Total Building Collapse from a Single Column Failure

[ozeco41]

Isn't this a rewritten question of NIST said that this was the straw that broke the camels back and how universal it would be that a single straw actually could break a camel's back?

Reasonably close.

Split the two issues:

Isn't this a rewritten question of NIST said that this was the straw that broke the camels back

Yes it is and we need to be clear on two points:
a) When a "straw breaks the camels back" it is not that one straw which causes the break BUT all the other straws with that one merely being the final trigger into overload and failure. AND
b) NIST identified one specific "final straw" whilst Sander has suggested another candidate for "final straw". IMO both are plausible candidates for "final straw". Sander insists that his one is valid and NIST's one is not.

Then the totally separate question which is in the OP:

how universal it would be that a single straw actually could break a camel's back?

Well this one can be answered in two opposing ways - depending on how we define our context/terms:
c) Forming generic solutions out of specific situations is fraught with danger - even Bazant got it wrong. OR
d) Since we are discussing cascade failures there will always be at least one "final straw". The nature of a cascade failure is that there is always at least one "trigger" AKA "final straw". (There can be more.) So the statement is a truism.

It may take a few extra words to make those two clear for many members.

 

[LSSBB]

Reasonably close.

Split the two issues:
Yes it is and we need to be clear on two points:
a) When a "straw breaks the camels back" it is not that one straw which causes the break BUT all the other straws with that one merely being the final trigger into overload and failure. AND
b) NIST identified one specific "final straw" whilst Sander has suggested another candidate for "final straw". IMO both are plausible candidates for "final straw". Sander insists that his one is valid and NIST's one is not.

Then the totally separate question which is in the OP:
Well this one can be answered in two opposing ways - depending on how we define our context/terms:
c) Forming generic solutions out of specific situations is fraught with danger - even Bazant got it wrong. OR
d) Since we are discussing cascade failures there will always be at least one "final straw". The nature of a cascade failure is that there is always at least one "trigger" AKA "final straw". (There can be more.) So the statement is a truism.

It may take a few extra words to make those two clear for many members.

IMO, good synopsis of the thread, Oz.

 

[erwinl]

Reasonably close.

Split the two issues:
Yes it is and we need to be clear on two points:
a) When a "straw breaks the camels back" it is not that one straw which causes the break BUT all the other straws with that one merely being the final trigger into overload and failure. AND
b) NIST identified one specific "final straw" whilst Sander has suggested another candidate for "final straw". IMO both are plausible candidates for "final straw". Sander insists that his one is valid and NIST's one is not.

Then the totally separate question which is in the OP:
Well this one can be answered in two opposing ways - depending on how we define our context/terms:
c) Forming generic solutions out of specific situations is fraught with danger - even Bazant got it wrong. OR
d) Since we are discussing cascade failures there will always be at least one "final straw". The nature of a cascade failure is that there is always at least one "trigger" AKA "final straw". (There can be more.) So the statement is a truism.

It may take a few extra words to make those two clear for many members.

Thank you for the explanation.

 

[JSanderO]

In a cascading failure it is usually not a linear chain reaction like a row of dominoes. It is often a spreading of failures laterally, if you will into various disparate yet connected systems.

So in a building collapse as we saw.. we had failures of the water system, the sprinkler system, the main power system, the DC power system, HVAC system and probably the back up power systems... and of course the structural system and its components. These system failures act synergistically.

 

[Miragememories]

In a cascading failure it is usually not a linear chain reaction like a row of dominoes. It is often a spreading of failures laterally, if you will into various disparate yet connected systems.

So in a building collapse as we saw.. we had failures of the water system, the sprinkler system, the main power system, the DC power system, HVAC system and probably the back up power systems... and of course the structural system and its components.

These system failures act synergistically.

During the global collapse of WTC7, freefall acceleration occurred across an area the size of a football field, for 8 storeys....simultaneously!

That was a designed failure.

MM

 

[thedopefishlives]

During the global collapse of WTC7, freefall acceleration occurred across an area the size of a football field, for 8 storeys....simultaneously!

That was a designed failure.

MM

Oh, are we back to "freefall = controlled demolition" again? How many times are we going to ride this merry-go-round?

 

[JSanderO]

During the global collapse of WTC7, freefall acceleration occurred across an area the size of a football field, for 8 storeys....simultaneously!

That was a designed failure.

MM

Of course this was AFTER virtually ALL the interior had already collapsed... and the transfer structures had pulled in the 8 - MG27s off the coiumns and both the east and west wind shear truss inward.

 

[LSSBB]

During the global collapse of WTC7, freefall acceleration occurred across an area the size of a football field, for 8 storeys....simultaneously!

That was a designed failure.

MM

We had a thread about your freefall holy words. Not proof of CD. And off topic.

 

[Grizzly Bear]

So you want stronger buildings. How much stronger??? The collapses at WTC were not expected by the perpetrators - an unexpected "bonus" for their evil acts.

