Times LDEO collapse seismogram of WTC-7, compared to the by NIST time-stamped Cianca 9/11 photo

a reply to: LaBTop

You really do not understand what happens to steel when not protected by fireproofing and exposed to fire.

originally posted by: LaBTop
You really don't understand at all what a REAL thermobaric explosive is..... You just can't understand it.

Actually, you are the one that has no clue at all what they are, if one went off inside a WTC building the noise and blast effects would have been huge, and everyone for km would have seen and heard that effect.

But you think somehow that they were hush a boom silent explosives....

originally posted by: neutronflux
a reply to: LaBTop

The more you post with out addressing simple questions just shows how lacking you are in understanding science and you lack the comprehension to create elegant and precise answers. If steel looses enough stiffness and drops, no matter how much it expansion and grows, it lost it's ability to expert force and resist strain. What happens when you push a heated bar of steel that lost its ability to resist strain in to an anvil. It buckles and expands out in diameter. The steel holding the floors lost it's ability to hold a load and resist gravity from its straight down pull.

Well, to begin with, steel columns in a huge web of vertical and horizontal steel and concrete floors don't drop, they BUCKLE. Just as you yourself remarked in your last sentence, borrowed from some of your Truster sites. They keep repeating the anvil example, as if it wasn't shown to be total nonsense, a long time ago already.

Like in this paper :
911research.com...

It's a rebuttal of the NOVA Online text from their interview by Peter Tyson, editor in chief of NOVA Online, with Prof. Eagar. (Yes, he was too eager to collect some 9/11 fame)

This piece by "professor" Eagar and student Musso has to be some sort of record for the greatest number of lies, and points of misdirection, ever strung together in an "engineering" article. Comment is highlighted in red.

Read ALL the red and purple colored comments text, and you will perhaps start to understand why you put your money on the wrong horse.
A few examples which explain WHY your anvil remarks are far too simplistic and totally not applicable to the 9/11 WTC scenarios :

A fatal flaw in Eagar's theory, is that the tops of the trusses were embedded in the concrete slab, so even if a truss was heated to the point of failure, even if it was dripping molten steel, the concrete slab would still hold the truss up and it could not possibly fall as indicated in the animation. If one truss failed, its load was redistributed to the concrete slab and all the remaining trusses associated with that slab. So the failure of one, or even many trusses, does not lead to overall failure. There is absolutely no way that the trusses could collapse one after the other, as claimed by Eagar. Here is a quote from (a section on the WTC in) Multi-Storey Buildings in Steel [1], by Godfrey :

"Composite action between the concrete and the steelwork is ensured by extending the diagonal web members of the joists (trusses) through the steel decking and embedding them in the (concrete) slab."

This is what Eagar proposed, his misdirection animation of a truss falling, after failing by heat :



As you see, I posted this already as a still picture, but you did not pay attention, and did not try to find it by Google Photo Search, then you would have ended at this rebuttal page of the dis-informative words of Prof. Eagar. And you could have found also this photo of a buckled column top from the Broadgate fire :


911research.com...

Above is a photo of a number of 45 feet (13.5m) long trusses and a buckled steel column after the Broadgate Phase 8 fire (the WTC towers had 35 and 60 foot trusses). The fire occurred while the 14-story high-rise was under construction. Little of the steel was fire protected and the sprinkler system and other active measures were not yet operational. Even though a number of trusses and columns buckled, due to thermal expansion, no collapse was observed at Broadgate.

The system of design of the World Trade Center Towers is called tubular framing, since the perimeter frames of the building are designed to act as a cantilevered tube in resisting lateral forces. This design concept (the so-called tube within a tube architecture) has been employed in the construction of many of the world's tallest buildings. These include the John Hancock Center (1105 ft), the Standard Oil of Indiana Building (1125 ft) and the Sears Tower (1450 ft). In fact, it is the standard design for tall buildings. Vital to the structural integrity of these buildings are the composite floor slabs. In fact, if the floors were not composite, the buildings would eventually collapse.

