The SINGLE MOST IMPORTANT ANALYSIS of the events of 9/11.

a reply to: LaBTop

No the lie is that Thermobaric Bombs are "quieter" or "lower in frequency" than normal explosives. That is a lie. A bold faced lie. a blast big enough to lift a floor one foot is going to be heard and seen. You are so religiously held to that lie it is scary. That is called disinfo. Your links and "research" is a shining example of disinfo as well. You post walls of words that look great, but still come apart the moment any basic research goes into it. I have read through your "Thermobaric Bombs" and all I get from it is that it was all thought up in the mind ofa conspiracy nut who has some serious issues in la la land. I'm not going to soil this page by bringing up his name here but, you use his claims of this special weapon but has NO actual back up. None. Reposting his crap is not posting up facts. Thermobaric bombs in the WTC is a laugh riot. Even the actual truthers think this is nutty:
911research.wtc7.net...

And yes, you are claiming these are silenced thermobaric bombs because YOU JUST SAID that they are so low frequency they can just be drowned out by the outside noise. I mean, seriously, YOU SAID IT first!! I have yet to see or hear a thermobaric bomb that is large enough to lift a floor that is one acre in size one foot, and yet totally be missed by anyone standing less than 100ft away from it, and also not seen prior to detonation. You have no idea of how a thermobaric device works at all. No matter how much you stomp your feet and huff and puff about how genius you are and how we are soooo uninformed, the actual facts are, thermobaric bombs are loud. VERY loud. The more powerful they are, the louder they will be. Period. end of story. Alas, you also ignore the challenges of rigging all of this, maintaining the equipment, and making sure it didnt prematurely go off in the impacts and fires.

Plus your definition of "thermobaric bombs" or "barometric" bomb, is a misnomer. It all stems from that idiot Riconosciuto (dang I had to use it) . Such a genius yet upon further review, hes just another whackadoodle nut with outrageous claims. And you lap it up happily and build more on it. Dont you know that building a building on a foundation of sand is folly?

a reply to: lexyghot

I am so tired of that nonsense about TB. he expects us to believe that TBs that are powerful enough to lift the floors (mind you each is one acre in size) are not loud enough to be heard over helicopters and emergency vehicles. I have yet to see or hear "quiet" TBs. and if he is pushing those Riconosciuto style bombs then God help us. Even those bombs are suppose to be near nuclear in strength and yet, we missed them thanks to those darn emergency sirens and helicopters.

originally posted by: LaBTop
Originally posted by: wmd_2008
a reply to: LaBTop

Do you understand at all the quintessence of it?

NO, we say that a PROTECTED steel frame can't collapse only due to fire in 101 minutes and many on here with that belief post the Windsor Tower 18 hours / 1080 minutes fire pictures as evidence of that.

So lets break it down into simple terms for you and the others.
''"with steel perimeter columns""
Windsor Tower Floor Construction
"" Originally, the perimeter columns and internal steel beams were left unprotected in accordance with the Spanish building code at the time of construction""

Did that UNPROTECTED steelwork COLLAPSE only due to fire ALTHOUGH it was not IMPACTED or DAMAGED ? YES

The unprotected steel-glass facade ABOVE the 17th floor was completely destroyed, exposing the concrete perimeter columns. The UNPROTECTED steel PERIMETER columns above the 17th floor suffered PARTIAL (NOT complete) collapse, partially coming to rest on the upper 16th technical floor.

So can a fire ONLY, cause UNDAMAGED unprotected steelwork to collapse? YES.

FINE. All Windsor tower perimeter steel above the 17th floor collapsed PARTIALLY, BECAUSE it was UNPROTECTED with fire insulation foam. That was the reason they started the renovation project work, to protect all that steel above floor 16.

The failing floor at the WTC 1N tower had ALL its steel solidly protected by good insulation.
SO, WHY SHOULD IT FAIL MASSIVELY IN 101 MINUTES / 1 hr 41 minutes?

It may be an age thing but remember the jets caused STRUCTURAL damage do you think the sprayed on fire protection or other fire protection such as sheet rock and vermiculite in the structure was undamaged!

a reply to: wmd_2008

He also fails to take into account the building inspection that had been done that showed the fireproofing in many areas had crumbled away. But then, that isn't all that unusual.

I had some much more important things to read in the past 2 months.
Now I see some still unfinished work waiting for me.
This is the link to the 15 pages PDF-paper we are still discussing, and I strongly advice you, the persistent reader with enough physics, chemistry, mathematical and engineering background, to print it out in color, and lay it beside your screen, to be able to quickly check it up, while reading the discussions. Try to print it, one PDF-page at the time, to keep its screen format intact.
Do not forget to read my ref. 1 to 5, and then print those other 2 Beck pages too. For your still growing scientific 9/11 library.

Charles M. Beck's 2007 math analysis of the WTC towers collapses,
submitted to ASCE J. of Engineering Mechanics :
arxiv.org... (Introduction)
arxiv.org...

This is a beautiful piece of logic-based math. And Beck's other two pieces too!
Beck is one of the many, that persistently show us where Bazant & Verdure in their J. Engr. Mech. ASCE publications were using misconceptions and simplifications to bolster the official NIST theories and NIST's own misconceptions, fed by government pressure and lies, and despicable career pressure.

Page 1, last text-lines just above I. INTRODUCTION, it's Beck's main statement :

We discuss two non-obvious inconsistencies between the mathematical models of progressive collapse based on the NIST scenario, and the practical realizations of collapse in WTC 1 and 2 :
(i), the average avalanche pressure is 3 orders of magnitude smaller than the pressure the vertical columns are able to withstand, and
(ii), the intact vertical columns can easily absorb through plastic deformation the energy of the falling top section of the WTCs. (LT : a NATURALLY falling WTC top section. )
We propose a collapse scenario that resolves these inconsistencies, and is in agreement with the observations and with the mathematical models.

