Some Misunderstandings Related to WTC Collapse Analysis

[Jeffrey Orling]

The hat trusses said to have weakened and sagged forty inches, in tests sagged two to six, and could not have initiated collapse absent significant weakening of core columns--likely by charges, as no other cause presents.

Phil, I think you meant to say it was the floor trusses under the floor slabs between the core and perimeter which NIST claimed sagged 40+ inches and pulled in the south exterior wall of WTC 1 (North Tower) over several stories around the 98th floor. Of course, there are serious problems with this theory as they couldn't get the sagging trusses to pull the exterior columns inward in their FEA model and the trusses did not sag anywhere near what they claimed in their actual floor slab fire testing, as you state. The only legitimate mechanism to pull in the perimeter columns was a falling core and there was not enough heat to weaken the core and cause the acceleration observed over the first story of the fall.

In case you aren't aware, the hat truss was a large truss at the top three floors of the building, with A-frame outriggers connecting the core to the perimeter, intended to spread the antenna wind load induced moments out to the perimeter which cut down the vertical force required to counteract them due to the increased lever arm. Lauren put pictorials of it in post #292 of this thread.

The hat truss was a 3 story space frame interconnected with all the columns and bracing. It was a very rigid structure which carried and spread the 360 ton concentrated antenna loads to the building's columns. It was also part of the strategy to transfer/distribute wind shear loads.

The 360 tons attenna sat above the 3 weakest core columns in the center of the tower. To support this concentrated load they used the hat truss instead of using a 4th column and beefing them all up. the 3 columns were used to accomodate the service elevator which went from sub basement to the top mech floor.

The hat truss like DID transfer loads when the core columns beneath were severed and others weakened and the loads from say 98 up were hanging (in tension) from the hat truss. The column connections in the tower were not designed for tension but were to maintain position / alignment for axial load transfer. When core columns were severed the connections were not strong enough and they failed leading to the core above 98 or so to come apart. All floor loads above 98 were then cantilevered from the facade columns and the slabs began breaking free and dropping probably in huge sections which built to threshold ROOSD mass. The transition from static to unstable once it began happened very quickly... destruction of remaining capacity.

[Jeffrey Orling]

[quote=Lauren Johnson][quote]

Based on Jeffrey's words and my burning through the bottles of Visene squinting at the Top Down cartoon, he seems to be saying that the load was transferred to the perimeter columns via the hat trusses. The initiation of the collapse was the failure of the perimeter columns as they exceeded their designed load capacity taking the core columns down. The floor joists loaded with cement disconnected and formed the ROOSD mass.

Jeffrey, it's your call.[/quote]

Lauren,

This was a 4D process. LxWxHxT so it's hard to communicate in a sketch or even a narrative how this was taking place. Not a linear process by any means.

I tried to explain that there was what I call phase transition but not actually phase boundaries like discreet steps. There was a blending... a progression of weakening and forces (loads) were being redistributed as axial support was compromised and being eroded (or removed).

Bombs would be discrete events.. like the plane hitting and destroying the columns. Heat weakening is not a discrete event... it represents a process of erosion and weakening. This is not unlike rusting which will over time destroy the integrity and strength of the steel and it will fail (Miamus river bridge collapse - I95). So as in the lifting the leg from the floor is a discrete change in load transferring half your weight to the remaining leg. But if there was a weakening of the strength of your leg it would support less than half your weight and the other more than half.

In the tower cores there were many legs and so the load sharing was more complex and the loads on each column was not equal to begin with. Not all columns were equal.

The columns required bracing to maintain their design capacity. All floor loads were attached (hung) from/off the SIDES of the columns... the axial loads on the column were from the columns above. Loss of bracing also weakened the columns.

Could the core weakening have been done with devices? Of course. But the evidence is not there. We would also have to consider the nature of the two twin tower collapses. They were different and we can infer things about building performance from the studying the differences and the similarities. Each collapse adds to our understanding.

Tower 2 fell first, was hit off axis at an angle damaging the SE core significantly removing one of the 4 strongest columns (corner of the core). The damage occurred to the EAST of the massive elevator machine rooms which protected the NW side from more extensive damage. Tower 1 had few elevators at the strike elevation and the core was used for tenant space aside from 2 elevator shafts and mechanical shafts (risers). The fuel was able to spread throughout the floor and engage the entire floor in fire. WTC 2 came down when the NW side lost capacity to hold the top up. When release came... there was severe buckling of several of the NW columns... a motion which we see moved the bottom of the top to the NW and the entire top dropped onto the 78th floor with the ROOSD mass quickly built and ROOSD began.

