Critical Errors and Omissions in WTC7 Report Uncovered

[Pete Tar]

You should check the supporting videos.

Ha, well I was just going on the posts made and the tone therein, I was hoping the video's were the same.

 

[Jazzy]

All this is good stuff very informative but I fail to see the evidence that would have suggested or proved simultaneous failure to cause the period of free fall. I get that it could fall onto itself with the momentum and weight but where is there something explaining how the period of free fall could be possible. Because if you think about it IF thermite were used the only places they would need to use it would be the spots critical to cause the free fall gravity would do the rest as proven above

But once the restraint was relaxed on column 79, a pandora's box of consequences was opened.

The first consequence was that column 79 buckled. The load it was supporting was everything above it. It stopped accepting it. It shed its load. It would have squirmed sideways as it did so. By it, I mean the column length between the ceiling of that floor, and the floor beneath. The doubling of its effective length would have automatically quartered its resistance to Euler Buckling.

That meant the weight of everything above it had to be supported (including its own, through column/beam connections with their studs, and without cross-bracing) all the way to the roof by its neighbors, which were fifty feet away.

The next consequence would have been the unattached floor striking the floor beneath. If that happened to break its connections, the effective length of that section of Column 79 would have been tripled, and its resistance to buckling reduced to one ninth.

This was not a static process. Nor was it slow. Buckling failure is silent and rapid, and involves very little resistance once it occurs. C79 would have thrashed like a snake, and every attached floor above it would also have been rapidly detached, more or less simultaneously. This would be something similar to, but not quite, free fall.

Even so, the video's claim of collapse taking 6 seconds is incorrect by a factor of TWO. It took TWELVE seconds to collapse completely. The penthouse disappearing before the fascia began to move is the clue to that.

Or, in other words, the WTC7's collapse began six seconds before you believe it did. The building emitted a large puff of black smoke (caused by a falling floor).

This marked the start of collapse.

 

[thedude953]

Totally agree the process would have been swift and unrecognizable to the human eye, unfortunately it just doesn't give any evidence for the period of free fall. And the argument that the collapse would have started before we think it did although it may seem to make sense it really is just smoke and mirrors in the debate of the speed of the collapse because the "collapse" technically started when the fires did if your thinking about it like that. We know math proves the building or any building could fall as fast or close to as fast as it did. But it doesn't show in any way that everything would weaken so simultaneous or close enough to it to create free fall speed especially with being able to slow the video down and examine it so closely, it's clearly a synchronized fall I just don't think the math and physics explains the actual problem of this collapse.
I've read a few of jazzy postings and although obviously informed most of what I have seen on this particular issue from you are technicalities that don't explain the real problem and mostly just try to confuse anyone who disagrees. The simultaneous collapse and period of free fall are the problems not the collapse itself although still very coincidental

 

[Jazzy]

Totally agree the process would have been swift and unrecognizable to the human eye, unfortunately it just doesn't give any evidence for the period of free fall.

Buckling failure is characterized by silence, and a rapid acceleration to free fall tempered only by the resistance to bending of the column. It is very nearly free fall.

And the argument that the collapse would have started before we think it did although it may seem to make sense it really is just smoke and mirrors in the debate of the speed of the collapse because the "collapse" technically started when the fires did if your thinking about it like that.

No. It is exactly to the point. Buckling, when it occurs would only be recoverable if you had a spare column standing to one side which could take up the load it has just rejected. Otherwise it is as sure as death.

We know math proves the building or any building could fall as fast or close to as fast as it did. But it doesn't show in any way that everything would weaken so simultaneous or close enough to it to create free fall speed especially with being able to slow the video down and examine it so closely, it's clearly a synchronized fall I just don't think the math and physics explains the actual problem of this collapse.

I haven't used any maths at all so far. You have the cart before the horse. It was already as weak as it could be and still remain erect, immediately before it failed. You are a victim of a form of Zeno's Paradox. http://en.wikipedia.org/wiki/Zeno's_paradoxes

I've read a few of jazzy postings and although obviously informed most of what I have seen on this particular issue from you are technicalities that don't explain the real problem and mostly just try to confuse anyone who disagrees.

Promising. That's the cry who doesn't understand - yet. It certainly isn't my intention to confuse you. I want you to see.

The simultaneous collapse and period of free fall are the problems not the collapse itself although still very coincidental

The free fall of the fascia was a classic buckling failure. It occurred beneath the image frame when sufficient floors had piled up to cut all restraint to the exterior.

Once again, it was silent. Once again the upper portion almost achieved free fall, until it struck the wreckage beneath it.

 

[gerrycan]

I suspect you have over-fixated on the single beam.

The whole floor was heated, presumably from beneath, and all the beams (and column 79) were expanding, and sagging, and at half their original strength.

Considering the whole floor as a plane surface, its outside was constraining and cold, and strong, and its interior was weakening, while attempting to expand and sag between its column supports.

Where column 79 (and for that matter, any column) stood, there was a battle of forces. I agree with NIST that C79 was probably where the battle was fiercest.

Studs cannot take much beam sagging because tremendous leverage is exerted when the beam ends are angled. They too were at half-strength at 600 deg C.

I take it you accept that once C79 wasn't laterally fixed, and at half-strength, its Euler stability was compromised. Then you have to accept that the beams also had their own Euler stability.

So, even if the beam next to C79 hadn't walked off its support, what sort of instance may cause it to do so? I will suggest an answer to this: the failure of the studs by sagging beam leverage.

This could have been a failure elsewhere. The floor was already unstable, being restrained by its outsides. The exterior was in tension, the interior was under compression, wanting to walk up or down. The whole was elastic, like so many springs, and the shock loads caused by the sudden release of a fixing point would have been transmitted around it.

Exactly what was the trigger, no-one will ever know. Exactly how the sequence played out, no-one will ever know*.

It's a dynamic and three-dimensional problem poorly addressed by both you and NIST, but much more poorly by you, because they managed a realistic simulation.

And I believe it.

* Such situations being ideal traps for the religious.

.

