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9/11 Structural Engineer's poll
19

9/11 Structural Engineer's poll

9/11 Structural Engineer's poll

(OP)
A former colleague of mine who is a structural engineer (now retired and with apparently too much time on his hands smile) discusses various conspiracy theories on the net. One of them is the 9/11 theory that holds that the buildings that fell on that day did so due to a controlled demolition. (A theory he feels is “nonsense”.)

You've probably heard followers of this theory called “Truthers” (or worse). In any case, aside from telling my friend that he is/was apparently a member of the CIA (and trying to say he wasn't even a structural engineer), apparently another angle of argument is to say that the profession is somehow afraid to talk about it (noting a lack of support in journals, etc) or that my friend somehow doesn't know what the profession talks about. That got me wondering how much this is discussed beyond my (and his) experience. So the question I have as sort of a poll for structural engineers:

Is the controlled demo theory something that is a regular topic of conversation with your colleagues?

AND (if the answer to the above question is “yes”) Do you feel compelled to view it one way or the other?


Speaking for myself, I cannot think of a single time it has come up (except in conversations with my retired friend mentioned earlier). I've certainly discussed the failures on that day with other structural engineers as an example of progressive collapse. But not much beyond that.

However, public awareness on the topic (I would call it misinformation) seems to have done nothing but grow over the years......and will likely grow more in the years to come.....so I thought I'd ask fellow structural engineers for their thoughts and ideas as to be better equipped to answer the public’s concerns in the future.



RE: 9/11 Structural Engineer's poll

I am also retired and according to my wife have too much time on my hands. I've never heard of this conspiracy theory and do not think it should have any credibility. There have been numerous reports and articles of how the failures happened. My recollection is that the fires, because of the amount of jet fuel, were a big factor to the progressive collapses.

On that morning, one of our drafters came into my office to tell me a plane had crashed into one of the WTC buildings. My response was - "A plane hit the Empire State Building a long time ago and it was OK". Turned out it was a small plane.

When he came back a while later with the report that the second building was hit, we spent a good part of the day, taking turns watching TV in the conference room, and keeping the entire office updated.

Our lives were changed forever that day! And 15+ years later we are still in recovery.

gjc

RE: 9/11 Structural Engineer's poll

It is not a topic of conversation with my colleagues. It does come up from time to time within certain circles of my friends.

I can't say it's ever been presented to me in any way that can be described other than "laughable".

RE: 9/11 Structural Engineer's poll

Most of the truthers' arguments seem to center around the combustion temperature of jet fuel (kerosene), and how that's not hot enough to melt steel.

No discussion about heat building up in a confined space.

No discussion about the burning magnesium from the airframe.

No discussion about how steel weakens as it is heated even if it doesn't melt.

RE: 9/11 Structural Engineer's poll

There are aspects of that day that will never pass the smell test. The physical evidence has all since been remelted and turned into macadam, and the snippets and video segments suggesting anything but a foreign-hatched plot have faded into oblivion in most people's memories. The truther's rabid testimony is akin to ramblings of schizophrenic madmen, effectively sabotaging any sane dialogue that might be had on the subject. Ridicule and scoffing become the defense mechanisms of those who cannot mentally process the unthinkable implication. This is JFK, in that the top-tier planners and organizers behind it got away with it, be they Arabs or not.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

RE: 9/11 Structural Engineer's poll

Quote (mtu1972)


I've never heard of this conspiracy theory...

I find that very hard to believe. It has been talked about all over the net as well as being at least given lip-service, if not outright support, by certain so-called 'journalists' at places like Faux News and other Right-wing media outlets.

As for the Empire State building incident, it was not exactly a "small plane" but rather a B-25 bomber. Granted, it may have been "small" compared to the 767's that hit the Twin Towers, but relative to the size of the Empire State building itself, it was still a large aircraft. I think the big difference was that the B-25 was attempting to land in Newark after a flight from New England and therefore was not full of fuel as were the 767's that had just taken off on transcontinental flights. Also, the stone facade of the Empire State building probably prevented the complete fuselage, including the fuel tanks, from actually penetrating through the side of the building thus limiting the fire and subsequent heating threat to the actual superstructure of the building.