In both towers the cores survived the ROOSD flow standing 50 stories before buckling from Euler forces. WTC2 makes it very clear that at release there is lateral translation because of the asymmetry of the load redistribution. Same with WTC1, but less obvious because of the nature of the initial damage. The movement of the antenna is one tell tale sign that the core AND the hat truss were compromised.

We don't actually SEE what we want to call the moment of initiation. It is lost in the PROCESS of load capacity destruction. We DO see some signs of this process in pre relaese movement... something that Tony ignores. As in the rust example we notice the bridge collapse but not the slow rusting of the pinned connection which failed.

I think the concept of the facade above 98 supporting the entire top is missing the point about the formation of the ROOSD mass. The facade movement, even some buckling or pulling in at some locations was an artifact of the collapse within... it is like a systemic infection which presents as rash on the skin. This is a tell tale sign that something WITHIN the body is under attack.

ROOSD mass destroyed the tower below the strikes zones. The strike zones caused core loss of capacity from mech damage and heat weakening and this led to the top collapse and then ROOSD.

However it is difficult to see the phases because it seems to go from static to collapse almost smoothly.

I think the debate is really whether the weakening could be caused by heat. The truth movement thinks this impossible. The temps and the core capacity are shrouded in mystery. It seems to me that some amount of heat could produce the observations. It's a big stretch to say this is impossible... and then declare it was placed devices... with no proof of their presence.

[Jeffrey Orling]

General comment about the engineering designs.

The engineering drawings for WTC 7 were finally released a few years ago, I believe as a result of a FOIA. These included the load calculations and all the specs for the steel.

This sort of information has not been released for the twin towers and doing so would assist in understanding how the collapse might have taken place. To me the only reason to not release this information is that the engineers and project developers don't want it scrutinized.

What other reason could there be?

[Jeffrey Orling]

What you aren't understanding is that the core failure doesn't allow 12 floor slabs to immediately contact each other. They can't do that, as they are connected to the columns, and 5 stories of columns would need to collapse before 5 floor slabs would be free to generate ROOSD. In other words, when the failure occurs at the 98th floor the 99th floor slab comes down onto the 98th floor slab, but not the other 11 floor slabs. They need to wait until their respective columns collapse. So 5 stories of columns would need to collapse before ROOSD would have the minimum number of floor slabs to generate it.

The real problem in the natural collapse theory concerns why the columns aren't resisting.

Tony,

It seems as if the core columns suffered loss of capacity from mechanical strike of the plane, weakening from heat, loss of bracing and this led to the core collapse .. the antenna dropping and the floors falling very rapidly pulling away from the facade...the recovered facade columns truss seats show what sort of forces and motion was in play. The ROOSD mass was being built behind the facade from the collapsing floors of the top section. This is the same as it was in WTC2. And there are reports of a sequence of booms which were likely sections of floor slabs collapsing onto the floor slab below. I don't think these were explosions... why? No reason to sequence them to drop the top... just have them go off all at once. Conclusion: sounds were artifacts of the collapse.. initial floor collisions.

[Jeffrey Orling]

I found this comment this morning:

"... NIST perceives one building. FEMA perceives another. Bazant perceives a third.

Tony Szamboti perceives yet another. Ryan Mackey perceives yet another. Richard Gage perceives yet another.

Each party is using highy fragmented, highly selective sets of observations and measurements to support their claims.

Each party, by using their own highly selective and fragmented sets of observations and measurements, is literally perceiving the building collapses differently than the others."

One wonders if each of the aforementioned stipulated to the same observations and measurements would they come to the same conclusion/explanation? The author of the quote seems to imply this. But even stipulating to what the data is... is not necessarily THE data, the complete set of data.

My position has been to acknowledge that my understanding is based on what I perceive and my limited understanding of structure and physics. All I've ever expected is that others who read my rants make up their own mind and do their own study... or be lazy and just repeat what X, Y, or Z says.