I think it was NIST who were overly fixated on this girder. They supposed that the whole area heated to 600 deg evenly, and we took that to have happened in our analysis. Steel will begin to sag over 600 which would render them to have lost just under half of their tensile strength. Looking at their animations their failure of column 79 is totally unrealistic, and had they included the correct dimensions and elements would have been even more impossible. I would imagine that the main transfer truss systems would have to fail, but I cannot accept that the failure of one column (79) could possibly cause a building to fail in this way. We recently did an analysis of their statements from 2008 re the issue which may be of interest


I disagree that we would 'never know' what caused this failure. Given accepted and correct forensic engineering analysis and finite element analysis modelling of the building, the event could possibly have been replicated and therefor a better understanding of exactly what did happen could be gained. This is after all a big claim, that fire can do this to a building of this type, and if it indeed can, we need to get to some proper answers, and NISTs analysis did not represent this. The amendments that they proposed to building regs do not really address this either. Whatever is true of this building collapse, the consequences are huge. Either we have been wrong for over a century in everything we thought we knew about highrise buildings, or NIST are wrong their analysis. I think the latter is the case. We need a proper investigation of the issue ASAP.

 

[gerrycan]

I have no comment on the technical accuracy of what you're putting forward - I am illiterate in this conversation, but I would like to say that this is the way to present an argument against the official story - no hyperbole, no ideology, no mention of Gulf of Tonkin or mind-control by mainstream media, just the brass-tacks.
It's refreshing - even if you turn out to be mistaken.
I'll follow with interest.

Couldn't agree more with this. The technical issues need to be addressed seperate from any political or ideological issues in order that we learn from what happened that day. Refreshing that this seems to be a forum that is capable of achieving this. Kudos for that.

 

[MikeC]

My point is that an amateur could tell the difference between 11" and 1 foot, i am sure you can. And I apologise if I was short with you.

Indeed - but I don't know where to look for that, why it is relevant, and what you conclude from it.

Perhaps I'm a bit old fashioned, but I'd like to see het points laid out clearly and preferably in print - the videos do nothing for me in that respect I'm sorry.

 

[gerrycan]

So basically, you're claiming in your videos that the way column 79's girder was set up means that thermal expansion could not have happened to a degree necessary for displacing it. You say that this is because of structural components that NIST overlooked including platforms that added to the distance necessary for the girder to "walk" off of its platform as well as other pieces that added rigidity to the girder and that the thermal expansion calculations included an incorrect change in temperature value and failed to account for the aforementioned structural components. Furthermore, you say that the girder would not have been able to walk the distance needed to fall off of its platform under any circumstances since the temperature needed for such expansion would have caused the steel to sag before anything else. Just so that everybody who is not able to watch the videos is all on the same page with you, is this a good summary of what you are claiming?

Yes, I would go along with that, there's a bit more to it obviously, but all in all, a pretty good summary. Thanks.

 

[gerrycan]

But once the restraint was relaxed on column 79, a pandora's box of consequences was opened.

The first consequence was that column 79 buckled. The load it was supporting was everything above it. It stopped accepting it. It shed its load. It would have squirmed sideways as it did so. By it, I mean the column length between the ceiling of that floor, and the floor beneath. The doubling of its effective length would have automatically quartered its resistance to Euler Buckling.

That meant the weight of everything above it had to be supported (including its own, through column/beam connections with their studs, and without cross-bracing) all the way to the roof by its neighbors, which were fifty feet away.

The next consequence would have been the unattached floor striking the floor beneath. If that happened to break its connections, the effective length of that section of Column 79 would have been tripled, and its resistance to buckling reduced to one ninth.

This was not a static process. Nor was it slow. Buckling failure is silent and rapid, and involves very little resistance once it occurs. C79 would have thrashed like a snake, and every attached floor above it would also have been rapidly detached, more or less simultaneously. This would be something similar to, but not quite, free fall.

Even so, the video's claim of collapse taking 6 seconds is incorrect by a factor of TWO. It took TWELVE seconds to collapse completely. The penthouse disappearing before the fascia began to move is the clue to that.

Or, in other words, the WTC7's collapse began six seconds before you believe it did. The building emitted a large puff of black smoke (caused by a falling floor).

This marked the start of collapse.

I would enjoy an intellectually honest discussion of this issue without the logical fallacy. You say......
"The first consequence was that column 79 buckled. The load it was supporting was everything above it"
The first consequence of what? Thermal expansion? Cannot happen, would take a temp of over 600 to do it, even allowing for unrestrained expansion and no shear studs anywhere, in fact, no resistance at all. As you said earlier, and NISt also say, steel begins to sag at over 600 deg. so loses the ability to push. And column 79 did not support everything above it, buildings just do not work that way.
As for the collapse time, i am comfortably enough with any collapse time, let's suppose it started collapsing in March 1994 if you like lol. Still in no way accounts for ANY period of freefall acceleration occurring, which i presume, like NIST you do not dispute. Buckling is neither silent, or in these circumstances, rapid, and as for eulers method, you should take a look at that again with regard to slenderness ratios etc, and please do not tell me that column 79 was slender because it is 47 storeys in height. I would rather not have a maths peeing contest with you, but if that's the way it is going, perhaps it would be better done on a different thread. I am happy to do that if you like.

 

[gerrycan]

Indeed - but I don't know where to look for that, why it is relevant, and what you conclude from it.

Perhaps I'm a bit old fashioned, but I'd like to see het points laid out clearly and preferably in print - the videos do nothing for me in that respect I'm sorry.

Hello Mike, the bill of materials posted earlier in this thread shows a plate that is clearly 1' and NIST said it was 11" to suit their thermal expansion nonsense. Sorry, for some reason i cannot get it to post here. It's on post#21.

 

[Pete Tar]

...I would rather not have a maths peeing contest with you...

Maths fight!
Better that than the usual devolving to political rhetoric and evangelising that usually takes place in a 9-11 standoff.

The initial query as to whether you are going to get this work published in a proper peer-journal (which you reacted to based on the phrase 'amateur debunkers' which wasn't about you but the audience of armchair experts that plague the internet) should be seriously considered. No prize for convincing people on a forum, but making a convincing case that stands up to scrutiny by engineers would be something else.

 

[gerrycan]

Maths fight!
Better that than the usual devolving to political rhetoric and evangelising that usually takes place in a 9-11 standoff.

