Total Building Collapse from a Single Column Failure

[JSanderO]

If I was in your spot, I would keep the opinions to myself, earn an engineering degree, at least a masters and try for a redo.
How long did you believe the inside job stuff?

never... I am too old to earn a degree....

 

[ozeco41]

the cause of sinking was not an issue... ships sink when they are holed...

towers don't totally collapse when they are on fire... usually... capice?

unusual circumstances call for unusual care in investigation.

Lousy analogy Sander:
The ships which sank - sank. The towers which collapsed - collapsed.

The cause of ships sinking was known - consequence of enemy attack. The cause of the collapses was known - aircraft impact and unfought fires.

Ships which are attacked don't usually sink.

Properly applied your analogy doesn't support you.

 

[Newtons Bit]

Good answer... or evasion...

NIST created a model... they said so... made up the inputs... a fake... may be the wrong world... but it's not far off...

THEY MADE IT UP...

Fine...

Which part was made up? Please be specific.

So why can't they say how it worked... or you or as I noted... why didn't they show one piece of steel to support their model?

I create and work with FEA models on a daily basis. These models are typically the only basis of design for dozens of buildings I've engineered. Did I "make it up"? Is the public at risk?

 

[JSanderO]

Lousy analogy Sander:
The ships which sank - sank. The towers which collapsed - collapsed.

The cause of ships sinking was known - consequence of enemy attack. The cause of the collapses was known - aircraft impact and unfought fires.

Ships which are attacked don't usually sink.

Properly applied your analogy doesn't support you.

OK... applies to the unusual case of the twin towers. But not so for 7wtc.

Several towers that day had debris fall on them... only wtc7 collapsed totally with fire as the proximate cause. Many buildings have fires and few to none go to total collapse. To me that makes 7wtc an outlier and worthy of study and explanation. Whether NIST got it exactly right is the issue... but it was worthy of study and explanation.

 

[JSanderO]

Which part was made up? Please be specific.



I create and work with FEA models on a daily basis. These models are typically the only basis of design for dozens of buildings I've engineered. Did I "make it up"? Is the public at risk?

Fire loads were assumed I believe for one. There were no thermo couples inside the tower no?

 

[Grizzly Bear]

OK... applies to the unusual case of the twin towers. But not so for 7wtc.

Several towers that day had debris fall on them... only wtc7 collapsed totally with fire as the proximate cause. Many buildings have fires and few to none go to total collapse. To me that makes 7wtc an outlier and worthy of study and explanation. Whether NIST got it exactly right is the issue... but it was worthy of study and explanation.

Only in so much as the design approach used on that building probably shouldn't be used routinely. The conclusions they reached mostly dealt with long-span beams and the degree to which they experienced thermal expansion/contraction which in this case - according to them - contributed to the collapse initiation.

Had the sprinklers in that building worked, I think the odds are 70/30 that the collapse might not have happened, but that's my own speculation. The point of NIST's conclusions was to identify the approximate cause of the collapse as well as potential design vulnerabilities that could impact other buildings whether they exist now, or will be built in the future. That issue about thermal expnsion/contraction has been somewhat debated (whether NIST focused too much on the expansion over contraction, or if they didn't focus enough on stresses caused by viscoelastic creep for example) and it doesn't shock me that there's been that debate considering the visual documentation is more limited than it is for the twin towers. But for the most part I agree with the general conclusion that the design and lack of active fire suppression were the main factors. I don't personally feel that those "debated" parts of the conclusion are so serious that it would radically change anything.... honestly.

I don't know of any other skyscrapers with exactly the same design as WTC 7, so the degree to which you can call it an "outlier" is in my informed opinion, limited. The similarities between buildings using the same construction materials ends pretty much at the point of the design approach. Buildings that are designed appropriately to code and experience conditions within the range of what they're expected to deal with in their life time usually won't collapse (it defeats the purpose of building them to code if they "usually" do). Buildings that either don't meet current code, or have unforeseen design vulnerabilities, or those that experience things outside of their design scope may perform better than expected under the circumstances, or they may not. But when dealing with structures everything you study is typically case by case since true 1:1 analogies in design are exceedingly rare.