Realize that his (i) and (ii) remarks are given for a non-realistic scenario, as offered by NIST.
NIST tried to convince us of a natural cause for the WTC collapses.
Caused solely by plane impacts and heat losses from fires for the steel, followed by column buckling. What Lexyghot c.s., also believe, is the Bazant et al. scenario. A long past station.

Let's now consider Lexyghot's two remarks which have some controllable indication in them :
(1) ""Nope. All columns buckled, ""
(2) ""Well, yeah, that's the results he got cuz he WILDLY overestimated the strength of the columns. ""
And let's show them to be quickies, written in a hurry.

The Twin Towers did NOT collapse caused by eventual NATURAL buckling of their vertical columns after they could not stand the load of its top mass and the heat of the fires anymore, caused solely by steel strength loss and weight stress and compression.
There's also no possible NATURAL hinging of a part, or the totality of the top impacted sections, since Beck proved buckling to be far out of reach in any natural WTC-event.
You have to add an additional huge human energy intervention to start an avalanche.

Look-up ultimate yield strength of A514 structural steel, in Wikipedia, or at the Acelor site..
Ultimately, for that 110 - 130 KSI ultimate yield strength range, an at least 5200 times (130/0.025, N.T.) and 2600 times (130/0.050, S.T.) stronger calculated collapse initiating yield force outcome would have been needed in the by Beck proposed NIST worst case scenarios.

To let the by Beck proposed, leftover-half of those 47 CCs and 136 PCs in these for NIST very advantageous scenarios, start to buckle (in WTC1N).
Included also the already by Beck assumed, 50% steel-strength leftover in those 23.5 CC and 118 PC columns, and also in the steel in the floors and crossbeams : in ALL the steel.
Realize that what Beck offered as an additional extra to the existing NIST OFFICIAL scenario, are the only extra losses that in fact, he WILDLY overestimated. Not his strength of all and every vertical columns, as Lexyghot tries to let you believe.

Note : PCs are 236 perimeter columns, CCs are 47 core columns.

Read the begin of Beck's rationale at the bottom of page 5 :

To obtain the values for our models we proceed as follows. For each structural element, the PCs and the CCs, we find the scaled ultimate yield force f = f(z), at the top (z = 0) and at the bottom (z = 1). The parameters r and s are then obtained

As obtained from his Eq.10a + 10b.
Those are the parameters r and s scenarios, he composed his below, page 9 double diagrams with. The PCS, CCs and PCs+CCs scenarios for WTC1N and WTC2S.
I added some even more realistic data points (squared) in his 2 diagrams, for NIST scenarios even more favorable, and still the collapse initiation lines positions in the diagrams show clearly, that the CCs were absent, only the PCs delivered any resistance. Meaning that those core columns were already severed.

files.abovetopsecret.com...


Beck proves with those 2 diagrams the NIST-proposed buckling to be impossible.
He proves the structural steel columns under and above f.ex. WTC1N its 93rd floor, possessed 2400 times more ultimate yield force strength f (in kilo-pounds/inch²), than the collapse initiation force he measured over the whole floor area in case of the by NIST proposed avalanche start.
In case of WTC1N, Beck found for the failing floor :
f = f(z) = 0.025 KSI, compared to the in the NIST report mentioned ultimate f = 58-60 KSI of the columns their structural steel (page 6, in between eq.11-12).
And thus that steel could not buckle at all, under those NIST circumstances, only when it got cut and displaced by explosives, could the remaining, and/or the already cut steel buckle at all.

These Towers collapsed because an additional event took place, i.o.w. the introduction of massive explosions to add to all of Beck's equations, explosions to cut these very strong steel columns.
And their buckling-preventing embracements, those very strong crossbeams inside and under all the core floors areas, were probably cut too, every third floor.
We will never know for sure, since nearly all evidential steel parts from the plane impact zones were not photographed or identified, as we can see on those official WTC-photos websites. From all those three stories high column parts we see laying around on the aerial photos from just after the events, we see no stubs of those crossbeams sticking out from their sides. Clean cut they are, as if those bolted or welded stubs were cleanly shaved off.
Note that after the two collapses, the top floor columns and beams can be expected to lay on the surface of the collapses area, seen in the aerial photos.
And those top core columns we see laying there, are straight, not buckled....

Review those photos of the inside of that huge hole in WTC-6. You see vertical columns with their four stubs still attached from their former crossbeams.....And that huge scooped-out hole was caused by some huge piece of WTC1N perimeter-surface, made-up by those Vierendeel columns packets, that peeled-off the north side of WTC1N, then it first fell a few hundred meters, collecting huge gravity acceleration, then it ploughed through the roof and all 6 floors of WTC-6 into its cellars.... Cutting crossbeams on its way down, but did not shave them off, cleanly....As in both Twin Towers happened.

Realize that a Collapse Initiating pressure ( C.I.p. ) in both towers, for the proposed by NIST column buckling scenario, resulted in two values as calculated by Beck from the NIST data, 0.025 KSI and 0.050 KSI = 25 and 50 psi.
Which means that C.I.p. was THREE ORDERS of magnitude smaller, than the known ultimate yield strength of standard A514 structural steel (NIST says 60 KSI, the Acelor plant says 130 KSI = 60,000 or 130,000 psi), which means not a THREE TIMES smaller, but a minimal 2400 to 1200 times and maximal 5200 to 2600 times smaller collapse initiating pressure.
Depending on which C.I.p. KSI-values you trust.
So, nature needed a nominal 2400 to 1200 times bigger force exerted by an avalanching floor, to even buckle these strong steel columns. But despicable creatures just needed some heavy cutter charges to achieve it.
And in fact, nature needed to overcome the ultimate strength of that steel, thus a 5200 to 2600 times bigger force, which nature had not at hand, but criminals had. TB's and HE cutter charges.

