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

Mick West

Administrator
Staff member
Not sure about "larger debunking perspective". I have in mind the full spectrum of 9/11 WTC interest...certainly if we focus the "teens - 20's" group you identify THEN effort on the model which suits them is the priority.

The larger debunking perspective for me is to reduce the number of people who end up firmly believing in bunk. These types of belief are most prevalent amongst the young, young people are more open to new information. So a model that suits them might help to prevent many thousands of people from falling down the rabbit hole. I can't really see why it would something that only applies to young people, just that you need to keep them uppermost in mind.

http://www.publicpolicypolling.com/pdf/2011/PPP_Release_National_ConspiracyTheories_040213.pdf

upload_2014-10-26_10-8-25.png
 

econ41

Senior Member
The larger debunking perspective for me is to reduce the number of people who end up firmly believing in bunk. These types of belief are most prevalent amongst the young, young people are more open to new information. So a model that suits them might help to prevent many thousands of people from falling down the rabbit hole. I can't really see why it would something that only applies to young people, just that you need to keep them uppermost in mind.
I agree fully with what you say. The problem could be that nothing I have recently posted attempted to "weight" the various sectors of demography merely in the interest of simplicity of explanation. And I haven't got it limited to 'teens - 20's' I was using your descriptor to flag that I was on the same wavelength.

If I was speaking to such a group in a semi formal setting I would want an "improved jenga blocks model" in my case of training aids - with more rigorous quantified material in case there were follow up questions.

--and those same resources could be of value in casual encounters with such persons if the opportunity suited use of such aids.

Irrespective of age.


Thanks for the link BTW.
 

Jeffrey Orling

Senior Member
The larger debunking perspective for me is to reduce the number of people who end up firmly believing in bunk. These types of belief are most prevalent amongst the young, young people are more open to new information. So a model that suits them might help to prevent many thousands of people from falling down the rabbit hole. I can't really see why it would something that only applies to young people, just that you need to keep them uppermost in mind.

The young people parrot the old, like Griffin, Gage, Jones, Harrit et al all who have expressed (willful) ignorance about the simple science of the collapse. As has been noted innumerable times... a concrete slab will fail when the load exceeds its static capacity. Those floors were designed to carry a static load with a safety factor of perhaps 2 about 75# / SF. If more load was presented they break. This is settled science. More load was presented.

Truth guys then say why don't see see evidence of slabs... as if it was the connections of the slabs to the frame which failed and not the slabs themselves.

When you have materials crashing down over 500-1000 feet you see a lot of grinding agitation... which will see the concrete reduced to sand and powder. This will not happen with a crash of 10 or 20 floors perhaps. The grinding was not unlike how stone is ground to dust in a tumbler.

Then they go on to declare it is impossible for the slabs to be rendered to fine grains of sand and dust... what they were made from. Concrete in the towers was sand *glued* with Portland cement which is a powder mixed with water that then binds to the sand in a matrix. Stone aggregates make concrete stronger...WTC floors had no stone aggregates. The fate of the slabs is KNOWN materials science. This is not a mystery.
 

Cube Radio

Member
I must say I consider psikey's removal from this thread gross and unjustified, although wholly predictable. I will no longer contribute myself and leave you gentlemen to your circle of mutual cogitation.
 

NoParty

Senior Member.
I must say I consider psikey's removal from this thread gross and unjustified, although wholly predictable.

The beauty part is that--in a free country--if psikey really wants to keep repeating
(and keep repeating, and keep repeating) the same issues with something that happened 13 years ago,
showing little or no response to data offered by the many who have patiently endured his repetition,
he is 100% free to set up one or 20 sites :) that trade in his unorthodox style/approach to discourse.



p.s. "gross" ?
 

jaydeehess

Senior Member.
Not being mentioned by official sources supposedly explaining the events in THIRTEEN YEARS.

Remarkable!

psik
I find it not particularly remarkable that no qualified engineering or science based organization has opined upon the possibility that magic caused the 911 collapses.
 

