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I think the point was that the building is significantly different from standard, box grid, curtain wall type structures which are filled with column lines from the core area to the exterior. In those types of buildings, the exterior columns bear a very small portion of the building loads.

In addition, the exterior walls were responsible for all of the lateral loads on the building, again, not like a typical building.

Originally posted by Rasobasi420
Are you saying that the report meant to say "the core consisted of 47 steel girders that bore an equal amout of weight as the outer walls."

No, I am definitely not saying that.

The distribution of the loads within the core area columns was not equal.

I don't buy it.
All 3 of these buildings fell straight down, and their concrete was all turned to dust. There was little to no macroscopic pieces of concrete. That doesn't happen when things fall from 1000 or so feet. Even WTC7 which has yet to be explained successfully. It has never happened before, or after that a building would fall straight down without specifically placed explosives. The building dropped at near freefall speed. Lower floors that had no damage collapsed completely with absolutely no resistance. This means that the entire building was on the brink of falling down before the planes hit them.

In order for buildings to fall exactly as they did, with the planes as the cause, everything must have gone wrong at once. Any redundancies would have had to fail at precisely the same time, and specific temperatures had to have been reached at that same time. Temperatures that have not been reported by any agency. The smoke from the towers was burning black, which means a cool fire.

When we piece it together the most likely way for this to go down was through planned demolition. Far more likely than being brought down by planes.

Originally posted by Rasobasi420
I don't buy it.
All 3 of these buildings fell straight down, and their concrete was all turned to dust. There was little to no macroscopic pieces of concrete. That doesn't happen when things fall from 1000 or so feet.

OK. Do you have any proof to back up this claim?

Originally posted by Rasobasi420
Even WTC7 which has yet to be explained successfully. It has never happened before, or after that a building would fall straight down without specifically placed explosives.

Wrong. There have been a number of construction related collapses that have fallen straight down. I’d google them up for you, but it’ll have to wait.

Originally posted by Rasobasi420
The building dropped at near freefall speed. Lower floors that had no damage collapsed completely with absolutely no resistance. This means that the entire building was on the brink of falling down before the planes hit them.

No, it means that the forces involved in the collapsing structure exceeded the ability of the structure to stay intact. There is nothing unusual about the speed in which the structure failed. Buckling failures are typically sudden and catastrophic.

Originally posted by Rasobasi420
In order for buildings to fall exactly as they did, with the planes as the cause, everything must have gone wrong at once.

No, everything did not have to “go wrong at once.” The failures were cumulative. Each failure, however, transferred gravity loads to the undamaged portions of the building. Eventually those columns reached the yield point and the entire system came down.

Originally posted by Rasobasi420
Any redundancies would have had to fail at precisely the same time, and specific temperatures had to have been reached at that same time. Temperatures that have not been reported by any agency.

No, it was not necessary for the entire floor to reach the same temperature at the same time. The key building component affected by the heat of the fires were the floor trusses.

These were particularly vulnerable because the sprayed on fireproofing would have been readily stripped off by the forces of the impact. Once the diagonals of the trusses buckled, the floors would have begun to sag.
As the fires swept across the floors, the trusses were heated to this point in turn. Even if they subsequently cooled off, the change in the geometry of the trusses meant that they were now pulling inward on the exterior columns.

Once one single floor began to sag, the critical load at which the exterior columns will buckle was cut down by 75%. If two adjacent floors start to sag, the critical load for the exterior columns is now only 11.11% of the original value. AND, you have an inward force pulling the columns out of line.

Originally posted by Rasobasi420
The smoke from the towers was burning black, which means a cool fire.

OK, bsbray junior. Whatever you say.

(That doesn’t make it true, however)

Originally posted by HowardRoark

Originally posted by Rasobasi420
I don't buy it.
All 3 of these buildings fell straight down, and their concrete was all turned to dust. There was little to no macroscopic pieces of concrete. That doesn't happen when things fall from 1000 or so feet.

OK. Do you have any proof to back up this claim?

Howard, why would you ask someone for proof of something that is readily evident in photos of Ground Zero? Are you waiting for a Ph. D. that sides with the official story to come along and look at the photos before you'll believe them?

Powder remains of concrete, sheet rock, etc., spread throughout Manhattan:

external image

Non-pulverized debris at Ground Zero (steel):

external image

The only intact concrete from the towers was from under them, in the basement levels.

There have been a number of construction related collapses that have fallen straight down. I’d google them up for you, but it’ll have to wait.

Yeah, make sure they're steel skyscrapers, too. Not one-story or concrete or wood buildings.

