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

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Tony,

We'll start with the simple stuff.

I'm not asking these for information. I know the answers. I want to see if you do.

1. Please draw the stress-strain curves (one curve for each temperature) implied by your values for E(Temp) from a strain of zero up to the max strain that you think is appropriate for your assumptions. (The assumptions that you haven't provided yet.)

2. Do you see any problem with using end constraints of "simple supports" for very low temps?

3. Why did you not build your model considering construction loads?

4. What are the underlying assumptions associated with the deflection curve for distributed load equation that you used? Paying primary attention to where the equation breaks down & gives wrong answers.

5. What is the fundamental theoretical justification used in the generation of the distributed load equation that you used?

That'll do for now.


Tom
 
Hey Chris7,

So, where was that equation that you assured me you had posted. The one that allowed me to calculate the deflections?

Wasn't there, was it.

You didn't know what you were talking about, did you.

You're simply faking it, aren't you.

Yup.
You know it.
I know it.

Do you really think that you're gonna be able to continue to hide it if I start prodding you for information?

If you think you'll be able to, you are dead wrong.

Your only strategy will be the one you started to use when I turned the heat up to "warm": stop answering.

Do you really think that nobody noticed?

You'd be wrong about that, too.
 
Can we even assume that the critical column was in exactly its right position and not sagging or expanding in any direction, given that it was in the line of fire of a nice hot blow pipe?
 
leftysergeant said:
Can we even assume that the critical column was in exactly its right position and not sagging or expanding in any direction, given that it was in the line of fire of a nice hot blow pipe?
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That is the key factor which C7 and TS have been deliberately avoiding. Sadly a lot of the debunkers also falling in line with C7's tactics. Deliberate because several posts on the thread have identified it and other "missing factors".

Believe it or not I first drew attention to the problem back at post 3707 in the Mohr v Gates discussion thread and followed it up here several times:
ozeco41 said:
...HOWEVER: A HINT.

He is treating the situation as if it only involves one factor - viz linear expansion/contraction. That is not reality so don't waste effort debating his "one factor" approach.

Cheers. :D
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...for my own reasons I decided to not identify the factors being ignored - I wanted both sides to start thinking about reality. Then tfk joined in the discussion and, in his usual style, spelled out and debated the details so I left the field to him. :rolleyes:

My first comment in this thread at post 151:
ozeco41 said:
I note that you are still treating it as a "one single factor" exercise C7 despite my cautionary post at http://www.internationalskeptics.com/forums/showthread.php?postid=8118276#post8118276 and your untruthful response at http://www.internationalskeptics.com/forums/showthread.php?postid=8118299#post8118299 ...
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How silly it is to claim that the girder was affected by heat but the columns were not.
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Some of my other comments are here:
http://www.internationalskeptics.com/forums/showthread.php?postid=8196866#post8196866
http://www.internationalskeptics.com/forums/showthread.php?postid=8128253#post8128253
http://www.internationalskeptics.com/forums/showthread.php?postid=8125353#post8125353
http://www.internationalskeptics.com/forums/showthread.php?postid=8125381#post8125381
http://www.internationalskeptics.com/forums/showthread.php?postid=8123012#post8123012
http://www.internationalskeptics.com/forums/showthread.php?postid=8120769#post8120769
http://www.internationalskeptics.com/forums/showthread.php?postid=8118276#post8118276
 
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ozeco41 said:
The problem they face down that track, even if they can prove NIST wrong on a detail, is "significance" and or "relevance". Does it matter if bolt 956 failed before weld 208? The more generic issue being "When does an error in a detail matter?"
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Indeed, NIST conclusions (chapter 4 of the report, "Principal Findings", and chapter 5, "Recommendations") don't even mention any detail on whether the girder walked off, or rocked off, or what. It's not considered principal. They just say that thermal expansion was a factor.

From 4.3.4 (Structural Response and Collapse, p.53, 95 in PDF):

[...]
  • Thermal expansion was particularly significant in causing the connection, beam, and girder failures, since the floor beams had long spans on the north and east sides (approximately 15 m, 50 ft).