See also Beck's lines on top of page 11, after this one : -- Bazant et al.(ref.10) argued that an avalanche propagating through the primary zone would get sufficiently compacted so that it could provide necessary pressure. --. Where Beck expressed two unsurmountable problems with Bazant's argumentation :

In Eq. (1) the term R* = R*(Z) comes from the average resistive force produced by the building. It measures how the building does oppose its own destruction by the avalanche, and
is intimately related to the so called, yield strength of the structural members that provide the vertical support to the building.

Read Beck's whole text in his chapter : C. Resistive Force: discrete vs. continuous. for his two problems he has with Bazant's rationale.

On page11, Beck calculated a scaled ultimate yield force f (Collapse Initiation pressure, or C.I.p. or p) of f = 0.025 KSI in WTC1N and f = 0.050 KSI in WTC2S.
The force exerted by the total mass of the plane impacted top of the WTCs, equally spread over an horizontal area of 206 yard² = 42435 yard (2472 inch² = 6110784 inch) with 236 perimeter columns around, and 47 core columns in center of that area.
That's a few thousands times smaller collapse initiation pressure ( f force ) than all the leftover WTC steel columns could thus easily withstand. NO BUCKLING !

Beck resolved Eq. 11 and 12 on page 6 first. Then recalculated Kg/m² to Kpound/inch² for PCs and CCs, to be able to compare to the known nominal KSI values for widely used types of structural steel of 38 to 58 KSI and ultimate KSI's of 100 to 130 KSI.

He found for the PCs (perimeter columns) a fPC(z) of about 0.2 + 1.2 * z
PCs in WTC1N : 0.2 + 0.120 = ~0.320 (z = 0.10)
PCs in WTC2S : 0.2 + 0.276 = ~0.476 (z = 0.23)

He found for the CCs (Core columns) a fCC(z) of about 0.6 + 1.5 * z

You should expect these following logical failure values for z, for the lowest, plane-impacted, already longest burning floors :
z1 for WTC1N = 1 - F1/FT = 1 - 93/110 = 0.1545 (Beck : however in reality 0.1)
z2 for WTC2S = 1 - F1/FT = 1 - 77/110 = 0.3000 (Beck : however in reality 0.23)
if the collapses started at the lowest plane impacted floors. They did not. They started at the top of the primary (impacted) zones (WTC1N : 99th and WTC2S : 85th), that's how Beck came to 0.1 and 0.23,

which is not logical at all, the fires had just reached those floors, how could the still cold steel in those just recently burning top-floors so fast buckle and fail.??.
While the fires in the already burned up lower floors were starting to smolder, and the steel in there was cooling quickly by the strong cooling effect of the wind high up there, regaining most of their nominal and ultimate yield strength again. :

Page 7 / 15 : Now that we have μ and ν for each building, we recall that the collapse initiation occurred at the top of the primary zone, at position z0 = 1 - F0/FT ,
where for WTC 1, 1z0 = 0.1, and for WTC 2, 2z0 = 0.23.
This allows us to construct the collapse initiation lines. The collapse starts at point z0 because the yield force of the compromised building, ˜R(z0), is not sufficient to resist the weight of the building above,
-˜R (z0) < m(z0) *g. (18)
Please observe, the collapse initiation lines are derived from static properties of the buildings, thus they do not depend on the mathematical model used to describe the dynamics of collapse.

KSI is the average compression-pressure expressed in kilo-pounds (1000 pounds) per square inch.
M = 4.5 *10^8 kg is NIST/Beck their estimated total mass of a WTC building (page 6, top), so you must then recalculate M in kilo-pounds, not kg's.
M = 4.5 .10^8 (= 450000000) x 2.205 = 99225000 pounds = 99225 kilo-pounds
g is the acceleration due to gravity at the Earth's surface and is the standard gravity defined as 9.80665 meters per second squared, or equivalently 9.80665 newtons of force per kilogram of mass.
In the case of a shock, e.g., a collision, the resulting g-force can be very large during a short time. In a building, this happens only when the majority of the vertical columns first buckle, then fail. Then the mass above the failure suddenly spans some distance, to f.ex. z1.
Problem for NIST, in a natural scenario; Beck proves no columns buckling, thus no collision.
Beck proves an unnatural, WMD scenario, where the huge resistive force in all or most vertical columns is removed by explosive forces.

REFERENCES

1. Role of Compaction Ratio in the Mathematical Model of Progressive Collapse
Charles M. Beck, 14 April, 2008.
Submitted to ASCE J. of Engineering Mechanics.
arxiv.org...
arxiv.org...

2. Descent curve and the phases of collapse of WTC 7
Charles M. Beck, February 18, 2013.
Submitted on 29 Jun 2008 (v1), last revised 20 Jan 2009 (this version, v4), to Cornell University Library (arXiv.org/physics).
arxiv.org...
arxiv.org...

Page 9/24 Beck remarks :

An apparent weight the top section exerts during the collapse on the Earth’s crust,
W′/(M*g), is given by Eq.(16) --snip--
We believe that W′, and in particular its time derivative, can be used in interpretation of
the seismic signal of the building’s collapse. As an attempt to connect the two brings forth
numerous additional complications which need to be properly addressed, we leave this topic
to future publications.