This approach makes debates not simply to win... but to make people think and learn. Everyone can learn something.

[Lauren Johnson]

Jeffrey, thank you for your comment @352. I will read it later.

Tony has a name and credentials as do you. Who is Major Tom and what are his credentials?

[Jeffrey Orling]

I can't answer with any specificity who Tom is. I believe he is a physicist and has created a web site which is or was a resource for all sorts of information about the WTC.

http://www.sharpprintinginc.com/911/

The JREF people think of him as a truther. The truth guys such as Tony seem to think of him as a OCT guy. I find his insights instructive.

When I left AE911T I began to feel free and try to find the answers that AE refused to provide. My questions seemed to cast me as a threat. That was bizarre. Dwain Deets, a fellow board member who supported my and eventually resigned and left AE at least partially because of how they treated me... remains a truther and a friend of sort. I know he's explored all sorts of answers... such as nukes and we've discussed it. I like and respect him. He's mostly involved in aviation issues I believe and I have nothing to add on that so I say nothing.

I do and I don't understand the anonymity thing. Sometimes it might embarrass someone if their friends and colleagues knew that they were so heavily involved in 9/11 regardless of their position. I spend time on net discussions and so forth in proportion to my other time demands. All of my output - the many slides... some of which I have posted here were produced mostly in the period from 09-13. I arrived at a ROOSD conclusion for the collapse phase and termed it a vertical avalanche in email discussions before I found 911FF and became aware of Tom's ROOSD acronym. Ozeco41 had arrived at a similar conclusion on his own. Both of us and others decided to accept the ROOSD acronym. It's handy and who cares who named it? I think it explains the collapse phase and why THOSE designs came down as they did. Lemkin doesn't agree. Bully Bully for him. I don't care. Apparently neither does Phil. Both believe what they want to... see what they to and seem set. It hardly matters. I am not trying to convince anyone... more like expose what I have learned... which may be wrong. Every needs to use the tools they can to solve the mysteries they see.

9/11 is a very complex technical and political and psychological puzzle. Event the debates about it reveal something about people and how they think.

[Albert Doyle]

Nobody is saying the core did not drop over the full 12 stories, but it did not disintegrate over 12 stories generating 12 stories of rubble at once. It failed at the 98th floor and dropped, as evidenced by the antenna dropping before the exterior roofline.

What you aren't understanding is that the core failure doesn't allow 12 floor slabs to immediately contact each other. They can't do that, as they are connected to the columns, and 5 stories of columns would need to collapse before 5 floor slabs would be free to generate ROOSD. In other words, when the failure occurs at the 98th floor the 99th floor slab comes down onto the 98th floor slab, but not the other 11 floor slabs. They need to wait until their respective columns collapse. So 5 stories of columns would need to collapse before ROOSD would have the minimum number of floor slabs to generate it.

The real problem in the natural collapse theory concerns why the columns aren't resisting.

You're not being honest Mr Szamboti. You are once again diverting us to an irrelevant side argument that doesn't answer the point. Not only that the side argument itself isn't valid.

You are creating these specious side arguments because you are trying to avoid answering where and when exactly the mass of the 12 storey section impacted the building below? In your arguments you would almost think the top section never applied its 12 stories of mass to the building below. But even a child could see that's impossible because the video shows us the top section falling on the building below. If you have a sharp eye you can actually detect a brief instant of deceleration where the top section impacted the bottom section right around the flash-over. That was your firm contact and that is where the full 12 stories applied its mass to the bottom section. You never get around to admitting this because you are trying to avoid it.

You are arguing hocus pocus above because you yourself admitted the core in the upper section dropped. Therefore it wasn't supporting the floors. What you do is argue a specious point but then ignore the main point. That point is at some point the 12 storey top section impacted the main building below and when it did it delivered the plus 5 stories of mass you required as a threshold of ROOSD. The reason you avoid like the devil admitting at what point the dropping top section applied its weight to the building below is because you know the status of the floors is irrelevant to this. The top section had to apply its mass to the bottom section because science requires it. All you needed was for the upper-most floor in the lower building to have enough force applied to it to initiate ROOSD and that is what happened. There is no scenario where this force wasn't met (which is why you don't offer one besides a vaguely implied CD with no specifics).

