WTC7 and the girder walk-off between column 79 and 44

[Gamolon]

You have succeeeded in completely confusing yourself here. Reread what I said and try again.

Answer me this.

As I asked above in another post, explain this to me.

You say each perimeter wall at that level was able to support 12,000,000 lbs. That was based on 59 columns x 200,000 lbs.

If I remove 33 columns due to them being severed by the plane impact, that gives us 5,200,000 lbs. able to be supported by the perimeter wall.

According to you, 10,000,000 lbs. was applied to each wall.

Please explain how I am misunderstanding that 10,000,000 lbs. > 5,200,00 lbs. and that this would not be a problem.

 

[Tony Szamboti]

I don't see a problem with it. Core column failure and subsequent failure of perimeter when the load redistributes easily explains it. And I don't see how the FoS of columns bowed inwards can be the same as for straight columns.

So much for your statement that "I believe you would need to take out about 50% of the columns along with fires to actually effect a collapse". For you, it seems that all it takes for the NIST analysis to produce a collapse is to "substantiate" the thermal weakening of the core and to "explain the collapse propagation across the entire building emanating from the south wall", therefore I guess that if these are proved possible, your 50% figure becomes ludicrous.

The east and west perimeter wall columns of the North Tower can be observed on video not to be bowed inwardly when the collapse started. Only the south wall, which was not on video tape, is alleged to have been bowed inwardly before the collapse.

 

[Tony Szamboti]

I love how the NIST report can be cited as both being full of lies and a valuable source of information. It's almost biblical; inerrant regarding yield strength, yet full of lies about fire propagation.

It is hard to make an error when simply reciting what the yield strength of the steel is from the drawings and specifications.

 

[Gamolon]

Read the NIST report and you will see that the exterior columns at the 98th floor were at least 65,000 psi yield strength.

Which report Tony? 1-3? 1-6?

 

[carlitos]

I'm not even close to being an expert at this but in 1-6 there are some exterior columns for the 96th floor of tower 1 specified to have 65 ksi, which is 65000 psi yield strength.

 

[tfk]

And this post demonstrates exactly the problem with trying to have a rational conversation with an irrational person.

You are trying to say ...

Please listen carefully.

Stop telling me what i am "trying to say".

Just like femr, you have shown zero competence at interpreting what I am trying to say.
To put a fine point on the matter, frankly you suck at interpreting what I am trying to say.

You will find a HUGE clue in "what I am trying to say" in … (wait for it) … "what I actually said".

If you are still confused, you are invited to ASK me what I am trying to say.
I will then TELL YOU what I am saying.

Now, let's get to the latest perfect example of your incompetence at interpreting what I said.

You are trying to say all of the fireproofing within 10 floors of the impact would have possibly been shaken loose due to the acceleration generated by the aircraft impact.

This is laughably stupid, Tony.

Nobody but the voices in your head said anything about " all the fireproofing within 10 floors".

Nobody said anything about "shaken loose due to the acceleration generated by the impact".

Virtually every single word in your futile attempt at interpreting what I am trying to say is 100% wrong.

Now let's look at what I really did say.
Taking out some explanatory text, you can read in my post the following:

Second fact: brittle substances that are form fit (i.e., sprayed on ...) onto ductile members invariably crack (& frequently dislodge) when the support member is flexed to any significant degree.

This effect is exactly why brittle marble & concrete structures on the first floor dislodged when the airplanes struck...

The towers, within about 10 stories of the impact, suffered an incredible dynamic loading and associated flexing of the support structure...

The stresses & flexure of the members between the impact floors & the adjacent (above & below) floors would likewise have been massive.

Now comes the tricky part for you (for some incomprehensible reason).

What I was trying to say, with this passage was the following:

Second fact: brittle substances that are form fit (i.e., sprayed on ...) onto ductile members invariably crack (& frequently dislodge) when the support member is flexed to any significant degree.

This effect is exactly why brittle marble & concrete structures on the first floor dislodged when the airplanes struck...

The towers, within about 10 stories of the impact, suffered an incredible dynamic loading and associated flexing of the support structure...

