Total Building Collapse from a Single Column Failure

Ozzie,

Thank you... And I apologize for not making the OP and question clear... I meant a typical one story column (section) in a multiple story high rise. .. which many case uses columns or 2 story height and offsets them (ie the end condition is not restrained... but that would not make too much difference I suspect.

In the case of 7wtc the collapse of the "single" column came AFTER the collapse of multiple floors.. I believe that is the assertion. And if so the column failure did not cause the floor collapse, but the floor collapse caused the column failure.

The floor collapse was supposedly caused by the girder walk off causing the floor slabs to collapse... or is this not what they say?
 
JSanderO said:
Ozzie,

Thank you... And I apologize for not making the OP and question clear... I meant a typical one story column (section) in a multiple story high rise. .. which many case uses columns or 2 story height and offsets them (ie the end condition is not restrained... but that would not make too much difference I suspect.
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No problem - took us a bit of time to get clear....;)

The most likely cause of one storey failure of a single column WITHOUT surrounding trauma would IMO be motor vehicle impact. The likely proximate cause of failure due MVA - bending of column and shear of column splice bolts. Then we get into problematic guesswork - it would take a serious MVA impact to even shear splice bolts - and only one splice likely within one story due to usually multi story length of columns segments.

JSanderO said:
In the case of 7wtc the collapse of the "single" column came AFTER the collapse of multiple floors.. I believe that is the assertion. And if so the column failure did not cause the floor collapse, but the floor collapse caused the column failure...
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Re examine my comments - starting at the other end of the logic train. We know EPH fell THEREFORE Col 79 must have failed. Likely ooops :blush: Plausible causes of failure being:
1) Euler buckling due removal of multiple floor bracing over multiple floors; OR
2) Gross overload by EPH somehow getting a lot heavier (discount that one); OR
3) CD - discount that one (we are not truthers committed to "Arse about logic")

Now the key point for me is that "1)" in some form or other is the only viable reason. AND NIST plus me say "multiple disconnections needed to cause Euler instability.

Hence it is not single factor of girder walk off - wherever that fits in the picture NOR is is single factor Sanders TT failure - wherever that fits in the picture.

And I don't think we will ever know with certainty. The rest of my speech you have seen before. :)

JSanderO said:
The floor collapse was supposedly caused by the girder walk off causing the floor slabs to collapse... or is this not what they say?
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Believe it or not I cannot remember how they (NIST) strung the bits together. You know me - agnostic on NIST. I'll go and check.


BTW I've reported the off topic stuff and asked for a thread split.
 
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Wrt col 79 failure in WTC_7 we do know that at one floor there was heat. Heat causes things to happen to steel, expansion and an increase in plasticity.

This would be the case for all steel structural members in the vicinity, to varying extent. That includes girder and girder components such as web stiffeners, beams, beam seats, and columns. It also includes heat effects to the concrete slab.

This effect is over the entire level vertically and proximate to the heat source, so two floor slabs are affected and a 3 meter length of column.

Normally the girder's seat supports a 12 inch or there abouts, wide flange iirc. This is deemed sufficient to support the expected max load plus margin of safety.

Should this girder flange width be reduced to 10% , with girder and seat also having been heated, will the load it is capable of transferring to the column still be within that design? Probably not, IMHO.

The beams are heated to varying degrees so are subject to various degrees of expansion. If this warps the girder that too will affect the girder seat supporting contact adversely.

Would gider fail? Very probable that it would.

Would girder failure allow local floor collapse. This depends to a certain extent on the load on that section of floor. We don't know what that was nor what it consisted on( ie. Items free to slide?). It also seems probable that this floor will collapse.

Now there is at least a two storey length of column with no support on one side. A one floor length of this column is heated.

Floor debris and floor load constituents fall onto the next lower floor which will be heated to a lesser degree.

Modeling every aspect in this would be problematic but it seems probable to me that column 79 could fail somewhere along its heated length given a rapid loss of a few floors.

One obvious bit of supporting evidence is the obvious presence of fire. Another is the first visible rooftop failure in the vicinity of column 79.

The question posed recently is whether or not this single column failure could apply to other structures.