What your argument does is indirectly suggest that somehow the upper core should have made solid contact with the lower core and resisted collapse. But any look at the specifics of that would show that the core was destabilized and broken and would not have met the lower core members squarely. The damaged area was a mess and the core pieces dropped in scattered randomness. So, where exactly is the resistance you allude to but never quite get around to describing? What you are avoiding admitting is a physical interface occurred between the top section and bottom where the requirements for ROOSD on the bottom section were met. The action of the drop pushed the outer frame outward enough and the inner core inward enough to free the bottom section's floor pads for dropping.

Proof of ROOSD is seen in the first dust jets at the very top. A sharp eye will detect the timing of those jets occurs after the floor drop and not before meaning they were caused by the drop and did not cause the drop itself. It they were explosives charges initiating the collapse they would have occurred sooner. A sharp eye will see they happen in perfect timing with ROOSD.

An explosives charge creates a very specific and identifiable audio fingerprint. It creates a sharp crack sonically that radiates out in the air ahead of the dust jet. This is unavoidable and never varies. Especially with such prominent dust jets as those seen in the falling tower video. It would be impossible for the numerous media microphones around the tower to not catch this distinct audio fingerprint. The reason why there were no such audio identifications is because the dust jets were caused by pneumatic air blasts and not explosives. This is a simple forensic determiner that is beautiful in its simplicity and fatal to the Controlled Demolition theory - which is why Tony is repeatedly unable to answer it. Thank you for your "rebuttal"...

[Albert Doyle]

In this David Chandler video Cutter Charges in the North Tower of the World Trade Center, suspicious evidence of coordinated sequential charges strategically placed is presented, particularly in the case of the corner composed of two fourteen-inch box columns connected by steel plate, clad in aluminum, containing no window:

David Chandler is just narrating things into his video that he wants to see. Anyone can see the alleged corner charges are just billowing smoke from the collapse. These are just more mushy arguments that schmooze general blasts into one type of universal cutter charge that fits any size. Meanwhile Phil doesn't notice that Tony claimed burn-type thermite cutter packs initiated the drop of the upper section and that is why there were no blast jets there. Yet you have his partner in the video directly contradicting that and saying these were explosive charges. We are then back to the original question Tony answered by saying they were thermite cutter packs and not explosives. That question was: "Why are the dust jets on the lower floors much faster in velocity than the alleged charges on the top floors?" Look at the speed of the alleged explosive blast jets on the lower floors. They are visibly much faster than those dust jets at the initiation point at the upper section (as Tony admits). You can't just schmooze this stuff you have to give a credible scientific answer. Meanwhile go to the You-Tube video I linked of controlled demolitions. The corner columns were right there on the face of the building. If they were exploded by charges they would create the type of demolition blast seen in the You-Tube video. You don't see that. You see a slow puff of smoke that billows out as the section disconnects. What CDer's don't realize is this is, once again, firm proof of NO controlled demolition. With the corner column so close to the surface if it was a thermite cutter application it would burn through visibly and create a glowing red hot burn section that would throw sparks as it burned. You don't see that. If it was an explosives pack it would create a highly visible blast shock. You don't see that. CDer's are so under the spell of their theory that they fail to do even simple empirical analysis like this that easily disproves what they are saying. When the top section collapsed the corner column had to separate from the rest of the building at some point because of stress tolerance. That's all you're seeing here. And the fact it spired for a few seconds tells you there was vertical resistance in the outer frame (essential to ROOSD).

Also by David Chandler

Destruction of the World Trade Center North Tower and Fundamental Physics


(see attachment)

Explicitly invoking Newton's Third Law puts this result in another light. Since the forces in the interaction are equal and opposite, the falling block exerts a force of only 36% of its weight on the lower section of the building. In other words, as long as the falling block is accelerating downward we have the counter-intuitive result that the force it exerts on the lower section of the building is significantly less than its static weight. It is difficult to imagine how an upper block exerting a force of only 36% of its static weight could crush the larger, stronger, undamaged lower section of the building to the ground, when the building, at any level, was designed to support several times the weight above it. Assuming a safety factor of between 3 and 5 [12], the observed acceleration implies that close to 90% of the strength of the lower section of the building must have been eliminated by forces other than the supposed "pile driver," suggesting that some sort of controlled demolition was at work.