Buckling failures are typically sudden and catastrophic.

Buckling failures have never occurred on so grand a scale as you claim happened on 9/11 with the Twin Towers, so I don't know what you're referencing here.

Originally posted by Rasobasi420
In order for buildings to fall exactly as they did, with the planes as the cause, everything must have gone wrong at once.

No, everything did not have to “go wrong at once.” The failures were cumulative. Each failure, however, transferred gravity loads to the undamaged portions of the building.

Both towers fell symmetrically. That doesn't happen from random failures, or even very ordered failures, in a system like this. There's something called chaos. For the towers to have both fallen so symmetrically without lopsiding would require something with astronomical odds against it to have occurred: all of the columns on any given floor all failing within about a 10th of a second of each other, very cleanly.

Take a collapse time and divide by the number of floors (110) and see what you get. That's how long each floor had to fail without the structure lopsiding. The floors were 12.5 feet high each, too. Take all of this in, along with the strength of steel and the vast amount of it in those towers, and imagine what we're talking about.

And we don't even know what NIST is saying caused each floor to collapse, because they haven't gone beyond their explanation of how the first floor fell.

Eventually those columns reached the yield point and the entire system came down.

NIST makes a lot of claims like this. 'Oh, after the first floor fell, the rest was inevitable. No questions to be asked.' These statements are vague and have nothing to support them.

These were particularly vulnerable because the sprayed on fireproofing would have been readily stripped off by the forces of the impact.

The fireproofing would only matter if the steel could be heated to critical temperatures with the given fires, whereas much above 400 C would cause steel to glow in broad daylight, and steel hasn't even lost any critical strength at 400 C. Anybody see any glowing steel before collapse? NIST tested over a hundred steel samples and found only a couple columns with heating to just 250 C or so.

It isn't very likely at all that any steel was heated enough to fail. BYU Professor Steven Jones has made this clear, as what seems like his biggest grievance with NIST's report.

Originally posted by Rasobasi420
The smoke from the towers was burning black, which means a cool fire.

OK, bsbray junior.

Whatever you say.

(That doesn’t make it true, however)

Nice rebuttal.

[edit on 16-3-2006 by bsbray11]

Let us be clear hear on buckling failure. Imagine a table with four legs subject to an increasing load, till the weakest leg fails by buckling. Buckling is an unusual failure in that it does not require an increasing load to continue failure, but in fact the required load drops, eventually, to a minimum value of one quarter of the failure load, assuming three buckle points. That is why it is rapid, because of the decreasing load. So the other legs will be asked to now carry a larger share of the load, and the nearest neighbour, the leg next to it will be asked to carry a larger proportion of the load shed by the first leg than the other two legs further away. If all of the other three legs were close to failure this will push the second leg into failure. Now try it with eight legs, then sixteen.......

Or you can get a cardboard tube, stand it on end and pile books on top, one at a time till it buckles. Straight down? or off to the side.
Unfair you say because it is only one tube. So get eight tubes, line them up however you like and put a board across the top
Try with a stack of tube, board, tube, board as high as you like, climb on top, then get someone to chop a hole in the side, before passing you a number of concrete blocks to represent the increasing load, or loss of resistance, although this will be an evenly distributed load rather than assymetric loss of strength, but you are going to need all the help you can get. Straight down? Or in a heap at the side?

Exactly the same argument applies to the towers. The damage is assymetric, the loss of strength affects volumes of the towers columns, not neat identical damage and rate of change of damage across the volume of single storeys or some other near rectangularly bounded volume. That defies the evidence.

If the columns had failed in compression, or tension(?) then the idea of symmetric shifting of loads, may have had some merit, but in these instances the failure load and the load to continue failure have a different relationship. Bazant Zhou talk about this.

The upper section and upper pieces of the tower existed in a state of unstable equilibrium in that direction. The collapse exhibited the characteristics of a process in stable equilibrium - exactly the opposite. The fact remains that if the failure had occured due to the factors recognised by the OCT then the result would have been an assymetric collapse.

Gordon.

In order for the perimeter columns to carry no load, the floors would have to be cantilevered from the core. They were not, so the outer columns were asked to carry themselves, 5/8ths of the floors, 5/8ths of the maximum floor loading, and a proportion of the hat truss and other stuff up there. The core would take the remainder of the floor load plus all the elevator loads, including the motors and other stuff particularly grouped around or in the core and especially at maintenance levels, and the majority of the antennae, hat truss, etc.