Time to show Charles M. Beck my seismic work. He can see them in my signature LINKS under each post of mine in this website. Especially my workup of the WTC7 seismogram, coupled with the timestamps in it, and the photo with NIST timestamp of the onset of collapse. I thus proved that the first biggest peak in the WTC7 seismogram happened in Manhattan a few seconds before anyone saw any movement in, on and around WTC7. About two seconds later, the eastern penthouse on top of WTC7 started to dent, then sunk away, then the west penthouse sunk away too, then the whole parapet roof line started to fall in free fall for 2.3 seconds over ~26 meters (~8 floors). Then that huge chunk of the building met the underlaying construction, and the second much lower seismic peak arrives on the seismogram, since deceleration hit in. That peak and the rest of the much lower seismic peaks depict the rest of the following natural collapse crushing forces.
Note : Review the first few of his References...he reads the911forums too. Open that einsteen link and read that whole page, then thread.

3. Fill in a Google search : FrancescoBarni_PhD_Thesis.pdf
The 152 pages, 2011, Francesco Barni PhD Thesis about Progressive Collapse initiators and how to prevent them.
Try this link too.
Barni's first interesting steps towards a total valid hypothesis and its implementation in future to understand and then prevent progressive collapses. 152 PDF-pages.
Very interesting prototypes of some theoretical, mathematically correct steps to understand how progressive collapses do start, and how to prevent them in the future.
There's room for improvements in the methodology, and these aspects are further discussed.

Page 110/152 it's getting interesting. See also Fig 6.1

6.1 Description of the used structural models
The presented examples are implemented using Finite Element models derived from one developed by the National Institute of Standards and Technology (NIST) for an ongoing research program (Refs [20], [21], [42]) aimed at understanding the behavior of structures during Progressive Collapse (figure 6.1).
The models can be used to perform both dynamic and static analyses, with geometrical and material nonlinearities; furthermore, they are able to spot the moment in which a section becomes detached, which corresponds to Collapse condition in the first proposed methodology.
In most studies carried on so far, element behavior derived from seismic engineering studies has been used to model Progressive Collapses. The NIST tests highlight that, in some cases, the actual behavior can be very different. Thus, for certain aspects the used models are advanced. On the other side, they still need improvement under several aspects, which will be highlighted in the text.

From page 136 on, Chapter 7.1 and 7.2 you find the Summary and Conclusions.
Chapter 8 lists several aspects that need to be further considered to improve the proposed
methodologies and elaborates on some of them. Other ideas that might be developed are also
described.

4. An Overview of Progressive Collapse in Structural Systems by Phillip J. Georgakopoulos.
dspace.mit.edu... (2005, Abstract from his 55 pages MIT Thesis)
61146362.pdf 9.025Mb, Preview, non-printable (open to all)
61146362-MIT.pdf 9.022Mb, Full printable version (MIT only, need password).
His first assessment on the long road to a precise description of P.C., with 51 drawings.
He considers the Oklahoma City Murrah building blast, and the WTC buildings, as progressive collapses. And how to possibly prevent the likes in the future. Again, not conclusive at all at the moment of publication. We are still far from setting iron-cast mechanical and mathematical rules for P.C.'s, and how to prevent them.
He seriously discusses possible blast loads from page 13 to 25.
And design issues with steel structures from page 44 on.
See his reference list on page 54 too, he mentions these links a lot :
The ASCE Library : www.ascelibrary.org...
Houghton & Karnes : www.mhpse.com...

Note : retrofitting methods are for building owners far too costly and time-consuming.
The new (page 48) SidePlate connection plate solutions are sporadically implemented only in a few new builds (page 50), and those are all three, military/government objects. Thus, all the old & new public-accessible high rise buildings in private hands (greed : please, no extra reinforcements costs) still have the same progressive collapse blast risks as before 9/11.
I wonder if the new WTC-7 have these SidePlate column-beam/girder connects implemented?

5. The Lagrangian Formalism, the Principle of least action, a.k.a. Principle of stationary action, a.k.a. Hamilton's principle :
www.scholarpedia.org...
Lagrange (and first Euler) proposed a theorem where the classic 3 Newtonian vectors were changed to a full set of vectorial probabilities.
This appears in a perfectly elastic scenario, as proposed by Beck under Eq.1 on page 2/15, in his main ref. arxiv.org...
Note the minus signs in front of the values U and L, for potential energy, and energy associated with the structure of the building.
To fulfill the Lagrangian formulation in the formula : Lagrangian l = K − U − L , where K is the kinetic energy of the building.

originally posted by: LaBTop.

Look-up ultimate yield strength of A514 structural steel, in Wikipedia, or at the Acelor site..
Ultimately, for that 110 - 130 KSI ultimate yield strength range, an at least 5200 times (130/0.025, N.T.) and 2600 times (130/0.050, S.T.) stronger calculated collapse initiating yield force outcome would have been needed in the by Beck proposed NIST worst case scenarios.

For your numbers to be true, this would mean that the towers were also wildly overbuilt. to the order of being able to support a building that was 100 miles tall.

You sure you want to stick with this statement?

Realize that what Beck offered as an additional extra to the existing NIST OFFICIAL scenario, are the only extra losses that in fact, he WILDLY overestimated.

Here's the problem with this, and one that you will avoid acknowledging.

It's true that he wildly overestimates the damage. But he also wildly overestimates the column strength.

I did a spot check of a few of the now known core column dimensions vs what he uses (24 x 54 x 1.25) for all of the core columns. I got anywhere from him estimating 7x too strong to down around 2.2x. On average, Id put it that he's overestimating the core strength by a factor of 4.

He also overestimates the ext column strength. He says they are 14 x 14 x 1/2. they are not that thick. they are either 1/4 or 5/16. SO he may be doubling the strength.

Therefore, he can take away the entire core, and still have more than 100% of the intact column strength (PC and CC combined)

Overall, I'd estimate that he begins with a PC and CC combined strength that is roughly 2.5 - 3 times too strong, takes away a bunch of it, and STILL has more capacity than the towers ever had.

There's no reason to rebut it beyond that. It's on you to get some traction with this on something other than a forum board.

arxiv.org...

