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

[pgimeno]

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.

So? That means that when it failed, the top imposed a (dynamic - the "drop from 0 height" kind) asymmetric load on the rest of perimeter columns that made them fail progressively from side to side of each wall. Your point?

Mine keeps being that your 50% figure for columns necessary to be broken to produce collapse, is ludicrous, and that NIST do explain collapse initiation.

 

[Animal]

Flexing would not cause the SFRM to dislodge on all of the trusses on the complete other side of the building and the central core and several floors above the impact. The SFRM had an adhesive bond strength of somewhere around 2 to 2.5 psi. That is actually pretty strong for light airy stuff. Most industrial strength tapes only have an adhesive bond strength of about 4 to 5 psi.

TFK is simply blowing smoke and doing precisely what he is attempting to accuse me of. If what he were saying was true NIST would have done a test on some SFRM coated steel truss parts on a shaker table in the bat of an eye. They didn't. Why didn't they?

Simply FOS.
Everyone that works in the industry knows how fragile the stuff is. I had one project that close to 20% of the stuff had to be replaced simply from workers walking on the roof above. And that was a recent application.
(Big fight by the GC about who was paying for it too)

Your claim of its strength is nonsense. (Just like all your other claims)
As others have stated, you are just pulling these claims out or your butt.

 

[Tony Szamboti]

So? That means that when it failed, the top imposed a (dynamic - the "drop from 0 height" kind) asymmetric load on the rest of perimeter columns that made them fail progressively from side to side of each wall. Your point?

Mine keeps being that your 50% figure for columns necessary to be broken to produce collapse, is ludicrous, and that NIST do explain collapse initiation.

It is hard to understand how you think the upper section imposed a dynamic load on the east and west perimeter walls after the south wall allegedely failed according to NIST. This is still a static situation because nothing was moving yet. The redistributed loads that NIST shows on the east and west wall columns are nowhere near enough to cause them to fail, so NIST does not explain the propagation of the collapse across the building.

If you believe they do then cite where you believe they do and we can discuss that.

 

[Tony Szamboti]

Why didn't they test the adhesive used on the tiles in the lobby? I would guess so the study didn't take 30 years. One would assume most of everything meant to protect the building was completely **********.

They didn't need to test the tiles in the lobby as they weren't claiming they were partly responsible for the ultimate failure of the building.

 

[BasqueArch]

Now that I think about it, I don't remember any photograph of a piece of steel with SFRM in GZ. All I remember lacked it.

FEMA report WTC 5- Fire delaminates SFRM. Real life test

“The 7th floor framing was shop-coated. In some locations, the paint appeared to be in good condition and not discolored by the fire. Paint usually blisters and chars when heated to temperatures of about 100 degrees Centigrade (212 degrees Fahrenheit). This indicates that the fire protection material remained on the steel during the early phase of the fire and may have fallen off relatively later in the fire as the beams twisted, deflected, and buckled. Additional measures for proper adhesion may be required when applying spray-on fire protection to painted steel. …………….

On the lower floors, the steel beams appeared to have heat damage from direct fire impact and there was little or no evidence of shop painting, indicating that fireproofing material was either missing before the fire or delaminated early in the fire exposure.”
http://911research.wtc7.net/mirrors/guardian2/wtc/WTC_ch4.htm

Here we see beams with little bits of SFRM remaining and beam deflections greater than 2”.

 

[Tony Szamboti]

Getting back to the main subject of this thread…the girder doesn’t just walk off column 79, it explodes off.

When the 4-7/8” high strength bolts connecting the girder to the column fail (shear off), they release a great deal of built up force and potential energy. That potential energy is converted to kinetic energy, and the girder quickly explodes off the bearing seat.

It would be like a bomb going off.

The girder was expanding towards the columns when it would have broken the bolts and when they break it would tend to move towards the columns and onto the seats at columns 44 and 79 even more due to the restraint being removed.

If the bolts between the girder and the seat are broken by the beam expansion the girder would just be moved the amount it had previously been restrained by the bolts. It can't move further as it is restrained by the beams, and it has been proven that the beams could not expand enough to push the girder off its seat at column 79 and it is restrained by the column flange at column 44.

 

[Animal]

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.

Project much?

 

[BasqueArch]

I work with the stuff fairly regularly. I always budget for repair because the stuff is in fact very fragile.

BTW, Who said it had to dislodge it all?

Perhaps if you used gentle drywall, dainty AC, refined electrical, finicky plumbing, delicate sprinkler subs you wouldn't have this problem now would you.