Some have said (elsewhere)that the hat truss held a proportion of the weight of the columns, but this does not make any sense from a design point of view, and how would they build it? They would have to cantilever the hat truss out from the core, then stretch the columns up till they met the hat truss in order to connect them. Hardly likely, is it?

Gordon.

Originally posted by bsbray11

Originally posted by HowardRoark

Originally posted by Rasobasi420
I don't buy it.
All 3 of these buildings fell straight down, and their concrete was all turned to dust. There was little to no macroscopic pieces of concrete. That doesn't happen when things fall from 1000 or so feet.

OK. Do you have any proof to back up this claim?

Howard, why would you ask someone for proof of something that is readily evident in photos of Ground Zero? Are you waiting for a Ph. D. that sides with the official story to come along and look at the photos before you'll believe them?

Powder remains of concrete, sheet rock, etc., spread throughout Manhattan:

external image

That proved nothing, since there is not data on how far that was taken from the collapse point.

Rasobasi420 stated thatthere were no macroscopic pieces of concrete.


How far do you expect these pieces to travel compared to the finer particles?

here is some debris on a parked car.

Gordon, are you familiar with this shot of the inward bowing of the south face of WTC 1 shortly before it collapsed?



Or are you going to claim, like some have, that this is a heat related optical distortion ?

Originally posted by HowardRoark
That proved nothing, since there is not data on how far that was taken from the collapse point.

That stuff was all over Manhattan. I could post more pics if you want, showing whole streets covered in this powder both within the WTC Complex and along the streets outside of it. But where are the larger chunks of concrete?

How far do you expect these pieces to travel compared to the finer particles?

Farther than the masses of steel columns that were ejected outwards.

here is some debris on a parked car.

Posting a single picture of two fist-sized pieces of concrete trivializes this whole issue.

110 floors, with 4" or thicker concrete slabs between each floor. That's a lot of concrete, Howard. Don't you have anything besides this, and pictures of concrete from the basement floors? Can you even show that those pieces of concrete came from the floor slabs between the floors of a WTC building?

And please explain what part of the collapses would grind the 4" inch slabs throughout the buildings, as well as the sheet rock and etc., into such a fine powder, as seen all over the streets in NYC?

Remember that the trusses contained the slabs, and were failing on their ends, allegedly. So I'm wondering how so much concrete became so thoroughly and consistently pulverized in these circumstances, so that we have nothing but concrete powder flying through the air.

Originally posted by HowardRoark
Gordon, are you familiar with this shot of the inward bowing of the south face of WTC 1 shortly before it collapsed?

Ok, Howard, what does this have to do with what Gordon was just talking about? He was just saying how the cores carried the greater load, and that buckling should have resulted in an asymmetrical collapse.

Did you even read those posts?

Or are you going to claim, like some have, that this is a heat related optical distortion ?

No.
If you read the theory you will see that the relatively slow acting thermite base charge would be responsible for downward movement of the core as it was unloaded. This load would necessarily be transferred via the hat truss to a nominally vertical load on the perimeter columns, and via the floors to an increase in the nominally horizontal force acting inwards on the perimeter columns. This phenomenon would be most evident in and around the area of aircraft impact and thermal damage.

Nist however have a poor explanation for this phenomenon in that the downward movement of the core through creep and plastic distortion when compared with the differential linear expansion of the core and perimeter columns, and with due notice taken of the linear expansion of the floors, does not account for this deflection. For a more detailed account of this see the work of Lamont & Lane. You can also visualise the fault in logic - the core heats up and expands, upwards, can't go down. It then distorts because of the weight pressing down over time under high temperature - the bottom of the tower has not deflected downwards, the top has gone up, then down - where is the net downward movement which pulls inwards on the perimeter? Certainly not at or below a level which has not been significantly heated. Also you have to compensate for the fact that the floors have got longer, so you have to have a movement to compensate for that. Where is all this force coming from? The horizontal component of the floor mass, acting through an angle which has a cosine of close to zero? Acting on only a few columns?

Gordon.

We are told that the floor sections had lengths of 35' and 60'.
What was the length and breadth of the building?
What was the size of the core?
What was the difference, ie the span? 35' and 60'?
What was in the corner?
To what were its ends attached?
Is the answer to this question made clear in the official version?
Do they mention that in these floor sections we have one end transmitting an inward pulling force connected to every other perimeter column, but still forced to deflect all the columns because of the spandrel plates, while at the other end we have all of the reactions acting on a single member of far smaller dimension? Does Nist mention the dimension of this member?


This member would by its existence act to transfer wind load throughout the structure in preference to the floor trusses, and the role of the trusses was to carry the floor load.

Gordon.