This is a different question to whether or not col 79 in WTC 7 would fail. Yet some posters seem to be conflating the two issues.

Column 79 in WTC7 was one of only a few columns, in the vicinity, that ran from foundation to rooftop. Others in the vicinity began around the 5th to 8th floor. It was part of a structure that employed a long span, open floor concept. The structure relied heavily on the core system to support an elevated foundation for the top 40 storeys, and several special constructs of which TT1 is an example and is close to column 79.

Is a single column failure such as proposed for WTC7 directly applicable to other steel structures?
Possibly but given that several WTC7 specific elements of construction were important to the progression of collapse to global collapse, it becomes less likely.

No one or two things that is common to many or most steel structures were responsible for this progressing to global collapse.

But that's just my opinion.
 
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Grizzly Bear said:
The "single column failure" is little more than a best guess based on exterior analysis of the collapse, and simulation based on knowing the building's construction.
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The thing is though, the structural drawings on which NIST claimed to have based their analysis on show that they did not base their simulation on an accurate representation of the structural elements at the point they supposed the collapse initiated. They omitted 2 stiffener plates, beam stubs, and also did not account for the connection failure that would have had to occur at column 38 in order for the studs on beam K3004 to fail.
 
gerrycan said:
The thing is though, the structural drawings on which NIST claimed to have based their analysis on show that they did not base their simulation on an accurate representation of the structural elements at the point they supposed the collapse initiated. They omitted 2 stiffener plates, beam stubs, and also did not account for the connection failure that would have had to occur at column 38 in order for the studs on beam K3004 to fail.
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...of which no one has established that their presence in the model would have made one jot of difference to the final outcome of it being possible for WTC7 to collapse due to unfought fires.
 
gerrycan said:
The thing is though, the structural drawings on which NIST claimed to have based their analysis on show that they did not base their simulation on an accurate representation of the structural elements at the point they supposed the collapse initiated. They omitted 2 stiffener plates, beam stubs, and also did not account for the connection failure that would have had to occur at column 38 in order for the studs on beam K3004 to fail.
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Which means nothing. Fire caused the collapse, 911 truth can't do better with less than 0.1 percent of all engineers at A&E for CD lies and fantasy.
No matter how many opinions there are on errors NIST made, it does not change fire did it.

The thing is, no CD. A single column failure is better than what 911 truth has. Guess 911 truth can't get past the fantasy of CD, and other silly claims based on opinions, failed opinions.

Not sure why engineers at A&E are unable to join reality, guess they don't have the skills to avoid being fooled by the idiotic lies of CD. Where is the paper which covers your claims? What difference does it make? None.

You see, in the real world when we build a building and worry about what happened to WTC 7, we hire structural engineers to study and improve our new building - wait, this is how they built the new WTC 7... sort of.

Anyway, WTC 7 fell due to fire NOT fought; no other high-rise in history had fires not fought - or is there? Gee, I know two high rise buildings that failed in fires fought. What logic does 911 truth use to make up lies about 911, like CD?
 
LSSBB said:
...of which no one has established that their presence in the model would have made one jot of difference to the final outcome of it being possible for WTC7 to collapse due to unfought fires.
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So you are saying that NIST have no analysis that shows what difference the inclusion of these elements would have made to their hypothesis. I agree.
So, what in your opinion was the function of these elements with regard to the analysis, and do you agree with NIST when they say that when the girder's web went beyond the edge of the seat plate, it would have failed?
 
gerrycan said:
So you are saying that NIST have no analysis that shows what difference the inclusion of these elements would have made to their hypothesis. I agree.
So, what in your opinion was the function of these elements with regard to the analysis, and do you agree with NIST when they say that when the girder's web went beyond the edge of the seat plate, it would have failed?
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My opinion is meaningless. I find the conclusion plausible and I see no evidence of any other cause for the building collapse beyond unfought fire, limited impact damage, and something gave way under one of the penthouses, the interior of the building collapsed, and then the exterior. No flash, no bang, no detonators, no confessions, no paper trail. I am no NISTophile, nor am obsessed with NISTeria. If I felt motivated to NISTpick, I would create my own computer simulation. Have you?
 
