# Use of Scale Model or Full Sized models for investigating 9/11 collapses

#### psikeyhackr

##### Member
1319625000/2000 = 659,812.5 tons
I said:
more than 300,000 tons of concrete per building

There were two buildings.

What is the problem?

The largest contract for fabrication of structural steel is held by Pacific Car and Foundry Co., of Seattle. It is \$21.79 million for 55,000 tons of steel for the towers' bearing wall panels from the ninth floor up.

In all there are 5,828 of these panels, each about 10 ft wide, 36 ft high, with the heaviest individual panel weighing about 22 tons. Each panel consists of three box columns, 14 in. square, made up of plate up to 3 in. thick and, connected by 54-in, deep spandrels.
http://911research.wtc7.net/mirrors/guardian2/wtc/eng-news-record.htm

The average weight of the panels:

55,000 ÷ 5,828 = 9.44 tons

But the heaviest panels were 22 tons so there were plenty panels weighing less than 9 tons. I have seen posters mention 4 ton and 6 ton panels but no source with any authority.

But it is totally ridiculous that we have not been told the weights and quantities of each variation. That would tell us the distribution of weight for the perimeter upwards from the 9th floor.

My model has the WTC collapsing once a floor is loaded past 30,000,000 pounds, and it can't stop until the ground. My model is simple, and has the collapse time of 12.08 seconds. I can almost do my model in my head, I needed excel for the collapse time.

The FLOORS you keep talking about were outside the core. Didn't the core above impact zone have to come down on the intact core below? So the weight of the upper core wasn't on the floors.

The standard 84 "floors" were about 750 tons.

NIST NCSTAR 1-1A PDF p47

(205.67 * 205.67) - (85.67 * 135.67) = 30677.3 sq ft
Concrete Slab 36.5 psf 559.86 tons
rebar in slab 1.5 psf 23.01 tons
582.87 tons
steel deck 2.0 psf 30.68 tons
Struct Steel 10.0 psf 153.39 tons
184.07 tons
Total 50.0 psf 766.94

84 Levels with standard floor slabs

10 thru 24 = 15
26 thru 40 = 15
45 thru 58 = 14
60 thru 66 = 7
68 thru 74 = 7
79 thru 91 = 12
93 thru 106 = 14

There were 19 panels on each side of the tower and 4 corner panels that should have weighed about as much as two panels. But the panels were 3 stories tall.

So 22 ton panels would be:

22 * ((4 * 19)+2) / 3 = 572 tons

but 4 ton panels would be:

4 * ((4 * 19)+2) / 3 = 104 tons

So the perimeter at the 9th floor weighed 75% as much as the floor assembly. But that would be 5.5 times as much as the weight of the perimeter at the 109th floor.

But the weight of the core on each level should be even greater than the perimeter. The core had concrete slabs and plumbing and electrical with equipment for elevators.

Kat Dorman, also known as One White Eye, computed the collapse time based on equal masses being slowed down by nothing but the Conservation of Momentum. He got 11.5 seconds. But that presumes no energy being lost breaking connections which would slow things down thereby increasing the time. How could the floors remain perfectly parallel to the ground? If they tilt there will be more friction slowing things down further.

Perfection only happens in math and thought experiments. Reality is much more messy.

psik

#### psikeyhackr

##### Member
So since when do moderators decide to dish out avatars. I have been banned a number of times but never before encountered a moderator that would do that, and I have left the avatar blank for years.

#### Jeffrey Orling

##### Senior Member
I said:

There were two buildings.

What is the problem?

http://911research.wtc7.net/mirrors/guardian2/wtc/eng-news-record.htm

The average weight of the panels:

55,000 ÷ 5,828 = 9.44 tons

But the heaviest panels were 22 tons so there were plenty panels weighing less than 9 tons. I have seen posters mention 4 ton and 6 ton panels but no source with any authority.

But it is totally ridiculous that we have not been told the weights and quantities of each variation. That would tell us the distribution of weight for the perimeter upwards from the 9th floor.

The FLOORS you keep talking about were outside the core. Didn't the core above impact zone have to come down on the intact core below? So the weight of the upper core wasn't on the floors.

The standard 84 "floors" were about 750 tons.

There were 19 panels on each side of the tower and 4 corner panels that should have weighed about as much as two panels. But the panels were 3 stories tall.

So 22 ton panels would be:

22 * ((4 * 19)+2) / 3 = 572 tons

but 4 ton panels would be:

4 * ((4 * 19)+2) / 3 = 104 tons

So the perimeter at the 9th floor weighed 75% as much as the floor assembly. But that would be 5.5 times as much as the weight of the perimeter at the 109th floor.

But the weight of the core on each level should be even greater than the perimeter. The core had concrete slabs and plumbing and electrical with equipment for elevators.

Kat Dorman, also known as One White Eye, computed the collapse time based on equal masses being slowed down by nothing but the Conservation of Momentum. He got 11.5 seconds. But that presumes no energy being lost breaking connections which would slow things down thereby increasing the time. How could the floors remain perfectly parallel to the ground? If they tilt there will be more friction slowing things down further.