Originally posted by gordonross
Nist however have a poor explanation for this phenomenon in that the downward movement of the core through creep and plastic distortion when compared with the differential linear expansion of the core and perimeter columns, and with due notice taken of the linear expansion of the floors, does not account for this deflection. ...
Also you have to compensate for the fact that the floors have got longer, so you have to have a movement to compensate for that.

Well said. I've been saying this for months, and Fire Engineering firms not in the employ of the U.S. government have been saying it for much, much longer. E.g. the UK's globally-respected Arup Fire Engineering

www.arup.com...

The WTC towers behaved very well following impact and in response to multiple floor fires indicating that it was a
robust system. The draft NIST report appears to rely on dislodged fire protection. Our main concern with this conclusion is that thermal expansion can swamp all other behaviours and this is not discussed in the NIST report yet. We believe it should be included in a thermo-mechanical analysis to predict the response of any structure to fire, particularly when determining a probable collapse mechanism.
[...]
Collapse mechanism proposed by NIST in April 5 Presentation Report:

The basis of NIST’s collapse theory is also column behavior in fire. However, we believe that a considerable difference in downward displacement between the core and perimeter columns, much greater than the 300mm proposed, is required for the collapse theory to hold true.

Why upward expansion of the column would act against the mechanical shortening:

Crude initial calculations indicate that the elastic downward deflection at half the modulus (say at approx. 500C) will be roughly 38mm. Assuming plastic strains, a maximum yielding of approximately 190mm is possible. If the downward displacement is 300mm as assumed, the rotation at the perimeter connection would be 300mm vertical over an 18000mm span - extremely small.
The floor elongation must be less than 2.5mm to generate tensile pulling forces on the exterior columns as a result of the column shortening in the core. Thermal expansion of the floor truss would be 65mm at 300°C over a length of 18000mm. Therefore the 2.5mm is swamped by thermal expansion and the core columns cannot pull the exterior columns in via the floor simply as a result of column shortening. The NIST collapse theory also states that “floors weakened and sagged from the fires, pulling inward on the perimeter columns. Floor sagging and exposure to high temperatures caused the perimeter columns to bow inward and buckle—a process that spread across the faces of the buildings. Collapse then ensued”.

This is similar to some of our collapse proposals but no mention of thermal expansion is made, the floor buckling and lack of support to the columns seems to be entirely due to loss in strength and stiffness in their view which we would consider to be only part of the story.

You have voted gordonross for the Way Above Top Secret award. You have two more votes this month.

You have voted gordonross for the Way Above Top Secret award. You have one more vote left for this month.

You have put into words what my thoughts on the subject for a while are so elequently. Keep up the good work.

Originally posted by wecomeinpeace
I've been saying this for months, and Fire Engineering firms not in the employ of the U.S. government have been saying it for much, much longer.

Yep, gotta love those Brits.
fire-research.group.shef.ac.uk...

Originally posted by HowardRoark
Gordon, are you familiar with this shot of the inward bowing of the south face of WTC 1 shortly before it collapsed?

Or are you going to claim, like some have, that this is a heat related optical distortion

?

1 sec before it collapsed? 1 min befor it collapsed? 1 hours before it collapsed? How shortly before it collapsed Howard. When you can tell us such thing the evidence you show, which i fail to see, may be applicable.

IIRC, It was a few minutes before the collapse.

Five or 10 maybe?

It’s in the NIST report somewhere. I’ll look for it later tonight.

Originally posted by HowardRoark
Yep, gotta love those Brits.
fire-research.group.shef.ac.uk...

I don't have an image capturing program where I am, so please be kind enough to show the temperature development charts that are meant to accompany those graphs in the file you linked to. You know, the ones that show temps of 800C and more to produce the compression deflections shown. I'm sure they must have slipped your mind.

There seems to be something missing from the above diagram. I know, it's the core. Why have you shown us a study of a truss unrestrained at the core when this factor is central to the point being made? For all the relevance your last post holds, you might as well show us temperature load modelling for a batch of Grandma Roark's cookies baked in the oven last Sunday.

And the study you link to is for unprotected truss assemblies. I'm still waiting for your reply to my request for how the projected loss of fireproofing from the impacts was tested and quantfied by NIST.

What part of “Standard Fire” is hard to understand?

Originally posted by wecomeinpeace
And the study you link to is for unprotected truss assemblies. I'm still waiting for your reply to my request for how the projected loss of fireproofing from the impacts was tested and quantfied by NIST.

Hell, it was falling off, before, the planes hit.

I wonder why Howard always ingores Gordon's posts.