The stresses & flexure of the members between the impact floors & the adjacent (above & below) floors would likewise have been massive.

Read the two passages carefully, Tony, & see if you can detect the subtle relationship between them.

Now, look for "all the fireproofing". Not there.
[Pssst, Tony, competent engineers understand that, if 95% of the fireproofing remains but 5% is removed, then the column WILL FAIL at the location of the removed fireproofing. If I may offer a comment, engineer to alleged engineer, your "all the fireproofing" strawman is brain-dead stupid. Google: "weak links" and "chains".]

Next, look for "acceleration generated by the impact" in my comment. Not there.

What you will find are the terms "dynamic loading" and (three times) "flexing"

Try really hard to figure it out, Tony. I know it's hard. I know it's subtle. But put on your Thinking Beanie.

That means you understand that there was no chance for the debris field moving downward from the impact at the 95th and 96th floors to have any chance of reaching the 98th floor on the other side of the building (and we do know the collapse initiated at the 98th floor in the North Tower).

Ahhh, this must be where you got "… all the fireproofing within 10 floors …"
Because you are such a superb engineer that you can instantly do the math in your head that "98 - (96 or 95) = 10".
Brilliant, Tony.

This passage of yours means that you are substituting "what you want to hear" into "what I really said".

I said that the spray on insulation could be removed, not only by debris impact, but also by flexing of the support columns.

I said that significant flexing of the support columns extended several floors above & below the impact floor.

Why don't you address what I really said, instead of the strawman that you substituted?

... (and we do know the collapse initiated at the 98th floor in the North Tower).

OK, Tony. You're up.

Please identify the element that failed that started the whole collapse sequence.

Then please explain how you know it was this element. And not some other nearby element.

Like so many other things, you offer only baseless assertions.

Now prove your assertion.

The problem for your theory is that NIST didn't go that way as they did no test to show what you are saying. They only did debris blast testing on steel coated SFRM. They might have mentioned acceleration and vibration, but they did no testing to show it was possible. When you want to prove something in engineering you do a test.

My "theory" doesn't involve acceleration or vibration in the slightest, Tony.

It involves flexing of the supports. At slow accelerations, fast accelerations or any accelerations in between. The only significant parameter is the magnitude of the strain in the foam as a result of the amount of flexure.

The upper floors of the towers flexed (in the towers primary oscillation mode) so much that at least one of the survivors said that he "knew that the top of the building was going to topple over." Thankfully, he was wrong. But not by much.

How about the 2nd oscillation mode (which was the specific one that I described)?

We know, without an iota of doubt, that the floors adjacent to the impact zone flexed significantly. Their flexure is the ONLY way for the building to have absorbed the energy of the plane.

It's called Castigliano's Theorem. Every competent mechanical engineer knows about it. You, in stark contrast, seem to be unfamiliar with the concept.
You might want to look it up.

How many cycles of expansion / compression do you think that the foam attached to the outside of the support members experienced in the 30 seconds after impact before the oscillation damped out, Tony? Do you think that it was "less than 1 cycle"? More than 1 cycle?

How many cycles of expansion & compression do you think that it'd take to crack some (10, 20 or 30 year old) brittle foam attached to the outside of the columns? 1/2 cycle? 1 cycle? More than 1 cycle?

SFRM has very low mass and the force on its bond would have only been F = ma where "m" was its mass and "a" the acceleration of the building due to the impact. It is quite unlikely that the SFRM would have dislodged all the way on the other side of the building and that is why NIST did not test a specimen on a shaker to prove it.

Mass of the foam is irrelevant.
Acceleration of the foam is irrelevant.

Your personal digital-rectal extraction regarding the "force on the bond" is both ludicrous & irrelevant.

Flexure of the columns & foam out of their neutral position is relevant.

In the building's primary oscillation mode, in which columns would the flexure of the support columns have been largest as a result of the impact , Tony?
___

Coda:

Christ, Tony, once again, this whole response of yours reeks of abject incompetence.

How are you not completely humiliated to write this crap & sign your name to it?

 

[Animal]

Christ, Tony, once again, this whole response of yours reeks of abject incompetence.