Perfection only happens in math and thought experiments. Reality is much more messy.

psik

Here you can figure out the weight of any panel with an excel spread sheet... I did most of the work for you... if the site would accept a PDF or jpeg upload... email me.

#### psikeyhackr

##### Member

So you don't know the difference between evidence and an assumption.

psik

#### psikeyhackr

##### Member
Here you can figure out the weight of any panel with an excel spread sheet... I did most of the work for you... if the site would accept a PDF or jpeg upload... email me.

No one has any data on the weight of any panels other than that 22 tons. Gregory Urich did a linear interpolation but that is all. And he had to make the heaviest panel 19 tons to keep from having negative numbers at the top.

psik

#### Mick West

Staff member
So since when do moderators decide to dish out avatars. I have been banned a number of times but never before encountered a moderator that would do that, and I have left the avatar blank for years.

Since around 2012.

#### Mick West

Staff member
Quibbling over numbers is silly. You can get a perfectly reasonable ballpark figure.

@psikeyhackr, isn't your point that collapse is impossible no matter what the weight? You think you demonstrated that with your paper model?

Then what's the problem with not knowing exact weights? Surely if someone builds a scale model, then no matter what weight they pick, it will not collapse (according to your interpretation of your test results)?

#### Mick West

Staff member
Unless someone is actually planning to use some data in a scale model, there's really no point discussing it.

If you wish to endlessly nit-pick theoreticals, please go to PMs.

#### jaydeehess

##### Senior Member.
The NIST says there was 100,000 tons of steel in each tower. If we accept the source claiming 425,000 cubic yards of concrete means more than 300,000 tons of concrete per building.
There were two buildings.

What is the problem?

You switching between quoting a number for "each tower", then referring to a number which includes both towers.

However, I also noted that calculating for a 4 inch slab over the entire floor for 110 floors gives a result much less than that total.
77000 tons of concrete is vastly different than 300,000 tons, which leads me to suggest that the greater proportion of concrete was in the foundation and consisted of heavier grade concrete.

OTOH I note that at 700 tons of concrete per floor that fits well with NIST saying a typical floor assembly being 750 tons.

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#### Jeffrey Orling

##### Senior Member
No one has any data on the weight of any panels other than that 22 tons. Gregory Urich did a linear interpolation but that is all. And he had to make the heaviest panel 19 tons to keep from having negative numbers at the top.

psik
My work for the facade is no more made up than what Greg Ulrich did and was based on:

1. the data about the core columns from Len's site.
2. the known weight of the heaviest panel ergo the columns which made it up plus the spandels of known dimensions
3. careful observation from construction and collapse debris photos
5. minimum thickness of plate for the top box columns
6. same rate of decrease in wall thickness that was used for the fabricated core columns 0.125"
7. the assumed proportion of the facade column weight to the entire assumed weight of all the steel.
8. some of NIST's descriptions

So there are *assumptions*... one of them being that Len Waters' core column data is accurate. It appears consistent and sensible.

But again this site will not accept uploads today. You can email me and I send you the work.

#### jaydeehess

##### Senior Member.
The FLOORS you keep talking about were outside the core. Didn't the core above impact zone have to come down on the intact core below? So the weight of the upper core wasn't on the floors.
There was ,"floor" in the core as well.
When collapse initiated, that is to say, when we observe the upper section begin to drop, it is obvious that columns are no longer aligned through the initial collapse level(s). If , at this point, the core columns at that level were intact we would have seen evidence of this with the outer portion (core to perimeter) falling first. We would have seen the antenna, for instance, drop well after the perimeter walls.
So, knowing that the columns are no longer aligned how do you propose that the gravitational and dynamic loads of the falling upper section be transferred to the lower section columns.
Your column crush model requires that this be the dominant mechanism of collapse.

Very little of that falling mass is going to impact directly and axially on the column tips of the lower section. The vast majority of the force will impact the floor, within and exterior to, the core area. Outside the core , the truss connections will immediately be overloaded and fail. Within the core , floors were on beams but those beams, and their connection to the core columns, are not designed to take this force. In addition, as the upper section comes down, its column sections will be hitting the lower core floor close to the lower section columns. That is where, of course, the connection of beam to column is. Some of those connections then are taking the brunt of the force from the upper section core.

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#### Jeffrey Orling

##### Senior Member
There was ,"floor" in the core as well.
When collapse initiated, that is to say, when we observe the upper section begin to drop, it is obvious that columns are no longer aligned through the initial collapse level(s). If , at this point, the core columns at that level were intact we would have seen evidence of this with the outer portion (core to perimeter) falling first. We would have seen the antenna, for instance, drop well after the perimeter walls.
So, knowing that the columns are no longer aligned how do you propose that the gravitational and dynamic loads of the falling upper section be transferred to the lower section columns.
Your column crush model requires that this be the dominant mechanism of collapse.