Eagar totally ignores the fact that the floor slabs were composite (that is, studs or projections from the steel beams were embedded in the concrete slab) preferring to believe the fiction that the floors just rested upon the beams supporting them.

How many times did I tell you that the floors were huge COMPOSITE structures.?

Eagar : ""That's essentially how the World Trade Center absorbed an airplane coming into it. It was somewhat like the way a net absorbs a baseball being thrown against it.""

This is deliberate misdirection. It would be more accurate to say that the towers absorbed the impact of the planes as a sheet of glass absorbs the impact of a bullet. Note that a baseball does more damage to a window than a bullet (even if we arrange that both have the exactly the same momentum). As we all know, the bullet will make a neat little bullet hole while a baseball will smash most of the glass out.

It is the speed (and shape) of the projectile that determines whether the impact damage is localized or spread across a large area. The faster the projectile, the more localized the damage. Other common examples illustrating this effect are, the driving of a nail through a piece of wood, and the firing a bullet through a fence-post. Both are done at speed and thus do only local damage. In both of these examples, the wood just a centimeter or two from the impact point, is essentially undamaged. Similarly, the aircraft impacts were at great speed and severe damage localized to a few floors.

And I told you also numerous times already, that the compacting, while decelerating, plane debris, left over after punching through the exterior columns that was formed by triplets of steel exterior columns (Vierendeel triplets) pushed those CUT-OUT triplets in front of that plane debris, as a snow plough pushes snow and ice in front of its plough.
Thus, there was no severe cutting of CORE columns, as so many of these amateur engineers try to tell us repetitively. All that cut-out debris was piled up IN FRONT of those huge strong CORE columns. You can see those piles in HD pictures of the insides of the two plane impact holes.
Thus, the bullet example must be read as two very wide, big bullets that entered both towers, breaking Vierendeel triplets under and above them, pushing those forward in front of the suddenly compacted plane aluminum hull and its wing struts with their two huge jet engines. While those compacting plane parts were decelerating at an immense speed, measured in milliseconds.
They also had to overcome the cutting blade function of the huge composite steel plus concrete floors. Which were only partly folded up.

These critical temperatures are only part of the picture. If individual components are exposed to temperatures in excess of those quoted, then they may fail. However, these same components when incorporated in larger structures can be heated to much greater temperatures before failure occurs. The June 1990 Broadgate fire occurred in a high-rise while under construction. Consequently, little of the steel was fire protected. Even though the fire blazed for 4.5 hours, the building did not collapse and runaway type failures did not occur. To investigate the implications of the Broadgate fire on fire standards, the British Steel and the Building Research Establishment performed a series of six experiments at Cardington on a simulated, eight-story building. Here is a quote from one of the research reports from these experiments.

Steel beams in standard fire tests reach a state of deflections and runaway well below temperatures achieved in real fires. In a composite steel frame structure these beams are designed to support the composite deck slab. It is therefore quite understandable that they are fire protected to avoid runaway failures. The fire at Broadgate showed that this (runaway failure) didn't actually happen in a real structure. Subsequently, six full-scale fire tests on a real composite frame structure at Cardington showed that despite large deflections of structural members affected by fire, runaway type failures did not occur in real frame structures when subjected to realistic fires in a variety of compartments. [2]

And here is a quote from the FEMA report into the WTC collapse (Appendix A).

In the mid-1990s British Steel and the Building Research Establishment performed a series of six experiments at Cardington to investigate the behavior of steel frame buildings. These experiments were conducted in a simulated, eight-story building. Secondary steel beams were not (fire) protected. Despite the temperature of the steel beams reaching 1,500-1,700°F (800-900°C) in three of the tests (well above the traditionally assumed critical temperature of 1,100°F (600°C), no collapse was observed in any of the six experiments.