Nice pseudo-science but not sound. Chandler enters enough classic textbook math to make those uneducated in science take him at his word as to his conclusions. There's a simple explanation that Chandler avoids however. That is that the unsupported floor sections lacked so much critical structural support that the 36% he cites was enough to do the job. What we have been explaining all along is that the design of the tower was so vulnerable that it would only take the force Chandler cites to set-off ROOSD. Chandler does exactly what Tony does. He distracts with an irrelevant side argument that doesn't address the actual dynamics occurring at the time in the buildings. The above is a specious argument because the top section doesn't need to "crush" the bigger lower section. It just needs to trigger the potential energy created by the suspended floor design and create the lateral forces that follow ROOSD. This process is much more complex than the basic over-simplified model Chandler cites which fails to apply an accurate observation of the actual events as they occurred. Chandler tries to get away with his 90% claim by not recognizing the serious lateral forces involved with a floor collapse.

Also of note Graeme MacQueen and Tony Szamboti, The Missing Jolt: A Simple Refutation of the NIST--Bazănt Collapse Hypothesis


< snip >


Conclusions

We have tracked the fall of the roof of the North Tower through 114.4 feet, (approximately 9 stories) and we have found that it did not suffer severe and sudden impact or abrupt deceleration. There was no jolt. Thus there could not have been any amplified load. In the absence of an amplified load there is no mechanism to explain the collapse of the lower portion of the building, which was undamaged by fire. The collapse hypothesis of Bazant and the authors of the NIST report has not withstood scrutiny.

Quack rubbish. There would be no jolt because the top core had been disconnected. The only structure capable of making this resistance jolt would be the outer frame. That frame came down and fell into the void created by the floor collapse. The reason Chandler offers no specific engineering details of what members would be involved in that jolt is because he needs to keep it at the simple level in order to perpetrate his theory. Once the walls were out of alignment there was no structure to jolt. And the floors couldn't offer this because they were unsupported. However a sharp eye will detect a very brief moment of contact right at the lowest fire level where the collapse squares-off and proceeds as one event. No mechanism except for ROOSD.

In examining the claim of the NIST theory of collapse, that fire weakened the steel and the top twelve floors fell as a solid block it is shown by the analyses by David Chandler, Graeme MacQueen and Tony Szamboti to fail at every level.

The steel was not weakened by jet fuel fires which had lives too short to attain the critical temperatures for the necessary time.

If you look at the collapse video there was some serious heat causing the smoke billows on the SW corner. Something was burning hot there. Chandler has no clue what was burning where or how hot and what members were strained by having load shift passed onto them by the damaged members. Once again applying textbook theory to a dynamic event. What they are doing is forcing their most self-serving thin film of evaporating fuel model of burn-off but the real conditions are telling you it didn't happen that way. So is the smoke. (So is the molten metal in the South Tower)

The observed collapse was not one floor resulting in the top twelve acting as a solid block with 31g or thirty-one times its static or dead weight or load.

Except for the video that shows that. Tony never gets around to explaining exactly what it was. Instead he sort of suggests CD without explaining the exact process.

The hat trusses said to have weakened and sagged forty inches, in tests sagged two to six, and could not have initiated collapse absent significant weakening of core columns--likely by charges, as no other cause presents.

I disagree and think there was enough damage from the impact to sever many core columns plus heat.

Tests that no doubt favored Tony's evaporative film version of the fires and never included the furnace effect.

Claims by "investigators" who did not investigate fail: explosions were heard, evidence of charges was reported. The smooth collapse of the structure shows none of the "jolt" necessitated by the official explanation.

All too general to have any meaning.

The Pile Driver takes its place with the Magic Bullet, the Flat Earth, the Phlogiston theory of combustion in the gallery of hoaxes.

And at 411 Elm Street, every time the elevator door opens, P.T. Barnum gets his wings.

Unearned vs the facts in my opinion. It's damaging to Deep Political science to accept most-likely false theories too quickly IMO.

[Lauren Johnson]

Unearned vs the facts in my opinion. It's damaging to Deep Political science to accept most-likely false theories too quickly IMO.

Albert, so what is your take on the collapse of the buildings? The terrorists pulled it off? LIHOP? MIHOP? What? So far, all I have heard from you is everybody except Jeffrey is an idiot. Is that all you got?