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JERF are NISTians and can't find any fault with any aspect of their explanations. Most simply default to the correct cause (one of them and the main one) as being fire. JERFs don't do much in the way of details.

In a sense they are functionally like truthers who debunk aspects of the official story. JERFs have debunked most if no all of the bullet points of the 911 truth scientists/engineers. Debunkery does not explain what happened.

And it's more than likely that all that can be done is produce a credible model and fit it to the observations. There really aren't sufficient observations... such as temp data to truly construct an accurate model. So both sides of this debate make them up...

The thing is the truth side has no coherent mechanism AND narrative of how CD was done or worked. They're masters of the black box and smoke and mirrors and arguing CD from disbelief.
 
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gerrycan

So you are saying that AE 911T have no analysis that shows what difference the inclusion of these elements would have made to their hypothesis. I agree.
So, what in your opinion was the function of these elements with regard to the analysis, and do you agree with AE911T when they say that it would prevent failure?
 
LSSBB said:
My opinion is meaningless.
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I disagree - your opinion as expressed in the next bit is IMNSHO spot on
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LSSBB said:
...I find the conclusion plausible and I see no evidence of any other cause for the building collapse beyond unfought fire, limited impact damage, and something g gave way under one of the penthouses, the interior of the building collapsed, and then the exterior...
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That opinion aligns with mine as posted many times. I'll bet you have also said it before.
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The "big question" in most of these WTC7 discussions is "Was there CD" - there was no CD - or, being pedantic by the "scientific method", no one has ever put forward a plausible hypothesis in favour of CD. So CD is not in the discussion until someone puts forward a prima facie hypothesis pro CD.

AFAICS there are only two other areas for legitimate discussion which are being conflated into this thread viz:
1) Was NIST correct in detail AND only ONE detail is being questioned - which was that "girder walk-off contributed to failure of Col 79". Read that statement again because AFAICS it is the correct scope of the issue - esp "only ONE detail" and "contributed" NOT "caused" - if I'm wrong someone can correct me.

2) Personal interest in details - which is independent of the "Was there CD" question. Bottom line is we will never know with certainty.

So girder walk-off is plausible; there was no CD and whether NIST was right or wrong on that single detail the rest of their explanation is valid.

Does anybody here deny "East Penthouse" fell?
Does anybody here deny "Col 79 was under EPH THEREFORE Col 79 must have failed"?
Does anybody here deny "In absence of any case for CD Col 79 failure would result from loss of horizontal bracing leading to Euler buckling"?
(To avoid the false dichotomy - Does anybody here deny "that doubling/tripling of weight of EPH can be discounted as the only other plausible cause of failure of Col 79 - viz gross overload."? :rolleyes: that one for the logic pedants ;))

That lot will do for now.

As I see it all the discussion about details is flawed because the starting point premises are wrong. And folk are coming at the logic arse about - working from speculation over details rather than working from known facts.
 
jaydeehess said:
gerrycan

So you are saying that AE 911T have no analysis that shows what difference the inclusion of these elements would have made to their hypothesis. I agree.
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I would expect that AE911:
1) has full access to the Szamboti reasoning; AND
2) has none better than Szamboti - whether or not they are relying on T Sz's analysis.

It is a strawman because the T Sz analysis has been shown to be "not proven" on this forum - probably several other forums.

The issue of those details:
A) Adds nothing to debate whether explaining the actual collapse OR seeking to prove/disprove CD; WHILST

B) It may help those obsessed with "Prove NIST wrong at any price" to prove a minor point of arguably irrelevant detail.

So let's not conflate "explain the collapse" with "prove NIST wrong'' - its too confusing.

:D
 
ozeco41 said:
I would expect that AE911:
1) has full access to the Szamboti reasoning; AND
2) has none better than Szamboti - whether or not they are relying on T Sz's analysis.

It is a strawman because the T Sz analysis has been shown to be "not proven" on this forum - probably several other forums.

The issue of those details:
A) Adds nothing to debate whether explaining the actual collapse OR seeking to prove/disprove CD; WHILST

B) It may help those obsessed with "Prove NIST wrong at any price" to prove a minor point of arguably irrelevant detail.

