Moderated WTC 1 features list, initiation model / WTC 2 features list, collapse model

[Dog Town]

Merely typing a claim constitutes "debunking".

In all fairness, we're only debunking 911 crazed twoofers. It ain't all that.
As you have proven repeatedly! Howz that math thing working out for ya?

 

[dafydd]

Early motion of the antenna relative to both the NW corner and SW corner fire from the NW NBC viewpoint:

[qimg]http://femr2.ucoz.com/dreh.gif[/qimg]

[qimg]http://femr2.ucoz.com/_ph/6/437537321.png[/qimg]


How does the antenna move independently of the SW corner fire if the whole upper unit is tilting southward?

The same early antenna motion is seen from other viewpoints.

So? What does this prove? Please tell me.

 

[newton3376]

Basquearch post 858: "Because the center perimeter columns of the south wall fell first pulling down the 2 hat trusses attached to them and the antenna, then south wall collapsed towards both south wall corners, then collapse of east and west walls towards north wall, then collapse of north wall."

Do you have the slightest bit of evidence for this? Sounds like you are just chanting the old NIST song with much tinier angles.


This is a great clip because the angle allows us to see a close-up of the northwest corner and we can see the SW corner 104th fl fire right next to it.

http://www.youtube.com/user/femr2?&MMN_position=312:312#p/u/100/HZinSlMeL4g

You would need to bury you head deeply in the samd not to see they begin to visibly move downward at just about the same time.

You have points on the NW corner and near the SW corner.

You could test all these silly ideas by just comparing the 2 points.

Parallax error? Holy $@*#!

Debunking on this forum seems to mean never fact-checking crappy ideas as long as they cast the illusion of contradiction. Rarely do I ever see a "debunker" on this forum fact-check his own claims.

Merely typing a claim constitutes "debunking".

U.S. and world history being questioned. Origins of wars being questioned. Let's try to be more honest when debating. please.

YAWN

Once again....unimpressive.

Haven't several people already pointed out to you the issues of trying to use grainy clips from videos to make these conclusions of yours?

Haven't several people showed you gross math errors?

I mean for the love of Zeus...you didn't use a square root for the magnitude of a vector! I'd call that epic fail....

If you think you have something then try to get it published in a peer reviewed journal.....if you think we are harsh with exposing your errors just WAIT unti you try to get this crap through peer review...

ROFL

 

[achimspok]

Because the center perimeter columns of the south wall fell first pulling down the 2 hat trusses attached to them and the antenna, then south wall collapsed towards both south wall corners, then collapse of east and west walls towards north wall, then collapse of north wall.

As in WTC2, had the core collapsed first the top would not have tilted away from the core. At WTC7 the interior columns fell first and top did not tilt.

If NIST knew the core collapsed first, of what benefit to the conspiracy is it to claim the perimeter failed first instead.

Amazing debunker logic.
All the spandrels of at least 12 floors were broken to allow the middle part of the south wall to sag without affecting the corners.
All the floor slaps of those floors were broken too - twice - for the hanging weight.
The outriggers were strong enough to deform the entire hat truss by bowing all the core columns below.
Now the antenna sagged and tilted.
...still no sign of collapse at the corners of the 98th floor but the still intact outer parts of the south wall now decided to allow a little progression towards the corners and Bingo!

What's about publishing a peer reviewed paper?
Oh, it's essentially what the NIST report says?
Wow! That's impressive! What do you say Newton?

ROFL

 

[carlitos]

 

[tfk]

achimspok,

I asked you in another thread, but didn't receive a response.

What is your profession?

If you're an engineer, what type?
What is your professional background?

I'm just curious.


tom

PS. Major Tom, if you want to answer the same questions, that'd be cool, too.

 

[newton3376]

Amazing debunker logic.
All the spandrels of at least 12 floors were broken to allow the middle part of the south wall to sag without affecting the corners.
All the floor slaps of those floors were broken too - twice - for the hanging weight.
The outriggers were strong enough to deform the entire hat truss by bowing all the core columns below.
Now the antenna sagged and tilted.
...still no sign of collapse at the corners of the 98th floor but the still intact outer parts of the south wall now decided to allow a little progression towards the corners and Bingo!