OneWhiteEye

Senior Member
I must say I consider psikey's removal from this thread gross and unjustified, although wholly predictable. I will no longer contribute myself and leave you gentlemen to your circle of mutual cogitation.
I've gone back and forth with him for years at about a half dozen forums, including one in which I had the power to ban him - and I did. For all the thousands of posts we've exchanged in many locations, this is the first time I'd heard he believed in 'dustification'. psikeyhackr has traditionally avoided positive claims which could be dissected and refuted, rather practiced denial by way of ridicule. If you Google "TONS of STEEL and TONS of CONCRETE" (do it, seriously, I beg of you), you won't be able to get through all the matches in one day. This is how many places and times he's done pretty much the same thing, and always with the same result: decent, intelligent people going around in circles forever unless one of two things happen:

1) people get wise and ignore him
2) he's removed from the discussion

Both rarely happen, but the second more so than the first. It may not seem fair to you but, from my perspective, keeping him in a discussion isn't fair to others who are well-meaning but either lack the self-control to ignore him (e.g. me) or are being newly exposed (like some/most here). Mostly the latter. If you do the Google search I mention and look at some of those threads, you'll see the same scenario played out time and again. Many times word for word... and I mean that literally since it's not uncommon to see the exact same text from psikey as if it's copy and paste. Funny, though, I think it's written anew each time.

For that reason, I fully support Mick's decision since this forum seeks to minimize pointless tail-chasing in favor of focused, concise argument. It's appropriate to remove influences which pull it astray. This was the justification for psikey's removal in another forum, though I chose to go all the way and ban him from the forum. In this sense, Mick is being generous - and I wish to stress that - because psikey still has the opportunity to participate in other discussions.
 

OneWhiteEye

Senior Member
For the record, it's not my intent to bag on psikey in his absence. I've actually grown to like the guy. I wasn't joking when I said he had talents. At any one of hundreds of more general/popular discussion boards, there is no cause for removal. And so it is! I still engage him (though lightly and not always contentiously) by choice at other places.
 

econ41

Senior Member
I've gone back and forth with him for years at about a half dozen forums, including one in which I had the power to ban him - and I did.
That is my experience also. Mostly on one forum where I was sub-forum moderator. I tolerated his "insult in every post" style for ~2 years. Mostly he made snide comments about my engineering and physics skills. Finally the senior admin banned him...not me.

For the record I admire the effort which psikey has put into his various models. I have said so on multiple forums and many times. They are IMO quite good models for illustrating what they actually illustrate. BUT they do not represent WTC 9/11 Twin Towers collapses. And I have been periodically informing psikey of that reality since late 2007.

Like OWE "I've actually grown to like the guy." I'm not joking when I admire his effort in constructing models. They are exactly the type of models I would recommend - have been recommending in this thread - whether for lay audiences or as introduction for more serious persons including professionals who are new to the topic. And, again like OWE "I still engage him (though lightly and not always contentiously)"
 

jaydeehess

Senior Member.
On the OT issue of moderation here, I would inform all that on the BAUT site ( if they even still accepted any 9/11 related threads - they do not) psikey would have suffered mod action well before this. In a hypothetical thread there in which one posts a model purporting a relevance to a real life situation, and then fails to address issues brought up by other posters, the thread is locked. Do this enough times and a permanent ban is handed out.

So, while he may have gotten much further on other sites, he would not have gotten as far as he did on this site, on BAUT.

The obvious then should not require stating but:
Forum moderation is handle in a wide spectrum of fashions across the internet. There are usually venues on beach forum by which disagreement in moderation actions and/or appeals can be heard.
Since this is not a government agency, the right to free speech does not apply. Its a private venture, location.
 

Mick West

Administrator
Staff member

The first simulation is a toy. The second one is using the wrong NIST simulation (the one without damage). If you use the one with damage, it matches more closely - close enough given the fidelity of the simulation. There's still more distortion of the skin though.
 

Jeffrey Orling

Senior Member
I think the NIST sim goes off because it used the col 79 failure to drive the collapse when 79 was a consequence of the failure which were more extensive and below it.. The insides were gutted and the penthouse collapses were the tell tale signs of this... but I suspect more of the insides were actually gone and there was nothing to telegraph this on the exterior. If there were aerial vids I bet it would show the entire roof dropped inside. There were long span beams to the north facade and I am guessing that the north curtain wall would not fold in smaller sections as the NIST sim shows. Note that MOST of the north facade was supported at the end of 8 MG27 cantilevers.
What appears to have occurred is that the failure initiated in the TT1 region with was adjacent to column 79... spread westward across the north of the core taking down columns 73, 70, 67, 64, 61 and to the east 79 and displacing the massive E-W girder which connected these 5 columns (purple in my cartoon) and supported the south end of the 8 - MG27s. This entire floor section "slipped" southward and down into the core over the con ed sub station pulling free from the north wall. The core spanned over con ed and so it had little axial load paths inside the core over con ed. The kink of the north wall was directly north of column 73 which was the west end of TT1 and the first to fail. This is what the building movements tell us about what was going on inside.
 

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jaydeehess

Senior Member.
The second one is using the wrong NIST simulation (the one without damage). If you use the one with damage, it matches more closely - close enough given the fidelity of the simulation. There's still more distortion of the skin though.
I find this is the case many times when truthers compare NIST sim to video. They often use the 'no prior damage' scenario.

