Total Building Collapse from a Single Column Failure

[gerrycan]

NIST-pick all you want;

Thanks, I will.

I thinkfire still did it.

 

[LSSBB]

Thanks, I will.

Fire is all that was observed and clear evidence was found for as an initiating cause.

 

[gerrycan]

Fire is all that was observed and clear evidence was found for as an initiating cause.

So how did fire manage to initiate the collapse? Do you agree with the CTBUH or with NIST? Clearly, at least one of them is wrong

 

[tsig]

So how did fire manage to initiate the collapse? Do you agree with the CTBUH or with NIST? Clearly, at least one of them is wrong

Fire hot, steel weakens.

 

[DGM]

So how did fire manage to initiate the collapse? Do you agree with the CTBUH or with NIST? Clearly, at least one of them is wrong

It doesn't really matter. CTBUH simply thinks the cooling phase was more responsible. Both a plausible.

 

[gerrycan]

Fire hot, steel weakens.

I agree. Heat weakens steel and causes it to expand also. Only up to about 600 degrees though at which point it will tend to sag and lose the ability to push.
My question though, was who do you agree with, NIST or the CTBUH?

 

[DGM]

I agree. Heat weakens steel and causes it to expand also. Only up to about 600 degrees though at which point it will tend to sag and lose the ability to push.
My question though, was who do you agree with, NIST or the CTBUH?

I like the CTBUH just a little better.

 

[LSSBB]

Fire hot, steel weakens.

This, plus steel expands when heated.

 

[gerrycan]

It doesn't really matter. CTBUH simply thinks the cooling phase was more responsible. Both a plausible.

I think you are getting confused with the "rock off" theory that NIST mentioned. The CTBUH actually disagreed totally with NISTs analysis that C79 buckling was the cause. They also asked about elements that it turns out NIST omitted from their analysis.

 

[chrismohr]

Gerrycan the president of CTBUH would disagree with your conclusions. He said explicitly that his organization supports the principal findings of the NIST Report and made it clear that the differences are minor "Tweaks" not catching fundamental flaws. He got so sick of 9/11 Truith people invading CTBUH's blogs with accusations of the "NIST Fairy Tale" etc he had to shut them down. Chris Sarns and others were greatly inflating the significance of the differences between NIST and CTBUH and NIST and the president rejected entirely their attempts to use CTBUH to discredit NIST.

 

[gerrycan]

Gerrycan the president of CTBUH would disagree with your conclusions.

My conclusions are that the stiffener plates and beam stubs should have been included in the analysis. Had the CTBUH and the wider public been given access to the structural drawings at the time that the report was out for public comment, then statements such as this from the CTBUH:
"If the girders had fin plates or end plates would the building have
survived?"
Would have been examined far more closely. Turns out that the girder did have plates, and NIST left them out of their analysis.

He said explicitly that his organization supports the principal findings of the NIST Report and made it clear that the differences are minor "Tweaks" not catching fundamental flaws.

"The Council does not agree with the NIST statement that the failure was a
result of the buckling of Column 79." ~ CTBUH
That is more than just a "minor tweak"

 

[DGM]

"The Council does not agree with the NIST statement that the failure was a
result of the buckling of Column 79." ~ CTBUH

Naturally you will link to the full statement so no one will think you took this out of context.

 

[gerrycan]

The context is that the CTBUH disagreed with NIST about column 79 buckling and causing the collapse, and asked about the presence of elements that it turns out NIST omitted from their analysis.
Do you think that NIST should have included the stiffener plates and the beam stubs in their analysis?

 

[DGM]

The context is that the CTBUH disagreed with NIST about column 79 buckling and causing the collapse, and asked about the presence of elements that it turns out NIST omitted from their analysis.
Do you think that NIST should have included the stiffener plates and the beam stubs in their analysis?

So no link? Just a question? You first.

 

[gerrycan]

So no link? Just a question? You first.

If you are not conversant with what the CTBUH had to say to NIST about this report when it was out for public comment, you should familiarise yourself with the topic, then comment. I have the pdf here, for some reason the link is down.

 

[DGM]

If you are not conversant with what the CTBUH had to say to NIST about this report when it was out for public comment, you should familiarise yourself with the topic, then comment. I have the pdf here, for some reason the link is down.

I'm very familiar with what they said. They don't support your view on the importance of these "omissions".

This is off topic BTW.

 

[pgimeno]

The CTBUH does not, and has never agreed with the initiating event that NIST proposed for the collapse of WTC7. In fact, they picked up on the fact that NIST omitted structural elements from their analysis while the report was still out for public comment. NIST did not reply to their concerns.

And what did they do? Demand a new investigation?

 

[gerrycan]

I'm very familiar with what they said. They don't support your view on the importance of these "omissions".

This is off topic BTW.

So why did they ask specifically about the inclusion of plates that were not present in NISTs analysis? They obviously were asking because they thought these elements would have made a difference to the failure supposed by NIST.

How do you know that the CTBUH do not think that these omissions are important?

They asked about an inclusion, not an omission. This is because they were using NISTs analysis to conclude that the plates were not present. If they had access to the structural drawings at the time, their question would have been put very differently surely.

Bottom line - NIST omitted elements that the CTBUH asked if the inclusion of same would have prevented building failure.

I entirely understand your hesitancy to broach this topic, and the efforts of jref to marginalise it.

 

[DGM]

So why did they ask specifically about the inclusion of plates that were not present in NISTs analysis?

Because that's what people do. You ask and you get answers, you acuse and you get ignored.

They obviously were asking because they thought these elements would have made a difference to the failure supposed by NIST.

Your assumption. You have no idea what they thought.

How do you know that the CTBUH do not think that these omissions are important?

How do you know they do?

They asked about an inclusion, not an omission. This is because they were using NISTs analysis to conclude that the plates were not present. If they had access to the structural drawings at the time, their question would have been put very differently surely.

You're assuming again.

Bottom line - NIST omitted elements that the CTBUH asked if the inclusion of same would have prevented building failure.

Assertion with no evidence.

I entirely understand your hesitancy to broach this topic, and the efforts of jref to marginalise it.

You don't understand, that's the problem. We're waiting for you to go to step one.

 

[gerrycan]

Because that's what people do. You ask and you get answers, you acuse and you get ignored.

The concerns of the CTBUH were not answered by NIST in regard to the omission of end/fin plates on the girder in question.

Your assumption. You have no idea what they thought.

No, they thought that the inclusion of end plates may have had an effect on the supposed failure analysis. They were correct. They would have, and they were present. A fact that was made clear when the drawings were released.

You don't understand, that's the problem. We're waiting for you to go to step one.

I understand that you are on a hiding to nothing when it comes to this particular aspect of NISTs analysis. I think you understand that all too clearly also, as do they.

Do you think that NIST should have included the plates and beam stubs in their analysis? , You seem to have trouble answering this