To get a feeling for how amazingly fire-resistant composite steel structures really are, consider this:

Test 6: The office demonstration test fire at Cardington:

A compartment 18m wide and up to 10m deep with a floor area of 135m2, was constructed on the second floor, using concrete blockwork. The compartment represented an open plan office and contained a series of work-stations consisting of modern day furnishings, computers and filing systems. The test conditions were set to create a very severe fire by incorporating additional wood/plastic cribs to create a total fire load of 9.4 pounds per square foot (46kg per square meter). Less than 5% of offices would exceed this level (mainly office libraries). The fire load was made up of 69% wood, 20% plastic and 11% paper.

The steel columns were fire protected but the primary and secondary beams (and their connections) were not. The maximum atmosphere temperature was 2215°F (1213°C) and the maximum average temperature was approximately 1650°F (900°C). The maximum temperature of the unprotected steel was 2100°F (1150°C) with a maximum average temperature of about 1750°F (950°C). The steel beams would have only have had 3% of their strength at 2000°F (1100°C), with such little remaining strength left in the steel, the beams could only contribute as catenary tension members. It is also clear that the concrete floors were supplying strength to the structural system by membrane action.

The structure showed no signs of collapse.

One of the conclusions derived from the Cardington tests, was that fire protection for the beams (trusses) was not necessary (in a composite steel structure).

Do you understand what the Cardington tests conclusively showed.?
That the COLUMNS did not fail, AT ALL. And also not the COMPOSITE floors.
At much harsher conditions than in the Twin Towers.
Let it be in WTC-7, that really is a full blown joke, what NIST and ARA came up with, after years of searching for an acceptable explanation, WITHOUT being allowed to also consider EXPLOSIVES.

By the way, Charles M. Beck also showed you that even when we delete 50 % of all the steel from his equations, and to top it off, declare that the remaining half of it lost half of its strength, those towers could STILL NOT COLLAPSE by fire and plane impacts.!

And when you look at that pesky little animation of the initial north tower collapse, at the top right of this article, you see that the failing floors were not on fire at all.
And that the floors that failed, must have most of their fire proofing still attached. And these were good for 2 hrs. After 2 hrs, that horizontal and vertical steel would at last start to be effected by the elevated temperatures of localized fires that burnt out quickly since all materials that could burn, had burned already.
Global collapse occurred however long before that.

NOVA: You've pointed out that structural steel loses about half its strength at 1,200°F, yet even a 50 percent loss of strength is insufficient, by itself, to explain the collapse.

Eagar: Well, normally the biggest load on this building was the wind load (Author comment : actually the biggest load was the gravity load), trying to push it sideways and make it vibrate like a flag in the breeze. The World Trade Center building was designed to withstand a hurricane of about 140 miles an hour, but September 11th wasn't a windy day, so the major loads it was designed for were not on it at the time.
As a result, the World Trade Center, at the time each airplane hit it, was only loaded to about 20 percent of its capacity. That means it had to lose five times its capacity either due to temperature or buckling -- the temperature weakening the steel, the buckling changing the strength of a member because it's bent rather than straight. You can't explain the collapse just in terms of temperature, and you can't explain it just in terms of buckling. It was a combination.

Eagar claims that the exterior columns buckled. The exterior columns were visible from outside the building. There was no visible evidence that these columns buckled before the collapse. There is also no visible evidence that these columns were very hot. Photographs of these columns in the debris heap, showed no indications of thermal buckling (I guess the conspirators will claim that the reason no photographs showed thermal buckling of the exterior columns, was that they made sure that such columns were the first to hauled away and melted down). Eagar jumps from buckled columns to buckled beams in a few more lines, mixing up the two as if they are essentially the same.

I just lately told you again, that as good as all exterior columns do not show any signs of bending NOR BUCKLING at their tops and bottoms, but show sheared out bolts and sheared-off welds.
Which is a solid indicator that those exterior column ends were pushed out of their seats inside the tops or ends of the adjacent Vierendeel triplet column ends.
By a Thermobaric explosion that blew up whole floor segments.