The initial query as to whether you are going to get this work published in a proper peer-journal (which you reacted to based on the phrase 'amateur debunkers' which wasn't about you but the audience of armchair experts that plague the internet) should be seriously considered. No prize for convincing people on a forum, but making a convincing case that stands up to scrutiny by engineers would be something else.

I actually could go a maths fight, geek that i am, ha ha .....As for the publishing issue, there isn't really much of a need, the drawings are clear, and NIST have begun to address their error and admitted the plate length error publicly, and also the increased 'walk off' length required by this, (this was not the case when the video was originally published, and we approached them with this info and more). The published papers that are required are the structural drawings and that means that NIST need to further admit that the girder had stiffener plates on it, and once they do that, it is game over for their theory.

 

[Boston]

Lots of stuff not working Mick and I've no way to send you a private message or read or respond to any. Grrrrrr. frustrating.

I thought the video lecture was very clear and concise Jerry, if you have a chance to write a transcript and include the diagrams with all references clearly noted and identified in a "references" section I can either turn it in for peer review for you, or I can just send you the contact information for you to do it yourself. I'd personally shoot for technology review or AJEAS, because I think you've got a slam dunk and you might as well go for the prestige.

I think you've got a winner. I wonder, how does the model work as you surpass that 600°C temp and if you consider the expansion of the girder, seems like its not going to expand that much before it wedges itself into its own seat and begins to deflect. Kinda adds a lot of resistance to the slid off its connection argument. If anything there's way more resistance to this girder moving any direction but down due to all the other factors yet to be considered. The corrugated deck for instance is tacked down to the joists ( speaking of which do you have a construction detail on that ? ) The joists will be welded to the beams and the beams welded/bolted to the girder. Oh and i had lunch with a guy who's got a class A GC license, told him about your hypothesis and he loved it, he also thought the girder wouldn't pass code without shear studs. You might want to look up the code on that for additional verification. In any case the major girders are braced on all sides by all kinds of joists and concrete decking, these things aren't built like a house of cards, they are very seriously engineered so this type of failure simply can't occur.

I'm really not hearing a rational argument against the hypothesis so I'd say you should shine it up some and either present it yourself or let someone familiar with the system to it for you

PS and of course the credits all yours, I'm just offering to facilitate the process.

PPS a peer review would lend a lot of credibility to the hypothesis, and it would help get the word out as well as further the cause concerning a new and this time real investigation.

 

[MikeC]

Hello Mike, the bill of materials posted earlier in this thread shows a plate that is clearly 1' and NIST said it was 11" to suit their thermal expansion nonsense. Sorry, for some reason i cannot get it to post here. It's on post#21.

I saw that - what I don't see is what you say the NIST identifies as 11", and how you have concluded that they are the same part - for example is item PF on the bill of lading shown anywhere in the drawing that is included with post #15

 

[John Smith]

But once the restraint was relaxed on column 79, a pandora's box of consequences was opened.

The first consequence was that column 79 buckled. The load it was supporting was everything above it. It stopped accepting it.

Wrong. During the massive renovation in 1989, they were able to remove columns and almost entire floors without there be any threat to the structural integrity of the building. That's what the building's inbuilt redundancy (i.e., if multiple columns and massive sections of floors are lost or removed, the weight of everything above shifts into standing/undamaged columns) allowed for.

From New York Times article:

BEFORE it moves into a new office tower in downtown Manhattan, Salomon Brothers, the brokerage firm, intends to spend nearly two years and more than $200 million cutting out floors, adding elevators, reinforcing steel girders, upgrading power supplies and making other improvements in its million square feet of space.

The work, which began last month at Seven World Trade Center, reflects both the adaptability of steel-framed towers and the extraordinary importance of fail-safe computer and telephone systems for the brokerage industry. According to many real estate experts, no company has ever made such extensive alterations to a new office building in Manhattan.

Much of the new electrical, air-conditioning and mechanical equipment will serve three double-height trading floors. To create the extra height, workers are removing most of three existing floors, using jackhammers to demolish concrete slabs and torches to remove steel decking and girders beneath the concrete.

After the girders are cut into sections small enough to fit into a construction elevator they will be sold as scrap for about 4 cents a pound.

In some office buildings, that alteration would be impossible, but Silverstein Properties tried to second-guess the needs of potential tenants when it designed Seven World Trade Center as a speculative project.

''We built in enough redundancy to allow entire portions of floors to be removed without affecting the building's structural integrity, on the assumption that someone might need double-height floors,'' said Larry Silverstein, president of the company. ''Sure enough, Salomon had that need.

''And there were many other ways that we designed as much adaptability as possible into the building because we knew that flexible layout is important to large space users.''

MORE than 375 tons of steel - requiring 12 miles of welding - will be installed to reinforce floors for Salomon's extra equipment.

http://www.nytimes.com/1989/02/19/r...uilding-within-building-cost-200-million.html

 

[Jazzy]

I think it was NIST who were overly fixated on this girder.

No more than you. In fact, less so.

They supposed that the whole area heated to 600 deg evenly, and we took that to have happened in our analysis.

It follows naturally that insulated materials become evenly heated. Nobody should argue with that.

But I am aware that what follows from that is a topic you always ignore, so I shall point it out. Heated INSULATED materials KEEP THEIR HIGH TEMPERATURES FOR A VERY LONG TIME. Bear that in mind. I'm sure we shall return to it.

Steel will begin to sag over 600 which would render them to have lost just under half of their tensile strength. Looking at their animations their failure of column 79 is totally unrealistic

You bring a two-dimensional static analysis to the table with a one-dimensional argument, and complain their animation is "unrealistic". Hmmm.

had they included the correct dimensions and elements would have been even more impossible.

This is "deck-chairs" argument. If you have read what I have recently written you must surely acknowledge this.

I would imagine that the main transfer truss systems would have to fail, but I cannot accept that the failure of one column (79) could possibly cause a building to fail in this way.

To me the situations are equally difficult to explain. The first is: how did that floor plane resolve its external tension with its internal compression, where beams were sagging and putting their studs into shear? The second is: how did the floors pile up to push those bridging trusses sideways? ...Equally difficult.