What's about publishing a peer reviewed paper?
Oh, it's essentially what the NIST report says?
Wow! That's impressive! What do you say Newton?

ROFL

What I said still stands....

 

[newton3376]

achimspok,

I asked you in another thread, but didn't receive a response.

What is your profession?

If you're an engineer, what type?
What is your professional background?

I'm just curious.


tom

PS. Major Tom, if you want to answer the same questions, that'd be cool, too.

I doubt either of them is an engineer...looking at their errors.

Of course we DO have a few examples of engineers who happen to be truthers, so I guess it's possible. It baffles me that any engineer (or scientist) can make such errors in physics, math, and engineering.

 

[Major_Tom]

It's a useful time to study the NIST WTC1 collapse initiation scenario in detail.

There is not much within the NIST report on the WTC1 collapse initiation sequence. I looked through all NIST reports looking for everything on the WTC1 collapse initiation sequence of failure I could find.

I was only able to find the following comments. If anyone can find any further information on the WTC1 initial failure sequence, please post it.


If not, this is the complete set of quotations of the NIST on the initial failure sequence available. From these limited comments I'll attempt to decipher a model of the NIST WTC1 collapse initiation scenario.



From NCSTAR 1-6D, Ch 5, section 5.2, p312 to 318 (draft form from p305 to 312), in a section titled "WTC 1 Collapse Sequence" and 1-6draft 9.3.1, p 287-295 in a section titled "Probable collapse sequence of WTC1". Relevant sections are reproduced below.
...................

1-6D, p 312:

Table 5–1. Summary of main events that led to the collapse of WTC 1.
Event Number........ Event
1 .......................Aircraft impact
2 .......................Unloading of core
3 .......................Sagging of floors and floor/wall disconnections
4........................Bowing of the south wall
5 .......................Buckling of south wall and collapse initiation

This is a simple list of what the NIST believes caused the collapse of WTC1. It is important to understand the order of these 5 events. Events 2 and 3 are what leads to event 4. This is the heart of the NIST WTC1 failure sequence. South wall destabilization is what triggered total collapse. It was the massive floor sagging in the south OOS region, the long span trusses, that leads to the total destabilization and collapse of WTC1.

The massive sagging is indispensible to the NIST model of collapse initiation. Without the massive sagging in the long span trusses in the OOS south region, the NIST has no explanation or model of what led to collapse.




The following quotation describes events 4 and 5 in detail.

1-6D, pg 314:

Bowing of South Wall

The exterior columns on the south wall bowed inward as they were subjected to high temperatures, pull-in forces from the floors beginning at 80 min, and additional gravity loads redistributed from the core. Figure 5–6 shows the observed and the estimated inward bowing of the south wall at 97 min after impact (10:23 a.m.). Since no bowing was observed on the south wall at 69 min (9:55 a.m.), as shown in Table 5–2, it is estimated that the south wall began to bow inward at around 80 min when the floors on the south side began to substantially sag. The inward bowing of the south wall increased with time due to
continuing floor sagging and increased temperatures on the south wall as shown in Figs. 4–42 and 5–7. At 97 min (10:23 a.m.), the maximum bowing observed was about 55 in. (see Fig. 5–6).

Buckling of South Wall and Collapse Initiation

With continuously increased bowing, as more columns buckled, the entire width of the south wall buckled inward. Instability started at the center of the south wall and rapidly progressed horizontally toward the sides. As a result of the buckling of the south wall, the south wall significantly unloaded (Fig. 5–3),
redistributing its load to the softened core through the hat truss and to the south side of the east and west walls through the spandrels. The onset of this load redistribution can be found in the total column loads in the WTC 1 global model at 100 min in the bottom line of Table 5–3. At 100 min, the north, east, and
west walls at Floor 98 carried about 7 percent, 35 percent, and 30 percent more gravity loads than the state after impact, and the south wall and the core carried about 7 percent and 20 percent less loads, respectively. The section of the building above the impact zone tilted to the south (observed at about 8°,
Table 5–2) as column instability progressed rapidly from the south wall along the adjacent east and west walls (see Fig. 5–8), resulting in increased gravity load on the core columns. The release of potential energy due to downward movement of building mass above the buckled columns exceeded the strain
energy that could be absorbed by the structure. Global collapse ensued.