FEA are limited by the amount of detail one inputs. To my untrained eye it looks like the elasticity of elements was off possibly because the FEA used the same value for all elements?
 

Jeffrey Orling

Senior Member
I find this is the case many times when truthers compare NIST sim to video. They often use the 'no prior damage' scenario.

FEA are limited by the amount of detail one inputs. To my untrained eye it looks like the elasticity of elements was off possibly because the FEA used the same value for all elements?

FEAs are extremely limited in the face of the complexity of these events which in the case of 7wtc lasted 7 hrs. And if there was a heat cause.. there was... it was working on more of the structure than the flr 13 column 79 region. FEA for these collapses is a fool's errand.
 

jaydeehess

Senior Member.
FEAs are extremely limited in the face of the complexity of these events which in the case of 7wtc lasted 7 hrs. And if there was a heat cause.. there was... it was working on more of the structure than the flr 13 column 79 region. FEA for these collapses is a fool's errand.
Well looking through tons of steel that cannot be positively placed and much of which was within the hot rubble zone would have been more foolish IMHO.
So investigators were stuck with observables. That demonstrated fire would have affected col 79 at the 13th floor while there are as no evidence of any heat effects of nearby columns or structures that would cause a similar effect as a col 79 failure.
Since building physical scale models and investigating variations of collapse scenarios is prohibitavly expensive, the only tool left is the FEA.
Obviously such an FEA is going to be limited and will diverge from reality the further from t=0 one let's it run.
However the salient point would be initiation of global collapse. Once the facade begins moving it no longer matters anyway.
 

Jeffrey Orling

Senior Member
This is so silly. The amount of data about 7wtc seems to be very much limited... to what they see in some vids? YIKES! Well sure if that's what you are working with and you need to SHOW "evidence" then you go with what you got... or as the song goes if I not near the girl that I love... I love the girl I am near.

What I do find interesting about TT1 is that both FEMA and Cantor seemed to suspect this at first and it was abandoned. Perhaps for lack of evidence and it would only be speculative since they had no data.. not there was no data from down there.
 

jaydeehess

Senior Member.
How would you propose identifying specific components in the rubble in the first place , and then identifying when they broke and what caused it?

You are pooh poohing the lack of data as if there was a way to obtain more. Was there?
 

Cube Radio

Member
@Mick West You may say that the first model I posted is a toy but it was constructed with the same physically accurate modelling software you have claimed you could use to build a model of the Towers collapsing in just a month of part time work. However you have also said such an effort would be prohibitively expensive (even though the software is free).

The comparative video of NIST's unverifiable cartoon vs. reality was produced by @One WhiteEye's friend femr2. @jaydeehees may attempt to characterise him as a "truther" but that would be a weak attempt to denigrate a huge volume of research into the 9/11 collapse event, including the only intellectually honest computer modelling effort that has been discussed at any length on this thread, as I'm sure @OneWhiteEye would agree.

And yes, of course more data could have been collected, for example by analysing the WTC7 steel John Gross has been pictured with.

@Jeffrey Orling your ideas are pure speculation. It is a mystery to me why people like you invoke the initial collapse of the penthouse as evidence to support their armchair theorizing. How do you imagine the penthouse collapse falsifies the CD hypothesis? It is consistent with that idea.

According to NIST's own theories only a small explosive device that dislodges column 79 would produce the global collapse event. There is even video soundtrack evidence of a low frequency explosion just before the penthouse falls.
 

Jeffrey Orling

Senior Member
Low frequency explosion? What is that? So what's the deal were 8 stories of 81 columns taken out simultaneously as AE claims or not?

I have proposed a speculative theory. What else can one do? Truthers don't even describe the mechanism... to them it's all black box called BOOM.

My speculative theory attempts to account for all the visual evidence in the public record that I am aware of. I would expect all sorts of building systems to explode when building is on fire... including but not limited to electrical and mechanical equipment.

I believe there has been some video analysis that the collapse of the EPH shows a wave of destruction all the way down as far as the camera frame allows. This was done using the reflection distortion of the facade which is apparently telegraphing the collapse behind it. That analysis rings true to me. So either the EPH drove down thru the building... or everything below it collapsed and the EPH fell into the *hole*. I find the later more sensible.

The EPH covered a large area of the east side of the building... 10 column lines (actually 9 above floor 7) and TT1 and TT2. It makes sense to me that all of those column lines collapsed because all of the EPH drops. Only col 75, 78 and 81 and the famous col 79 were not framed into TT1 and TT2 and these were at the southern edge of the EPH aside from col 79 on the NE.