Very little of that falling mass is going to impact directly on the column tips of the lower section. The vast majority of the force will impact the floor, within and exterior to, the core area. Outside the core , the truss connections will immediately be overloaded and fail. Within the core floors were on beams but those beams and their connection to the core columns, are not designed to take this force. In addition, as the upper section comes down, its column sections will be hitting the lower core floor close to the lower section columns. That is where, of course, the connection of beam to column is. Some of those connections then are taking the brunt of the force from the upper section core.

The was loss of columns, perhaps some weakening and some slight misalignment... enough that there was no long adequate bearing... a 1/2" lateral movement would reduce the bearing to 3.3% of the aligned condition... This will cause web and flange crippling... FAILURE. Probably leading to additional lateral movement... So there would be few if any columns axially coupling the upper loads to the lower columns.

The site will again no accept uploads,

#### jaydeehess

##### Senior Member.
Unless someone is actually planning to use some data in a scale model, there's really no point discussing it.

If you wish to endlessly nit-pick theoreticals, please go to PMs.
This is the crux of the matter.

One one hand psikeyhacker touts his completely unscaled model of column crush dominated collapse, and then complains that your unscaled model of floor connection dominated collapse is unscaled wrt the towers.

The further complaint is that no true scale model has been constructed. However NIST did a full scale computer model of collapse initiation that demonstrates massive over load of floors and concludes, correctly in the opinion of the vast majority of persons with or without structural engineering qualifications, that arrest is not possible.

If a further full scale computer model included the next five levels and demonstrated that forces on connections and floors only increased, would that be enough for critics? Probably not, they'd want to model the full ~100 more levels. Given the complexities and chaotic nature of the trajectory of individual components in any collapse, the ridiculousness of such a demand would be obvious.

So, how far down is far enough?

#### jaydeehess

##### Senior Member.
The was loss of columns, perhaps some weakening and some slight misalignment... enough that there was no long adequate bearing... a 1/2" lateral movement would reduce the bearing to 3.3% of the aligned condition... This will cause web and flange crippling... FAILURE. Probably leading to additional lateral movement... So there would be few if any columns axially coupling the upper loads to the lower columns.

Yes, but that is just greater detail than my description of what characterized the initial collapse. It would be initial condition data for a computer model of collapse progression after that point. By the time the upper section has moved a few feet downwards columns are no longer in play as far as taking the load of the collapse.

Column failure drove initiation of the collapses. Whether core failed first or perimeter failed first is academic, all columns failed within a short span of time.
Care must be taken to not conflate progression and initiation.
Unfortunately many cannot seem to do that. It seems that psikeyhacker is among that group, assuming that since collapse began with column failure, then column failure dominated continuing collapse.

This inabilitity is also seen when we see the off repeated " jet fuel cannot supply enough heat to fail the columns" meme. Since jet fuel started the fires, and fire reduced the capacity of columns to support loads, then jet fuel must be what failed the columns. Such people are seemingly blind to the fact that jet fuel ignited office furnishings fires across several levels and that office contents fires raged and progressed around the structure in different paths on each floor. Jet fuel fires were the initial condition of the fires that lasted about an hour before collapse.

Same thing for impact damage vs. fire damage. There the inability is manifest when people say such things as " the structure was built to withstand aircraft impact" or "fire does not collapse steel structures". In the case of the towers , the structure was beset with both. Impact damage was the initial condition of the structure as fire damage began.

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#### Jeffrey Orling

##### Senior Member
Yes, but that is just greater detail than my description of what characterized the initial collapse. It would be initial condition data for a computer model of collapse progression after that point. By the time the upper section has moved a few feet downwards columns are no longer in play as far as taking the load of the collapse.

Column failure drove initiation of the collapses. Whether core failed first or perimeter failed first is academic, all columns failed within a short span of time.
Care must be taken to not conflate progression and initiation.
Unfortunately many cannot seem to do that. It seems that psikeyhacker is among that group, assuming that since collapse began with column failure, then column failure dominated continuing collapse.

This inabilitity is also seen when we see the off repeated " jet fuel cannot supply enough heat to fail the columns" meme. Since jet fuel started the fires, and fire reduced the capacity of columns to support loads, then jet fuel must be what failed the columns. Such people are seemingly blind to the fact that jet fuel ignited office furnishings fires across several levels and that office contents fires raged and progressed around the structure in different paths on each floor. Jet fuel fires were the initial condition of the fires that lasted about an hour before collapse.

Same thing for impact damage vs. fire damage. There the inability is manifest when people say such things as " the structure was built to withstand aircraft impact" or "fire does not collapse steel structures". In the case of the towers , the structure was beset with both. Impact damage was the initial condition of the structure as fire damage began.

I think that it is wrong to think ROOSD literally began when the roof line moved down. The process was a series of mechanisms and ultimately ROOSD dominated and accounts for the destruction of everything below the plane strike or "collapse zone".