How are you not completely humiliated to write this crap & sign your name to it?

Because his little troofer brigade laps it up and sends a thrill up his leg?

 

[Clayton Moore]

Seriously. It knocked the lobby all to hell. Why on Earth would you expect anything to survive undisturbed within a few floors either way of the impact regardless of angle?

The concussion of the plane impact knocked the lobby all to hell?

 

[tfk]

NCSTAR 1-6 just tries to say the core was thermally weakened. It does not provide a substantiated analysis for that statement. Additionally, it does not provide any substantiation for overload and failure of the east and west perimeter wall columns, which had a factor of safety against gravity loads of 5.00 to 1. The NIST load redistribution on the perimeter is at worst about 30% more than what was normally on the columns which was about 20% of their capacity. So here we have 1.3 x 20% = 26% of their capacity. In that case the columns would have still had a factor of safety of just under 4.00 to 1.
...

Wrong.
Laughable.
Hysterical.
Pathetic.

Grade = F.

Freshman mechanical engineering FAIL.

 

[tfk]

The concussion of the plane impact knocked the lobby all to hell?

Yup, it did.

Whether you understand it or not.

The clear choice being, obviously, "not".


Bury a wooden yard stick in the ground.
Slap it really hard about 6 inches from the top.
Observe where it breaks: at ground level. Exactly where the stresses were highest.

Observe where it did NOT fail: everywhere else except ground level. Exactly where the stresses were lower.

Too difficult for you to comprehend, Clayton?

 

[Animal]

Yup, it did.

Whether you understand it or not.

The clear choice being, obviously, "not".


Bury a wooden yard stick in the ground.
Slap it really hard about 6 inches from the top.
Observe where it breaks: at ground level. Exactly where the stresses were highest.

Observe where it did NOT fail: everywhere else except ground level. Exactly where the stresses were lower.

Too difficult for you to comprehend, Clayton?

Crap, you had to say "wooden" yard stick.......now our resident carpenter wanna be engineer will chime in
after all he "knows" structures

 

[Clayton Moore]

Answer me this.

As I asked above in another post, explain this to me.

You say each perimeter wall at that level was able to support 12,000,000 lbs. That was based on 59 columns x 200,000 lbs.

If I remove 33 columns due to them being severed by the plane impact, that gives us 5,200,000 lbs. able to be supported by the perimeter wall.

According to you, 10,000,000 lbs. was applied to each wall.

Please explain how I am misunderstanding that 10,000,000 lbs. > 5,200,00 lbs. and that this would not be a problem.

33 columns severed? No way. Even it were true the portion of the building above the failure would fail towards the area of the failure not straight down.

And if 33 columns were severed the reaction wouldn't take an hour.

I doubt if two engines and the landing gear could come in contact with 33 columns.


Wait. Are you saying the skin of the building(s) was providing meaningful support for the floors?

 

[Justin39640]

The concussion of the plane impact knocked the lobby all to hell?

Um, yeah. It did.

 

[BasqueArch]

NCSTAR 1-6 just tries to say the core was thermally weakened. It does not provide a substantiated analysis for that statement. Additionally, it does not provide any substantiation for overload and failure of the east and west perimeter wall columns, which had a factor of safety against gravity loads of 5.00 to 1. The NIST load redistribution on the perimeter is at worst about 30% more than what was normally on the columns which was about 20% of their capacity. So here we have 1.3 x 20% = 26% of their capacity. In that case the columns would have still had a factor of safety of just under 4.00 to 1. So NCSTAR 1-6 Chapter 8 does not explain the collapse propagation across the entire building emanating from the south wall, and interestingly Dr. Bazant picks up after the upper section is already falling.

So we have this big hole in the official story where nobody explains how a south wall failure could cause a propagation across the building. That is why I asked you to try and explain it. If you really think it was a natural occurrence you should be able to do that.

Wrong.
Laughable.
Hysterical.
Pathetic.

Grade = F.

Freshman mechanical engineering FAIL.

Collapse propagation - At first gradually, then suddenly.
TFK is right.
One word - moment shear.
Read, understand Bazant.