Did the entire EPH collapse or not? If it was the entire EPH footprint then more columns than 79 were involved or "removed" from supporting it.

NB that very soon after the drop of the EPH the central area (screen) and then the WPH drop. We can assumed that the structure beneath the center portion on at least the north side... then the West portion lost axial support (columns "failed"). This would include column failures in the following sequence... (73 already gone under the EPH) then 70, 67, 64 and 61 which rested on the North end of cantilever TT3 which was supported on columns 61a and 62. Columns 62, 61a, 64, 67, 70. 73, 74, and 75 were around the west, north and east side of the core... which of course has mostly elevator shafts within it.

NB that the north wall was supported on 8 MG27 cantilevers... it contained columns 47, 48 , 49, 50, 51, 52, 53, and 54... none of which directly coupled axially to the foundation. The 8 MG27's rested on 47a, 48a , 49a, 50a, 51a, 52a, 53a, and 54a on the north side which did extend to bedrock... and on the south were framed into a massive EW transfer girder (purple in sketch ) framed to the north side of 73, 70, 67, 64 and 61.

Logic tell us that the columns under the EPH collapsed along with TT1 and TT1 this seems to have destroyed the integrity of the EW transfer girder attached to 73, 70, 67, 64 and 61.... and likely pulled TT3 Eastward collapsing into the core over the con ed. This left the 8MG27s with no south side support and probably all the floor ares North of the columns 73, 70, 67, 64 and 61. slid down to the south as they dropped with no support. The pulled the columns 47, 48 , 49, 50, 51, 52, 53, and 54 southward causing the entire north curtain wall to bend inward seen as it comes down. The kink in the curtain wall begins just north of column73 at the eastern end of the series of 8 MG27s and extends west and eastward.

NB there is no way to know when the corrosion seen in some of the steel took place... before during or after the collapse. We certainly wouldn't expect that the corrosion would NOT take place after the collapse. Of course the pile of steel with burning fuel and all manner of chemicals being mixed together with water would be a highly corrosive environment for steel. How could it NOT be? It took months to remove the steel... and it was in the corrosive environment for months. Even if the steel had corroded BEFORE the collapse ... it certainly corroded AFTER the collapse.

The above is my analysis which correlates the building movements observed with the structure within. We can't say with any certainty what caused the chain of events.. the westward progression of column failures. It did not happen simultaneously. We can't even know for sure which of the columns under the EPH or which of the transfer trusses TT1 or TT2 failed first. It appears that a failure of any one of the 10 columns or 3 transfer trusses on the east side could begin the collapse of the other 9 and the trusses and westward progression of the failures across the north of the core.

It appears that any failure at col 79 on floor 13 would be a result of the above not a cause of it.

Is this "pure speculation"? No more so than any other analysis which attempts to correlate structure and observed building movements would be. I challenge anyone to refute this analysis. One of course could dismiss it because there is no evidence of the cause to initiate this progression of failures. That is not a refutation of the mechanics of the progression.

This failure scenario accounts for the approximate 2.25 seconds / 105 feet of vertical fall of the roof line at about free fall acceleration... as those 8 MG27 cantilevers were 105' above grade with nothing below their north ends.

NB that the structure below the facade had very few columns from floor 7/8 to the foundations. On the east and west were braced frame structures with only 4 vertical columns each... so the 15 columns on the east and 15 on the west above floor 7 were supported on 2 braced framed - 7 story tall trusses. 2 of those 4 columns were corner columns. The south had a 6 story tall lobby with no lateral bracing northward to the core.

This very clever design to span over the con ed was more like a Rube Goldberg house of cards structure completely dependent on the integrity of the three transfer trusses the massive E-W girder north of the core carrying th e 8 MG27s and the two 7 story braced frames on the east and west.

Any engineer looking at this structure AND the videos of the movement will come to a very similar analysis. And that's exactly what Cantor did and what FEMA did in 2001/2002. And that's what NIST chose not to study for unexplained reasons... perhaps because they had no pics of fires down there?
 

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Jeffrey Orling

Senior Member
@Cube Radio

"It is a mystery to me why people like you invoke the initial collapse of the penthouse as evidence to support their armchair theorizing. How do you imagine the penthouse collapse falsifies the CD hypothesis? It is consistent with that idea.

According to NIST's own theories only a small explosive device that dislodges column 79 would produce the global collapse event. There is even video soundtrack evidence of a low frequency explosion just before the penthouse falls."

Why is a mystery that anyone trying to explain the mechanism of the collapse "invokes" the actual building movements. It would intellectually dishonest to IGNORE the observations... such as the EPH drop.

