Architects, Engineers, and Scientists Analyze Failings of NIST's WTC 7 Final Report!

Originally posted by mirageofdeceit
A few things that seem to be consistently missed/side-lined:

* NIST never investigated the core column collapse for WTC1 and 2. Every official documentary/video I've seen, shows the core remaining intact, even when they're explaining how a pancake collapse works

This is a valid point, but somewhat irrelevant. NIST didn't investigate anything after collapse initiation as there is no reliable way to do so. The only models existing after that are massively simplified in order to reduce the complexity.

* When NIST explains the WTC7 collapse, they neglect to explain how the building collapses globally when one column is allegedly at fault

Please make sure you've read NCSTAR 1-9A, there's quite a thorough discussion of the collapse model there.

* How one column can even be responsible for total global failure at the same time

It wasn't just "one column", but even so the initiating column had a relatively unique layout and design. The report explains this reasonably well.

* Why the building appears to be intact until it all suddenly fails

It doesn't, you can see the east penthouse fail, followed by window breakage, then a slight movement of the building for a second or two until the main collapse phase starts.

* Why all the NIST videos of a global collapse look nothing like the actual collapse, and terminate about 1 second after collapse begins

They are simulations, they become less accurate as they progress.

* Why the exterior walls never showed signs of buckling, or failed, when the supporting columns down one side all failed, *PRIOR* to global collapse of the building (thre is no evidence of this in any video of the Windows, either)

They do, I don't know what your point about 'of the Windows' is supposed to mean, but you can clearly see large amounts of broken windows underneath the east penthouse collapse, and the building perceptibly moves before the main collapse phase starts.

* How a couple of news channels could possibly report the event 23 minutes early. Who fed them the information? Who were the structural engineers watching the building, giving updates?

It was a false report put out by (iirc) Reuters, they later retracted it. Firemen were the people who determined the building would collapse and they had been saying this from about 2:30pm

* Why is it WTC2 collapsed 57 minutes after impact, yet it was 7 hours before WTC7 collapsed (don't say fireproofing)?

Uh, fireproofing. That and the size and progression of the fires, the lack of impact damage as severe etc. There are a number of reasons, a good one being that the buildings were nothing alike?

* How did the columns in WTC7 manage to fail the way they did pre-global collapse without sections of the building falling asymmetrically, yet it only took the failure of one column to bring down the building (their model)?

Sections of the building failed asymmetrically.

I want answers to these questions. Fire does not explain all this.

What does?

If this is true, and the dribbles of molten goo came from melted airplane, then the only conspiracy was the one hatched and executed by Bin Laden and associates.

BBC News...

Scientists say an understanding of how the Twin Towers collapsed will help them develop the materials needed to build fusion reactors.

New research shows how steel will fail at high temperatures because of the magnetic properties of the metal.

The New York buildings fell when their steel backbones lost strength in the fires that followed the plane impacts.

Dr Sergei Dudarev told the British Association Science Festival that improved steels were now being sought.

The principal scientist at the United Kingdom Atomic Energy Authority (UKAEA) said one of the first applications for these better performing metals would be in the wall linings of fusion reactors where temperatures would be in a similar range to those experienced in the Twin Towers' fires.

'Not melting'

The key advance is the understanding that, at high temperatures, tiny irregularities in a steel's structure can disrupt its internal magnetic fields, making the rigid metal soft.

"Steels melt at about 1,150C (2,102F), but lose strength at much lower temperatures," explained Dr Sergei Dudarev, principal scientist at the United Kingdom Atomic Energy Authority (UKAEA).

At room temperature, the magnetic fields between iron atoms remain regular, but when heated, these fields are altered allowing the atoms to slide past each other, weakening the steel.

"[The steel] becomes very soft. It is not melting but the effect is the same," said Dr Dudarev.