We recently did an analysis of their statements from 2008 re the issue which may be of interest

I don't think so, unless it offers a timeline with dynamic events happening at discrete locations, which it truly cannot.

I disagree that we would 'never know' what caused this failure.

I know you do. But some things, though they obviously happened, cannot be described. Unforeseen events are built into the construction of all buildings. Misalignments, tolerances, reworking, material specifications, all introduce a range of possibilities. Unforeseen dynamic events (pipe runs, heavy equipment location, mass air movement) subtly alter trajectories. There is no certainty to be found here.

NIST knew this. Their simulation was preceded with these observations. You have yet to understand this, by your demonstrated intolerance.

Given <snip> ASAP.

See above.

I would enjoy an intellectually honest discussion of this issue without the logical fallacy. You say: "The first consequence was that column 79 buckled. The load it was supporting was everything above it". The first consequence of what?

You hadn't read my previous post, perhaps, which went: "So, even if the beam next to C79 hadn't walked off its support, what sort of instance may cause it to do so? I will suggest an answer to this: the failure of the studs by sagging beam leverage. This could have been a failure elsewhere. The floor was already unstable, being restrained by its outsides. The exterior was in tension, the interior was under compression, wanting to walk up or down. The whole was elastic, like so many springs, and the shock loads caused by the sudden release of a fixing point would have been transmitted around it".

Here's two tips: a) read what the person you are arguing with has written. Not to do so is dishonest, and b) try to make the best sense you can of what he is trying to say. Not to do so is dishonest. Your dishonesty then reflects on him, and he will tend to resent it.

Thermal <snip> way.

See above.

Collapse time in no way accounts for ANY period of freefall acceleration occurring, which i presume, like NIST you do not dispute.

But NIST actually DID account for near-free-fall acceleration, and I agree with it.

Buckling is neither silent, or in these circumstances, rapid

[...]. Not in my experience. The internal collapse buckling was so silent that you don't believe it occurred. The silent external collapse of the plane surfaces of the exterior we all witnessed.

as for eulers method, you should take a look at that again with regard to slenderness ratios etc, and please do not tell me that column 79 was slender because it is 47 storeys in height. I would rather not have a maths peeing contest with you, but if that's the way it is going, perhaps it would be better done on a different thread. I am happy to do that if you like.

You make him sound like some dilettante when in fact he is the father of civil engineering. He is its Newton.

If you had taken care to read what I have written, you would have noticed that I pointed to a direct square law trend to instability starting with the loss of a single floor connection. But that doesn't mean I meant to say it buckled immediately. Just that it was going to buckle if a collapsing floor (free-falling as it went) was to cause the floor beneath it to collapse also, and so on, which obviously happened. And of course the column was slender, by definition, once a few floors were detached. Piss away. Waste your time if you like.

Wrong.

Nope. WTC7 is obviously non-redundant in many respects. A truly redundant structure would be a three-dimensional mesh of tetrahedral struts. WTC7 is mainly a non-redundant structure of floor laminae with external wind-force bracing, with its internal columns standing on bridge trusses. That is highly non-redundant. You could hardly make it more so.

''We built in enough redundancy to allow entire portions of floors to be removed without affecting the building's structural integrity, on the assumption that someone might need double-height floors,'' said Larry Silverstein

Now there speaks a true engineer, eh. It's amazing what cherries may be picked when you go looking.

''And there were many other ways that we designed as much adaptability as possible into the building because we knew that flexible layout is important to large space users.''

It moderates the idea that WTC7 was permanently bonded together in every way, doesn't it? See Boston below.

The fact of the matter is that as no-one, but no-one, ever pulls a building apart without incorporating temporary bracing first. I've been on both sides of this, the design, and the rigging.

Maths fight!

Bring it on.

query as to whether you are going to get this work published in a proper peer-journal

A "proper" peer-journal would be AE9-11 Truth. This argument is peerless as far as engineers would be concerned, and that's not far.

but making a convincing case that stands up to scrutiny by engineers would be something else.

Ain't that the truth.

there's way more resistance to this girder moving any direction but down due to all the other factors yet to be considered.

But that's MY argument too. Think of that whole floor in a giant push-me, pull-you, squeezed by its periphery, and you're getting there.

The corrugated deck <snip> can't occur.

See above.

I'm really not hearing a rational argument <snip> the credits all yours, I'm just offering to facilitate the process.

The site has been running slower and slower for several days and at this point, is completely non functional.

It runs perfectly for me. Those truther sites are full of bugs and viruses.

 

[Jazzy]

Just an afterthought.

WTC7 was struck by pieces of WTC1, caught fire, and burnt for seven hours before it suddenly, and silently, collapsed.

What was the reasoning for wiring it up when there wasn't (obviously) an available plane?

Or did they wire it up thinking there was an available plane, then there wasn't one, and luckily WTC hit it, and started fires?

Knowing that there was no water, and with the firemen saying WTC7 was about to collapse, they let off these explosives anyway, so as to conceal their existence?

Knowing they could do anything, I suppose they could come up with water-cooled digital logic radio-controlled detonators, and water-cooled thermite explosive packs...

But weren't they taking a bit of a risk there? It's not like them to take risks, or even get things right in the first place.

Couldn't they find a cheaper way of shredding documents and destroying hard-drives? (That's enough - Ed.)

 

[gerrycan]

Just an afterthought.

WTC7 was struck by pieces of WTC1, caught fire, and burnt for seven hours before it suddenly, and silently, collapsed.

What was the reasoning for wiring it up when there wasn't (obviously) an available plane?

Or did they wire it up thinking there was an available plane, then there wasn't one, and luckily WTC hit it, and started fires?

Knowing that there was no water, and with the firemen saying WTC7 was about to collapse, they let off these explosives anyway, so as to conceal their existence?

Knowing they could do anything, I suppose they could come up with water-cooled digital logic radio-controlled detonators, and water-cooled thermite explosive packs...

But weren't they taking a bit of a risk there? It's not like them to take risks, or even get things right in the first place.

Couldn't they find a cheaper way of shredding documents and destroying hard-drives? (That's enough - Ed.)

I am not even responding to your BS, sorry. Say something that adds to the exchange and I will.

 

[Dan Wilson]

Yes, I would go along with that, there's a bit more to it obviously, but all in all, a pretty good summary. Thanks.