And for the record, I think this whole "9/11 Truther" movement is a bunch of crap. This is just another classic example of what can happen when a nation is attacked by a group utilizing asymmetrical means.

John R. Baker, P.E. (ret)
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RE: 9/11 Structural Engineer's poll

JohnRBaker - I must be oblivious but I truly had not heard any of this. I get my news from the major networks and MSNBC, Time magazine, and a Sunday newspaper. From a technical standpoint I get information from ASCE, Structure magazine, and Modern Steel Construction. I don't recall any reporting of a conspiracy theory.

Note: A quick internet search has just shown me that these theories have been in place since just after the incident. I can't believe I never stumbled on this over the last 15 years.

I do believe that the Bush administration may have overlooked some clues, but I can't accept some covert conspiracy theory.

Visited NYC last summer for the first time and one of our stops was the WTC Memorial. Like my Italian grandmother used to say, "I may be slow to learn, but I never forget". I will be doing more searches regarding this.

gjc

RE: 9/11 Structural Engineer's poll

(OP)

Quote:

I must be oblivious but I truly had not heard any of this. I get my news from the major networks and MSNBC, Time magazine, and a Sunday newspaper. From a technical standpoint I get information from ASCE, Structure magazine, and Modern Steel Construction. I don't recall any reporting of a conspiracy theory.

Don't feel bad mtu1972. There is pretty much a underground conspiracy industry out there. You can find all kinds of crazy web sites claiming all sorts of things.

Thanks for the replies so far guys. Keep them coming.

JAE, Buggar, Kootk, etc if any of you are reading this.......I'd like your input as well (i.e. some of my favorite posters on the structural boards).

RE: 9/11 Structural Engineer's poll

Quote (JohnRBaker)

As for the Empire State building incident, it was not exactly a "small plane" but rather a B-25 bomber. Granted, it may have been "small" compared to the 767's that hit the Twin Towers, but relative to the size of the Empire State building itself, it was still a large aircraft. I think the big difference was that the B-25 was attempting to land in Newark after a flight from New England and therefore was not full of fuel as were the 767's that had just taken off on transcontinental flights. Also, the stone facade of the Empire State building probably prevented the complete fuselage, including the fuel tanks, from actually penetrating through the side of the building thus limiting the fire and subsequent heating threat to the actual superstructure of the building.

The B25 actually did punch a hole through the side of the facade of the building.

http://a.abcnews.go.com/images/US/gty_esb_bomber_c...

14 people were killed, 11 of them inside the building. One of the B25's engines punched a hole in the opposite side and landed on the roof of a building about a block away.

During that incident the B-25 was on landing approach, flying in heavy fog, and was probably moving very slowly.

A B-25 also only weighs about 20,000 lb empty. Much smaller than most people think.

RE: 9/11 Structural Engineer's poll

Perhaps, but I suspect that the wings, where most of the fuel would have been stored, were sheared off, even if the main fuselage penetrated the building facade. Granted, one engine did end-up inside the building, but the other ended-up on the roof of another building a couple of blocks away indicating that NOT all of the plane slammed into the side of the building, that at least part of one wing, with the engine attached, missing the building completely. And if that B-25 had been fully loaded with fuel, and had been flying at closer to normal speed, like the 767's were, and it had hit fully and squarely on the side of the building, perhaps a bit lower down, it could have done significantly more damage than it did, perhaps even to the extent of compromising the overall structural integrity of the superstructure, maybe even to the point of causing a catastrophic collapse.

John R. Baker, P.E. (ret)
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RE: 9/11 Structural Engineer's poll

(OP)
I think another big difference was the fact the Empire State Building wasn't built with the "tube" design philosophy. Not saying anything is wrong with the approach, but it doesn't quite have the ability redistribute things in such a situation.

World Trade Center 7 (which certainly wasn't hit by a plane) had a "tube" design approach as well......but it was a bit odd in terms of it had a number of cantilevers (and other systems) to redistribute the vertical load. The building's layout (in plan view) overshot it's foundation (which was placed years prior the building being built). The result was that a lot of vertical load had to be redistributed from some of the upper floors down to the foundation. Perhaps this made the building more susceptible to the fire that brought it down.