He said blacksmiths had exploited this property for hundreds of years - it allows iron to become pliable at temperatures much lower than its melting point.

reply to post by fmcanarney

Dear Non-laughing fmcanarney,
The cock-and-bull part is claiming that anything but two aircraft full of fuel and travelling at 400mph hit and destroyed the towers. I have seen every alternative explanation of why they came down from demolition charges to thermite and there is no evidence for any of it, including the missile hit. There is heresay and speculation. What is claimed is that the perpetrators that were clever and determined enough to bring the buildings down under the cover of the airplane hits weren't smart enough to hide their crime. Why would they have bothered with thermite? Thermite has significant light output when it goes off and it isn't a dull orange goo. Thermite is used to fill cracks in large castings and melt through light materials. To melt a beam, a goodly amount would need to be used. To melt many beams, a lot would have to be used. Cutting charges would have required a lot less mass of energetic material but cutting a lot of beams would have been noticed. They are not quiet cutters. Why not just cleverly saw through beams or stealthily unbolt them since everyone would have known which floors the planes would strike, especially with such skilled pilots at the stick. Fortunately they didn't come in on a steeper angle of attack and clip the towers on much lower floors.
No one could have predicted how the towers would have behaved before the event because big airliners colliding with enormous buildings is completely out of our experience. If there was any collusion, it was allowing the hijackers to use the aircraft as the biggest cruise missiles on the planet. Inspecting videos of molten something dripping from a hole does not qualify as evidence of melted steel. Engineers can only guess at the conditions in that building at that time. They can say that the beams that were tested didn't experience temperatures near the melting point of steel. The beams don't have to melt for the bolts to shear or the structure to become unstable. Can anyone calculate the physical and thermal stresses on the floor beams and attachment bolts not knowing what internal damage was done to the building?

Non-laughing Pteridine

Since when have blacksmiths used construction grade steel on horseshoes and wagon wheels?

Pteridine, not meaning to offend you but what do blacksmiths exploiting magnetic particles in steel have to do with the steel in WTC1-2-7.

The majority of jet fuel burned in the dramatic explosions on impact. You have to subject steel to direct heat, not heat transferred by air, direct heat on the steel to begin to heat it up sufficiently for it to soften.

If you were going to heat a piece of 1/2 inch rebar with a propane torch, burns at what 3,000 degrees F. till it got hot enough to glow it would take a long time. Just to heat up two inches in the middle. And that is with the propane flame touching and dancing on the section of rebar.

For faster results use compressed oxygen and acetylene which produces a flame of 7,500 degrees F. Heat the rebar up to glowing and remove the flame. In a very short time the rebar is cooling down. The steel in WTC was massively larger in thickness and surface area than rebar.

Plastic/paper fires do not produce sufficient heat to indirectly via air or directly with contact to heat that size of steel anywhere close to a "Melting point" It is impossible. I am not going to produce links and scientific evidence to support this reality, as it is supported by common sense.

Go to a hardware store and get a propane torch.
find a railroad spike, piece of rebar or some other such piece of steel. And proceed to heat the steel up to where it "melts".

Although the propane fire is hot enough to melt steel, the fact that the cold part of the spike or the rebar will draw away or wick the heat from the hot part to the cold part and you will never "MELT" the steel.

The mass of the beams in the WTC buildings is more that enough to draw away and wick any heat applied directly or indirectly to the steel.

And by the way a blacksmith must put the horseshoe into the fire, hear that INTO the fire, to get enough heat to transfer into the mass of the horseshoe.

So the magnetism/alignment is cock and bull.

But if you work in a high rise building or know someone who does I just happen to have for sale some magnetic alignment devices that increase the melting temperature of the steel in a highrise to above 2850 F. They can be plugged into a 110 wall socket and when attached to the steel support beams will guarantee the building will be impervious to jet fuel fires for thirty six hours. The price includes a first time purchase discount of 20%. I am asking $249,000.00 per unit, free shipping included. I even have a smaller model for vehicles that operate off car batteries.



[edit on 13-9-2008 by fmcanarney]

reply to post by fmcanarney

What pteridine is correctly referring to is better known as the 'Curie Point' which is the temperature at which ferromagnetic materials lose their magnetic properties. The actual temperature at which this occurs varies greatly depending the actual alloy. For instance, the Weller company makes (or used to make) a range of soldering irons that use the Curie point to control the tip temperature by using specially produced alloys which lose magnetic properties in the 200C-400C range.

For steel this point is at a cherry red temperature (800C-1000C) and it's coincidentally the point at which the steel becomes very workable with a hammer and anvil (IE softer, pliable but not molten). Modern day blacksmiths determine they have reached the minimum temperature with a magnet as it doesn't stick to the steel any longer.