 

[JSanderO]

Only in so much as the design approach used on that building probably shouldn't be used routinely. The conclusions they reached mostly dealt with long-span beams and the degree to which they experienced thermal expansion/contraction which in this case - according to them - contributed to the collapse initiation.

Had the sprinklers in that building worked, I think the odds are 70/30 that the collapse might not have happened, but that's my own speculation. The point of NIST's conclusions was to identify the approximate cause of the collapse as well as potential design vulnerabilities that could impact other buildings whether they exist now, or will be built in the future. That issue about thermal expnsion/contraction has been somewhat debated (whether NIST focused too much on the expansion over contraction, or if they didn't focus enough on stresses caused by viscoelastic creep for example) and it doesn't shock me that there's been that debate considering the visual documentation is more limited than it is for the twin towers. But for the most part I agree with the general conclusion that the design and lack of active fire suppression were the main factors. I don't personally feel that those "debated" parts of the conclusion are so serious that it would radically change anything.... honestly.

I don't know of any other skyscrapers with exactly the same design as WTC 7, so the degree to which you can call it an "outlier" is in my informed opinion, limited. The similarities between buildings using the same construction materials ends pretty much at the point of the design approach. Buildings that are designed appropriately to code and experience conditions within the range of what they're expected to deal with in their life time usually won't collapse (it defeats the purpose of building them to code if they "usually" do). Buildings that either don't meet current code, or have unforeseen design vulnerabilities, or those that experience things outside of their design scope may perform better than expected under the circumstances, or they may not. But when dealing with structures everything you study is typically case by case since true 1:1 analogies in design are exceedingly rare.

I have no problem with the broad conclusions and recommendations of NIST. I don't support CD or any other sources of energy than what we saw with our own eyes.

I do find that the explanations for the collapse were not very good to say the least and it was more than failed sprinklers which did the towers in in the end.

I use the term outlier because if you can show me another 47 or so story tower built over top of a major power sub station using massive complex field erected transfer structures to support them. Of course they building used the same materials and connections as any steel building does. In that sense it is not an outlier. And the same for the twins... There was understandably a feint to the structural design issues trying to pin the collapse on sagging trusses which pulled the facade in the tower complete collapsed... yea right... if you believe that one I've got a bridge to sell you.

NIST's fail was not in the causes but in the mechanisms and locations those cause were applied to begin the progression of failures which led to the total destruction of the buildings. I'm not sold on sagging trusses and walking girders.... by a long shot. And their fail was about what I... wanted to learn for the investigation... how did they come apart as they did and end as totaled buildings.

I didn't learn.

 

[DGM]

I do find that the explanations for the collapse were not very good to say the least and it was more than failed sprinklers which did the towers in in the end.

And NIST agrees. The design did play a part. Just not the part of the design you focus on.

NIST's fail was not in the causes but in the mechanisms and locations those cause were applied to begin the progression of failures which led to the total destruction of the buildings. I'm not sold on sagging trusses and walking girders.... by a long shot. And their fail was about what I... wanted to learn for the investigation... how did they come apart as they did and end as totaled buildings.

It's not a fail. They found no evidence for failure in the area you preferred. They spent a lot of effort looking for this evidence and didn't find it. You disagree.

I didn't learn.

I'm not sure you want to unless they reconsider your hypothesis.

 

[JSanderO]

And NIST agrees. The design did play a part. Just not the part of the design you focus on.

It's not a fail. They found no evidence for failure in the area you preferred. They spent a lot of effort looking for this evidence and didn't find it. You disagree.

I'm not sure you want to unless they reconsider your hypothesis.

dunno bout that... I'm still looking for answers.

 

[DGM]

dunno bout that... I'm still looking for answers.

Maybe if you try a bit harder to answer Newtons Bits' question.

"Which part was made up? Please be specific.".

He would also respond in kind. I, for one learn from his posts.

 

[JSanderO]

Maybe if you try a bit harder to answer Newtons Bits' question.

"Which part was made up? Please be specific.".

He would also respond in kind. I, for one learn from his posts.

I have asked in this thread from the get go how does a single column "failure" attributed to a girder walk off at floor 13 lead to total building collapse.