I also suspect that the impact of heat is not well understood or articulated. People seem to think the key effect of the heat was to weaken the columns to failure. And so they argue if there was enough heat to do that. (there wasn't)

But heat caused other problems which ultimately led to column "failure" some buckling and others being dragged completely out of alignment, others experience the crippling I mentioned. I think the KEY effect of heat which seems to be little discussed is the elongation of the bracing, the subsequent warping of the frame including shearing and failing structural connections.. and of course nudging columns laterally and off axial alignment.. THAT was the straw which broke the camel's back... maybe one straw at a time as the frame heated up and the core warped.

#### Jeffrey Orling

##### Senior Member
Len who?

Do you mean Lon Waters? He had column cross sections but nothing on the horizontal beams in the core or the perimeter.

http://www.sharpprintinginc.com/911...er_op=view_page&PAGE_id=13&MMN_position=18:18

psik
Yes I mean Lon. But the sizing of the core bracing is pretty trivial because the floor loads were pretty uniform inside the core. This is hardly significant except to you who has not explained why? The floors inside the core were I believe designed for 75# live load... I don't recall but it's mentioned in the appendix of the NIST reports in the docs from LERA.

There were no horizontal beams *in the perimeter*... the OOS floor was supported by trusses except for the mech floors which had WF beams and yes... thicker slabs. The facade had 52" high spandels... probably 1/2" thick in the upper section, and maybe 3/4" in the middle and 1" in the lower.... not more.

#### jaydeehess

##### Senior Member.
I think that it is wrong to think ROOSD literally began when the roof line moved down. The process was a series of mechanisms and ultimately ROOSD dominated and accounts for the destruction of everything below the plane strike or "collapse zone".

I'm not saying that. There are details at every point in time. However in modeling whether physical or computer, one will have to forgo some of those details.
For instance, where, along their length did individual columns fail? Not likely that all columns failed even at the same storey, but most likely all failed within the zone that was on fire directly following the aircraft impact.

I doubt that ROOSD was characterized by " pancaking" in that this suggests that floor plans came down as a unit.

I also suspect that the impact of heat is not well understood or articulated. People seem to think the key effect of the heat was to weaken the columns to failure. And so they argue if there was enough heat to do that. (there wasn't)

But heat caused other problems which ultimately led to column "failure" some buckling and others being dragged completely out of alignment, others experience the crippling I mentioned. I think the KEY effect of heat which seems to be little discussed is the elongation of the bracing, the subsequent warping of the frame including shearing and failing structural connections.. and of course nudging columns laterally and off axial alignment.. THAT was the straw which broke the camel's back... maybe one straw at a time as the frame heated up and the core warped.
Columns were subjected to lateral pressure by expanding braces, greater load due to severed-at-impact columns, nonaxial loads due to tilt of upper section, and even if heated a bit will try to expand along their length ( as in trains rails) all of which contributes to deformation of the column.

#### psikeyhackr

##### Member
This is the crux of the matter.

One one hand psikeyhacker touts his completely unscaled model of column crush dominated collapse, and then complains that your unscaled model of floor connection dominated collapse is unscaled wrt the towers.

His model doesn't even stand straight up. He has it leaning on a smooth surface. His "floor" that HE tries to make an issue of is not even a single piece but you want to accuse me of making a big deal about scaling.
[...]

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#### Mick West

Staff member
His model doesn't even stand straight up. He has it leaning on a smooth surface. His "floor" that HE tries to make an issue of is not even a single piece but you want to accuse me of making a big deal about scaling.
[...]

But my model actually has MORE degrees of freedom than yours, which is essentially one dimensional. All the inclined plane does is constrain it in one horizontal direction (and reduce gravity a bit). Your dowel does the same thing, but in two axes.

##### Member
Unless someone is actually planning to use some data in a scale model, there's really no point discussing it.
Unlike you to attempt to close a discussion in this way, Mick. If someone was planning to make a scale model -- either physically or virtually -- then surely accurate data must come first.

the opinion of the vast majority of persons
...is irrelevant to whether or not a model of the complete destruction of the towers can be made, isn't it?

Given the complexities and chaotic nature of the trajectory of individual components in any collapse, the ridiculousness of such a demand would be obvious.
Predicting exactly the movement of individual components may be neither possible nor required; demonstrating that general and global collapse can occur is necessary, as at the moment that's what "the vast majority of persons" can only believe.

#### Mick West

Staff member
Unlike you to attempt to close a discussion in this way, Mick. If someone was planning to make a scale model -- either physically or virtually -- then surely accurate data must come first.

Not at all. First must come the ability to understand the limitations of a scale model.

It also depends on what you are doing psikeyhackr has a "model", but it's not really modelling what happened. My model models what happened a little better, but of course is nothing at all like reality.

And then as noted, you can't make a 6' tall model of the towers accurate to scale, as it would have to weigh several times more than a solid block of gold.

I think computer models are going to advance quicker than physical models. And they are already a lot more useful for large scale simulations.

3D printing is interesting, but it's only going to make a very small model, and it's not going to be made from the actual steel and concrete that's relevant to the discussion. And you won't be able to get the mass in there.