The NIST believes that the inward bowing (IB) of the south wall began about 10:06. The south OOS flooring sagged a massive amount over the next 17 minutes, leading to up to 55 inches of IB near the center of the south face by 10:23.

It is important to realize how much floor sagging must take place over the 17 minutes between 10:06 and 10:23 for the NIST explanation of IB to be accurate. Without a massive rate of floor sagging between 10:06 and 10:23, the NIST explanation for IB makes little sense.




The following quotation identifies what the NIST believes is the first exterior sign of the WTC1 collapse and the global motion of the portion above the failure zone.


1-6draft, p 288, Table 9-5 titled "Observations for WTC1", fifth entry:
and
1-6D, p 312, Table 5-2, last entry

Tower began to collapse – first exterior sign of collapse was at
Floor 98. Rotation of at least 8 degrees to the south occurred before
the building section began to fall vertically under gravity.

In reality, the first external sign of collapse initiation is along the 95th floor west wall. In reality, all vertical features of the portion of the building above the collapse zone tilted within 1 degree during the initial column failure sequence.





The following quotation describes what the NIST believes to be the initial column buckling sequence and early global motion of the portion above the initiation zone.

1-6draft p 290, figure 9-8 on probable collapse initiation sequence for WTC1:

3. Collapse Initiation
• The inward bowing of the south wall induced column instability, which progressed rapidly horizontally across the entire south face.
• The south wall unloaded and tried to redistribute the loads via the hat truss to the thermally weakened core and via the spandrels to the adjacent east and west walls.
• The entire section of the building above the impact zone began tilting as a rigid block (all four faces; not only the bowed and buckled south face) to the south (at least about 8º) as column instability progressed rapidly from the south wall along the adjacent east and west walls.
• The change in potential energy due to downward movement of building mass above the buckled columns exceeded the strain energy that could be absorbed by the structure. Global collapse then ensued.

There is no visual evidence that shows the south wall failing before other portions of the building. The early global motion described does not match the visual record. Column instability progressed through the entire structure within a tilt of 1 degree of any building feature which was originally vertical (such as the antenna or any of the corners).




The following quotation describes events 4 and 5 in detail.

1-6draft, p 294:

Buckling of South Wall and Collapse Initiation

The inward bowing of the south wall increased as the post-buckling strength of bowed columns continued to reduce. The bowed columns increased the loads on the unbuckled columns on the south wall by shear transfer through the spandrels. Consequently instability progressed horizontally, and when it engulfed the entire south wall, it progressed along the east and west walls. Moreover, the unloading of the south wall resulted in further redistribution of gravity loads on the south wall to the east and west walls and to the thermally weakened core via the hat truss. At 100 min, the north, the east, and the west walls at Floor 98 carried about 7 percent, 35 percent, and 30 percent more gravity loads than the state after impact, and the south wall and the core carried about 7 percent and 20 percent less loads, respectively. The section of the building above the impact zone began tilting to the south at least about 8° as column instability progressed rapidly from the south wall along the adjacent east and west walls, as shown in Fig. 9–13. The change in potential energy due to downward movement of building mass above the buckled columns exceeded the strain energy that could have been absorbed by the structure. Global collapse ensued.

The percent of increased or decreased load must refer to the NIST computer model only since it is impossible to know this for the actual building. In reality, vertical features of the section of the building above the impact zone tilted less than 1 degree by the time that the initial column failure sequence was completed.




The final quotiation describes the global movement of the portion above the initial failure zone.