I am not attempting to falsify anything. I am attempting to DESCRIBE the sequence of how the structure likely failed. What kicked it off... is impossible to determine. And I suppose a "CD" attack of TT1 would cause the same progression of failures or of column E1 or E2.

Before you look at the CAUSE(s) of the initiation... you need to understand how it actually collapsed. None of the sims I have seen respect the structure and how the load transfer region was likely involved. The tower was not a grid of 81 columns.... certainly not below floor 8. And how ironic it is that the load transfer structures topped off at 105' the precise distance of the *FF* collapse. So you have a 105 foot high region of very unusual structures at the base of the tower... especially below the EPH and this is of no interest? Where there are probably 24 or so column below floor 8 which coupled directly to the foundation.. That is...81 above floor supported by 24 columns using load transfer structures... 57 columns had essentially nothing directly below them connecting them to bedrock. You want to know why there was "no resistance".. the answer is that MOST of the columns had nothing but transfer structures below them!

I greatest irony of AE911T's professionalism is that they completely ignore the structure and especially below floor 8! Or maybe it's not irony but a bad joke!
 

jaydeehess

Senior Member.
[ femr2. @jaydeehees may attempt to characterise him as a "truther" but that would be a weak attempt to denigrate a huge volume of research into the 9/11 collapse event, including the only intellectually honest computer modelling effort that has been discussed at any length on this thread, as I'm sure
When did I do that? I have made reference to femr2's work myself many times.
 

jaydeehess

Senior Member.
Honestly the discussion taking place here recently belongs more in the 'plausibility of demolition thread'.

Would taking out col 79 with explosives do the same thing as removing column 79 through loss of lateral support? Yeah, d'uh.

I second J.O.'s query, what is a low frequency explosion?
 

Mick West

Administrator
Staff member
Please stick to discussing Models in this thread. If it goes off topic, posts will be deleted.
 

Jeffrey Orling

Senior Member
Mick, my post was trying to explain why I found the NIST sim and the other one not accurate because they did not deal with the structure below floor 8.
 

Mick West

Administrator
Staff member
Mick, my post was trying to explain why I found the NIST sim and the other one not accurate because they did not deal with the structure below floor 8.

But it devolved into a TL/DR post expounding your personal theory, when you could simply have posted the above sentence.
 

Mick West

Administrator
Staff member
@Mick West You may say that the first model I posted is a toy but it was constructed with the same physically accurate modelling software you have claimed you could use to build a model of the Towers collapsing in just a month of part time work. However you have also said such an effort would be prohibitively expensive (even though the software is free).

I think you are conflating a number of things I have said. If you want to tell me so much about what I said, then please quote me.

Blender is not physically accurate, but you could use it to demonstrate the mechanism for collapse. You would need to actually model the building in a way that reflected the actual support structure (and hence the mode of collapse). I could do that in a month.

The blender model in your video is obviously not a good representation, collapsing into a pile of infinitely strong evenly sized slabs. It seems to use the same fracturing mode of failure throughout.

To actually build a physically accurate model gets more expensive, because of the high complexity of the buildings.
 

Michael M.

New Member
My questions are: why would there be? and: what would that look like?

Consider, there are two possibilities here.

A) The collapse was from the impact damage and the fires
B) The collapse was aided in some way, like with explosives

Now from my perspective, option A seems by far the most obvious. There seems nothing at all to indicate option B is true, and all the objections to option A boil down to "looks odd to me", or rather specious misapplications of models and statements like "violating Newton's laws".

I feel my opinion is shared by the vast majority of the worlds structural engineers, scientists and physicists. Once the collapse started, then total collapse was inevitable.

So from my perspective, the ONLY reason to make a model is to explain things to people who think it looks wierd. Now as I debunker I like explaining things, hence spend 30 minutes making that model earlier. But there seems to be no good reason to spend $1 Million to make a model JUST so things can be explained.

Tell me, what exactly would satisfy you? What would it look like?

First let me say that I appreciate Mick's professionalism in this thread + I haven't actually read all the pages of this very long thread. But I just had to post the rather obvious reasons why we would need to be able to model better these catastrophal failures:

* In order to better understand how to avoid such events in the future.

- Is it eg. possible that rather minor damage or fire can cause whole steel structured skyscraper to collapse in short time (including the possibility of having eg. explosions in just one or couple of floors)?

- Or is it possible that even couple of steel columns' failure at some position of skycraper + floor failure can bring much of the structure down (if not whole building)?

* How many current buildings are in danger of same sort of event?