Eagar: Exactly. If there was one part of the building in which a beam had a temperature difference of 300°F, then that beam would have become permanently distorted at relatively low temperatures. So instead of being nice and straight, it had a gentle curve. If you press down on a soda straw, you know that if it's perfectly straight, it will support a lot more load than if you start to put a little sideways bend in it. That's what happened in terms of the beams. They were weakened because they were bent by the fire.

(LT : His soda straw argument is again based on a SINGLE straw. Just as that pesky anvil argument. In the WTC floor areas heating situation, we have to include the huge composite steel and concrete floors keeping any axial displacement from happening in that web of 47 core columns. And don't forget the horizontal cross beams under those core area floors.
See the photo of the buckled top of that column in the Broadgate fire :

That goes even much more for the CORE areas, those had much thicker concrete and steel beams inside them. Especially the six (3 double) Maintenance floors, their concrete floors were even 3 times stronger constructed, to hold the extra weight of heavy machinery there.)

Eagar is, as usual, incorrect here. Buckling of beams does not necessarily lead to failure, in fact, in fires it is beneficial. For example, a laterally restrained beam (that will buckle at relatively low temperatures due to the lateral restraint) will not suffer runaway till around 900°C, whereas, a simply supported beam carrying the same loads (that will not buckle) will suffer runaway at around 450°C. So the beam that undergoes buckling is much preferred in a fire situation. Here are two more quotes from research papers examining the Cardington experiments.

In structures such as the composite steel frame at Cardington, the slab strongly restrains the thermal expansion strains and consequently develops large membrane compression and tension forces in the composite steel-concrete floor system. The membrane compressions can be limited by the large downward deflections which occur through thermo-mechanical post-buckling effects and thermal bowing (these are nonlinearly additive). The resulting behavior is then a combination of displacement and force responses. The heated steel part of this composite system, if unprotected, rapidly reaches its axial capacity (through local buckling and strength degradation), and produces a beneficial effect by limiting and then reducing the total membrane compression, so allowing increased expansion of the steel through softening and ductility. This is clearly a desirable behavior here, as it reduces the force imposed on the structure by the expansion forces and allows the damage to be localized. [3]

In composite floor slabs, buckling of the steel beams as a result of large compressions induced by restrained thermal expansions, is a positive event. The buckle allows the increase in length, as a result of thermal expansion, to be accommodated in downward deflections relieving axial compressions. [4]

So, in buildings comparable to the World Trade Center, buckling, paradoxically, has a beneficial effect.

But the steel still had plenty of strength, until it reached temperatures of 1,100°F to 1,300°F. In this range, the steel started losing a lot of strength, and the bending became greater. Eventually the steel lost 80 percent of its strength, because of this fire that consumed the whole floor.

If it had only occurred in one little corner, such as a trashcan caught on fire, you might have had to repair that corner, but the whole building wouldn't have come crashing down. The problem was, it was such a widely distributed fire, and then you got this domino effect. Once you started to get angle clips to fail in one area, it put extra load on other angle clips, and then it unzipped around the building on that floor in a matter of seconds.

-- more --

NOVA: Many other engineers also feel the weak link was these angle clips, which held the floor trusses between the inner core of columns and the exterior columns. Is that simply because they were much smaller pieces of steel?

Eagar: Exactly. That's the easiest way to look at it. If you look at the whole structure, they are the smallest piece of steel. As everything begins to distort, the smallest piece is going to become the weak link in the chain. They were plenty strong for holding up one truss, but when you lost several trusses, the trusses adjacent to those had to hold two or three times what they were expected to hold.

More crap from Eagar. Does he really believe that the towers were only held together with a couple of rivets and duct tape. Here is a quote from the FEMA report into the WTC collapse (Chapter 2).

Pairs of flat bars extended diagonally from the exterior wall to the top chord of adjacent trusses. These diagonal flat bars, which were typically provided with shear studs, provided horizontal shear transfer between the floor slab and exterior wall, as well as out-of-plane bracing for perimeter columns not directly supporting floor trusses.