Going back to the BSB model. Even though it's not a very useful model in proving the integrity of the building, it's interesting to consider what they had to do in their attempt to make it as close as possible. Basically they build everything with linear dimensions (width, height, depth, any length) reduced to 1/10x. This reduces the cross sectional area (and hence the strength) of all the structural members to 1/100th. So (simplistically) the reduced structure should get able to support loads of 1/100th of the original (square). However the primary load is the weight of the structure itself, which is reduced to 1/1000th (cube).

So to get anything close to relevant results, they need to add 9x the weight of the reduced structure in a non-load-bearing manner. The do this by gluing iron ingots to each floor, the equivalent of about three feet thick.

Now, consider what you would have to do if you were to apply similar correction to a smaller model of the tower, one that someone might build at home on a 3d printer. Say you made a 1/200th scale mode, so you are building a model that's 1368/200 = 6.84 feet (with a base of about 1 foot square). Now ignore for the moment the issues of modeling the tiny connections, and girders flanges that are a thousandth of an inch thick. How much should it weight?

Well, if it's a perfect scale model, it would weigh 1/(200*200*200) = 1/8,000,000th of the original. Estimates vary, but let's take a common figure for the weight of a tower is 300,000,000 kg. So the weight of our model is 300/8 = 37.5 kg.

However, since we've scaled it 200x, the actual weight loaded on the model needs to be 200x as much, or 7,500 kg.

So for our 1/200th scale model to work, we would have to cram 7,500 kg into about 7 cubic feet. That's about 16,500 pounds per cubic foot.

Solid gold weighs 1206 pounds per cubic foot. So the 1/200th scale model is non-starter.

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#### Keith Beachy

##### Senior Member
Unlike you to attempt to close a discussion in this way, Mick. If someone was planning to make a scale model -- either physically or virtually -- then surely accurate data must come first.

...is irrelevant to whether or not a model of the complete destruction of the towers can be made, isn't it?

Predicting exactly the movement of individual components may be neither possible nor required; demonstrating that general and global collapse can occur is necessary, as at the moment that's what "the vast majority of persons" can only believe.
The ability to accurately estimate the WTC mass at any level of abstraction picked has been done, and can be done. Not an issue. This is a complaint of no data that has been going on for 5 or 6, or is it 8 years, when it can be estimated.

With zero evidence of outside help of explosives or thermite, or anything, the WTC towers collapse prove it did occur. The problem for 911 truth is to show it can't; which is impossible. Building scale models by 911 truth can only prove failure for 911 truth claims, if they make a valid model. When 911 truth builds a valid model of the collapse, it will debunk 911 truth claims. Irony, if they are competent at models, they debunk their claims. Gage will not be funding any scale model study, it could ruin his funding.

Has anyone who wants to prove the WTC can't collapse tried to get money from Gage? Not sure why his thousands of "experts" touted by 911 truth followers have not done a model to prove the gravity collapse is an illusion.

Now the problem is making a scale model for something denied by a movement which has failed to make a valid claim for 13 years. Does 911 truth have to add high explosives and thermite to the model? How do they do that? Not sure how you can make a scale model to model the weakness which feeds the collapse, a floor can only hold so much mass. How do you do that. If the washers in the washer model are floors, when more than 11 hit a lower floor it has to fail, not stop the overload of washers; The WTC floors failed when the mass exceeded the capacity.

#### jaydeehess

##### Senior Member.
The further complaint is that no true scale model has been constructed. However NIST did a full scale computer model of collapse initiation that demonstrates massive over load of floors and concludes, correctly in the opinion of the vast majority of persons with or without structural engineering qualifications..
...is irrelevant to whether or not a model of the complete destruction of the towers can be made, isn't it?

Predicting exactly the movement of individual components may be neither possible nor required; demonstrating that general and global collapse can occur is necessary, as at the moment that's what "the vast majority of persons" can only believe.

Salient point bolded.

Did not consider it like you to parse statements.

#### econ41

##### Senior Member
...Predicting exactly the movement of individual components may be neither possible nor required; demonstrating that general and global collapse can occur is necessary, as at the moment that's what "the vast majority of persons" can only believe.
That is the key issue for WTC1 and WTC2 collapse modelling - slightly redefined as demonstrating "initiation stage" and "progression stage" can occur. Or "did occur without CD assistance" to go a step further. Some folk may want a "transition stage" in there but at the present stage of my thinking that separate step is not needed. Once "initiation" allowed "top block" to fall ROOSD (Or "Three Mechanisms Model") was already under way. That latter is a bold statement which goes too far off topic so I wont support it here. Several members are familiar with my thoughts from other places.

But from the perspective of this OP there are two distinct stages where modelling could assist:

1) Modelling the cascade failure of "initiation" where I suggest that both physical and computer models would be of limited utility - not practical irrespective of cost - simply too many unidentifiable and probably unquantifiable variables. How would anyone define a complex cascade model that is 3D and fully represents the actual cascade failure(s)? And you cannot define a model if you cannot describe what it is modelling.