As stated earlier in this thread, there's very little evidence of steel having reached these sorts of temperatures pre-collapse though.


[edit on 13/9/2008 by Pilgrum]

Originally posted by fmcanarney
The mass of the beams in the WTC buildings is more that enough to draw away and wick any heat applied directly or indirectly to the steel.

This is completely incorrect. The most vulnerable elements in the WTC towers were the trusses. These trusses had only a few square inches of contact space to the rest of the steel in the towers, but hundreds of square inches of surface area which was involved in flame.

If you think that you couldn't heat anything up, why don't you show some calculations. Show us how there was plenty of steel to steel contact in order to allow this heat to be wicked away. So far we have only your opinion.

EDIT...sorry.

[edit on 13-9-2008 by ThroatYogurt]

Originally posted by ThroatYogurt

EDIT...sorry.

[edit on 13-9-2008 by ThroatYogurt]

What I was referring to (took me a while to find) was this: z10.invisionfree.com...

As you can see, even when I take absolutely ridiculous error margins into account, the surface area available for thermal conduction to perimeter and core columns was under 6% of the total surface area available. Of course thermal conduction depends also on the difference in temperature, but it's obvious simply from these figures how the steel could not magically wick heat away.

Originally posted by exponent
These trusses had only a few square inches of contact space to the rest of the steel in the towers, but hundreds of square inches of surface area which was involved in flame.

Just so no one is confused, NIST's failure mechanisms only needed trusses to be heated to the point of a certain amount of expansion (which they didn't really define) so that a certain amount of force would be applied laterally to the perimeter columns (also no calculations from NIST for that). Then the perimeter columns are somewhat deflected, and supposedly after so much of this (they also didn't say how many would need to be deflected or by how much) the "global collapse" ensued, which NIST simply called "inevitable," again without showing any work.

Just trying to make it clear that, not even the "official" reports are actually saying heat itself caused actual significant strength loss in the steel columns or even the trusses

reply to post by exponent


Dr. Greening did some calcs. See his analysis of NIST here: the911forum.freeforums.org...
This is pretty interesting:

NIST’s computer simulation of the collapse of WTC 7, as presented in Chapters 8 and 12 of NCSTAR 1-9, is remarkable for the low temperatures - as low as 100 °C – at which failures of connecting elements such as bolts and studs are predicted to have first occurred in WTC 7 after about 3:00 p.m. on 9/11. These failures were caused, so NIST asserts, by the thermal expansion of asymmetrical framing beams and girders on the east side of floors 12/13. Nevertheless, in NIST's model, complete separation of column 79 from lateral restraints to buckling is predicted to occur only at temperatures well above 300 °C. Thus NIST’s collapse initiation hypothesis requires that structural steel temperatures on floors 12/13 significantly exceeded 300 °C - a condition I believe that could never have been realized with NIST’s postulated 32 kg/m2 or lower fuel loading.

The floor trusses were also in immediate contact with the concrete floors. Concrete will also wick heat away. Though not as quickly as steel. The fires transferred heat through the medium of air and direst contact to the steel. Air is a poor coupling media for heat.

Originally posted by bsbray11
Just so no one is confused, NIST's failure mechanisms only needed trusses to be heated to the point of a certain amount of expansion (which they didn't really define) so that a certain amount of force would be applied laterally to the perimeter columns (also no calculations from NIST for that).

This is not wholly accurate. NIST predicts that initially trusses expand when heated, but after enough time and heat, parts of the truss will buckle and it will fall entirely into tension. At this point it pulls inward on the perimeter columns, rather than pushing outward. This inward deflection coupled with the increase in gravity loads due to core deflection, perimeter column damage etc eventually leads to collapse.

You claim that they don't define the amount of expansion, but this is not true, NIST provides visualisations of their models with scales showing the predicted amount of floor deflection. As this is the predicted failure mechanism I think this is what you would be asking for. You also claim there's no details of force or deflection of perimeter columns, but NIST provides both estimates of inward force and the measured deflection from photographs.

"global collapse" ensued, which NIST simply called "inevitable," again without showing any work.

NIST referenced Bazant's work, which does show his calculations.

Just trying to make it clear that, not even the "official" reports are actually saying heat itself caused actual significant strength loss in the steel columns or even the trusses

Yes they are, the predicted steel temperatures exceed 600C in places, and this inherently results in large scale steel weakening.