Eagar claims that the trusses were connected to the perimeter wall only by what he calls, "angle clips". The truth is that every 160 inches, the perimeter wall was solidly attached to a 24 x 18 inch metal plate that was covered with shear studs and set in the concrete slab. In addition a pair of 6 foot long, flat, steel bars lined with shear studs were welded to the plate and to the top chord of the adjacent trusses. These bars were also set in the concrete slab. Between these plates similar pairs of 6 foot long, flat, steel bars connected directly to tabs on the perimeter columns. So these features, as well as the angle clips, connected the perimeter wall to the concrete slab and hence to the rest of the building. Below, is a picture of these plates and steel bars before the concrete slab was poured. The plates are the dark rectangular objects along the perimeter wall. The steel bars are the V-like features :

And that's exactly what I showed you in my above post, with the drawings of some of those parts in it.

And still you guys keep coming up with these decennial old arguments, long ago debunked.
It's getting a tad bit sad, the desperate manner in which you, JREF and 9/11Myths reading guys, show their pitiful arguments.

These are solid, scientifically based, engineering and fire protection arguments, you should study those instead of the nonsensical drivel at JREF or 9/11 Myths :

[1] Multi-Storey Building in Steel, GB Godfrey (Editor), Collins, London, England, 1985.
[2] Behaviour of Steel Framed Structures under Fire Conditions; School of Civil & Environmental Engineering; The University of Edinburgh (partial HTML document , full PDF document 3.5MB).
[3] Structural Performance of Redundant Structures under Local Fires; J.M.Rotter, A.M.Sanad, A.S.Usmani and M.Gillie; Proceedings of Interflam99 - Edinburgh (PDF document 0.8MB).
[4] The Behaviour of Multi-storey Composite Steel Framed Structures in Response to Compartment Fires; Susan Lamont. PhD Thesis, University of Edinburgh, 2001. (partial HTML document , full PDF document 50MB).

a reply to: LaBTop

"By the way, Charles M. Beck also showed you that even when we delete 50 % of all the steel from his equations, and to top it off, declare that the remaining half of it lost half of its strength, those towers could STILL NOT COLLAPSE by fire and plane impacts.! "

I am sure that is a great comfort to the families who lost loved ones that day. Mr. Beck says it couldn't happen that way....

www.abovetopsecret.com...

What Can be Done about Trolls?
When you suspect that somebody is a troll, you might try responding with a polite, mild message to see if it's just somebody in a bad mood. Internet users sometimes let their passions get away from them when seated safely behind their keyboard. If you ignore their bluster and respond in a pleasant manner, they usually calm down.

However, if the person persists in being beastly, and seems to enjoy being unpleasant, the only effective position is summed up as follows:

The only way to deal with trolls is to limit your reaction to reminding others not to respond to trolls.

When you try to reason with a troll, he wins. When you insult a troll, he wins. When you scream at a troll, he wins. The only thing that trolls can't handle is being ignored.

What Not to Do
As already stated, it is futile to try to "cure" a troll of his obsession. But perhaps you simply cannot bear the hostile environment that the troll is creating and want to go away for a while.

Do not feed the trolls.

a reply to: LaBTop

OH....so I should stop responding to you. Thanks for the info.

a reply to: cardinalfan0596

those towers could STILL NOT COLLAPSE by fire and plane impacts.! "

Until the conspiracy crowd can come up with proof something else it just jaw flapping.

originally posted by: hellobruce

originally posted by: LaBTop
You really don't understand at all what a REAL thermobaric explosive is..... You just can't understand it.

Actually, you are the one that has no clue at all what they are, if one went off inside a WTC building the noise and blast effects would have been huge, and everyone for km would have seen and heard that effect.

But you think somehow that they were hush a boom silent explosives....

You lack a huge part of your natural logical reasoning.
I showed you about hundred times now that WTC-7 collapse video from Ewing.

www.youtube.com...


With that huge deep explosion sound in it, just 2 seconds before you see the east penthouse roof starting to fold.
And then you see, but do NOT hear anything from it, the whole building starting to globally collapse in that same OFFICIALLY endorsed, FOIA freed video, after about 8.3 seconds.