 

[Gamolon]

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?

Clayton,

I am talking about the perimeter walls. The 33 columns I am speaking of were the ones severed by the plane impact IN the perimeter wall of WTC1. Here is the quote in question from Tony located in another forum.

Using Gregory Urich's mass analysis for the 98th floor perimeter columns, their wall thickness would have been .289". The yield strength at this location was at least 65,000 psi, so a 14 inch box column with about a 16 square inch cross section could handle about 200,000 lbs. with a 5 to 1 safety factor. Given this for 59 columns, each perimeter wall could support about 12 million lbs. with a 5 to 1 safety factor or 48 million lbs. counting all four perimeter walls. The total weight of the upper section of WTC 1, from the 98th floor up, was about 69 million lbs. and the core took about 42% of that load leaving about 40 million lbs. for the perimeter to support.

Tony wants everyone to believe that the perimeter walls should have held based on their 5 to 1 factor of safety and his calculations. I have shown that using his same logic and numbers contained in his quote above that the perimeter wall should have failed. Hence the following quote from me.

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 shows the perimeter wall should have held, yet using his same numbers, I show that the perimeter wall should have failed. What gives? How is it possible that using Tony's same numbers and thinking get opposite results? I would like him (or even you if you want) to address this.

This shows me that Tony's approach/thinking is fatally flawed.

 

[Gamolon]

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?

Another way to think about it. Tony claims that the perimeter walls could support 12,000,000 lbs. each with a factor of safety of 5 to 1. 33 columns of one wall were severed by the plane impact reducing the amount able to be supported by that perimeter wall by 53% or 6,360,000 lbs.

The weight of the "98th floor and above" section didn't change load-wise did it? That 6,360,000 lbs had to redistribute somewhere right? It couldn't have just vanished...

Using Tony's logic, that 6,360,000 lbs. was redistributed to the remaining 3 walls. The remaining three walls were already holding up 10,000,000 lbs. according to Tony's calculations. Now was have to add another 2,120,000 lbs. to the remaining 3 walls. That puts us at 12,120,000 lbs. per perimeter wall.

UH OH!

Remember, Tony said that the perimeter walls, WITH a factor of safety of 5 to 1, could support up to 12,000,000 lbs. each.

12,120,000 > 12,000,000 isn't it? Doesn't that mean failure?

 

[NoahFence]

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.

Are you kidding me? Have YOU taken into account the massive fireball yet, or are you still trying to convince yourself that all that happened was a tiny little alumninum tube went into the building?

 

[NoahFence]

TS - can you provide me a list of buildings you've been involved in so I don't go in them?

kthxbai.

 

[pgimeno]

It is hard to understand how you think the upper section imposed a dynamic load on the east and west perimeter walls after the south wall allegedely failed according to NIST. This is still a static situation because nothing was moving yet.

Ok, not a full 0 height drop situation, as the columns were already compressed, but certainly with a dynamic component which made the load equivalent to something between 1 and 2 times the static one. Load redistribution implies movement, do we agree on that?

The redistributed loads that NIST shows on the east and west wall columns are nowhere near enough to cause them to fail, so NIST does not explain the propagation of the collapse across the building.

That needs proof. A bare assertion doesn't cut it. Can you point out the redistributed loads that NIST shows on the east and west wall columns, indicating why they are not enough?

If you believe they do then cite where you believe they do and we can discuss that.

It's your assertion. You defend it.

 

[alienentity]

Tony's also conveniently forgetting that SFRM was dislodged in WTC 5 and 6 by the debris impacts. Because they didn't collapse he's not interested in the phenomenon, even while it would make for a good case study.

 

[alienentity]

Looks like lots of SFRM was missing in this shot.....

 

[DGM]

They didn't need to test the tiles in the lobby as they weren't claiming they were partly responsible for the ultimate failure of the building.

How would they know this unless they spent countless hours testing? They should have left no stone unturned, right?

 

[ozeco41]

Another way to think about it. Tony claims that the perimeter walls could support 12,000,000 lbs. each with a factor of safety of 5 to 1. 33 columns of one wall were severed by the plane impact reducing the amount able to be supported by that perimeter wall by 53% or 6,360,000 lbs.

The weight of the "98th floor and above" section didn't change load-wise did it? That 6,360,000 lbs had to redistribute somewhere right? It couldn't have just vanished...

Using Tony's logic, that 6,360,000 lbs. was redistributed to the remaining 3 walls. The remaining three walls were already holding up 10,000,000 lbs. according to Tony's calculations. Now was have to add another 2,120,000 lbs. to the remaining 3 walls. That puts us at 12,120,000 lbs. per perimeter wall.