1-6draft, p 317:

Finding 26: The WTC 1 building section above the impact and fire area tilted to the south as the structural collapse initiated. The tilt was toward the side of the building that had the long span floors. Video records taken from east and west viewpoints showed that the upper building section tilted to the south. Video records taken from a north viewpoint showed no discernable east or west component in the tilt. A tilt to the south of at least 8 degrees occurred before dust clouds obscured the view and the building section began to fall downwards.

Video records from the north show the antenna begin to tilt slowly westward from 9.5 seconds before visible failure. Video records show that all vertical features of the building tilted within 1 degree by the time the initial column failure sequence was completed.


.............................................................................

Dr Bazant also offers a condensed summary of what he believes caused the initial buckling sequence in WTC1 in B&V, p 2, column 1 in a section titled "Review of Causes of WTC Collapse". This section is reproduced below.

Dr Bazant, from Bazant and Verdure:

Review of Causes of WTC Collapse


Although the structural damage inflicted by aircraft was severe, it
was only local. Without stripping of a significant portion of the
steel insulation during impact, the subsequent fire would likely
not have led to overall collapse (Bažant and Zhou 2002a; NIST
2005). As generally accepted by the community of specialists in
structural mechanics and structural engineering (though not by a
few outsiders claiming a conspiracy with planted explosives), the
failure scenario was as follows:

1. About 60% of the 60 columns of the impacted face of framed
tube (and about 13% of the total of 287 columns) were severed,
and many more were significantly deflected. This
caused stress redistribution, which significantly increased the
load of some columns, attaining or nearing the load capacity
for some of them.

2. Because a significant amount of steel insulation was stripped,
many structural steel members heated up to 600°C, as confirmed
by annealing studies of steel debris (NIST 2005) (the
structural steel used loses about 20% of its yield strength
already at 300°C, and about 85% at 600°C (NIST 2005);
and exhibits significant viscoplasticity, or creep, above
450°C (e.g., Cottrell 1964, p. 299), especially in the columns
overstressed due to load redistribution; the press reports right
after September 11, 2001 indicating temperature in excess of
800°C, turned out to be groundless, but Bažant and Zhou’s
analysis did not depend on that).

3. Differential thermal expansion, combined with heat-induced
viscoplastic deformation, caused the floor trusses to sag. The
catenary action of the sagging trusses pulled many perimeter
columns inward (by about 1 m, NIST 2005). The bowing of
these columns served as a huge imperfection inducing multistory
out-of-plane buckling of framed tube wall. The lateral
deflections of some columns due to aircraft impact, the differential
thermal expansion, and overstress due to load redistribution
also diminished buckling strength.

4. The combination of seven effects—(1) Overstress of some
columns due to initial load redistribution; (2) overheating
due to loss of steel insulation; (3) drastic lowering of yield
limit and creep threshold by heat; (4) lateral deflections of
many columns due to thermal strains and sagging floor
trusses; (5) weakened lateral support due to reduced in-plane
stiffness of sagging floors; (6) multistory bowing of some
columns (for which the critical load is an order of magnitude
less than it is for one-story buckling); and (7) local plastic
buckling of heated column webs—finally led to buckling of
columns (Fig. 1(b)). As a result, the upper part of the tower
fell, with little resistance, through at least one floor height,
impacting the lower part of the tower.

This is a repeat of the NIST claim that sagging long span trusses in the south OOS region pulled the south perimeter inwards, leading to global instability and collapse.


I'll reduce this information to a simple list so that we all have a clear understanding of what the NIST believes caused the collapse of WTC1.

This list will be a "CliffsNotes" version of the official explanation of the collapse of WTC1. This is your theory, guys, so please try to understand it before defending it.

 

[DGM]

I'll reduce this information to a simple list so that we all have a clear understanding of what the NIST believes caused the collapse of WTC1.

.

So you're going to condense what NIST says so we (and the world) can understand it better. Splendid, can't wait.

 

[Major_Tom]

The quotations above are the scenario in it's entirety. If you have other NIST quotations to add to the description of the NIST understanding of the WTC1 column failure sequence, please post them.

I don't need to condense it much because it is already so small.

As the discussions of the Bazant papers BV, BL and BLGB have indicated, I need to explain your own theories to you as simply as possible to move the discussion forward.