"Now, as the avalanche enters the storey it first encounters the resistive force from the vertical columns, call
it R1. Over the fractional length λ1 the vertical columns maintain ultimate yield force under compression."

And this is why this paper can be ignored regarding collapse times.

He assumes infinitely strong floors and connections, and that all resistive force is from the columns.

Sorry, Labtop, but you've hitched your cart to a lame pony.

The big mental block many people have is they can't get their head around the fact that if the floors fail the exterior wall will fail.
And once those two start they will tear apart the core.
Just one big boiling mess all the way to the ground.

Your answers are so ridiculously simplistic, when considering Beck's three referenced by me publications, that I can only hope you to follow this advice and read his rationale on page 4 and 5 of my ref 1.
This one : arxiv.org...

There he very clearly explains what was and still is wrong with the papers of Bazant et al. and thus the NIST scenario, that you also adhere to : First buckling of all columns, then an avalanche.
Did you perhaps not read those 2 new references written by Beck?
And did you not understood that Beck went with all the data from the Final NIST reports?
Those are the steel strengths from NIST, not some he assumed.

Beck calculated that 0.025 KSI compression force for WTC1N, which was 3 orders in magnitude smaller than the by NIST given ultimate yield strength for the WTC steel used in the PCs.
0.025 KSI is a few thousand times smaller than 36 to 58 KSI nominal steel strength, or 100 to 110 KSI ultimate steel strength.
Nothing you wrote can change that outcome. So why would any of those strong steel columns buckle at all? If not assisted by explosives.

I'll try it in other words.
Beck proves with NIST's own data for WTC steel in hand, that ONLY the NATURAL weight of the damaged and burning top part of the WTC buildings could never ever let all of their steel columns buckle, as NIST and you proposed.
Even when he removed half of ALL the vertical steel in his NIST (Bazant) models, and on top of that, reduced ALL steel strength in half, in his NIST scenarios calculations.

In my ref.1, I can find only one difference with his 2006 paper.
Beck took the total mass of the WTCs in 2006 as ~450 million kilogram, and in 2008 as ~320 million kilogram. (4.5*10^8 to 3.2*10^8 kg)
NIST probably rectified that estimated weight a tad bit down in 2008.

originally posted by: LaBTop
Your answers are so ridiculously simplistic

Yep, cuz that's all it takes to show that Beck is an idiot, and that you are a fool for repeating what he's written as some damning evidence of an inside job.

We can all agree that buildings have a FOS of ~3.

Engineering a building such as the TT's requires extensive education, training, and experience.

But what you're saying is that they were so inept and so wrong in what they were doing that they designed a building with an FOS of somewhere between 2600 and 5200......

So, either you're right, and they were absolute idiots..... or you're wrong, and you're nothing but an internet warrior with a raging case of Dunning-Kruger Syndrome......

I know which one the rational will choose.

a reply to: lexyghot

I didn't want to spoil your Christmas, guys....so now, here it comes.
Next time, you should really take more time to read, and comprehend a scientifically correct written article. Like those three from Charles M. Beck....outstanding math beauties !

And refrain from childishly insulting external and internal scientists. You guys seem to get an awful amount of moderation slack lately, especially in this so important 9/11 forum.
Which was THE forum that really accounted for this site its huge member list explosions between 2004 and 7. You know why?
Because defenders and critics LISTENED to each other.

Lexyghot : But what you're saying is that they were so inept and so wrong in what they were doing that they designed a building with a FOS of somewhere between 2600 and 5200..... .

No, it's far more simple.
Beck proves with his B E A U T I F U L math that an additional energy force of such huge factors in energy magnitudes must be introduced to his calculations, to overcome the build-in strength of the by the architects chosen steel.

That additional energy force in this case being :
..... E X P L O X I V E S ......LOTS of them. To even begin any collapse initiation.

And that additional energy force should be in fact nearly two times stronger, since he has quite overdone his willingness to please the NIST global collapse onset-scenario, by removing 50% of the vertical steel, and 50% of its strength in his NIST-pleasing scenario calculations.
Now at last also known as the NIST-lexyghot scenario.

When we do not take in account a 50% loss of vertical columns nor 50% steel heat loss, as Beck did, but we take the real by NIST assumed plane impact damage to the vertical columns, and the real heat loss for some steel components assumed by them, we need to introduce even much more explosive force to get the global collapses going.
Nearly two times more than your assumed factor of safety figures : ""FOS of somewhere between 2600 and 5200"".
That factor, thus in reality, would become a steel strength-overcoming factor of somewhere between 5200 and 10400.......

There was no buckling, there was high-explosives steel cutting, or blowing up (literally) by TB's, as the initiating event. Or both.
After that, in the wake of the following debris avalanche, while Nature kicked in with overloads of mass, buckling did sporadicly occur.
Because the planners really did not want to take any risk, and kept cutting and blowing up concurrent floors, to be sure that that global collapse reached ground level. They did not want to be left over with expensive to clean up, and researchable "candles in the wind".

originally posted by: lexyghot
arxiv.org...

""Now, as the avalanche enters the storey, it first encounters the resistive force from the vertical columns, call it R1. Over the fractional length λ1, the vertical columns maintain ultimate yield force under compression"".

(1) And this is why this paper can be ignored regarding collapse times.
(2) He assumes infinitely strong floors and connections, and that all resistive force is from the columns.
Sorry, LaBTop, but you've hitched your cart to a lame pony.

No. Your first assumption has nothing to do with your second one in this case.
And is blatantly false.
And stop insulting capable people.

NO again. He does not assume infinitely strong floors and connections, and that all resistive force is from the columns, for his collapse times equations and resulting calculations.
He only does this one time as a simplification for his resolve of NIST's discrete model equation.
You really have no faint idea of the math involved, as you show with this kind of remarks.

