Total Building Collapse from a Single Column Failure

[Reactor drone]

Hypothetically - what if the same program were used to produce an FEA using NISTs own variables, and the girder didn't fail?

Which programs were used for the models in the Pepper letter? There's no mention of their methodology anywhere in the letter but it doesn't appear to be either LS-DYNA or ANSYS.

 

[jaydeehess]

Why doesn't AE911 just endorse what CTBUH said or ask them about the stiffeners? At least CTBUH proposed an alternative collapse mechanism.

I could surmise why AE911T doesn't contact the CBTUH, but that would be as much conjecture as my suspecting that they did and aren't saying anything about it.

 

[NoahFence]

Want to try that again?

I understood it perfectly.

 

[gerrycan]

That, it seems to me, would require that the CBTUH never bothered to check back and see what NIST later wrote. That they are unaware now of the stiffeners.

And what exactly did NIST write about the plates after that.
I challenge you to quote me even just ONE word.
Let's not forget that now.

 

[BrianH]

But, you keep saying that NIST "admitted " this and that. So, the CBTUH doesn't know all about that? It also must be blissfully unaware of anything that AE911T has said since 2008 as well. Apparently they were aware of truther claims up to 2008. There is nothing to suggest that they haven't come across anything since then. Of course I don't know for sure.

However, as pointed out ad infinitum, it matters very little.
The sole, only, single observable possible driving force of collapse initiation is the fires,
AND,
The definite most probable cause of the first grossly observable event, the in falling of the EPH, is failure of col 79.

Furthermore, the structural fea indicates that a col 79 would progress to a global collapse in a fashion consistent with the observed collapse.

Stiffener plates are minutia that you are clutching at.

I don't see why it is relevant, maybe I am missing something? The CTBUH question was referring to the recommendations section of the NIST report, specifically the one recommending improved connections. Fin and end plates would have been stronger connections than the ones used. They are relatively flexible and are not really intended to stiffen a girder.

 

[LSSBB]

You're big on asking and small on answering yourself.

The only question I won't answer that I am aware of, is your beam length question, because I don't feel like taking the time to do a proper analysis on it, since you haven't shown that you have done so yourself. If you have done so, please point to your full computational analysis of the beam and it's loading, under the full range of temperatures that it encountered.

 

[gerrycan]

The only question I won't answer that I am aware of, is your beam length question, because I don't feel like taking the time to do a proper analysis on it, since you haven't shown that you have done so yourself. If you have done so, please point to your full computational analysis of the beam and it's loading, under the full range of temperatures that it encountered.

Funny. Do you write your own material?

 

[LSSBB]

Funny. Do you write your own material?

Why do you ask the question of beam length when you don't have a proper analysis yourself? Or is it easier to pick apart what I said and try to make fun of it?

 

[jaydeehess]

The drawings which proved the relevance of the question asked by the CTBUH in 2008 were not released until some 4 years after. I think that the inclusion of drawing #9114 was a total blunder on the part of NIST and they probably should have kept it tucked away with the rest of the "2000 series" and FW drawings.
It took less than 2 months after the release for us to bring this to the direct attention of NIST.

And what exactly did NIST write about the plates after that.
I challenge you to quote me even just ONE word.
Let's not forget that now.

Say?
What is it about drawing 9114 that NIST should have hidden?

 

[Porkpie Hat]

We do. That's why the CTBUH asked about the inclusion of these elements without having seen the drawings.

And the then Chairman of the CTBUH stated,

"I believe that the NIST report is a responsible attempt to find the cause of the failure, however there are many questions that are not answered in any detail and several of these questions are already on the discussion forum. I think that with a responsible dialog and debate that the NIST report can be much better and clearer than it is in the current form.

However, that being said, I would like to be clear that I see no credibilty whatsoever in the 911 truth movement and I believe, like the vast majority of tall building professionals, that all the failures at the WTC ( WTC 1, 2, 5, 6 and 7) were a direct or indirect result of the planes that were flown into the two towers. I have carefully looked at the evidence that the 911 truth movement presents and I cannot see any evidence of a controlled demolition. Unfortunately the 911truth movement web site does not allow any opinions contrary to their own, or I would have presented my views.