I don't think many posters realize that besides this handful of quotes, a description by the NIST of the initial column failure sequence for WTC1 does not exist.


Consider the deeper question of whether the NIST has correctly identified the actual cause of failure of WTC1.

That depends wiether the information is the quotes above is correct. To the degree that the information in the quotations is incorrect, we can conclude that the NIST could not correctly identify the true mechanism of failure.


Which would mean, as mentioned earlier, that the true failure mechanism of WTC1 remains a mystery to this day.


At the beginning of each NIST report on the WTC towers, in the introduction, the NIST clearly states the most fundamental goals of the reports. P{lease review what the stated purpose and scope of these reports are.


Specifically:

The specific objectives were:

1. Determine why and how WTC 1 and WTC 2 collapsed following the initial impacts of the
aircraft and why and how WTC 7 collapsed;
2. Determine why the injuries and fatalities were so high or low depending on location,
including all technical aspects of fire protection, occupant behavior, evacuation, and
emergency response;
3. Determine what procedures and practices were used in the design, construction, operation,
and maintenance of WTC 1, 2, and 7; and
4. Identify, as specifically as possible, areas in current building and fire codes, standards, and
practices that warrant revision.

What is the first and foremost stated objective of the +20 million dollar NIST reports, repeated before each report?

So once again, did the NIST correctly identify the mechanism by which WTC1 and 2 collapsed? For +20 million dollars, did they achieve their first and foremost stated objective?

 

[sheeplesnshills]

Which would mean, as mentioned earlier, that the true failure mechanism of WTC1 remains a mystery to this day.

You mean apart from being hit by an airliner and uncontrolled fires over at least 10 floors?
I think that this was likely the most important mechanism involved in the failure. Some folks might enjoy trying to work out exactly which beam did what but its of no practical value.

 

[sheeplesnshills]

"So once again, did the NIST correctly identify the mechanism by which WTC1 and 2 collapsed? For +20 million dollars, did they achieve their first and foremost stated objective? "

For all practical purposes yes. The exact mechanism is of no importance to anyone as there were only two WTC towers and they are both gone. They showed that impact damage and fire given certain reasonable assumptions could cause a progressive collapse.

This knowledge can be applied by future architects, structural engineers and builders to perhaps increase time before collapse, improve egress from such a building, or even perhaps design so that collapse may not occur at all given similar impact.

The exact failure mechanism cannot be discovered as there are simply way to many unknowns. Your attempt to find it has no logical basis.

 

[Patriots4Truth]

Quote:
Which would mean, as mentioned earlier, that the true failure mechanism of WTC1 remains a mystery to this day.

You mean apart from being hit by an airliner and uncontrolled fires over at least 10 floors?
I think that this was likely the most important mechanism involved in the failure. Some folks might enjoy trying to work out exactly which beam did what but its of no practical value.

I have a big problem with people saying such sweeping statements as the one above or this one:

Fire and impact damage caused steel to weaken, the surviving structure had trouble handling the remaining load and eventually collapsed, no CD needed.

Q. Why don't you list every single step and provide evidence at every single step?
A. Why would I have to do that? It's what happened.
Q. Where's your support from NIST?
A. No U!
...

 

[twinstead]

No. You gotta draw the line somewhere. Fire and impact damage made the buildings collapse. There is NO legitimate disagreement on this among the world's experts. Exactly how much detail of the collapse mechanism should have been studied is something engineering geeks can debate on their own.

 

[Patriots4Truth]

"So once again, did the NIST correctly identify the mechanism by which WTC1 and 2 collapsed? For +20 million dollars, did they achieve their first and foremost stated objective? "

For all practical purposes yes. The exact mechanism is of no importance to anyone as there were only two WTC towers and they are both gone. They showed that impact damage and fire given certain reasonable assumptions could cause a progressive collapse.

For one, it's of importance to people who care about the science of the collapse. Certaintly, there is a lot to learn from the collapse.