I have nothing to challenge or question your claims at the moment, I would just ask why what Jazzy said couldn't be true. I would also ask just as a side note, do you have an alternative as to what happened? Or are you just presenting a critique?

 

[Grieves]

Just an afterthought.

WTC7 was struck by pieces of WTC1, caught fire, and burnt for seven hours before it suddenly, and silently, collapsed.

What was the reasoning for wiring it up when there wasn't (obviously) an available plane?

Or did they wire it up thinking there was an available plane, then there wasn't one, and luckily WTC hit it, and started fires?

Knowing that there was no water, and with the firemen saying WTC7 was about to collapse, they let off these explosives anyway, so as to conceal their existence?

Knowing they could do anything, I suppose they could come up with water-cooled digital logic radio-controlled detonators, and water-cooled thermite explosive packs...

But weren't they taking a bit of a risk there? It's not like them to take risks, or even get things right in the first place.

Couldn't they find a cheaper way of shredding documents and destroying hard-drives? (That's enough - Ed.)

Abandoning the engineering issues for the standard 'tell me a story so I can make fun of it..!' evade. The quickening is complete. There can be only one.

 

[gerrycan]

I have nothing to challenge or question your claims at the moment, I would just ask why what Jazzy said couldn't be true. I would also ask just as a side note, do you have an alternative as to what happened? Or are you just presenting a critique?

He is saying that I am fixating on one single column, which is EXACTLY what NIST did. In examining their explanation, if I strayed very far from the initialing event that would be an incompetent incoherent way to deal with the issue. Jazzy seems more interested in some childish point scoring exchange rather than a serious discussion that is focused on an honest search for the truth about what happened to this building. I recognize that this site seems to be a place that facilitates such an exchange and I welcome that. Jazzy is long on rhetoric and short on facts. He needs to show his working, I don't think he will, and I will respond if/when he does.

 

[Mick West]

I'm still curious if there is actually any photographic evidence of the shear studs in beams in WTC7 debris. From the discussion in the video it seems like the debris girders would be bristling like hedgehogs with shear studs everywhere.

 

[Mick West]

Found some:

Full image:

Hard to say which floor that would be from.

Also there's some here, in the upper right

 

[gerrycan]

Found some:


Full image:


Hard to say which floor that would be from.

Also there's some here, in the upper right

There is no dispute at to whether the beams (as opposed to the girder) had shear studs on them. All the floor beams would have them, they would be required to make the floor system composite, and nobody would try to build a structure like this without them. I have spoken to a few people, some of whom had direct involvement in the project who agree. They are shown on a few drawings to be present on the girder in question, and the question is, why would the floor not be required to have them on all floors at the girder spanning 79 to 44. The crossed beams there look like wind girders and would have them in abundance. The beams to the east of column 79 that NISt say did the pushing mostly had less than these, typically 28 on each.
I would still maintain that the girder that NIST claim 'walked' off the footing at floor 12/13 would have them, but I am happy enough to debate the issue of the walk off without the need for them being there. The real question re studs in general, is why NIST firstly admitted their presence and then played the issue down later, once they had decided on the thermal expansion excuse. The issue of the 11inch Vs 12 mistake is just absurd, considering that NIST had the drawings all along, and their refusal to acknowledge the stiffener plates allows them to cling to the thermal expansion fantasy. We have once again requested that they make an admission re these plates, but I don't expect them to do that, as it would truly sink their theory yet further. I believe there may also be information imminent re the steel that NIST did retain from WTC7, and will keep you posted as to this if you like.

 

[Mick West]

Quick clarification - are you using any specific criteria for "beam" vs. "girder"?

 

[gerrycan]

A girder is more of a primary load carrying element, but the terms are often used interchangeably. A useful way to think about it in this instance is that if any one of these beams were removed, the girder would be fine, but if the girder were to be removed, the beams would no longer perform their structural function.

 

[Mick West]

What's the source of Drawing 9114? Where's the full original drawing?

 

[gerrycan]

Hope this has worked, I could find you a link to the whole set if you like, they were released under a FOIA request.

 

[Jazzy]

I am not even responding to your BS, sorry. Say something that adds to the exchange and I will.

Look, sunshine, so far I have made these statements/asked these questions which you haven't yet had the decency either to acknowledge or properly reply to:

The whole floor was heated, presumably from beneath, and all the beams (and column 79) were expanding, and sagging, and at half their original strength.

Studs cannot take much beam sagging because tremendous leverage is exerted when the beam ends are angled. They too were at half-strength at 600 deg C.

So, even if the beam next to C79 hadn't walked off its support, what sort of instance may cause it to do so? I will suggest an answer to this: the failure of the studs by sagging beam leverage. This could have been a failure elsewhere. The floor was already unstable, being restrained by its outsides. The exterior was in tension, the interior was under compression, wanting to walk up or down. The whole was elastic, like so many springs, and the shock loads caused by the sudden release of a fixing point would have been transmitted around it.

It's a dynamic and three-dimensional problem poorly addressed by both you and NIST, but much more poorly by you, because they managed a realistic simulation.

The next consequence would have been the unattached floor striking the floor beneath. If that happened to break its connections, the effective length of that section of Column 79 would have been tripled, and its resistance to buckling reduced to one ninth.

This was not a static process. Nor was it slow. Buckling failure is silent and rapid, and involves very little resistance once it occurs. C79 would have thrashed like a snake, and every attached floor above it would also have been rapidly detached, more or less simultaneously. This would be something similar to, but not quite, free fall.

the video's claim of collapse taking 6 seconds is incorrect by a factor of TWO. It took TWELVE seconds to collapse completely. The penthouse disappearing before the fascia began to move is the clue to that.

Buckling failure is characterized by silence, and a rapid acceleration to free fall tempered only by the resistance to bending of the column. It is very nearly free fall.

You have the cart before the horse. It was already as weak as it could be and still remain erect, immediately before it failed. You are a victim of a form of Zeno's Paradox.

The free fall of the fascia was a classic buckling failure. It occurred beneath the image frame when sufficient floors had piled up to cut all restraint to the exterior. Once again, it was silent. Once again the upper portion almost achieved free fall, until it struck the wreckage beneath it.