Not that I disagree with this interpretation but I firmly believe under the available context that an immediate collapse scenario was their specific goal at the get go. My reasoning for thinking this is because they struck so much lower in the South Tower, which would have naturally left the structure more vulnerable to failure.

Now, at that last sentence is where I dive back into the subject at hand.... How much stronger do we want buildings to be? The way I look at it, is that we can design a building pretty much for anything that money can buy.

A single point failure is possible in any system under the right set of circumstances, and we as architects and engineers try to design for those scenarios that we can account for within budgetary, and contextual practicality. And as you point out:

The reasonable prudent professional designing a high rise will look first to providing secure egress for the people in the event of fire and major damage. [The] multiple redundancy of fire fighting measures primarily to ensure time for escape of the occupants. He may look at progressive collapse resistance but the priority will remain protect the people #1 protect the building a distant #2. Despite anyone's efforts to reverse those priorities.

That's pretty much the success story of WTC 1, 2, and 7 regardless of how conspiracy theorists touting the CD theory want to spin the dial. The buildings did not survive the attacks, but the vast majority of occupants survived. But at the same time, there were issues in building construction of those towers that ultimately came to the forefront as a result of the attacks as well...

I did not allege criminal behavior. I suggested some questionable decisions were made by planners, developers, Con Ed, engineers, the Mayor's office and so forth which seem to play a contributory role in the collapse.

None of this was brought out. NIST coulda... perhaps shoulda.

That I find odd.

As far as I know, at the time of its construction building 7 was compliant with local building codes. But as you may already be aware building codes often change over the years and IIRC "7" was on top of a rather unique site. I'm not discounting that there aren't lessons to be learnt or that there's no valid criticism coming out of what you're saying, but it is important I think to take that under consideration as well.

I'm not sure how prevelant construction standards such as those in WTC 7 were or are now, admittedly

 

[ozeco41]

IMO, good synopsis of the thread, Oz.

Thank you.

Thank you for the explanation.

No problem.

 

[ozeco41]

In a cascading failure it is usually not a linear chain reaction like a row of dominoes.

Correct.

It is often a spreading of failures laterally, if you will into various disparate yet connected systems.

Even if we stay with the structural cascade failure it is at least a couple of orders more complicated that the combination of the row of dominoes model PLUS your legitimate addition of lateral spread.

For the specific instances of WTC1 and WTC2 cascade failures of the initiation stage here are just two of the complexities:

The "domino model" is a series of binary yes-no steps. The next domino is either stable or is not. Add in Sanders "lateral spread" to a domino model and we see bifurcating/trifurcating/quad/quint/hex...whatever BUT every one of those paths of toppling dominoes is a serial process of discrete binary yes-no events.

All of the load re-distributions involved in WTC cascade were complex "analogue" events. The "load imposer" being an elastic complex frame where any transfer of load instantly gets counteracting negative feedback.

(In what I hope is lay persons language and using a column in compression as the example - as the load on that one column causes that column to shorten the load applying member - the top portion structural frame - would need to move with it to keep applying the same force. It cannot move 'with it' - it is elastically constrained AGAINST following the movement because it is also resting on a range of neighbouring columns AND therefore it stops applying the same load. Hence "negative feedback")


The second (and related) complexity is that, whilst all the domino topples are distinct disconnected events, the cascade failure of WTC1/2 was not. There were large numbers of interconnectivities always acting. You could stop a domino cascade by going downstream of the racing topple wave and tipping one domino in the reverse direction. All dominoes downstream of that point are "saved". No such opportunity for WTC. More to the point there is no place in a WTC style cascade for such an intervention.

I'll pause there - the point being that the WTC cascade failures of intiation were orders of magnitude more complex that a domino topple.

And that is limiting ourselves to the structural failure. As is his practice Sander broadens into other issues:

So in a building collapse as we saw.. we had failures of the water system, the sprinkler system, the main power system, the DC power system, HVAC system and probably the back up power systems... and of course the structural system and its components. These system failures act synergistically.

All true but I don't think that broadening the topic helps get across the message of the true complexity of the structural failures - whether WTC1, WTC2 which were reasonably accessible to view OR WTC7 which was mostly hidden.

 

[jaydeehess]

During the global collapse of WTC7, freefall acceleration occurred across an area the size of a football field, for 8 storeys....simultaneously!

That was a designed failure.

MM

E X P L A I N
How one deduces that FFA can only be achieved via demolition. So far yourcompatriots have that as a bald assertion devoid of any technical backing.
That said you will also need to explain how the measured acelleration went over FFA. Your compatriots have even less to say about that detail.

Given the number of times that these problems with ae911t's unsupported assertions havebeen brought up, you are embarrassing yourself by continuing to harp on it.