2) Modelling the "progression stage" or global collapse where the reality is so simple that models could be of limited value. Mick's "blocks" model is a useful unquantified visualisation for laypersons which demonstrates two of the three mechanisms. But hardly suited for quantification.

The big issue for discussion of progression stage at the twin towers remains the ambiguity between models and abstracts which have columns in line and the real event which did not have columns in line. The difference so fundamental that it cannot be right to claim "columns in line" as a valid approximation for "ROOSD" or whatever you call it - floor strip down by falling weight.

And we still see people lost between the two. The legacy of the Bazant & Zhou 2001-2 approximations still being carried forward and applied to the real events. psikey's models and written thoughts have always been ambiguous on that factor - definitely "columns in line" models and therefore not valid representation of WTC actual collapse. And it was early 2008 when I first addressed that aspect with psikey - long before the paper loops models.

So IMO models not practical for WTC Twins "initiation" and, whilst possible, of no value for WTC Twins "progression".

The discussion of the various approaches to "columns in line" modelling are interesting - OneWhiteEye has done a lot if basic physics modelling but not directly applicable to WTC 9/11 events at the macro level - the principles may be of some value if translated into the 9/11 actual setting.

##### Member
First must come the ability to understand the limitations of a scale model.
As I said at the start of this thread, Mick: the square cube law must be understood to construct a scale model. However it seems the consensus is that a virtual model is a more realistic proposition looking forward -- particularly in view of Moore's Law -- so, again: what could be more fundamental to such a project than accurate data?

Salient point bolded.
What you call a salient point was such a transparent appeal to authority I didn't bother to repeat it. Even if everyone in the world with a structural engineering degree thought the mechanism of progressive collapse leading to global failure has been understood, it wouldn't bring a model that illustrates this understanding any closer to becoming a reality.

Curiously though people like yourself, Keith Beachy and econ41 are caught in a paradoxical position where you are essentially claiming that the mechanism of progressive collapse leading to global failure is so obvious, commonsensical and self-evident to anyone with relevant qualifications that it is not worth proving to be understood through the fundamental scientific standard of reproducibility -- while at the same time claiming that the effort to do so is "not practical" and "of no value".

This paradox is evident throughout the arguments on this thread. Keith Beachy even attempts to shift the responsibility for demonstrating reproducibility onto those who dare to point out to the "scientific" consensus that reproducibility in this question -- upon which there is such supposed universal agreement -- has never been achieved.

#### econ41

##### Senior Member
so, again: what could be more fundamental to such a project than accurate data?...
A word of caution - the need is for data that is relevant and significant to the purpose and of accuracy appropriate to the need.
Curiously though people like yourself, Keith Beachy and econ41 are caught in a paradoxical position...
I don't see the paradox. Cannot the two parts co-exist?
...where you are essentially claiming that the mechanism of progressive collapse leading to global failure is so obvious, commonsensical and self-evident to anyone with relevant qualifications...
I only made that claim for the progression stage. The "initiation" stage I suggest is vastly more complex and little understood in detail.
...that it is not worth proving to be understood
That referred only to "progression" and I acknowledged a role for whole mechanism "visual display" models - such as Mick's - which only demonstrates two of the three mechanisms - no "core strip down" component. I do not see what a macro level model would prove in "understanding" the mechanism. And I acknowledged that element level models such as floor joist impact to shear modelling may have value.
through the fundamental scientific standard of reproducibility
The exercise is in engineering forensic analysis of a one off event which wil not be replicated full scale. I suggest the reproducibility aspect - used for developing new hypotheses >> theories is not properly applicable PLUS neither practical for "initiation" nor of any value for "progression".
-- while at the same time claiming that the effort to do so is "not practical" and "of no value".
I suggested "not practical" OR "of no value" for the respective two situations - not "and".

#### Jeffrey Orling

##### Senior Member
My sense is the erosion of capacity involving the warping of the core frame and lateral displacement of the columns progressed in a manner that would be impossible to know. One could perhaps create a model with a set of inputs/variables which would then over time work *through* a complex interconnected matrix of structural nodes consuming *fuel* creating more heat eroding more capacity, more warping and more lateral displacement of columns an so on. I see this progression analogous to a fire spreading through a 3 dimensional forest or a sink hole expanding over time. The growth is somewhat opportunistic depending on local conditions at the nodes (structural elements of the core). Slight change of the variables... in the case of the model (and the real world) the load fuel load or fire resistance and what node(s) it was acting on will determine how the capacity destruction in the core progresses.

Another factor is that the hat truss likely played a role.. almost the opposite of bedrock... anchoring core columns from above and supported by the core and the facade. The 3 D hat truss matrix had the ability to transfer axial loads to some extent. The effect of this load transfer would be to add yet another factor contributing to loss of column capacity via adding load to remaining columns.

My sense is that this would be a very complex model to run with many variables. Bottom like would be that the heat would eventually destroy capacity and fail the system as we witnessed.