RE: 9/11 Structural Engineer's poll

3

Quote (WARose)

the profession is somehow afraid to talk about it

THAT is an argument for controlled demolition theory? Firstly, that basic argument is part of a boiler plate tactic from people trying to muddy the waters of clarity. If they can get you on a tangent that cannot be readily disproved, then they have already won without being correct.

Secondly, there hasn't been much discussion, because 99.9% of structural engineers respect the general findings from the original NIST, ASCE, & FEMA reports. These reports aren't from some single cockamamie engineer who reads infowars.com articles all day. They consist of many layers of peer reviewed information, qualitatively and quantitatively. Is everything in those reports likely to be without flaw? - no, of course not. Of course, the doubters prey on errors, ambiguity, etc. and treat them as evidence that brings the whole system down.

We are in an age where any bozo with an internet connection is an "expert" at everything. The real experts, of whom are intimately familiar with the nuances of the circumstances at hand, are shrugged off as "insiders" and inherently corrupt. The conspiracy theorists (CT's) take advantage of these ideas and implant them as a priori. No matter the quantity/quality of evidence and rigor of corroboration, the CT's rely on tenants rooted in mistrust and respond with a barrage red herring arguments.

"It is imperative Cunth doesn't get his hands on those codes."

RE: 9/11 Structural Engineer's poll

I am not a structural engineer. However, as I watched the unfolding events of 9/11 on a TV at work I clearly recalled curious statements made by a Civil Engineering professor in an elective course some 20+ years earlier. The course was an optional 'elective' course in 'Mechanics of Materials'.

One was a statement about multi-floor steel frame buildings, that should one level collapse with more than 3 or 4 floor levels above it then typically the entire building will pancake. The other was a statement about the issues of fire damage to steel structures and the very specialized experience needed by a structural engineer to evaluate the structure afterwards, which impressed upon me the complex changes that can occur in steel under such conditions.

I have chanced upon the conspiracy theory videos on the internet but don't personally know of anyone who takes them seriously. But as an engineer I mostly interact with rational objective-thinking people who don't suffer from a paranoid world-view. Most of the conspiracy videos out there are made by those who like to troll on the fear of others rather than those who really believe in such stuff.

RE: 9/11 Structural Engineer's poll

Quote (JohnRBaker)

Perhaps, but I suspect that the wings, where most of the fuel would have been stored, were sheared off, even if the main fuselage penetrated the building facade. Granted, one engine did end-up inside the building, but the other ended-up on the roof of another building a couple of blocks away indicating that NOT all of the plane slammed into the side of the building, that at least part of one wing, with the engine attached, missing the building completely. And if that B-25 had been fully loaded with fuel, and had been flying at closer to normal speed, like the 767's were, and it had hit fully and squarely on the side of the building, perhaps a bit lower down, it could have done significantly more damage than it did, perhaps even to the extent of compromising the overall structural integrity of the superstructure, maybe even to the point of causing a catastrophic collapse.

You misunderstood.

The plane hit the building full on. Splat.

The fuselage punched a relatively clean hole right through the wall of the building. This is visible in all of the photos. Both wings left big gashes. There's not a huge number of photos available that show a lot of the facade, so its impossible to say for sure what happened to the wings themselves- I suspect they mostly disintegrated. Not a lot of mass there, as you stated.

One of the engines hit an elevator shaft and fell to the bottom. The other engine went THROUGH the building, punched another hole in the far wall, and came to rest inside of/on top of another building a little less than a block away (not a couple of blocks- 1 single block.)

This means the second engine fell about 900 feet while traveling forward only 250-300 feet- so when it exited the building it was not going very fast. But it did go through the building. All of the news accounts agree on that, and the photos that show the impact zone do as well- the engine on a B-25 is not very far from the fuselage. If the plane had hit the building in such a way that one engine could completely miss the building and be launched free, the fuselage would have basically had to impact the corner of the building, and it did not.

The fire also burned on 11 floors of the building. This was not a small fire contained on the two floors that were hit.

RE: 9/11 Structural Engineer's poll

I stand corrected smile

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
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RE: 9/11 Structural Engineer's poll

Any controlled demolition conspiracy theory about the WTC collapse is complete rubbish. I know a lot of engineers, and not one would even suggest such a thing. The WTC towers collapsed because of conspiracy of terrorists.