David Scott - CTBUH Chairman"

http://www.skyscrapercity.com/showpost.php?p=24814132&postcount=14

So attempting to use the CTBUH's honest commentary on the report by 9/11 "truthers" is nothing but a cheap attempt to borrow/steal legitimacy from an organization which has the respect of the tall building community.

But hey, thanks for playing

 

[Porkpie Hat]

You can't seriously think that the CTBUH agrees with NIST on the initiation surely? Whilst I fully accept that the CTBUH said that they did not agree with the "911 truth movement", they did not specify which views they did not agree with. They did however ask if the inclusion of stiffener plates would have prevented the failure that NIST supposed. They asked this while the report was out for public comment.
Seems to me that they spotted that NIST had made some serious errors and their questions went unanswered.

Yet nothing they commented on made them dismiss the report on whole the way you and your ilk do.

Who to trust?

A respected organization specializing in tall building construction or a cult like movement that's never....moved a nano meter since its inception?

Such tough choices!

 

[pgimeno]

More bare assertion "Sound engineering practice" would dictate that any omissions are clearly stated and accounted for in the analysis.

You're not qualified to assess that. My assertion is backed by what people with experience in the field of simulations have already told you and you have ignored. Your assertion is not backed by any relevant expertise whatsoever.

More bare assertion. You do not and could not know this to be the case.

Fair enough. Let me restate: There's no qualified structural engineer with experience in forensics known to have been able to back your accusations to date.

AE911T relies on the authority of the engineers and architects that form their membership to convince the public. It's about time for them to put up or shut up, don't you think? It's obvious that your (or Tony's) expertise is lacking. You need professional help. Who would support your case better than the thousands of members of that organization?

That stated the girder was pushed 6.25".
Impossible.

No, it didn't.

We went through this already. You probably missed it.

The errata says no such thing. You keep assuming walk-off distance equals expansion distance. You don't justify why. Your assumption seems to be that the girder moved from the seat as much as the beam expanded. You don't justify that assumption. Such assumption doesn't account for the seat not being in its original position, nor for the girder moving with one of its ends fixed.

Clearly not
"2) If the girders had fin plates or end plates would the building have
survived? "

Yeah, would it, gerry? Can you answer the question yourself?

Here's a hint: The building did not survive.

The inclusion of the plates increases the required walk off distance.

You have not proved that. Newton's Bit has made a case of the girder rolling off the seat, and Tony has handwaved it with disbelief about the status of the connections that the NIST report shows to be with a 75%-99% damage.

Your case is full of holes that you seem to have no interest in filling. That doesn't support your cause.

 

[Porkpie Hat]

Aaaahahahahahah!

Why don't you include the entire paragraph in the "conclusion" section in your next post. I would, but my PDF reader does not allow select&copy..

This?

"Draft NIST Report on World Trade Center 7 is a comprehensive
assessment of the events that led to its collapse.
The Council does not agree with the NIST statement that the failure was a
result of the buckling of Column 79. We believe that the failure was a result of
the collapse of the floor structure that led to loss of lateral restraint and then
buckling of internal columns. This is an important distinction, as NIST appears
to be seeking improved performance from floors rather than columns.
The Council would like to know if there are any simple changes to the floors
and connections that would have resulted in a better performance than
occurred."

http://www.ctbuh.org/Portals/0/People/WorkingGroups/Fire&Safety/CTBUH_NISTwtc7_ DraftReport.pdf

Ya, it really doesn't help the cause if one is a member or supporter of A$E.com.

 

[jaydeehess]

This?

"Draft NIST Report on World Trade Center 7 is a comprehensive
assessment of the events that led to its collapse.
The Council does not agree with the NIST statement that the failure was a
result of the buckling of Column 79. We believe that the failure was a result of
the collapse of the floor structure that led to loss of lateral restraint and then
buckling of internal columns. This is an important distinction, as NIST appears
to be seeking improved performance from floors rather than columns.
The Council would like to know if there are any simple changes to the floors
and connections that would have resulted in a better performance than
occurred."

http://www.ctbuh.org/Portals/0/People/WorkingGroups/Fire&Safety/CTBUH_NISTwtc7_ DraftReport.pdf

Ya, it really doesn't help the cause if one is a member or supporter of A$E.com.