I appreciate you have a reasonable understanding of NISTs theory, but it sounds like you may have only read NCSTAR 1. If you have time I really would recommend a good read of NCSTAR 1-6 (and all the subreports) as they do go into as much detail as you could expect. They don't take things as far as WTC7s simulation but as you can see people have complained that this is inaccurate, the complaints would be much more significant for WTC1 or 2.

Originally posted by fmcanarney
The floor trusses were also in immediate contact with the concrete floors. Concrete will also wick heat away. Though not as quickly as steel. The fires transferred heat through the medium of air and direst contact to the steel. Air is a poor coupling media for heat.

This is true enough, although concrete is quite a good fire insulator compared to most common metals. Regardless, this does nothing to advance your theory that the steel in the WTC could not heat up. You must provide evidence for this, and even if we include the amount of steel in contact with floor pans and thus in contact with concrete, the surface area is still very small. Trusses are composed of many cylindrical rods, and operate in a complex manner. They are notoriously vulnerable to fire and difficult to predict their behaviour.

I am more than willing to entertain your hypothesis, but you need to provide some sort of evidence to suggest that NIST is wrong rather than speculation alone.

[edit on 13-9-2008 by exponent]

Well, 1120 C. on a few trusses is not consistent with total collapse model.
Bolts which hold trusses together are a much higher grade (9-11) of hardness than trusses. What are the dimensions of the trusses and support columns?

There were no planes full of fuel at WTC7. Yes there were fires in WTC7 but the fire was moving in order to follow and consume new fuel. As the fuel source is consumed the steel previously in contact with the fire will begin cooling as the fire moves on to follow the fuel source. After all the contents of an office once consumed in a fire disappear and cannot continue fueling a fire.

In the areas of fire windows were broken out which allowed heat to escape with little or no effect on steel.

Originally posted by fmcanarney
Well, 1120 C. on a few trusses is not consistent with total collapse model.
Bolts which hold trusses together are a much higher grade (9-11) of hardness than trusses. What are the dimensions of the trusses and support columns?

This information is in the NIST report. I am interested in what you think is not consistent though.

There were no planes full of fuel at WTC7. Yes there were fires in WTC7 but the fire was moving in order to follow and consume new fuel. As the fuel source is consumed the steel previously in contact with the fire will begin cooling as the fire moves on to follow the fuel source. After all the contents of an office once consumed in a fire disappear and cannot continue fueling a fire.

This is accurate, the failure in WTC7 occurred (somewhat) at lower temperatures, the steel was better protected and the primary reason for its failure was that the fire was not fought. If sprinkler systems were working, or firefighters did not make the decision to pull out of the building then it's quite likely WTC7 would not have collapsed.

In the areas of fire windows were broken out which allowed heat to escape with little or no effect on steel.

You have not shown anything to make us believe this, you are just speculating. Windows are also a source of oxygen, which will increase the temperature of the flames. Your point is actually valid in some conditions, obviously heat can escape more easily through a broken window, but you don't know that it will have 'little or no effect'. NIST actually set large office areas on fire to test what would happen. How do you know that they are wrong and you are right?

No I will just continue to speculate as you have diagnosed exponent, as that is a perogative of mine. You can continue to accept the thermal expansion heated truss theory. I believe there was a fire in one of the towers @1973 that burned, at times, in excess of 500C for four hours and did not necessitate the replacement of one truss.

The February 1975 World Trade Center North Tower Fire.


This 110-story steel-framed office building suffered a fire on the 11th floor on February 23, 1975. The fire started at approximately 11:45 P.M. in a furnished office on the 11th floor and spread through the corridors toward the main open office area. The fire department on arrival found a very intense fire. It was not immediately known that the fire was spreading vertically from floor to floor through openings in the floor slab. These 300-mm x 450-mm (12-in. x 18-in.) openings in the slab provided access for telephone cables. Subsidiary fires on the 9th to the 19th floors were discovered and readily extinguished. The only occupants of the building at the time of fire were cleaning and service personnel. They were evacuated without any fatalities. However, there were 125 firemen involved in fighting this fire and 28 sustained injuries from the intense heat and smoke. The cause of the fire is unknown.
The WTC North Tower suffered no serious structural damage in this fire. In particular, none of the trusses needed to be replaced.

guardian.150m.com...