Heated INSULATED materials KEEP THEIR HIGH TEMPERATURES FOR A VERY LONG TIME.

You bring a two-dimensional static analysis to the table with a one-dimensional argument, and complain their animation is "unrealistic".

How did that floor plane resolve its external tension with its internal compression, where beams were sagging and putting their studs into shear?

How did the floors pile up to push those bridging trusses sideways?

But some things, though they obviously happened, cannot be described. Unforeseen events are built into the construction of all buildings. Misalignments, tolerances, reworking, material specifications, all introduce a range of possibilities. Unforeseen dynamic events (pipe runs, heavy equipment location, mass air movement) subtly alter trajectories. There is no certainty to be found here.

So, even if the beam next to C79 hadn't walked off its support, what sort of instance may cause it to do so? I will suggest an answer to this: the failure of the studs by sagging beam leverage. This could have been a failure elsewhere. The floor was already unstable, being restrained by its outsides. The exterior was in tension, the interior was under compression, wanting to walk up or down. The whole was elastic, like so many springs, and the shock loads caused by the sudden release of a fixing point would have been transmitted around it.

The internal collapse buckling was so silent that you don't believe it occurred. The silent external collapse of the plane surfaces of the exterior we all witnessed.

Think of that whole floor in a giant push-me, pull-you, squeezed by its periphery, and you're getting there.

So what effing "exchange" are you talking about, exactly?

Abandoning the engineering issues for the standard 'tell me a story so I can make fun of it..!' evade. The quickening is complete. There can be only one.

See above.

He is saying that I am fixating on one single column, which is EXACTLY what NIST did. In examining their explanation, if I strayed very far from the initialing event that would be an incompetent incoherent way to deal with the issue.

Ignoring the whole of the rest of the building, and in particular the rest of the floor impinging upon column 79, is deeply and truly "an incompetent incoherent way to deal with the issue".

Jazzy seems more interested in some childish point scoring exchange

Again I ask - what "exchange"? Everything above in blue has taken no part of any "exchange".

rather than a serious discussion that is focused on an honest search for the truth about what happened to this building. I recognize that this site seems to be a place that facilitates such an exchange and I welcome that.

In a pig's ear.

Jazzy is long on rhetoric and short on facts.

No. I am long on REASON. It's you that is substituting exchange with rhetoric. The "facts" are already established. The interpretation of these "facts" is the issue.

He needs to show his working

My working to which non-existent exchange do you mean?

You need to acknowledge my statements and answer my questions, without allusions to hypocrisy and deception/deflection.

I don't think he will, and I will respond if/when he does.

I think you're right because neither of us knows what you're talking about.

 

[Jazzy]

Hope this has worked, I could find you a link to the whole set if you like, they were released under a FOIA request.

There are NO shear studs on Column 79. Just two fixing bolts, top and bottom.

Now that's a critical error/omission!

Or perhaps we need the rest of the set to make sense of this.

 

[Mick West]

There are NO shear studs on Column 79. Just two fixing bolts, top and bottom.

Now that's a critical error/omission!

Or perhaps we need the rest of the set to make sense of this.

Are you confusing shear studs (studs on top of a beam that embed in the concrete)

with bolted shear plates?:

Because I don't think that shear studs would show on that diagram, as it's just a connection diagram.

 

[Boston]

LMAO

Girders tend to hold the beams, beams tend to hold the joists, joist hold the subfloor/decking/floor. If you really want to get technical there's perlins and subperlins as well as girt beams and a whole slew of other terms. But for the purposes of this conversation I think we can all agree that a girder is in support of the beams that held the trusses which held the floors.

Sheer studs are what rise vertically off the top of the beam and embed in the concrete, the corrugated pans are cut out to accommodate them and often the pans are welded down to the beams at these cut outs. Also if you look at the drawing offered for our consideration you can see there is a change in direction of the floor pans and beam layout that would have facilitated further welding of the pans directly on top of the girder in question. There would also be an accompanying change in direction of any internal mesh or rebar, guys tend to overlap that stuff and tie wire it into place. Makes that area of floor stronger than the typical floor section.

there's another sticky little issue with the walked off its seat hypothesis, anyone notice that other beam coming in at a rather high angle to the girder on the back side of where the alleged push originated from ? Makes it kinda hard for that beam to walk anywhere if you ask me.

 

[Mick West]

It's still a little confusing though as the actual WTC7 blueprints sometimes refer to those girders as beams (As in Drawing 9114, "Beam to Column Connections")

 

[Jazzy]

Are you confusing shear studs (studs on top of a beam that embed in the concrete) with bolted shear plates? Because I don't think that shear studs would show on that diagram, as it's just a connection diagram.

I must be. I can't see the relevance. There's no shear resistance apart from the bolts shown, and the concrete floor would have expanded with the steel. The concrete shear studs only serve to keep the support trays attached, so that the floor would tend to move as a single piece.

The floor, heated from beneath, would sag initially merely due to the temperature gradient across it. Later on it would tend to straighten, were it not for the fact it was halving its tensile strength, and creeping. When tied together through the columns to all the other floor elements its "center" would move in the direction of any opening in the floor. It would also be trying to squirm (up or down) due to being under compression by the cold, non-expanded exterior periphery.

A hot loaded column, as Column 79 certainly was, would have had plenty of time over seven hours to sag vertically down (allowing everything it supported to do mostly the same) and distort sideways to follow this movement, being at a temperature 125 deg C above its creep transition point.

Being out-of-line in such a manner would have made it extremely prone to buckling collapse: Euler's Law refers to classically vertical/horizontal structures only. Two consecutive collapsed floors would put it past critical even if it were straight.

You have to account for nine or ten inches too much of compressed steel/concrete across the floor plane, with the periphery in tension. I think that if C79's centerline were to be five inches out-of-vertical, then floor collapse and column buckling might well be a simultaneous event.

This could easily happen if the fire moved through the building. Consider one side of the floor already up to temperature, sagging and pulling. Then if the fire crossed to the other side it could heat the floor, causing it to expand before it began to sag. That would create a powerful sideways push on the central columns. This process was observed in the tower fires, where first the floors expanded, pushing the external columns outwards, then they crept and sagged, pulling the same columns inwards.