Damn, it's not that easy to let conservative Western alliance citizens, Americans and Europeans alike, with a misplaced superiority complex, and some seriously misled, patriotic-colored mindsets, gain insight in complicated mathematical 9/11 reasoning.
Especially when they clearly show to have not the faintest idea where the real culprits are situated in that reasoning.
I'll reluctantly, give it another try, to explain where Lexyghot's reasoning is so wrong, as can be seen by my emphasizes in Beck's complete reasoning (in my next post).

Below is how Beck's reasoning is really set up.
First read on page 1, his small-script abstract text, the short reasoning/rationale text above his 1.INTRODUCTION, then you'll start to understand how he construct his papers.

After that, read Beck's complete reasoning, with my additional emphasizes in it :

Beck, Page 1 : We examine static features ( collapse initiation lines, derived from the ultimate yield strength of the structural steel) and dynamic features ( duration of collapse, lines computed using mathematical models); two features of events that comprised the collapse in WTC 1 and 2.
We show that :

(a), the dynamic and static aspects of the collapse are mutually consistent and weakly dependent on the class or type of mathematical model used, and

(b), that the NIST scenario, in which the buildings collapse after a sequence of two damaging events (airplane impact and subsequent ambient fires), is inconsistent with respect to the structural strength of the buildings.

Our analysis shows that the force that resisted the collapse in WTC 1 and 2 came from a single structural element, the weaker perimeter columns, while the second structural element, the stronger core columns, did not contribute.

We discuss two non-obvious inconsistencies between the mathematical models of progressive collapse based on the NIST scenario, and the practical realizations of collapse in WTC 1+2 :

(i), the average avalanche pressure is 3 orders of magnitude smaller than the pressure the vertical columns are able to withstand, and
(ii), the intact vertical columns can easily absorb through plastic deformation the energy of the falling top section of the WTCs.

Note 1 : Contrary to what Lexyghot thinks ("" and that all resistive force is from the columns."" ), Beck clearly talks about the floor material avalanche, which of course has static resistive force and collects resistive force from just before the first failing moment on, and after that from any next floor too.
Note 2 : NIST quoted the WTC architects, that the core columns contributed for 2/3 and the perimeter columns for 1/3 to the resistive force that supported the horizontal and vertical mass of those towers.

This is Beck's complete reasoning below, not the above cut-out few sentences by Lexyghot (bolded by me below, in there) :

C. Resistive Force: discrete vs. continuous.

The resistive force R is the force the building opposes its own destruction, by the avalanche. Bazant et al.(ref.10) call it the “crushing force,” and for the most part of their calculation they assume that its magnitude is a constant with respect to height.

For our investigation we relax that assumption by allowing R to vary with height in a simple linear fashion,

f(z) = - R(z) / M*g = r + s*z, -----> Eq.(7)

where M is the total mass of the building, and z = Z/H is the scaled height. As we will see later, when we discuss the load-bearing capacity of the structure of WTC 1 and 2, this will turn out to be a more accurate description.

Let us now discuss the resistive force within the discrete (floor) model.
We posit that the building is rigid, i.e., that the floor that the avalanche is currently penetrating sits on an infinitely strong structure.
( LT : because he is first describing the DISCRETE NIST/Bazant MODEL, not the CONTINUOUS MODEL. In which discrete model he observes one floor only, starting to collapse, assuming it is SITTING on an infinite strong structure, like for example the Earth. )
With that assumption the interaction between the building and the avalanche is localized to the floor of contact between the two and not beyond.

[the above cut-out lexyghot quote: ]
Now, as the avalanche enters the storey, it first encounters the resistive force from the vertical columns, call it R1. Over the fractional length λ1, the vertical columns maintain ultimate yield force under compression.
[ /lexyghot quote]

In other words, for the first phase of floor destruction the fractional distance λ1 corresponds to the yield strain λY , while R1 corresponds to the ultimate yield force.

Assuming that avalanche has passed the fractional distance λ1, the columns fail. The failure mode of the columns is debatable: if the columns are compressed by the avalanche than they fail by buckling. However, if the avalanche front consists of crushed material, so that the ends of the vertical columns facing the avalanche are free, then the failure mode may be bending, as well. Either way, we assume that during this phase the column does not offer any resistance. In other words, for the fractional distance of λ2 the avalanche falls freely, R2 ≡ 0.(LT : ≡ means identical to)

Note my bolded, italicized and underlined text amplifications, they are consistent with the clear intention these words are written with.
He assumes static features (the conditions in the building on the verge of collapse), only to not complicate matters unnecessarily in his NIST-alike discrete model .

Thus he assumes ONLY an infinitely strong structure UNDER the avalanche starting area, for the very short time and distance λ1, which is at most a few millimeters and milliseconds for structural steel, before eventually its yield strain λY is reached. Which costs a huge yield force R1, ultimately 60 -110 KSI (60,000 to 110,000 pounds/inch²). He finds 0.025 and 0.050 KSI (25 to 50 pounds/inch²), as found by him in real time, when the building already starts to collapse, and thus by far not reached its natural yield strain, let it be its ultimate one.
And later on he proves by solely the static features of those buildings, that these columns could never reach buckling caused by natural events, since the resolved r and s parameter values for his collapse initiation lines in his diagrams on page 9 come out far too low in that diagram to ever let that happen.
It only happened because another huge energy source was added to the collapse events.
E X P L O S I V E S .
And need to be added to Beck's equations to let the NIST/lexyghot scenario ever be valid.

Here is an easy question for LaBTop to answer, since he seems to have all the answers. Please show me the detailed reports of the damages suffered by the buildings. Show me the report on the areas where the fireproofing was crumbled away, and where the impact knocked it free. Show me the exact damage suffered to the cores of the Towers by the impact. No supposition, no guesses, show me the exact details.