911research.wtc7.net...

Originally posted by fmcanarney
No I will just continue to speculate as you have diagnosed exponent, as that is a perogative of mine. You can continue to accept the thermal expansion heated truss theory. I believe there was a fire in one of the towers @1973 that burned, at times, in excess of 500C for four hours and did not necessitate the replacement of one truss.

Well you're free to speculate all you like, but what is the point? It adds nothing to the discussion and can prove nothing?

Regarding the 1975 fire, I have discussed this in another thread with ULTIMA1. There are many different factors between the two fires. The steel in 1975 had no fireproofing damage, the fire was fought and only occupied a relatively small area. There was actually some minor damage which occurred, but it was not too serious.

You can't be making the argument that steel is invulnerable to fire, so you must be (unless I am mistaken!) making the argument that the fires on 911 were not significant enough to damage the steel. How do you resolve this with NISTs tests which do not agree with you?

Originally posted by exponent
How do you resolve this with NISTs tests which do not agree with you?

Are you talking about the computer simulations?

That's easy: they kept modifying the simulation parameters. If you don't know what I'm talking about already, then someone else can post the relevant part of the NIST report or I can do it later. They assumed a priori that fire and impact damages caused the collapses, and then they kept simulating the fires on computers and increasing the amount of heat until they could start producing failures.

If you're talking about actual lab tests, I would love to see the test where NIST showed expanding trusses deflecting perimeter columns.

Originally posted by exponent
You claim that they don't define the amount of expansion, but this is not true, NIST provides visualisations of their models with scales showing the predicted amount of floor deflection.

Do you have any idea how showing that allows verifying their actual calculations or simulations independently? Why do you think it would be important to consider those kinds of calculations in the first place?

You also claim there's no details of force or deflection of perimeter columns, but NIST provides both estimates of inward force

I actually didn't know this. Can you link to it? And does it add this force to the tensions from the spandrel plates and end-to-end connections (which would have tried to hold the columns in place)?

"global collapse" ensued, which NIST simply called "inevitable," again without showing any work.

NIST referenced Bazant's work, which does show his calculations.

Bazant's work has been criticized for assuming variables where either experimental data or the actual structural documentation needs to be consulted, among other problems. The paper was written 2 days after 9/11, before any investigation whatsoever, and with absolutely no precedent on which to base the physics.

If you've never read this, take a shot: 911research.wtc7.net...

Yes they are, the predicted steel temperatures exceed 600C in places

But they physically found no evidence for this, or even for heating above around 200-300 C. Not to mention steel glows dark red in broad daylight at this temperature. In general it is an insane temperature to transfer to much steel, because of how much heat energy is required to do it. Maybe not for the truss connections but certainly for the columns, especially the core columns. They were enormous heat sinks. There are websites that follow NIST's math and show they ultimately assumed the equivalent of 500 wood stoves' output of heat energy for so much square footage in their simulations. Have you ever looked at that math? Would you be willing to or do you find yourself automatically assuming it's wrong and that NIST is still pure?

Nobody had any comments on Dr. Greenings work that I linked to above? I will not link to it again as it is just a few posts up this page. I will leave you with another quote from the material he presented:

NIST’s fire simulation would have us believe that a very substantial heat release rate was sustained for over 2 hours over a floor area of about 500 m2 in building 7. Thus Figure 9-13 of NCSTAR 1-9 shows that a heat release rate of 200 MW was attained on floor 12 at about 3:00 p.m. on September 11th and remained above 200 MW until well after 5:00 p.m. But we need to ask: Is a 200 MW fire consistent with a fuel loading of 32 kg/m2 - the value used by NIST for its floor 12 fire simulations? The answer appears to be no. Thus a 200 MW heat release rate for 2 hours implies a total energy release of 1,440 GJ. If the combustible material on the 12th floor of WTC 7 is assumed to release 20 MJ/kg, we have to conclude that 72,000 kg of office material was combusted over an area of 500 m2, or there was a fuel loading in WTC 7 of 144 kg/m2 – a value over four times NIST’s assumed fuel loading.

Pay particular attention to the last sentence as this seems to be a reoccurring theme throughout NIST's work on the WTC reports.