You're right, Gerrycan, whether a backing plate is eleven or twelve inches across has little relevance to the general state of this WTC7 floor. Or to anything...

 

[gerrycan]

There are NO shear studs on Column 79. Just two fixing bolts, top and bottom.

Now that's a critical error/omission!

Or perhaps we need the rest of the set to make sense of this.

Now that's a critical error/omission! lol. You clearly do not understand what a shear stud is, let alone what function it performs. Also, look at the welding that is called out at the top of the plate.

 

[gerrycan]

I must be. I can't see the relevance. There's no shear resistance apart from the bolts shown, and the concrete floor would have expanded with the steel. The concrete shear studs only serve to keep the support trays attached, so that the floor would tend to move as a single piece.

The floor, heated from beneath, would sag initially merely due to the temperature gradient across it. Later on it would tend to straighten, were it not for the fact it was halving its tensile strength, and creeping. When tied together through the columns to all the other floor elements its "center" would move in the direction of any opening in the floor. It would also be trying to squirm (up or down) due to being under compression by the cold, non-expanded exterior periphery.

A hot loaded column, as Column 79 certainly was, would have had plenty of time over seven hours to sag vertically down (allowing everything it supported to do mostly the same) and distort sideways to follow this movement, being at a temperature 125 deg C above its creep transition point.

Being out-of-line in such a manner would have made it extremely prone to buckling collapse: Euler's Law refers to classically vertical/horizontal structures only. Two consecutive collapsed floors would put it past critical even if it were straight.

You have to account for nine or ten inches too much of compressed steel/concrete across the floor plane, with the periphery in tension. I think that if C79's centerline were to be five inches out-of-vertical, then floor collapse and column buckling might well be a simultaneous event.

This could easily happen if the fire moved through the building. Consider one side of the floor already up to temperature, sagging and pulling. Then if the fire crossed to the other side it could heat the floor, causing it to expand before it began to sag. That would create a powerful sideways push on the central columns. This process was observed in the tower fires, where first the floors expanded, pushing the external columns outwards, then they crept and sagged, pulling the same columns inwards.

You're right, Gerrycan, whether a backing plate is eleven or twelve inches across has little relevance to the general state of this WTC7 floor. Or to anything...

I can kind of see where you are getting confused with this, and rather than confusing you more, is there a facility on here to actually talk real time? I think I could maybe clear up some of the misconceptions that you have about the nature of this connection and the elements around it. Would take too long in text. Maybe it is not made as clear as it could be in the videos. The plate in question isn't a backing plate, it is plate 'pf' and is underneath the girder at column 79. It isn't shown in the above illustration that you use. This is NIST referring to the plate:-

Here is where plate 'pf' is, note there is another plate called out as 'pg' below it :

This is the bill of materials for the elements:

So plate 'pf' is beneath the girder at column 79 and is 1 foot long. So why would NISt say that it was 11 inches? Because a walk distance of 5.5 inches was more conceivable, it suited their story to make the walk distance less. 5.5 is still ridiculous, but it suited them better than 6 (the girder would be deemed to have failed once it had walked halfway). Once you take into account the larger plate below 'pf' (pg), the walk distance is increased further, also when the stiffener plates are added to the girder the walk distance goes up to >9inches because the vertical load would transfer back to the web of the girder.
By misrepresenting this connection, NIST have woven a tangled web (no pun intended), and should be answering these serious questions as to why every error they made allowed their fairytale of thermal expansion to look a little more plausible.

 

[gerrycan]

It's still a little confusing though as the actual WTC7 blueprints sometimes refer to those girders as beams (As in Drawing 9114, "Beam to Column Connections")[/q

LMAO

Girders tend to hold the beams, beams tend to hold the joists, joist hold the subfloor/decking/floor. If you really want to get technical there's perlins and subperlins as well as girt beams and a whole slew of other terms. But for the purposes of this conversation I think we can all agree that a girder is in support of the beams that held the trusses which held the floors.

Sheer studs are what rise vertically off the top of the beam and embed in the concrete, the corrugated pans are cut out to accommodate them and often the pans are welded down to the beams at these cut outs. Also if you look at the drawing offered for our consideration you can see there is a change in direction of the floor pans and beam layout that would have facilitated further welding of the pans directly on top of the girder in question. There would also be an accompanying change in direction of any internal mesh or rebar, guys tend to overlap that stuff and tie wire it into place. Makes that area of floor stronger than the typical floor section.

there's another sticky little issue with the walked off its seat hypothesis, anyone notice that other beam coming in at a rather high angle to the girder on the back side of where the alleged push originated from ? Makes it kinda hard for that beam to walk anywhere if you ask me.

Yes there was actually quite substantial mesh above the girder (element spanning column 79-44, just to be clear lol) and you are also correct about the beam to the west that gives the girder lateral support. Also it is worth remembering that even if the floor beams to the east and the girder itself failed, this does not leave the column entirely unbraced. There is also additional bracing in a sort of diamond shape around the column connection that isn't shown on these drawings to provide support for piping. I reckon that the drawings that NIST need to be releasing are fieldwork drawings (FW prefix). Maybe these would show additional work that would be done to the girder also, but I can't be sure as they claim not to have them, (which I do not believe for a minute).

 

[Boston]

Now that's a critical error/omission! lol. You clearly do not understand what a shear stud is, let alone what function it performs. Also, look at the welding that is called out at the top of the plate.

Bulls eye

 

[Boston]

Yes there was actually quite substantial mesh above the girder (element spanning column 79-44, just to be clear lol) and you are also correct about the beam to the west that gives the girder lateral support. Also it is worth remembering that even if the floor beams to the east and the girder itself failed, this does not leave the column entirely unbraced. There is also additional bracing in a sort of diamond shape around the column connection that isn't shown on these drawings to provide support for piping. I reckon that the drawings that NIST need to be releasing are fieldwork drawings (FW prefix). Maybe these would show additional work that would be done to the girder also, but I can't be sure as they claim not to have them, (which I do not believe for a minute).

I grew up around this type of construction so its easy for me to follow along, I really like what you've come up with, even had I the prints I might not have caught all these errors you have. I owe you a pint for a job well done. I'd again admonish you to polish up this argument and present it for publication, there's nothing science enjoys more than a well constructed rebuttal.