You will not be able to. NO ONE knows the exact shape the buildings were in, therefore ANY explanation is going to be an educated guess. You can publish all the papers you want, and they will be nothing better than a guess.

A reply to: cardinalfan0596

I'll do you a favor, and honestly rewrite your short last burst, since I can thus read it also as :

FEMA, NIST, Bazant, ASCE, LDEO can publish all the papers they want, and they will be nothing better than a guess.
Btw, in your eyes, these US government-payed institutions threw thus about 100 million dollars away for some flimsy investigations of 9/11.

Of course all their calculations are based on educated guesses, not wild guesses. And mixed-in with known hard facts.
And those educated guesses are commonly known as ESTIMATES.
Beck, in his 2008 paper, page 4, explicitly stated that as such :

Rather than guessing, we proposed a procedure for estimating R [ref. 4], where one first finds the ultimate yield strength Y of the vertical columns using their specifications, following which the resistive force R is estimated from a simple linear model, R = ε · Y , with ε = 0.25 being the ultimate yield strain of structural steel under compression. Applying this to WTC 1 and 2 led to an initial estimate of R(x2)/(M.g) = r + s · (x2/H), with r ≃ 0.2 and s ≃ 0.7.

Beck offered NIST extraordinary slack by removing half of the core and perimeter columns from his calculations, and to top it off and show to us how ridiculously wrong the NIST reports outcomes were, he softened all vertical and horizontal steel in the WTC's to 50% of their original strength.

And in that proposed crazy "NIST-alike" scenario, half of the towers their half as strong vertical steel columns could STILL easily withstand an eventual NATURAL failure, IF solely caused by plane impact and following fires.

Regarding my above Note 2 : NIST quoted the WTC architects, that the core columns contributed for 2/3 and the perimeter columns for 1/3 to the resistive force that supported the horizontal and vertical mass of those towers.
For an additional estimate for the strength of the WTC floors (thin composite steel decks with thin re-bar concrete layers on top), see Beck Oct, 2007 page 11 :

Consider the average pressure created by the avalanche at the bottom of the primary zone, z1 = 1 − F1/FT, which is given by
p = [M g / a² ] · z1 (Eq.22)

Here, a = 206′ = 2472′′ is an approximate length of the side of the building. We get (1)p = 0.025 KSI for WTC 1, and (2)p = 0.050 KSI for WTC 2, which is three orders of magnitude smaller than the nominal 36-100 KSI (ultimate 58-110 KSI) the vertical columns were able to maintain while yielding in plastic deformation.
Bazant et al.10 argued that an avalanche propagating through the primary zone would get sufficiently compacted so that it could provide necessary pressure. We see two insurmountable problems with this suggestion :

First, the avalanche front can only “grow” thicker - it cannot expand laterally in such a fashion that would allow its edges to be strong enough to crush the vertical columns.
Second, for compaction to happen the floor material has to be compressed between two solid surfaces, and we see that there are no such surfaces on either end of the avalanche front.

In fact, the strength of the vertical columns will redirect the avalanche (which now consists only of destroyed floor material) to the region in-between the columns.
The formation of such avalanche is promoted by the relative weakness of the floors, the resistive force ƒ of which is ƒ ∼ 0.02 (Ref.16 NIST), per each floor, as compared to the resistive force of the intact vertical columns, ƒCC + ƒPC ≃ 0.8 + 2.7 · z

Of course those estimated average avalanche pressures (25 and 30 pounds per inch², PSI) found by Beck while filling in known values for steel, are ONLY for a NATURAL collapse. These ridiculous low figures already strongly indicate that NIST "forgot" an enormous additional energy injection. The one, to cut all core columns.

Beck calculated at page 11, under Eq.(23), a value for z1 = 1 - F1/FT which gives
z1 = 0.15 for WTC1, and z1 = 0.30 for WTC2.
He used at that time, the lowest plane-impacted floors.

Let's check it for the lowest plane-impacted floors :
z1 for WTC1N = 1 - F1/FT = 1 - 93/110 = 0.1545
z1 for WTC2S = 1 - F1/FT = 1 - 77/110 = 0.3000

Beck self-corrected those values in his next, 14 April 2008 paper, for the collapse-initiating floors :
z1 for WTC1N = 0.10
Since 99/110 = 0.100 (collapse started at the 99th floor in WTC1N)
z1 for WTC2S = 0.23
Since 85/110 = 0.227 (collapse started at the 85th floor in WTC2S)

Thus, instead of these values from Oct. 2007 :
ƒCC + ƒPC ≃ 0.8 + 2.7 · z (z = 0.1545 · 2.7 = 0.42) = 0.8 + 0.42 = 1.22 for WTC1N
ƒCC + ƒPC ≃ 0.8 + 2.7 · z (z = 0.3000 · 2.7 = 0.81) = 0.8 + 0.81 = 1.61 for WTC2S

it must be, as of since April 2008 :
ƒCC + ƒPC ≃ 0.8 + 2.7 · z (z = 0.10 · 2.7 = 0.27) = 0.8 + 0.27 = 1.07 for WTC1N
ƒCC + ƒPC ≃ 0.8 + 2.7 · z (z = 0.23 · 2.7 = 0.62) = 0.8 + 0.62 = 1.42 for WTC2S

May I hope that the still interested reader will read Beck's Feb. 2013 paper with an open mind?
Because he explained details for his two WTC 1+2 papers even better, in this mainly WTC 7 based paper.

I really would like to discuss Beck's suggestion in [ref 16] on page 23 in his Feb 2013 paper with some like minded people, to see if we could construct those 2 still missing descend curves for WTC 1 and 2 from all the available video material of the Twin Towers collapses, since NIST investigators ignored to do so.
Only David Chandler made one for the first visible seconds of the top corner of WTC1N, and saw no slowing down of the descend, which one should expect to see, caused by the enormous latent resistance build-in into these towers.