So, if we may believe those liars at NIST and ARA, that whole building collapsed without any additional sound of its collapse.
But their pet theory of column 79 collapsing, did produce a huge deep sound, HOWEVER, all the other columns failing in the same manner are silent events....? Are you serious.?

Well, then there are YOUR hush a boom silent explosives....not mine, mine is the definitely not silent, first huge and deep sounding one.
Just as the collapse initiation explosive sounds at 350 meters high are clearly to be heard in numerous posted by me, Twin Tower collapse videos, and were immediately followed by the resulting huge collapse sounds.

It's only you who invented those ""hush a boom silent explosives"".
It's quite childish to try to imprint a clear lie on someone else his posting history. I never said they were silent, YOU made that up.

originally posted by: cardinalfan0596
a reply to: LaBTop

"By the way, Charles M. Beck also showed you that even when we delete 50 % of all the steel from his equations, and to top it off, declare that the remaining half of it lost half of its strength, those towers could STILL NOT COLLAPSE by fire and plane impacts.! "

I am sure that is a great comfort to the families who lost loved ones that day. Mr. Beck says it couldn't happen that way....

Yep, it's as simple as that. You HAVE to include extra external energy, and a surprisingly HUGE extra amount of it, to force those buildings down.

a reply to: LaBTop

Like gravity?

a reply to: LaBTop

I wonder what several hundred tons of steel, concrete, furniture, office equipment.....would do when it drops straight down onto a weakened structure......

originally posted by: neutronflux
a reply to: LaBTop

Like gravity?

So you think you can add it again.? Like, two times?
It's already part of Beck's equations.

Or did you intend to be funny.? No cookie.

originally posted by: cardinalfan0596
a reply to: LaBTop

I wonder what several hundred tons of steel, concrete, furniture, office equipment.....would do when it drops straight down onto a weakened structure......

You still think a whole top block has dropped down at least one full floor height.?
Over the whole floor area around the core.? Or do you think the whole core also gave way.?
That's not how a natural collapse starts. It's a chaotic event, not a point event.

By the way, Charles M. Beck showed you it won't happen. You will have to add explosives to let it happen.
Lot's of others showed you even in that case, the initial static load won't be enough to get any further than about three floors, then a NATURAL collapse FOLLOWING an explosion, will halt in case of those Twin Towers, caused by massive deceleration.

Which was NOT measurable by the way, there was a steady downward movement in the first 6 seconds, no deceleration jolt to be measured. Which should have been VERY obvious in a NATURAL collapse.
Meaning that all resistance was removed in the path of the forming debris.

On to WTC-7 again.

WTC 7 Explosion - NIST FOIA Cbs-Net Dub5 09 :
www.youtube.com...



Posted by ShadowHerder, but won't play anymore on most boxes.

YouTube has made HTML-5 their player of choice. You can change that back to Flash Player with this beautiful Add On made by MRFDEV in Firefox, and see and hear at last this, reluctantly, but officially released video by NIST (under massive FOIA pressure) :
addons.mozilla.org...

MRFDEV : YouTube Flash Player has been successfully installed, thank you for giving it a try!
Now each time that you will load a YouTube video you will see the message "Playback isn't supported on this device" during one or two seconds, then the default HTML5 player will be replaced by the Flash Player. That's it, you have nothing to do!
If ever the message lasts more than a few seconds, press "ctrl + F5" on your keyboard to reload the page. You can also quickly enable and disable the add-on by clicking the button that has been placed in the main Firefox toolbar.

Press Ctrl plus F5 also when the comments section doesn't want to load, or you only get a black screen, or that revolving ""I'm busy"" thingy keeps going without anything showing up.