 

[DGM]

E X P L A I N
How one deduces that FFA can only be achieved via demolition. So far yourcompatriots have that as a bald assertion devoid of any technical backing.
That said you will also need to explain how the measured acelleration went over FFA. Your compatriots have even less to say about that detail.

Given the number of times that these problems with ae911t's unsupported assertions havebeen brought up, you are embarrassing yourself by continuing to harp on it.

It's all part of convincing their intended audience. There's no need for specifics or factual evidence when you have believers.

 

[jaydeehess]

First guess at the legals for that is:

Self assumed risk. The "chartering party" treated as an entity so the risk of hijack is from a member of the "chartering party" and therefore within itself.

The duty of care aspects start to arise when there is third party involvement.

Third party involvement such as would occur as the chartered aircraft begins coming apart as it impact the Capitol Building or the Whitehouse?

 

[ozeco41]

Third party involvement such as would occur as the chartered aircraft begins coming apart as it impact the Capitol Building or the Whitehouse?

stage 1 - my first focus point - who in the plane is at risk - my post suggesting that the charterers are one entity - so if one of them does the hijack the other members of the charter sort of involved as accessories - not "victims". So no "third party" at that stage.

stage 2 - "they" fly into something (generically they commit an act which impacts other parties) - that is your focus.

The "don't go there (yet?)" limit could be pragmatic politics - reasonable IMO - the chance of a Cessna doing serious damage not very high. The odds on someone chartering a JUMBO THEN hijacking it - remote - whether or not they "dry hire" the plane without pilot OR with pilot/crew included.

Still very preliminary thoughts so E&OE

 

[911KookDetector]

It's all part of convincing their intended audience. There's no need for specifics or factual evidence when you have believers.

It all just comes down to politics and ideology with the twoofers most of the time. Most notable charlatans like Dicky Gage, Steven E. Jones and David Ray Griffin are all anti-War protesters and despised Bush and his policies. They exploit the "believers" standard steadfast Libertarian/ anti-Bush ideologies and credulousness in order to get them to purchase endless amounts of kook DVD's, bumper stickers, posters, hats (often made out of aluminum foil) etc. from their website, thus enabling them to further their political agendas and fly first class around the country.
At no point in all of this do the CTers stop and consider why these scam artists have absolutely no scientific papers, experiments or mathematical calculations backing up their claims.

 

[chrismohr]

The freefall = controlled demolition argument Gage put out in my debate was:
1) Freefall = zero resistance
2) There's always some resistance involved, and some energy used, in breaking up the columns as they go down. That energy has the effect of slowing down the fall.
3.) Shortly before the NIST Report on Building 7 came out, Shyam Sunder at NIST actually said something very similar to what I wrote in points 1) and 2). Then NIST admitted freefall of Building 7 for 2.25 seconds and said this was consistent with what they had said before!

My responses: 1) Freefall = zero net resistance, not zero resistance
2) There are other forces possibly at play beyond just gravity and resistance, such as leveraging and torquing. And in fact, femr2 has shown slightly greater than freefall for one point on the top of the north perimeter wall of Building 7.
3) NIST has not explained any of this, and to my knowledge has never responded to 9/11 Truth's challenges of Sunder's statement that freefall = zero resistance. As I have said many times, if NST doesn't explain something for me, I can always look elsewhere to understand something I don't understand (places like right here, but also among independent, neutral scientists, which I have also done on over 100 occasions).

It seems a little unfair to say that Gage et al have no evidence that freefall = no resistance. They do explain it, I just think their explanation is incomplete, and that they are playing gotcha with things NIST says (which are not always totally 100% clear).

 

[Richard the G]

Did you say you are an engineer and design multistory steel framed buildings?

yes

 

[jaydeehess]

Chris, your post touches on one of the major problems with AE911T. They choose to do no research to bolster their own claim of demolition, instead playing gotcha with NIST.
AE911T has two focus points.
1) Prove NIST wrong. In this, no detail is too small, no amount of hyperbole or misrepresentation bordering on lying too great, and no charge of malfeasance is to be shunned.

2) Raise money. This is the main thrust of the organization. Monies raised go towards Gage's speaking tours and salary, and towards funding future fund raising campaigns. Little to none is used to fund research, especially research into proving the allegations of demolitions.

 

[Richard the G]

During the global collapse of WTC7, freefall acceleration occurred across an area the size of a football field, for 8 storeys....simultaneously!

That was a designed failure.

MM

That is an interesting hypothesis. How does one design a demolition like that.?

There was no evidence of cutter charges on any demolition photos. Nor anything seen by the hundreds of engineers who helped witht the search and recovery.

And how do you design the internal columns to fail a few seconds before the external. It would be have been some very clever engineers to have been able to identify that you could bring the whole building down by demolishing one or two columns at level 12ish

You see the official story and a CD theory could in principle be very similar. Except of course it destroys all the stupid ae911 truth arguments supporting an extravagant CD.