So let's not conflate "explain the collapse" with "prove NIST wrong'' - its too confusing.

:D
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Thanks for bringing up Tony. The man behind the curtain. Yes, we have been down this path before. If gerrycan wants to make more than an opinion, he needs to do some work, publish and get Structural Engineers to vet his work. At least Tony made it to the publish phase, even if his paper was just an exercise in strawman stabbing.
 
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LSSBB said:
...At least Tony made it to the publish phase, even if his paper was just an exercise in strawman stabbing.
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Which;
1) he declined to defend; AND
2) pulled the rug from under "Missing Jolt"

:rolleyes:

PS AND IIRC got me some "personal comments" for daring to point out both those factors.. ;)


....several times.
 
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ozeco41 said:
Does anybody here deny "East Penthouse" fell?
Does anybody here deny "Col 79 was under EPH THEREFORE Col 79 must have failed"?
Does anybody here deny "In absence of any case for CD Col 79 failure would result from loss of horizontal bracing leading to Euler buckling"?
(To avoid the false dichotomy - Does anybody here deny "that doubling/tripling of weight of EPH can be discounted as the only other plausible cause of failure of Col 79 - viz gross overload."? :rolleyes: that one for the logic pedants ;))
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Ozzie,

No one denines the EPH fell
No denies that col 79 was one of 9 under the EPH and they ALL had to "fail" for the entire EPH to collapse
Failure of column 79 does not lead to Euler buckling. Euler Buckling could lead to column 79 failure
No one is asserting that there were new loads over the columns

However...

No one explained how if a single column 79 failed all the other 9 columns under the EPH from failing so that the entire EPH could then collapse.

You seem to not want to look at the larger picture that one of the 9 columns could be the cause of the EPH collapse when it all 9 had to go at about the same time.

But you're not alone. No one has explained how column 79 caused all the other 8 to fail at once more or less.

NB: the attached shows the columns below flr 5. a single column was on TT#1 above

BTW note the columns which were supporting the WPH... all were part of the load transfer system of the 8 MG17s which were framed into columns at the north side of the core AND were in the E-W line between TT1 and TT#3.

So... one the EPH when down... why did the WPH go down? What column failed under it?
 

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JSanderO said:
Ozzie,

No one denines the EPH fell
No denies that col 79 was one of 9 under the EPH and they ALL had to "fail" for the entire EPH to collapse
Failure of column 79 does not lead to Euler buckling. Euler Buckling could lead to column 79 failure
No one is asserting that there were new loads over the columns
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Good so that clears up a few of the persistent implications - from you at least.

JSanderO said:
However...

No one explained how if a single column 79 failed all the other 9 columns under the EPH from failing so that the entire EPH could then collapse.
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AFAIK NIST has given a plausible explanation and you have proposed an alternative. The known facts include EPH did collapse. That much we know. And IMO we will never know all the details. So:
If we are seeking to understand the mechanism in fine detail we will be disappointed. And bleating on about it for months without dealing with the realities which I and others have posted will not progress understanding.
JSanderO said:
You seem to not want to look at the larger picture that one of the 9 columns could be the cause of the EPH collapse when it all 9 had to go at about the same time.
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apart from the irony of you accusing me of missing the big picture...:D

The "cause" is blatantly obvious. A lot of components failed. A lot of component had to have failed. What we don't know is the sequence - and at risk of repeating myself we never will. You and I have been down this path before on another forum

PLUS your attribution of causality to any single column is flawed as I have said many times. Try not to use "cause" or "lead" unless you are very clear as to what you mean. Again a point I have explained previously

JSanderO said:
But you're not alone. No one has explained how column 79 caused all the other 8 to fail at once more or less.
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True. For at least two reasons:
1) The engineering one - it was a cascading failure of multiple structural elements so no one has and no one will ever definitively state the precise sequence. Nor do we have any valid reason why we need to know more in detail other than for personal curiosity or to prove NIST wrong; AND

2) The language pedantry issue. No one can explain how Col 79 "caused" because it didn't "cause" nor did it "lead".
 
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