bad with the analogies bill. so what role did the viscoelastic dampers play bill?

 

[Newtons Bit]

I'm going to have to do some math again, aren't I?

 

[Gamolon]

If you have a tall thick tree and you build a perimeter structure around and run beams to the tree all around attached n the same way as in the WTC you could say it provides lateral support to the tree. But you would also be aware that the tree did not actually need the support and was just being used as a convenient place to hang one end of the beam..

Explain that to the tree that topples over in a high wind.

 

[A W Smith]

I'm going to have to do some math again, aren't I?

Hold off just a sec. I'm expecting bill to chime in with "viscoelactic dampers keep your keebler crackers moist"

 

[bill smith]

I'm going to have to do some math again, aren't I?

Yes and I'm going to have to put up that picture of the well-braced core when you do.