 

[tsig]

33 columns severed? No way. Even it were true the portion of the building above the failure would fail towards the area of the failure not straight down.

And if 33 columns were severed the reaction wouldn't take an hour.

I doubt if two engines and the landing gear could come in contact with 33 columns.


Wait. Are you saying the skin of the building(s) was providing meaningful support for the floors?

Fire.

 

[Tony Szamboti]

Collapse propagation - At first gradually, then suddenly.
TFK is right.
One word - moment shear.
Read, understand Bazant.

TFK isn't right. He is just making one big assumption with no legitimate basis for it. Although he likes to throw around terms like Castigliano's Theorem he doesn't quantify strain energy. The shock load was absorbed predominately in the exterior walls, the aircraft itself, and the floors on the side of the impact. There would have been little flexing of things like floor trusses on the complete opposite side of the building several floors above the impact zone and certainly not enough to break off the SFRM.

It is interesting that someone like him, who was proven wrong every step of the way concerning the girder walk-off impossibility in WTC 7, has the nerve to be so pompous.

 

[The Platypus]

The concussion of the plane impact knocked the lobby all to hell?

And there is where the entire problem with 911 cult kiddies begins... They can't seem to understand that when planes slam into buildings at high speed and explode, it can really screw up the building.

 

[BasqueArch]

TFK isn't right. He is just making one big assumption with no legitimate basis for it. Although he likes to throw around terms like Castigliano's Theorem he doesn't quantify strain energy. The shock load was absorbed predominately in the exterior walls, the aircraft itself, and the floors on the side of the impact. There would have been little flexing of things like floor trusses on the complete opposite side of the building several floors above the impact zone and certainly not enough to break off the SFRM.

It is interesting that someone like him, who was proven wrong every step of the way concerning the girder walk-off impossibility in WTC 7, has the nerve to be so pompous.

Wrong re flexing. The towers swayed, flexed over 2 feet past plumb and cycled in both directions. Ceiling tiles fell, sheetrock cracked, doors jammed. Damaged finishes down to the lobby. Fireball that blasted windows off their frames blasted SFRM. SFRM is fragile, you can scrape it off with your fingers. A layer of rust covered most steel, SFRM detatched off the flexing steel.

Girder fell off.

 

[Tony Szamboti]

Wrong re flexing. The towers swayed, flexed over 2 feet past plumb and cycled in both directions. Ceiling tiles fell, sheetrock cracked, doors jammed. Damaged finishes down to the lobby. Fireball that blasted windows off their frames blasted SFRM. SFRM is fragile, you can scrape it off with your fingers. A layer of rust covered most steel, SFRM detatched off the flexing steel.

Girder fell off.

I did the analyses for the girder to see if it could have walked-off in either a lateral or axial way and it could not have. Your supposition turned out to be wrong there and there is no longer any argument about it. The NIST girder walk-off collapse initiation scenario for WTC 7 has been proven to be impossible and it shouldn't be a surprise that they did not do a physical test to try and validate their theory there.

As for the NIST allegation that SFRM was knocked off by debris or vibration/flexing of the trusses on the opposite side of the building several floors above the aircraft debris in WTC 1, that is being shown to be impossible also, and it shouldn't be a surprise they didn't do a physical test for it either.

The NIST report conclusions are based on untenable theories and are therefore untenable themselves.

 

[beachnut]

...
The NIST report conclusions are based on untenable theories and are therefore untenable themselves.

Prove fires not fought did not destroy WTC 7 (which was witnessed on 911, fire destroyed WTC 7; like watching paper burn, and then you claims it was blown up - ). Fought fires destroyed One Meridian Plaza, Fought fires destroyed the Windsor Building in Spain. Fires not fought also destroy buildings - this is too easy. The nonsensical real cd deal remains, an eternal fantasy. Good luck.

Tony's real cd deal is based on delusions and fantasy, and is therefore untenable claptrap itself. Where is your theory published for the "probable" collapse sequence? Where is the "real cd deal" now?

Fire proofing falls off easy, are you going to say it can't? yep