    • Heating of the long beams resulted in proportionately large thermal elongation relative to the other components of the floor system, in effect, compressing the beams along their length. This led to distortion of the beams and breaking of the connections of the beams to the floor slabs. Furthermore, the simple shear connections used in the typical floor framing were not able to resist these axial compressive forces that developed as the floor framing was heated.

    • At Column 79, heating and expansion of the floor beams in the northeast corner caused the loss of connection between the column and the key girder. Additional factors that contributed to the failure of the critical north-south girder were (1) the absence of shear studs that would have provided lateral restraint and (2) the one-sided framing of the east floor beams that allowed the beams to push laterally on the girders, due to thermal expansion of the beams.

    • The fires thermally weakened Floors 8 to 14. As Floor 13 fell onto the floor below, a cascade of floor failures continued until the damage reached the massive Floor 5 slab, leaving Column 79 without lateral support for nine floors. The long unsupported length of Column 79 led to its buckling failure.
They simply don't consider that detail relevant as to put it in their conclusions. It isn't.

Which is why this image has no red sections marking the part of NIST's conclusions affected by the topic in this thread:

ncstar-1a-chapters-4-5-collage-highlighted.jpg
 
Christopher7 said:
Using their own statement, I have proven beyond a reasonable doubt that the fire on floor 12 had burned out at least one half hour before the collapse and therefore it did not heat the beams that pushed the girder that fell off its seat that triggered a cascade of floors that left column 79 unbraced so it buckled, initiating a horizontal collapse that led to the total collapse of WTC 7.
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Even if that were the case, which it isn't, you haven't proven that the fire on floor 13 had burned out at least one half hour before the collapse and therefore it did not heat the beams that pushed the girder that fell off its seat that triggered a cascade of floors that left column 79 unbraced so it buckled, initiating a horizontal collapse that led to the total collapse of WTC 7.

You have a long, loooooooong way to go to rule out fire-induced collapse. NIST proved a plausible mechanism. Regardless of whether the details on their initiation event are right or wrong, the mechanism (collapse of a floor triggering a cascade of floor failures) remains uncontested and keeps being plausible (floors do collapse during fires, see e.g. WTC5, One New York Plaza, the East Tower in Venezuela...). ETA: to a point that firefighters train specifically for that: http://www.youtube.com/watch?v=MNWvqr9805Y

ETA2: But you seem to think that by disproving NIST's initiation event you have ruled out collapse by fire. You can't be more wrong.

But keep trying.
 
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tfk said:
Tony,

We'll start with the simple stuff.

I'm not asking these for information. I know the answers. I want to see if you do.

1. Please draw the stress-strain curves (one curve for each temperature) implied by your values for E(Temp) from a strain of zero up to the max strain that you think is appropriate for your assumptions. (The assumptions that you haven't provided yet.)

2. Do you see any problem with using end constraints of "simple supports" for very low temps?

3. Why did you not build your model considering construction loads?

4. What are the underlying assumptions associated with the deflection curve for distributed load equation that you used? Paying primary attention to where the equation breaks down & gives wrong answers.

5. What is the fundamental theoretical justification used in the generation of the distributed load equation that you used?

That'll do for now.


Tom
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Your points here are insignificant to the issue at hand and asking for a level of precision that is orders of magnitude greater than necessary. Nobody uses the degree of precision you are asking for here, to settle the kind of problem we are discussing.

What you are saying is tantamount to you being a boat salesman who advertises a 30 foot boat and when a prospective buyer comes to physically see it and measures it with a tape measure and finds out it is only 20 feet long, you scream that he can't possibly know how long the boat is without using a large vernier caliper.

The methods used were more than sufficient and they show the NIST theory for collapse initiation in WTC 7 is impossible by a large margin, just like the boat example. I really can imagine you as that salesman from the way you talk here.
 
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Tony Szamboti said:
You are asking for a level of precision that is orders of magnitude greater than necessary.

What you are saying here is tantamount to you being a boat salesman who advertises a 30 foot boat and when a prospective buyer comes down and measures it with a tpe measure and finds out it is only 20 feet long, you scream that he can't possibly know how long the boat is without using a large vernier caliper.
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Actually, answering the questions would be a lot more convincing than attacking the person who asked them.

I'm not convinced that this girder debate makes a tinker's dam worth of difference, but it's interesting to watch.
 