Let's start there.

 

[DGM]

I have asked in this thread from the get go how does a single column "failure" attributed to a girder walk off at floor 13 lead to total building collapse.

Let's start there.

And you got answers.

If I remember correctly you doubted that the floor collapse would progress.

The single girder walk off was only the start of what caused the column to fail (You already know this).

Be specific. Why would the floor collapse not progress?

 

[JSanderO]

And you got answers.

If I remember correctly you doubted that the floor collapse would progress.

The single girder walk off was only the start of what caused the column to fail (You already know this).

Be specific. Why would the floor collapse not progress?

I am skeptical that a single floor section tipping would even lead to a multi floor collapse... as the floor was a composite and secured to other beams and the spandrel and so forth.

At the Twin towers we had floors sections drop when the plane struck and no cascading floor failures below or above from those initial drops. No?

 

[DGM]

I am skeptical that a single floor section tipping would even lead to a multi floor collapse... as the floor was a composite and secured to other beams and the spandrel and so forth.

We know you are. Remember, these areas were also not in pristine condition. NIST took it all into consideration. You seem to want to narrow it down to one piece.

At the Twin towers we had floors sections drop when the plane struck and no cascading floor failures below or above from those initial drops. No?

Apples and oranges. The towers structure was pristine at the time of impact and initial floor collapse. WTC 7 had burned for hours.

 

[Robrob]

Is it me or is much of the debate here seem analogous to demanding to know what "exactly" killed JFK; the loss of blood or the damage to the cerebral cortex and if so - which lobe?

 

[LSSBB]

Is it me or is much of the debate here seem analogous to demanding to know what "exactly" killed JFK; the loss of blood or the damage to the cerebral cortex and if so - which lobe?

Eh, I think it's more like whether therefor the doctors could have kept him in a vegetative state for another hour or so.

 

[ozeco41]

Is it me or is much of the debate here seem analogous to demanding to know what "exactly" killed JFK; the loss of blood or the damage to the cerebral cortex and if so - which lobe?

That is quite a good analogy....

...except one big difference.

With JFK the PM would have found the detailed answer.

No such autopsy for WTC7:
1) It was not needed at the time;
2) It was not feasible at the time;
3) We cannot reverse history and do it now;
4) There is no valid reason for trying; AND
5) We will never know.

PLUS Sanders arguments have been countered several times - to no avail.

 

[JSanderO]

That is quite a good analogy....

...except one big difference.

With JFK the PM would have found the detailed answer.

No such autopsy for WTC7:
1) It was not needed at the time;
2) It was not feasible at the time;
3) We cannot reverse history and do it now;
4) There is no valid reason for trying; AND
5) We will never know.

PLUS Sanders arguments have been countered several times - to no avail.

I am not sure all my points and concerns have been countered. My questions haven't been answered. I've been corrected a few times on points but these correction don't counter or undermine the basic thrust of the OP...

Of course, it's hard to find a site to even discuss this matter. Impossible on a truther site and apparently impossible on this site.

For whatever reason no one will explain a single column scenario in any... and I mean any level of detail.

 

[DGM]

I am not sure all my points and concerns have been countered. My questions haven't been answered. I've been corrected a few times on points but these correction don't counter or undermine the basic thrust of the OP...

Problem is the OP has little bearing on reality. The question is an un -intentional strawman at best, I won't go on from here.

Of course, it's hard to find a site to even discuss this matter. Impossible on a truther site and apparently impossible on this site.

Why are you not more open? Everyone here is willing to discus this, you don't seem to want to do it on anything other than your terms.

For whatever reason no one will explain a single column scenario in any... and I mean any level of detail.

Because it's a strawman you created.

 

[ozeco41]

Problem is the OP has little bearing on reality.

Despite that I comprehensively addressed the OP here and on several further occasions as the thread wandered and drifted along.

Because it's a strawman you created.

Sander could you do yourself and the rest of us a favour and read the NIST report NCSTAR 1A - Specifically the FOUR LS_DYNA analyses in Section 3.4 and the corresponding results in S4. Find out what NIST really did say.

You may get a pleasant surprise.