The events would indicate that these are valid points. Either there were some other reasons for the total structural failure than fire - and this is usually called conspiracy theory - or there might exist a grave danger that similar events (even from just fires and/or couple of rather small explosives) can bring whole skycrapers (or other tall buildings) down very rapidly and result in even thousands of lives lost.
 
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Mick West

Administrator
Staff member
But I just had to post the rather obvious reasons why we would need to be able to model better these catastrophal failures:

This thread is not really about the need for more modeling, which is just a cost/benefit argument. But more the practical nature of such models.

What type of model do you think is needed, and what exactly would it demonstrate/investigate?
 

econ41

Senior Member
First let me say that I appreciate Mick's professionalism in this thread + I haven't actually read all the pages of this very long thread. But I just had to post the rather obvious reasons why we would need to be able to model better these catastrophal failures:

* In order to better understand how to avoid such events in the future.

- Is it eg. possible that rather minor damage or fire can cause whole steel structured skyscraper to collapse in short time (including the possibility of having eg. explosions in just one or couple of floors)?

- Or is it possible that even couple of steel columns' failure at some position of skycraper + floor failure can bring much of the structure down (if not whole building)?

* How many current buildings are in danger of same sort of event?
Good points Michael M and they have been addressed in the thread but let me present a brief (OK - I was an optimist. :oops:) summary of my perspective. (Retired civil structural engineer with management experience including the level of policy which your questions raise.)

First I suggest we need to recognise two target audiences and two types of models.

The targets are either:

A)the professions and professionals involved in the building industry - high rise sector - and intended to solve problems those persons face; OR
B) persons including lay persons or members of other professions who may have an interest in some aspect of "why the buildings collapsed".

For brevity I will refer to those as "professional" and "lay" respectively in what follows.

The types of models are:
C) Professional research models intended to produce quantified data about some aspect of the events; OR
D) Demonstration of mechanism models.

The models needed for quantified reserch will tend to be partial models - models of specific sub-mechanisms. "Demonstration" models being more suited for visually showing what happened - often for a lay audience.

Now let me explain where those fit relative to the WTC 9/11 events and current state of understanding.

First recognise that all such buildings involve establishing of design parameters - usually with minimum requirements mandated by code. Which leads to a risk managed balance between safety levels and economic cost. All buildings designed to be safe - and safe by a good margin - within the envelope of design parameters.

All three WTC towers were taken well outside their design envelope.

The three "big factors" relevant to WTC collapse are:
1) All steel framed buildings are vulnerable to heat weakening effects from prolonged fire. All such buildings are designed with a view to two overlapping objectives in the event of fire. Those are:
(a) Ensure time for occupants to escape; AND
(b) Ensure time for active fire fighting measures to be implemented - taking over from any inbuilt passive or self powered fire inhibiting provisions.

2) WTC1 and WTC2 were hit by trauma way outside any design provision which was reasonable at the time they were built. That trauma overwhelmed the built in fire fighting strategy. (I wont derail but suggest it is not possible to design a commercially viable building with can structurally withstand any conceivable malicious attack.)

3) WTC7 was overcome by events so that it was taken outside the fire resistance aspect of its design. Note however that the primary fire objective of "get the occupants out" was achieved.

So with that setting of the scenario let me respond to each of your points:

* In order to better understand how to avoid such events in the future.
I suggest primary avoidance strategy would be to prevent such forms of attack. Obviously open to complex discussions.

- Is it eg. possible that rather minor damage or fire can cause whole steel structured skyscraper to collapse in short time (including the possibility of having eg. explosions in just one or couple of floors)?
Collapse due to "minor damage" was not what happened at WTC. So modelling WTC will not help prevent it. Design practice already includes assessing a wide range of "what if" situations including accident and malicious activity. I would suggest that there is no scope for modelling to assist.
- Or is it possible that even couple of steel columns' failure at some position of skycraper + floor failure can bring much of the structure down (if not whole building)?
Yes it is possible BUT the previous comments apply. We need to take care to follow the TWO paths of logic - i.e. "inside design parameters" OR "subject to deliberate malicious attack". My previous comments apply to the respective scenarios. In brief modelling doesn't help.

* How many current buildings are in danger of same sort of event?
Decide which scenario. I suggest non are in danger without deliberate malicious attack. And nothing structural can be done to reinforce exiting buildings in the event of deliberate massive attack. There may be some existing buildings where lessons from the WTC events could indicate modifications which may be prudent. BUT modelling is not the way to determine what is needed.

Now note that all your comments so far envisage the "professional" audience. None of them go to use of models for a lay audience.