RE: 9/11 Structural Engineer's poll

(OP)

Quote:

(MacGruber22)
THAT is an argument for controlled demolition theory? Firstly, that basic argument is part of a boiler plate tactic from people trying to muddy the waters of clarity. If they can get you on a tangent that cannot be readily disproved, then they have already won without being correct.

Quite true. I've seen them make a variety of arguments over the years (relative to our discipline)......among them (pardon if any of them seem so preposterous as to not warrant even mentioning):

1) No skyscraper has ever collapsed from fire before. (Some will go as far to say no steel structure has ever collapsed from fire.)
2) The collapse in the WTC Towers 1&2 should stopped after some point. That is: the collapse should have been arrested after crushing a relatively small number of floors.
3) The NIST (or whomever) didn't properly model the buildings or do a proper investigation. One specific complaint in that regard is apparently they didn't "model" some shear studs and stiffeners in WTC 7 that the Truthers feel would be critical to restrain thermal expansion.

My critique:

1) As far skyscrapers go: that's not entirely accurate. The Windsor Tower (in Madrid) was gutted by fire and had the steel portion of the upper building collapse. Interestingly enough: the core of that building was made of reinforced concrete and that portion survived the fire.

As far as smaller steel buildings go....that of course happens all the time: the Kader Toy Factory (in Singapore), Dogwood Elementary (in Virginia), Mumbai North Platform, etc being notable examples.

To me, a worthwhile comparison would be a building built with the "tube" design approach being hit by a 767 going at nearly 500 mph. IOW: There aren't too many comparisons to make. (None to my knowledge.)

2) I've run some numbers for the collapse and I frankly don't see what the argument is. After the collapse initiated, we are essentially talking a overwhelming force hitting the floors below......and it snowballs from there. Based on some I've listened to, it's like they are expecting the steel to "crumple up" (for the lack of a better way to put it) and that would end it. I came out with the sections buckling before plastic deformation could take place (on the sections I looked at). (Dynamic buckling came up in a project of mine some months back, so I've had to get reacquainted with the concepts recently.)

3) Frankly, I don't get what they are saying here. I've never included shear studs and/or stiffeners in a (overall) model of a building in my life. One argument I looked in on some time back, a Truther was claiming that a web/flange stiffener was going to somehow stop a girder from growing (axially) in thermal expansion.

So the arguments range from some you feel you need to run some numbers on.......to the downright crazy.

Quote:

(MacGruber)
We are in an age where any bozo with an internet connection is an "expert" at everything. The real experts, of whom are intimately familiar with the nuances of the circumstances at hand, are shrugged off as "insiders" and inherently corrupt. The conspiracy theorists (CT's) take advantage of these ideas and implant them as a prior. No matter the quantity/quality of evidence and rigor of corroboration, the CT's rely on tenants rooted in mistrust and respond with a barrage red herring arguments.

Yep, could not have put it better myself.


Happy New Year to all! cheers

RE: 9/11 Structural Engineer's poll

I've been swithering for a couple of days over whether to post these links.

https://xkcd.com/966/

https://xkcd.com/690/

Not a subject to joke about lightly, but sometimes humour is what it takes to get people to engage their critical faculties.

A.

RE: 9/11 Structural Engineer's poll

Thanks for the new word to my vocabulary, zeusfaber. I'm sure I will have a use for "swither" at some stage.

RE: 9/11 Structural Engineer's poll

Quote (WARose)

I've run some numbers for the collapse and I frankly don't see what the argument is.

Interesting that you felt compelled to attempt this. How many hours did you dedicate?

"It is imperative Cunth doesn't get his hands on those codes."

RE: 9/11 Structural Engineer's poll

Reminds me of another thread that was here or in the Pub about Flat Earth theories.

I'm back in manufacturing now, but when I was working in a purely civil/struc eng firm, it'd get brought up from time to time. Usually, someone will have seen something on Facebook or Youtube about a truther, or have run into someone they couldn't believe was a 'truther'. Then we'd start discussing how insane their arguments were, tearing them apart and going over exactly how possible it was that the buildings' structure WOULD fail, after looking up some data points.