It looks like one earlier than the one was referring to but says the very same thing.

It is astounding that gerrycan appears to imply that this is them disputing that col 79 buckled.

 

[Porkpie Hat]

It looks like one earlier than the one was referring to but says the very same thing.

And it seems to summarize that the CTBUH agrees with the gist of the final report on WTC 7 but disagrees with some specifics that wouldn't change the gist.

If I'm getting the gist of it that is.

 

[Animal]

Yet nothing they commented on made them dismiss the report on whole the way you and your ilk do.

Who to trust?

A respected organization specializing in tall building construction or a cult like movement that's never....moved a nano meter since its inception?

Such tough choices!

But but but....you are not playing according to Gerry's "plan"

 

[Animal]

Such assumption doesn't account for the seat not being in its original position, nor for the girder moving with one of its ends fixed.

Yep....the troofer tag team is challenged by basic geometry......they are too concerned with word usage.

 

[jaydeehess]

@Porkpie Hat
Basically they are saying that if NIST is going to recommend new codes for floors structures then the statement of originating event should refer to the floor structure failure rather than the column failure that occurred after that.

Its a matter of semantics and internal consistency.

 

[ozeco41]

This?

"Draft NIST Report on World Trade Center 7 is a comprehensive assessment of the events that led to its collapse. The Council does not agree with the NIST statement that the failure was a result of the buckling of Column 79. We believe that the failure was a result of the collapse of the floor structure that led to loss of lateral restraint and then buckling of internal columns. This is an important distinction, as NIST appears .......

HEY!!


WOW!!!

Thanks for posting that - way back when we were discussing the OP I raised that issue in a post directed at Sanders OP and his later clarifications.

I never knew that CTBUH agreed with mere little old me. I thought it was another of those bleeding obvious things that everyone chose to not see. My faith in humankind partially restored

The "single column failure of Col 79 could not "lead to the collapse - i.e.
"initiate" or "start" or "go first" in a fire induced collapse scenario". (It could in a CD scenario as NIST demonstrated with one of its four analyses.)

@Porkpie Hat
Basically they are saying that if NIST is going to recommend new codes for floors structures then the statement of originating event should refer to the floor structure failure rather than the column failure that occurred after that.

Its a matter of semantics and internal consistency.

I thought- still think - that happening after is inconsistent with leading.

At the very least use of "lead" is confusing.

And that is a separate issue from Tony and Gerrycan misreading what NIST said about the 11"/5.5" bit and a lot of people accepting and not calling them on the arse about logic.

 

[Tony Szamboti]

Now back to the current program.

BIG HINT
On the 11"/5.5" stuff - can everybody read what NIST actually said and make sure we all understand how Tony and gerrycan (plus Pepper et al) are reading NIST's explanation arse about.

It could save a lot of this detailed too and fro.

It is naïve to think that the NIST WTC 7 report distorted the seat width at column 79 for girder A2001 as 11" for any reason other than the reality that the maximum beam expansion was 5.5".

Of course, with the drawings finally being released it was found that the seat was actually 12" wide and the NIST WTC 7 report authors had to admit it. Their June 2012 erratum about it saying the girder would have to travel 6.25", without saying where the extra 3/4" comes from, was clearly an attempt at hoping nobody would notice they could not provide a complete answer. The additional fact that they did not discuss the stiffener omission in that erratum (although it had also been pointed out to them with the seat width issue) is even more damning, as it requires much more than an additional 3/4" of impossible travel distance for the girder to fall off its seat.

Unfortunately, there are no explanations for the seat width distortion and girder stiffener and lateral support beam omissions, other than intentional deception, because the real structure could not have failed as they claimed.

There is a lot to see here, regardless of the protestations of those here who want to claim there isn't but can't show why. The stiffeners and lateral support beams were very critical to the analyses of the collapse of WTC 7 and those responsible for those analyses had no business omitting them. If you actually think they were omitted for simplification, based on engineering judgement that they would not have a significant effect, somebody has a bridge to sell you.