So you concluding paragraph:

The events would indicate that these are valid points*. Either there were some other reasons for the total structural failure than fire** - and this is usually called conspiracy theory*** - or there might exist a grave danger that similar events (even from just fires and/or couple of rather small explosives) can bring whole skycrapers (or other tall buildings) down very rapidly and result in even thousands of lives lost.****

* I question the GLOBAL conclusion - reasons already outlined.
** There were - the "fire only" is a truth movement preferred "strawman".
*** Disagree - conspiracy theory is a theory that some conspiracy is involved when there is no evidence or argument to establish a prima facie case of conspiracy. Agreed however that "conspiracy theory" is an often misused term.
**** Hyperbole and conflation of aspects which do not lead to the conclusion. BUT this is the central point for a discussion.
 
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jaydeehess

Senior Member.
- Is it eg. possible that rather minor damage or fire can cause whole steel structured skyscraper to collapse in short time (including the possibility of having eg. explosions in just one or couple of floors)?
Yes. Case in point is WTC7, which, if one were to explosively take out col79 on a lower floor, quite possibly could end up taking the whole structure down.

- Or is it possible that even couple of steel columns' failure at some position of skycraper + floor failure can bring much of the structure down (if not whole building)?
Same question as the first basically.

* How many current buildings are in danger of same sort of event?
Unknown. It was partially the unique construction techniques that contributed to the structure's demise. However one could note the small sample size of about a dozen heavily damaged buildings in and around the WTC Complex of which only three completely collapsed.

The events would indicate that these are valid points. Either there were some other reasons for the total structural failure than fire - and this is usually called conspiracy theory - or there might exist a grave danger that similar events (even from just fires and/or couple of rather small explosives) can bring whole skycrapers (or other tall buildings) down very rapidly and result in even thousands of lives lost.
In only one building was fire the only proximate cause of collapse. The other two also had a 100 ton aircraft hit them at 400+ MPH and spread thousands of gallons of fuel over several floors.
The fuel was an accelerant that ignited wide area fires on four or more vertically adjacent floors. That immediate fire situation would normally, that is without the high speed distribution of accelerant, take several hours to develop.
So are other buildings in the danger that the towers were in? Not by a long shot.

What about WTC7's manner of demise? Sure, any structure suffering many hours of unfought fires would be in danger of full or partial collapse. You will note though that no one died in WTC7.
 
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Michael M.

New Member
Thank you for all for your toughtfull replies. I will try to find some time to address some of them better. Now I will just quickly try to describe more of my primary concern in this discussion:

The discussion seems to take for granted that there were so severe damages done to the buildings (by either aircraft of falling debris) that there is no need to try to inspect if the treshold to achieve collapse is even much lower than what it actually was. How can we be even relatively certain eg. that just a couple of drone(s) with explosives can not achieve the same result (or smaller aircraft, or just "amateur" = semirandomly placed small explosives), if we can not simulate what would happen in different scenarios?

That is where the simulation is needed: to obtain more understanding about different situations. I'm quite certain that eg. different kinds of joints will give wildly different results in real life in any such event. Thus there is really big need for any simulation that can model at least somewhat accurately this difference, given a certain situation (eg. impact points and forces). So this is the main question for me: how to simulate such scenarios?
 

econ41

Senior Member
Thank you for all for your toughtfull replies. I will try to find some time to address some of them better. Now I will just quickly try to describe more of my primary concern in this discussion:
Thanks for making your position clearer.

The discussion seems to take for granted that there were so severe damages done to the buildings (by either aircraft of falling debris) that there is no need to try to inspect if the threshold to achieve collapse is even much lower than what it actually was. How can we be even relatively certain eg. that just a couple of drone(s) with explosives can not achieve the same result (or smaller aircraft, or just "amateur" = semirandomly placed small explosives), if we can not simulate what would happen in different scenarios?
Within the scope of the topic of this thread - which is use of models - you already have my answer. There is nothing IMO that the professional engineers responsible for future designs would benefit from modelling.

And that is without me addressing the merits of your technical concerns. IMNSHO Modelling would not help.
That is where the simulation is needed: to obtain more understanding about different situations. I'm quite certain that eg. different kinds of joints will give wildly different results in real life in any such event. Thus there is really big need for any simulation that can model at least somewhat accurately this difference, given a certain situation (eg. impact points and forces). So this is the main question for me: how to simulate such scenarios?
There is a pre-requisite issue (or two)
What aspect of what scenario do you suggest modelling could help; AND
How would it help?

For the one example you give - joint strength - it is a generic topic and one area where:
The engineering profession already has a wealth of research data on a far broader base than available from WTC modelling; AND
What specific to WTC could be modelled to give better data for future buildings?
 
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Michael M.

New Member
Thanks for making your position clearer.