UH OH!

Remember, Tony said that the perimeter walls, WITH a factor of safety of 5 to 1, could support up to 12,000,000 lbs. each.

12,120,000 > 12,000,000 isn't it? Doesn't that mean failure?

Enjoy yourself trying to use 'Tony's logic' but remember the truth underlying my 'three rows of columns' diagram a few posts back.

IF you cut 33 columns in one face of the building that will obviously remove the support of the load previously carried by those columns.

Obvious so far.

BUT what is not obvious, unless you remember my simplified but true explanation, is that the load redistribution will also take the load off other columns which have not been cut - mostly those of the opposite face - by the same amount as given up by the cut columns.

And more or less double the load given up by the cut columns will be transferred to the core plus the other two sides.

And that is not intuitive to the non-engineers - and some engineers may also forget it.

Don't lose sight of Tony's comment when he attempted to reject my explanation:

Your sketches are not analogous to the complete wall of 59 columns with 40 inch center to center spacing on both the east and west perimeter walls and NIST does not provide a mechanism for their collapse.

...that statement is a clever bit of partial truth which could have been intended to mislead you.

My example remains a correct explanation of the underlying principle:

...The key issue is that taking out columns does not mean that their load is uniformly re-distributed. Taking out 1/4 of columns does not add 33% load to all other columns - even if the columns were originally equally loaded. ...
...What happens when columns are removed depends on which columns are removed and the spatial relationship of the columns that are left.

Here is a rough sketch which I did to illustrate the issue - a very theoretical building with three columns. Lets say three rows of columns:

Notice that cutting the columns of one side reduces the load at the opposite side to zero. That effect would apply in the more complex layout of the real WTC towers no matter how much Tony tries to hide the reality by his mendacious claims about my 'analogy' being wrong. Re-distribution depends on the layout of remaining columns and is not proportional to the percentage of columns removed. It depends mainly on the spatial layout of the remaining columns.

The bottom line for this ongoing discussion is - play with Clayton and Tony using 'Tony Logic' as much as you enjoy it BUT when it comes to load re-distributions the real situation would always be worse than their false assumptions about proportional redistribution would suggest.

It's a good step if you can show them wrong within the limits of their own false logic. The real situation would always be worse.

 

[ozeco41]

How would they know this unless they spent countless hours testing? They should have left no stone unturned, right?

Then there was the motto of the sixties viz: "Leave no turn unstoned."

 

[Gamolon]

Enjoy yourself trying to use 'Tony's logic' but remember the truth underlying my 'three rows of columns' diagram a few posts back.

IF you cut 33 columns in one face of the building that will obviously remove the support of the load previously carried by those columns.

Obvious so far.

BUT what is not obvious, unless you remember my simplified but true explanation, is that the load redistribution will also take the load off other columns which have not been cut - mostly those of the opposite face - by the same amount as given up by the cut columns.

And more or less double the load given up by the cut columns will be transferred to the core plus the other two sides.

And that is not intuitive to the non-engineers - and some engineers may also forget it.

Don't lose sight of Tony's comment when he attempted to reject my explanation:
...that statement is a clever bit of partial truth which could have been intended to mislead you.

My example remains a correct explanation of the underlying principle:

Notice that cutting the columns of one side reduces the load at the opposite side to zero. That effect would apply in the more complex layout of the real WTC towers no matter how much Tony tries to hide the reality by his mendacious claims about my 'analogy' being wrong. Re-distribution depends on the layout of remaining columns and is not proportional to the percentage of columns removed. It depends mainly on the spatial layout of the remaining columns.

The bottom line for this ongoing discussion is - play with Clayton and Tony using 'Tony Logic' as much as you enjoy it BUT when it comes to load re-distributions the real situation would always be worse than their false assumptions about proportional redistribution would suggest.

It's a good step if you can show them wrong within the limits of their own false logic. The real situation would always be worse.

Thanks Oz.

I'll never lose sight of the real situation and as you understand, I'm playing in their realm for the moment using Tony's logic, calculations, and numbers.

I would really like an answer from Tony or Clayton showing me how I am wrong when I arrived at my result using Tony's own numbers and logic. A result that shows the perimeter wall (or walls) should have failed and collapsed.

 

[Justin39640]

They didn't need to test the tiles in the lobby as they weren't claiming they were partly responsible for the ultimate failure of the building.

Hence why they didn't need to test for explosives either.