The idea that "people are scared to discuss it" because you don't see it in trade journals is like Glenn Beck's tired sensational strategy. He would make up some insane accusation, and then repeat "Why hasn't <person> denied this accusations or at least come out saying they aren't true?!" and make it sound like his accusations have merit /because/ they haven't specifically been denied. Truth is that the accusations are fringe-lunatic fabrications. They don't deserve the respect of being refuted in official channels that require the expense of time, effort, and someone on a payroll. The absence of refutation is not evidence of truth.

I remember when Bill Nye debated Ken Ham regarding evolution. Many people who understand evolution were irritated that Bill Nye would debate Ken Ham because it simply gave him a level of respect that his opinions (Creationism, specifically Young Earth) did not deserve, which may 'legitimize' Ham's opinions beyond their merit.

Same with 9/11 conspiracy theories. Professionals don't directly refute it in official channels because... there are much better ways to spend their/our time.

RE: 9/11 Structural Engineer's poll

And not going out of the way to refute the false claims is of course what has led to the so-called "fake-news" phenomenon. There's a large number of people out there who actually believe: "If I read it on the internet then is has to be true. After all, people are not allowed to post false claims or made-up stories as that's not how the internet works."

And while I had no intention of making this a political statement (however, Glenn Beck has already been mentioned so...), we can't ignore the political consequences of this sort of behavior where outrageous statements and/or claims are made and no one takes the proper time to refute them and set the record straight. If you don't believe that, you need to look no further than what happened in November. Case in point: The WSJ has just announced that they will no longer label the 'lies' being told by Donald Trump as 'lies', since that would be making a moral judgement and they claim that that's not the responsibly of journalists. A journalist's job, they claim, is to simply report what was said and let the reader decide whether it's true or not. When asked about the very high rate (some figures put it as high as 93%) of the times that statements made by Trump or his campaign were proven to be incorrect, or at best, grossly inaccurate, the editor of the WSJ stated that in the future they will simply consider these situations as having been a simple mistake with no intent to deceive or mislead unless it can be clearly demonstrated that that was the original intent.

Here's a link to the article discussing the new editorial policy at the WSJ:

http://www.huffingtonpost.com/entry/wall-street-jo...

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: 9/11 Structural Engineer's poll

I'm ok with WSJ's stance, and think they made the correct 'journalism-centric' decision. Fact-checking is a separate item from journalism. In interviews, it's often normal to challenge statements and claims if demonstrably false, or ask for clarification. When reporting incidents, it becomes too much of an editorial if the journalist chooses to constantly pepper in additive assessments.

Then again, there's the old adage about politicians and salesmen. How can you tell when they're lying? Their lips are moving! (or they're tweeting, to bring it current, I suppose)

NPR has a fantastic journalism ethics handbook available for anyone to read, and they amend/update it as required. It can be as minor as the correct pronoun to use for a person or as extreme as whether or not to address someone by an unjustified title and when it's unjustifiable. ( http://ethics.npr.org/ ) and I'm sure the WSJ has similar. That doesn't mean NPR won't occasionally post articles about "Truth-metering" someone's speech, but it'd be separate from the report of the speech itself.

It's the difference between an editorial and a news article. Especially when truth is neither black nor white, and the grey can never truly be 100% neutral when one considers what is left UNSAID or UNMENTIONED can sway things as much as how you phrase what IS said or mentioned.

RE: 9/11 Structural Engineer's poll

(OP)

Quote:

(MacGruber22)

How many hours did you dedicate?

Not many. Just a few. It was a slow day at work anyway. smile

RE: 9/11 Structural Engineer's poll

Oddly, in the last paragraph of the HP article, the WP editor tries to compare HRC's falsehoods with Trump's, but seems to forget there's a matter of massively different numbers. Of course, WP is a conservative bastion, isn't it?

TTFN (ta ta for now)
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RE: 9/11 Structural Engineer's poll

He was an editor for the WSJ (Wall Street Journal) which is part of Rupert Murdoch's media group. And yes, there is also the problem of "false equivalency" which is always used to justify the Right's defense of anything, including their support of Trump.