#### Keith Beachy

##### Senior Member
...
... those who dare to point out to the "scientific" consensus that reproducibility in this question -- upon which there is such supposed universal agreement -- has never been achieved.
There is no "scientific" consensus that reproducibility is in question, or do I mean needed. I have not found a rational engineer who thinks a model is needed for the collapse progression. 911 truth has no science basis, no evidence to question the collapse caused by impacts and fire. For me, the second tower to collapse confirms the first collapse, and the first the second. Full up models, twice. Already reproduced. I cheated too, I researched the chief structural engineer, he agrees with NIST that the collapse after initiation was inevitable. We can argue with Robertson, but will not win.

After I understood the WTC system, with more than 12 floors falling, the collapse will not stop.

One thing doubting Thomases could check is the support of the floors to the core, and to the shell. Is NIST right a floor can only hold 29,000,000 pounds? This model is possible at many levels, from a single connector to a partial floor assembly. When the floors are overloaded by the top section, the floors failed as each floor is over loaded. As the mass falls the shell is destroyed in small sections, and as the collapse progresses to lower floors the shell comes off in larger sections. How will a model express this as seen in video. The floors are the key,

911 truth, "skeptics" who can't believe the collapse progression as seen unless they have the experience themselves, an event that they will never have, since they ignore the collapse as seen. The 911 truth CD fantasy, ignores the fact CD is a gravity driven event, most the destruction is due to gravity, with a tiny fraction of energy due to explosives. It makes no sense to deny the gravity collapse happened, and those that do don't understand CD.

Maybe 911 truth doubting Thomases could check the NIST's 29,000,000 pounds a floor can hold before failure. A model which can made full up at various levels of abstraction, if I may. This is easy to check (easy, as in possible), a fact 911 truth could check, and see if NIST got something right.

#### Jeffrey Orling

##### Senior Member
For me, the second tower to collapse confirms the first collapse, and the first the second. Full up models, twice. .

This could be true, but is not a proof because it assumes the collapse was natural with the first confirming the second and second confirming the first. There are many reasons to reject CD but this is not one of them.

#### Mick West

Staff member
As I said at the start of this thread, Mick: the square cube law must be understood to construct a scale model. However it seems the consensus is that a virtual model is a more realistic proposition looking forward -- particularly in view of Moore's Law -- so, again: what could be more fundamental to such a project than accurate data?

Getting started with a simplified model would be vastly more fundamental. Getting started with a reasonable estimate would be vastly more fundamental.

Not having some officially sanction exact figures is just an excuse to do nothing. Especially to those who claim a rapid progressive collapse violates some law of physics. Since they are making that claim without using any exact figures, then they should be able to test it without knowing any exact figures.

AE911 does not know the "accurate data" you say is necessary. Yet they quite categorically state the collapse could not have happened as a result of the impact and fire. If AE911 can claim the towers should not have been able to collapse the way they did, simply by looking at them, then why can't they make a simple model that demonstrates this?

Specifically, why don't they make a model that simulates the actual mode of collapse that will then validate their #1 claim of evidence:

What accurate figures are needed to prove this? And if the figures are needed, then why are they claiming it is true?

##### Member
I don't see the paradox. Cannot the two parts co-exist?
Well, which claim would you prefer to support? The claim that NIST modelled the collapse initiation and didn't bother to model the event further because progressive and global collapse all the way to the ground was now "obviously" going to happen, or the claim that NIST didn't bother to model the rest of the collapse after initiation because it was "too complex" to do so?

We've seen both claims on this thread, but neither provide evidence of anything except the deep reluctance of supporters of the official collapse theory to have their ideas examined through experimental research, or address the methodology by which that might be achieved.

I suggest the reproducibility aspect - used for developing new hypotheses >> theories
I suggest you do not understand what reproducibility means in terms of the scientific method. Simply: if a phenomenon cannot be reproduced under experimental conditions -- repeatedly -- then it is not scientifically explained. As I've already mentioned, an exact reproduction of the collapse of the Towers is not what would be expected: however a demonstration that a similar high-rise tower structure can indeed crush itself to the ground under the dynamic momentum of a falling upper 20% of itself on any day other than 9/11 has not yet been achieved.

There is no "scientific" consensus that reproducibility is in question, or do I mean needed. I have not found a rational engineer who thinks a model is needed for the collapse progression. 911 truth has no science basis...
Another person who doesn't understand why reproducibility is central to the scientific method. Keith, the question of modelling the Towers has nothing to do with "911 truth". You seem to have as much trouble grasping this as you do grasping the simple fact that a collapse event is not in itself a model of itself.

AE911 does not know the "accurate data" you say is necessary.
Does NIST? If so, why didn't they produce a model, however fundamentally simplified, do you think? Because it was "obvious" what was going to happen after they modelled initiation, or because it was "too complex"?

#### Mick West

Staff member
Does NIST? If so, why didn't they produce a model, however fundamentally simplified, do you think? Because it was "obvious" what was going to happen after they modelled initiation, or because it was "too complex"?