Long story short I'd recommend two things, you might consider the use of the ignore feature, and lay out in detail exactly where NIST is making its claims IE note all pages and diagrams with foot notes and references, do the same for all information you are using to refute there claims. From there its a short hop to publication.

There's actually two beams to the west but the one closest to the column is the one I'd think has the best leverage against the kinda failure NIST is proposing. To my eye this beam is physically blocking the pathway NIST is suggesting the girder walked to fall from its seat. Not only was the monolithic nature of the subfloor inhibiting this motion but the supporting structure of beams and joists also would resist this motion. Basically there's a whole lot of stuff blocking this path to failure.

Again spectacular job researching the prints.

Cheers
B

 

[Jazzy]

I can kind of see where you are getting confused with this

You may well be reading carefully what I have written (I can hardly believe this), but what I have written certainly isn't sinking in.

If it were sinking in, there certainly wouldn't be a whole page of unacknowledged statements and unanswered questions outstanding.

The plain fact is that you are still refusing either to acknowledge my points or to answer my questions.

Don't confuse yourself any further. Answer them.

BEGINNING OF LIST

1) The whole floor was heated, presumably from beneath, and all the beams (and column 79) were expanding, and sagging, and at half their original strength.

2) Studs cannot take much beam sagging because tremendous leverage is exerted when the beam ends are angled. They too were at half-strength at 600 deg C.

3) So, even if the beam next to C79 hadn't walked off its support, what sort of instance may cause it to do so? I will suggest an answer to this: the failure of the studs by sagging beam leverage. This could have been a failure elsewhere. The floor was already unstable, being restrained by its outsides. The exterior was in tension, the interior was under compression, wanting to walk up or down. The whole was elastic, like so many springs, and the shock loads caused by the sudden release of a fixing point would have been transmitted around it.

4) It's a dynamic and three-dimensional problem poorly addressed by both you and NIST, but much more poorly by you, because they managed a realistic simulation.

5) The next consequence would have been the unattached floor striking the floor beneath. If that happened to break its connections, the effective length of that section of Column 79 would have been tripled, and its resistance to buckling reduced to one ninth.

6) This was not a static process. Nor was it slow. Buckling failure is silent and rapid, and involves very little resistance once it occurs. C79 would have thrashed like a snake, and every attached floor above it would also have been rapidly detached, more or less simultaneously. This would be something similar to, but not quite, free fall.

7) the video's claim of collapse taking 6 seconds is incorrect by a factor of TWO. It took TWELVE seconds to collapse completely. The penthouse disappearing before the fascia began to move is the clue to that.

8) Buckling failure is characterized by silence, and a rapid acceleration to free fall tempered only by the resistance to bending of the column. It is very nearly free fall.

9) You have the cart before the horse. It was already as weak as it could be and still remain erect, immediately before it failed. You are a victim of a form of Zeno's Paradox.

10) The free fall of the fascia was a classic buckling failure. It occurred beneath the image frame when sufficient floors had piled up to cut all restraint to the exterior. Once again, it was silent. Once again the upper portion almost achieved free fall, until it struck the wreckage beneath it.

11) Heated INSULATED materials KEEP THEIR HIGH TEMPERATURES FOR A VERY LONG TIME.

12) You bring a two-dimensional static analysis to the table with a one-dimensional argument, and complain their animation is "unrealistic".

13) How did that floor plane resolve its external tension with its internal compression, where beams were sagging and putting their studs into shear?

14) How did the floors pile up to push those bridging trusses sideways?

15) But some things, though they obviously happened, cannot be described. Unforeseen events are built into the construction of all buildings. Misalignments, tolerances, reworking, material specifications, all introduce a range of possibilities. Unforeseen dynamic events (pipe runs, heavy equipment location, mass air movement) subtly alter trajectories. There is no certainty to be found here.

16) So, even if the beam next to C79 hadn't walked off its support, what sort of instance may cause it to do so? I will suggest an answer to this: the failure of the studs by sagging beam leverage. This could have been a failure elsewhere. The floor was already unstable, being restrained by its outsides. The exterior was in tension, the interior was under compression, wanting to walk up or down. The whole was elastic, like so many springs, and the shock loads caused by the sudden release of a fixing point would have been transmitted around it.

17) The internal collapse buckling was so silent that you don't believe it occurred. The silent external collapse of the plane surfaces of the exterior we all witnessed.

18) Think of that whole floor in a giant push-me, pull-you, squeezed by its periphery, and you're getting there.

19) The floor, heated from beneath, would sag initially merely due to the temperature gradient across it.

20) Later on it would tend to straighten, were it not for the fact it was halving its tensile strength, and creeping.

21) When tied together through the columns to all the other floor elements its "center" would move in the direction of any opening in the floor.

22) It would also be trying to squirm (up or down) due to being under compression by the cold, non-expanded exterior periphery.

23) A hot loaded column, as Column 79 certainly was, would have had plenty of time over seven hours to sag vertically down (allowing everything it supported to do mostly the same) and distort sideways to follow this movement, being at a temperature 125 deg C above its creep transition point.

24) Being out-of-line in such a manner would have made it extremely prone to buckling collapse: Euler's Law refers to classically vertical/horizontal structures only. Two consecutive collapsed floors would put it past critical even if it were straight.

25) You have to account for nine or ten inches too much of compressed steel/concrete across the floor plane, with the periphery in tension.

26) I think that if C79's centerline were to be five inches out-of-vertical, then floor collapse and column buckling might well be a simultaneous event.

27) This could easily happen if the fire moved through the building. Consider one side of the floor already up to temperature, sagging and pulling. Then if the fire crossed to the other side it could heat the floor, causing it to expand before it began to sag. That would create a powerful sideways push on the central columns.

28) This process was observed in the tower fires, where first the floors expanded, pushing the external columns outwards, then they crept and sagged, pulling the same columns inwards.

29) You're right, Gerrycan, whether a backing plate is eleven or twelve inches across has little relevance to the general state of this WTC7 floor. Or to anything.

END OF LIST.

Please do not pretend any further that you have entered into a debate with me.