Damn.! Overseen this post!
Well, let's correct that now. You assumed I had trouble reading English texts....
It turns out you are the one having that trouble. Or not...?

Originally posted by: lexyghot

originally posted by: LaBTop.
Look-up ultimate yield strength of A514 structural steel, in Wikipedia, or at the Acelor site..
Ultimately, for that 110 - 130 KSI ultimate yield strength range, an at least 5200 times (130/0.025, N.T.) and 2600 times (130/0.050, S.T.) stronger calculated collapse initiating yield force outcome would have been needed in the by Beck proposed NIST worst case scenarios.

Lexyghot :For your numbers to be true, this would mean that the towers were also wildly overbuilt. to the order of being able to support a building that was 100 miles tall.
You sure you want to stick with this statement?

LT : Yup. He's not saying that the steel was too strong, he's showing you that at collapse initiation, a huge energy component is missing in his NIST-scenarios favoring calculations. Energy to insure that collapse would be starting at all.

LT : Realize that what Beck offered as an additional extra to the existing NIST OFFICIAL scenario, are the only extra losses that in fact, he WILDLY overestimated.

Lexyghot : Here's the problem with this, and one that you will avoid acknowledging.
It's true that he wildly overestimates the damage. But he also wildly overestimates the column strength.

LT : NO, he definitely did NOT.!

Lexyghot : I did a spot check of a few of the now known core column dimensions vs what he uses (24 x 54 x 1.25) for all of the core columns. I got anywhere from him estimating 7x too strong to down around 2.2x. On average, Id put it that he's overestimating the core strength by a factor of 4.

LT : Most importantly, you should learn to include links to your wild accusations.
911research.wtc7.net...

This image from the documentary Up From Zero shows the base of a core column, whose dimensions, minus the four flanges, are apparently 52 by 22 inches, with walls at least 5 inches thick.

That's at bedrock basement level. Huge massive steel columns, see the photo above that text at the bottom of that page link.
That's not at all the dimension of a core column at the 85th or 98th floor.
You sir, are seriously misleading readers. Just as you did here :

Lexyghot : He also overestimates the ext column strength. He says they are 14 x 14 x 1/2. they are not that thick. they are either 1/4 or 5/16. SO he may be doubling the strength.

LT : NO, he says the PC plates are 1/4" thick at the top of the building (not at their column piece top), and he later on assumes PERHAPS 1/2" at the bottom (of the buildings, not of one PC column piece length).
However, it is all of no importance really, since these estimates are purely hypothetical and are also irrelevant for the analysis of collapse :

page 5 : PCs, the external dimensions of which were 14”-by-14”, were made of structural steel the yield strength of which varied from nominal 36 KSI (ultimate 58 KSI) and thickness 1/4” at the top of the building to nominal 100 KSI (ultimate 110 KSI) at the bottom.[ref.2] The thickness of the steel plates at the bottom, to the best of author’s knowledge, is not yet publicly available. CCs were made of structural steel which varied from nominal 36 KSI (ultimate 58 KSI) at the top to nominal 42 KSI (ultimate 60 KSI) at the bottom. Neither the dimensions or the thickness of the steel plates used for CCs, to the best of the author’s knowledge, are yet publicly available. The NIST report [ref.2] claims that there were two types of CCs: “standard” and “massive,” where the four “massive” columns, one at each core’s corner, “together provided 20% of load-bearing capacity of the core.”
This was recently proven to be misleading [ref.13] : information released to the public shows that of 51 CCs at least 16 (along two longer sides) were of external dimensions 22”-by-55” and of thicknesses up to 5”. To obtain the values for our models we proceed as follows. For each structural element, the PCs and the CCs, we find the scaled ultimate yield force f = f(z), at the top (z = 0) and at the bottom (z = 1).
The parameters r and s are then obtained using --snip-- Eq.10a and 10b.
For the PCs we assume that the thickness of the plates at the bottom was 1/2”, yielding --snip-- Eq.11

where M = 4.5 · 10^8 kg is the estimated mass of the building, while g is gravity.
(LT: plates at the bottom of the tower! And you know why he uses that? Because of his statement about the ultimate yield strain has to be applied/calculated over the whole length of a column, ~ the height of the buildings.! )
As for the CCs, we do base our expectations on the following: all 51 column were of dimensions 22”-by-55”, while their thickness and strength varied from 1 1/4” and nominal 36 KSI (ultimate 58 KSI) at the top, to 5” and nominal 42 KSI (ultimate 60 KSI) at the bottom. This yields --snip-- Eq.12

Please note, the assumption of all 51 columns being the same appears to be corroborated by the floor plans : [ref.2] all CCs appear to have the same footprint. Also, while this estimate is purely hypothetical, it turns out that, it is also irrelevant for the analysis of collapse that follows.
We observe that from Eqs. (11) and (12) the ultimate safety factor of the WTCs is ƒCC(1) + ƒPC(1) ∼ 3.5. This is a reasonable estimate considering the dimensions of the buildings and the other safety requirements that entered the structural calculation (ability to withstand hurricane winds and an airplane impact).
From the properties of structural steel [ref.14] it is known that the yield strain under tension and compression are fairly similar, and is ∼ 21 − 25%. In our model this is represented by λ1, which we take to be λ1 = 0.2. The value of compaction limit we take from Bazant,[ref.10] λ∞ = 0.2, which leaves λ2 = 1 − λ1 − λ∞ = 0.6. From there, (r∗, s∗) in the continuous model are related to (r, s) in the discrete values as
r∗ = 0.25 · r,
s∗ = 0.25 · s. (13)

--more--