And if knowing probable identities of the initiation mechanism is not important to you, then why the hell are you sticking your head in conversations where the initiation is important to other people? (can you read the thread title?) You remind me a non-engineer chiming in during an engineering lecture just to say "this is not important!". Except you would get kicked out of the lecture hall and you basically can't get kicked off the internet for saying something stupid.

This knowledge can be applied by future architects, structural engineers and builders to perhaps increase time before collapse, improve egress from such a building, or even perhaps design so that collapse may not occur at all given similar impact.

The exact failure mechanism cannot be discovered as there are simply way to many unknowns. Your attempt to find it has no logical basis.

This might not be Major Tom's logical basis but what if someone wanted to find out the probability, with a proper degree of error, as to whether plane crash/fire was the damage initiation mechanism (that sets off the rest of the initiation). Maybe then I can understand why some nontechnical debunkers feel the need to chime in random technical conversations just to say the "this is not important" to people who actually care about *all* the technical stuff.

 

[Patriots4Truth]

No. You gotta draw the line somewhere. Fire and impact damage made the buildings collapse. There is NO legitimate disagreement on this among the world's experts. Exactly how much detail of the collapse mechanism should have been studied is something engineering geeks can debate on their own.

Q. What the hell do you think this thread is for? I didn't realize how possessive debuker regs were. If people knew this thread was yours maybe they would be posting more to your liking.

Q. Why don't you list every single step and provide evidence at every single step if you know WTC1's initiation mechanism so well?

Q. Why are you posting in the engineering geek thread if you aren't going to contribute any relevant engineering information? All you have is more broad sweeping statements. Good for you. You are being as repetitive as truther newbs.

 

[ergo]

No. You gotta draw the line somewhere. Fire and impact damage made the buildings collapse. There is NO legitimate disagreement on this among the world's experts. Exactly how much detail of the collapse mechanism should have been studied is something engineering geeks can debate on their own.

So you will be able to explain to us how WTC3, 5 and 6 were able to resist progressive collapse...?

 

[9/11 Chewy Defense]

So you will be able to explain to us how WTC3, 5 and 6 were able to resist progressive collapse...?

Maybe those darn 110 story buildings fell on them. Think McFly, think!

 

[beachnut]

Q. What the hell do you think this thread is for? ...

It is about nonsense, and failure. The OP says...

Does any known collapse initiation model match this visual record? (No).

The model; the kinetic energy impact of an aircraft, equal to the energy of 2,093 pounds of TNT, injecting 10,000 gallons of jet fuel on fire into multiple one acre floors of the WTC, damaging 11 times more than the design for an impacting airliner, failure of fires systems... Collapse. This is the correct model, it covers all the observables. As an engineer, I can get millions of peer reviews on this big picture model. 911 truth can only get idiots to sign up for their inside job.

Note: after idiots wake up to 911 truth being a fraud, they become humans with unlimited potential, essentially smart people. Say hello to the smart people! Hello recovered 911 truthers! Good job.

Q. Why don't you list every single step and provide evidence at every single step if you know WTC1's initiation mechanism...

Aircraft impact, 10,000 gallons of accelerant (ask a fireman what he/she thinks of 10,000 gallons of accelerant, equal in heat energy to 315 tons of TNT - can you check my work, all you engineering want to bees in 911 truth?), next uncontrolled fires lead to failure of a steel structure. Simple science, fire, gravity, and a little knowledge keeps the moronic lies and fantasy of 911 truth at bay.

Q. Why are you posting in the engineering geek thread ... .

Engineering? You got no engineering going on in 911 truth. Zip, zero engineering skills and/or knowledge are used by 911 truth to make up their lies and idiotic demolition inside job paranoid conspiracy theory fantasy. Zip. I can post in geeky engineering threads, Mom and Dad encouraged me to become an engineer, and the Air Force did too. Since 1974 I have been an engineer, qualified as an engineer, and can see the OP is nonsense based on ignorance in an over all failed effort to backing the delusion of demolition and conspiracy theories. Do you have an engineering degree? Only a grade school education is required to figure out 911 truth is delusional on 911 issues. Engineering is overkill. "Day after day it ... "