Both. It's obvious that the building was going to collapse, so why make a simplified model? And making a full model would be very complex, and ultimately just be a waste of money.

How can AE911 say the fall should have been arrested if they don't have accurate figures? Do you think they might be wrong?

#### Jeffrey Orling

##### Senior Member
They make all manner of unsubstantiated claims... it's part of the PR hype... Most people simply assume their claims are vetted. They are not.

##### Member
It's obvious that the building was going to collapse
It's not obvious that the building was going to collapse suddenly, quickly, and totally, no. Such a claim is as experimentally unvalidated as any claim AE911 might make about how the building would behave, so why do you take it to be so self-evident and attempt to shift the burden onto them? How is AE911 even relevant to the question?
why make a simplified model?
Some people have tried: videos have already been posted to the thread. To my knowledge, none have succeeded. Others may wish to try in future, if they have access to credible data.

#### Mick West

Staff member
It's not obvious that the building was going to collapse suddenly, quickly, and totally, no. Such a claim is as experimentally unvalidated as any claim AE911 might make about how the building would behave, so why do you take it to be so self-evident and attempt to shift the burden onto them? How is AE911 even relevant to the question?

Because the topic here is using models to investigate the collapse. AE911 claims the collapse is impossible as "the structural steel frame would have arrested any collapse from above". Now if this is true, then anything else is a moot point. Since it seems like a much easier task to build a model to illustrate the principle they are claiming, then that seems like a very obvious first step.

If the simple model proves collapse is impossible, then there is no need to build a more detailed model.

If the simple model proves collapse is possible, then we can go from there and see what we need to do to determine if it was too fast, or too symmetrical, or too dusty.

You need to have some good reason to spend millions of dollars on making a precise certified model just to verify if what we actually saw really happened without additional inputs (explosives, "attacks", etc.). So the sensible thing would be to use a much simpler model to demonstrate those good reasons.

##### Member
If the simple model proves collapse is impossible, then there is no need to build a more detailed model.
This I would agree with. What I don't understand is why you think NIST's claim that "the structural steel frame would not have arrested any collapse from above" is somehow self-evident, as NIST has provided no experimental modelling data to support such a claim. It seems to me you just prefer NIST's (non-)explanation, but that's not good enough.

That's because this same absence of experimental modelling data is the basis of your criticism of AE911 -- and yet AE911 were neither the organisation charged with explaining how the collapses happened in the way they did, nor were they the organisation that did spend millions of dollars modelling the Towers to the point of collapse, and yet went no further.

#### Mick West

Staff member
This I would agree with. What I don't understand is why you think NIST's claim that "the structural steel frame would not have arrested any collapse from above" is somehow self-evident, as NIST has provided no experimental modelling data to support such a claim. It seems to me you just prefer NIST's (non-)explanation, but that's not good enough.

It seems self evident when you think about the actual mode of collapse. Its not self evident if you think the steel frame has to be crushed one floor at a time - but when you realize that's not what happened, then it's seems very evident that at the very least all the office floors would have been stripped from the core at near free-fall speed, and the exterior walls would mostly fall outwards. The rate of collapse of the core itself after loosing all lateral support might be a quibble, but certainly does not seem unreasonable - especially given that large sections of it were observed to remain after the floors and exterior were stripped.

NIST was not charged with explaining how the collapse would continue, just how it got to a state where the structure could not possible support the dynamic load.

Are you saying you disagree with AE911 here? You agree it would fully collapse, you just think it maybe fell too fast?

Because if not, then the simply model is what you should be asking for, as it would prove your case, and be a lot more likely to be done by someone. Maybe even AE911.

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#### NoParty

##### Senior Member.
You need to have some good reason to spend millions of dollars on making a precise certified model just to verify if what we actually saw really happened without additional inputs (explosives, "attacks", etc.). So the sensible thing would be to use a much simpler model to demonstrate those good reasons.
And--as much as I hate to sound curmudgeonly--is there anyone in this room that isn't certain that
if \$10,000,000 were spent creating a model, exactly as AE911 & others requested, they wouldn't immediately
make new charges of deception the minute that the new model collapsed differently than they predicted?

##### Member
NIST was not charged with explaining how the collapse would continue
And that's the problem. No-one has been able to experimentally demonstrate -- even with a simple model -- what NIST failed to explain. Everything you say is "self evident" beyond the initiation of collapse is totally without experimental support, although there have been failed attempts to reproduce what you claim is obvious.

And--as much as I hate to sound curmudgeonly--is there anyone in this room that isn't certain that
if \$10,000,000 were spent creating a model, exactly as AE911 & others requested, they wouldn't immediately
make new charges of deception the minute that the new model collapsed differently than they predicted?
Not if all the variables as well as the model itself were made available for independent peer review, no.

That's what makes the NIST WTC7 model so unacceptable (besides its general inaccuracy, of course) and that's why I said at the start of the thread that femr2's approach was far more scientifically valid.

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