The most recent comment from the above video is an interesting one, try to find the logical omissions in his reasoning :

dlancer2k, 3 months ago (edited) :
You can see the support structure failing on the left side a whole six seconds before it fails on the right side. Right after the top left housing collapses, windows approx 8 floors down pop out. The windows are a result of the collapsed structure inside. If the broken windows were a result of explosives, they would've broken before the top left housing fell. Then after the windows stop popping out on the left side, the entire building is then being supported by the structures on the right side, and they can't handle the full weight, so the right-side structure buckles after six seconds, causing windows on the right side to pop out as the building falls. The whole thing takes about 12 seconds starting from initial left-side structure failure to finished collapse. Sorry, but that is nothing like a controlled demolition.
The left-side internal structures catching fire makes more sense.

Hint : read nr 4 of the 25 points article by Tony Szamboti.
Or, if you can't bring yourself to reading offered arguments, start an argument about it with me.
Make my day.

NIST 7 years later let ARA come up with that ridiculous heat expansion theory.
For those, who still think, just as NIST proposed, that a floor impacting girder, pushed off its seat at column 79, could have initiated an 8 floor ""pancaking"" failure beginning at floor 12 of WTC-7, here's why it could not have ever happened :

Tony Szamboti : I ran a modal analysis for the northeast beam and girder assembly and it shows the assembly (with the five beams attached at the east wall, three support beams attached at the north wall, and the girder just sitting unrestrained on its seat at Column 44) has a natural frequency (Fn) of 0.52 Hz.
Fn = 1/2π * SQRT(K/m)
Stiffness (K) can then be found with the equation
K = (Fn * 2π)2 * m
The weight of the beams and girder is just over 20,000 lbs., so mass (m) = 20,000/32.174 = 622 slugs so
K = (0.52 * 6.28)2 * 622 = 6,633 lbs./inch
Using Nordenson's potential energy of 3,473,000 in-lbs. and the same standard equation he uses to find deflection
P.E. = 1/2K *D2
D = SQRT(2*P.E./K) = 32.4 inches
Now using the standard equation Nordenson uses to find force
F = K * D = 6,633 lbs./inch * 32.4 inches = 214,909 lbs.

This is only about 1/3rd of the 632,000 lb. force needed to shear the girder seat and proves that the falling girder would not have sheared the seat and the northeast corner of floor 12 would not have collapsed if a girder at floor 13 came off its seat at column 79.

Below are views of the FEA results. In case you are wondering : the information on the upper left says 5.1693e-01 Hz, which I rounded up to 0.52 Hz. The vertical mode was the second mode.
The first mode was side to side and it was 2.2661e-01, which would be 0.23 Hz, but isn't germane here.
SOURCE : Natural frequency of WTC 7 northeast corner beam & girder assembly.pdf

Beside that Tony proves here that the whole NIST/ARA scenario of a failure at floor 12, caused by a collapsing girder at floor 13 is completely and utter cow manure, there is of course still the full FreeFallAcceleration period of 2.25 seconds at the start of the global collapse of WTC-7, for which the causes and results were never explained by NIST.
Because they know by now far too well, that there is only one explanation possible :

E X P L O S I V E S

Here are the two FEA analysis done by Tony (hold CTRL, and push the + key on your keyboard repeatedly 7 times to blow the drawings up to the maximum in Win-XP up to Win-10 plus Firefox browsers) :

originally posted by: [post=20951627]Informer1958

Yes explosions were captured on most News videos on 911, our eyes do not lie to us.

There are zero audio recordings that have the sound profile of explosives. To deny this is futile.

Explosions so powerful that it hurled thousands of tons of steel support beams over 600 feet

Since you cannot provide convincing evidence of this, it is rejected without comment, other than to point out that since this is YOUR CLAIM, you must provide convincing evidence of such an outlandish claim - that claim being that there were "Explosions so powerful that it hurled thousands of tons of steel support beams over 600 feet" and yet remain silent.

You also have not provided a motion tracking of any steel that exhibits the trait of being explosively hurled. This would be fairly simple to do, due to the wealth of videos that captured the collapse. This would be solid evidence, yet no one has ever done this, correct?

Why do you think this is?