Within the scope of the topic of this thread - which is use of models - you already have my answer. There is nothing IMO that the professional engineers responsible for future designs would benefit from modelling.

And that is without me addressing the merits of your technical concerns. IMNSHO Modelling would not help.
There is a pre-requisite issue (or two)
What aspect of what scenario do you suggest modelling could help; AND
How would it help?

For the one example you give - joint strength - it is a generic topic and one area where:
The engineering profession already has a wealth of research data on a far broader base than available from WTC modelling; AND
What specific to WTC could be modelled to give better data for future buildings?

I'm not advocating just for one spesific model. In other areas of science, simulations are used to estimate probabilities of some events. Often those probabilities are impossible to calculate exactly as the events are chaotic in nature. If one would have been asked about the probability of aircrafts brinning towers down prior the actual events, the estimations would surely been other than after them (do you agree?).
Thus we need ways to estimate better chaotic events like that. I will try to list better some possible starting points for this later on.
 

jaydeehess

Senior Member.
I'm not advocating just for one spesific model. In other areas of science, simulations are used to estimate probabilities of some events. Often those probabilities are impossible to calculate exactly as the events are chaotic in nature. If one would have been asked about the probability of aircrafts brinning towers down prior the actual events, the estimations would surely been other than after them (do you agree?).
Thus we need ways to estimate better chaotic events like that. I will try to list better some possible starting points for this later on.
If engineers were polled prior to 9/11 you'd have gotten a mixed reply.

Physical models are very restrictive. You either build full scale which is very expensive and limits you to one run at it.
Or
You build partial models or scaled models which allows more kicks at the can for the same dollars but gives you a skewed result.

The better bet is computer models. You can make multiple runs, changing some aspects on each, but you are limited by the computing power. More detail means a need for more power and longer calculation time.

Still, the events of 9/11 are the single most severe that a structure could encounter short of huge natural disaster such as major quake. Its not practical to design all large buildings to survive a large airliner and fire accelerated by thousands of gallons of fuel.

Hopefully the assymettric beam layout of WTC7 will be avoided in future structures, fire stairs not clumped together in the center of buildings and better constructed to protect their integrity.
 

econ41

Senior Member
I will try to list better some possible starting points for this later on.
Great idea - much easier to respond to specifics than to generic or generalised claims.
I'm not advocating just for one spesific model. In other areas of science, simulations are used to estimate probabilities of some events. Often those probabilities are impossible to calculate exactly as the events are chaotic in nature. If one would have been asked about the probability of aircrafts brinning towers down prior the actual events, the estimations would surely been other than after them (do you agree?).
Thus we need ways to estimate better chaotic events like that. I will try to list better some possible starting points for this later on.
I'm doubtful about use of physical models to "estimate probabilities". And very little of the WTC 9/11 events are truly chaotic in the scientific meaning of the word which would imply the events not susceptible to analysis. Non of the "confusion" (lay persons "chaos"???) is in engineering aspects that are of importance AND which we could model to gain better data.

I say "Yes!" to your "Do you agree?" question. However that does not explain how physical modelling will improve our knowledge for future buildings. What data could we get from a physical model that we do not already have from the real event?

We have most of the data we need for the engineering forensic analyses. And the data we do not have is mostly the data which we cannot get so we don't have the data to build the relevant physical model.

However most of what I am saying will sound pre-emptive. If you continue to gather your thoughts and raise more specific questions my or our responses may be more helpful for you.
 

benthamitemetric

Senior Member
Long time reader (and appreciator) of metabunk, first time poster.

This past summer while I was doing a particularly boring corporate project on the road, I had a bunch of time to really research the 9-11 truth movement and its claims. As someone who witnessed the towers collapse firsthand, such claims have always fascinated--though never persuaded--me. After a family member started getting into Alex Jones et al., however, I really wanted to be able to approach the topic the same way I approached many others in my life (as a corporate attorney) by diligently digging through the facts and weighing expert and inexpert opinions. The culmination of that research was a post to /r/skeptics on reddit that drew a moderate amount of attention, but then faded into the ether of the internet. You can find that post here.

The reason I post that in this thread is because that same search for research led me to many, many similar papers that were not WTC 7-specific, including one that actually documented *drum roll please* phsyical scale modeling of the fires of the floors of wtc 1 and 2: http://cedb.asce.org/cgi/WWWdisplay.cgi?161328

The paper is behind a pay wall, but I do have a full copy saved on my home computer if anyone is interested in more about its conclusions. Since I rarely see this article, or any of the others I cited on reddit, used in internet debates on the collapse of the towers or wtc 7, I thought I would share. There are plenty of more peer reviewed wtc 1 & 2-specific papers on other topics, as well.
 
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