MarkLindeman said:
Actually, answering the questions would be a lot more convincing than attacking the person who asked them.

I'm not convinced that this girder debate makes a tinker's dam worth of difference, but it's interesting to watch.
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The questions are not significant to the problem. I don't need a scale graduated in grams to know a chicken egg doesn't weigh 10 lbs., a lb. and ounce graduation will do fine, and the NIST explanation for the collapse initiation of WTC 7 is similar to saying the egg weighed 10 lbs.

You should answer the questions if you really want to know the results of the calculations in angstroms and don't mind wasting the time.
 
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Justin39640 said:
:boggled:
I would think that would apply to you too. Even more so since I can't ever recall you claiming to be an engineer.
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He's been avoiding claiming much of anything other than "you're wrong" for several months now. On some level, he knows he can't manage a real debate. Most recently, he said that if we don't prove his claim, we're clearly lying.
 
Christopher7 said:
I should have said oxygen starved to be more inclusive but what I said was correct. There was no oxygen shortage or buildup of unignited vapors with a steady breeze blowing thru the building.

Yes.

NIST admits that they did not use the photo evidence of where the fires were, just the broken windows. They did it that way so they could claim there was fire in areas where it had burned out. Their simulation does not match the photos and it has fires burning in the same area for much longer than 20 to 30 minutes. Simulation software output is only as good as the input data. GIGO.

I have built offices with dropped ceilings like the ones in WTC 7 from plans so I have a visual picture of every aspect of the construction including what is above the dropped ceilings. The photos of where the fire was on the exterior, common sense knowledge of how fires spread, confirmed by the statement in the final report of how the fire spread in this case, and the floor plan, are all that is needed to determine how the fire moved thru the interior.

To get from the south side to the north side, the fire had to burn the area in between. That includes the interior offices under the beams and girder in question.

This graphic is a rough estimate of where the fire front was in the interior at the specified times.

[qimg]http://img252.imageshack.us/img252/7508/floor12fireprogressiong.jpg[/qimg]


The NE section had burned out by about 3:45 and the fire was burning about 100 feet away from the NE section by about 4 p.m.
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Installing dropped ceilings does not make you a structural engineer.
 
LSSBB said:
Are you always your own judge of what you yourself proved and what is a reasonable doubt in your conjectures?
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Trials in trutherland pretty much consist of "Off with his head".
 
Tony Szamboti said:
Your points here are insignificant to the issue at hand and asking for a level of precision that is orders of magnitude greater than necessary. Nobody uses the degree of precision you are asking for here, to settle the kind of problem we are discussing.
What you are saying is tantamount to you being a boat salesman who advertises a 30 foot boat and when a prospective buyer comes to physically see it and measures it with a tape measure and finds out it is only 20 feet long, you scream that he can't possibly know how long the boat is without using a large vernier caliper.

The methods used were more than sufficient and they show the NIST theory for collapse initiation in WTC 7 is impossible by a large margin, just like the boat example. I really can imagine you as that salesman from the way you talk here.
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You might want to explain that to your running buddy.
 
000063 said:
Most notably the ones about NIST's intentions, which are pure mind-reading.
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Since no one outside of those involved in writing the NIST WTC 7 report can know for sure what their intent actually was, all that should be stated is that NIST was simply mistaken and needs to correct the report.
 
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Tony Szamboti said:
Since no one outside of those involved in writing the NIST WTC 7 report can know for sure what their intent actually was, all that should be stated is that NIST was simply mistaken and needs to correct the report.
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Yet you people have no problem laying the intent of "misleading" on their feet?

You may want to look up "hypocrite" on dictionary.com.
 
NoahFence said:
Yet you people have no problem laying the intent of "misleading" on their feet?

You may want to look up "hypocrite" on dictionary.com.
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I think society can leave aside any assigning of insidious motives, admit the reality that they didn't get it right the first time, and acknowledge that they need to do it over.

Can you?
 
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Tony Szamboti said:
I think society can leave aside any assigning of insidious motives, admit the reality that they didn't get it right the first time, and acknowledge that they need to do it over.

Can you?
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Just as soon as you submit your criticisms to any reputable journal on fire science or structural engineering on the planet.
 
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