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
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RE: 9/11 Structural Engineer's poll

"I remember when Bill Nye debated Ken Ham regarding evolution. Many people who understand evolution were irritated that Bill Nye would debate Ken Ham because it simply gave him a level of respect that his opinions (Creationism, specifically Young Earth) did not deserve, which may 'legitimize' Ham's opinions beyond their merit."

Many of us who have met Bill Nye are irritated that people give him a level of respect that his qualifications do not deserve. And he's a bit of a twit...

RE: 9/11 Structural Engineer's poll

I don't know much more than that he's a TV celebrity, champions scientific endeavors, and worked as a mech eng for Boeing, years ago. I don't think he gets much more consideration than that. I don't think anyone believes he's our generations Einstein. He's just popular.

RE: 9/11 Structural Engineer's poll

(OP)
Nye isn't my favorite skeptic.....that would go to Michael Shermer. I've been impressed with him most times I've seen him.

RE: 9/11 Structural Engineer's poll

Am I reading this right? The profession is afraid to talk about the controlled demolition theory as evidenced by a lack of support for it in the literature? There's probably not much discussion on or support for the Flat Earth Theory in geology literature or heliocentrism in astronomy literature either. Not because those professions are afraid to tackle those ideas, but because the ideas are nonsense and not worth discussing.

Surely it can't be that the profession is afraid of talking about the collapse in general, given it's at worst the second most studied case in progressive collapse design behind the Murrah Building. A search of "progressive collapse" "world trade center" brought up 1240 results on Google Scholar just now. For reference, a search of "progressive collapse" "murrah building" brings up 337 and "progressive collapse" "oklahoma city" brings up 705.

RE: 9/11 Structural Engineer's poll

Quote (MrHershey)


There's probably not much discussion on or support for the Flat Earth Theory in geology literature or heliocentrism in astronomy literature either.

Don't you mean 'geocentrism'...

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
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RE: 9/11 Structural Engineer's poll

I haven't spent a lot of time pondering this, but I did receive a publication from this organization a while back. It does seem strange to me, if the evidence they provide is true, that the building accelerated downward and there was no "pancaking" at each floor. If this was a top down collapse, wouldn't there be a momentary pause as the columns at each floor absorbed the additional weight from above before buckling? A thought I have to oppose this theory is that there is in fact a pause as the top 20+ floors slammed into the lower portion of the standing structure. This impact force was significantly more than the columns below could withstand, and therefore, wouldn't buckling be initiated at all/most levels simultaneously?

https://www.youtube.com/watch?v=ydu9M_64lRU&fe...

RE: 9/11 Structural Engineer's poll

....therefore, wouldn't buckling be initiated at all/most levels simultaneously?

Yes.

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RE: 9/11 Structural Engineer's poll

(OP)

Quote:

BadgerPE

If this was a top down collapse, wouldn't there be a momentary pause as the columns at each floor absorbed the additional weight from above before buckling?

I pondered that one once myself. However, given how quickly buckling can occur, it isn't that suspicious.

Quote:

BadgerPE

A thought I have to oppose this theory is that there is in fact a pause as the top 20+ floors slammed into the lower portion of the standing structure. This impact force was significantly more than the columns below could withstand, and therefore, wouldn't buckling be initiated at all/most levels simultaneously?

https://www.youtube.com/watch?v=ydu9M_64lRU&fe...

Let me say first: I am no impact guru. However, as I understand such a collision, the elastic portion that propagated very quickly would likely not buckle anything (by my numbers). The follow up plastic wave front (with much higher stresses and slower propagation) is likely what did it. That is why there was buckling not that far from the impacted points (as it snowballed).

By the way (regarding your YoutTube clip) I'd be careful listening to AE911Truth for much. (If you will notice, just about everyone they cite is not a structural engineer.) I've seen a lot of questionable claims from them at times.

RE: 9/11 Structural Engineer's poll

Quote (JohnRBaker)

Don't you mean 'geocentrism'...

LOL. Yes. Can't even refer to it correctly when I try.

RE: 9/11 Structural Engineer's poll

WAR

I certainly don't believe much of what AE911 puts out, but rather thought this video brought up a point worth discussing. I have never been a believer of the controlled demo argument, but I paused a bit with this theory because I never considered that possibility before.

RE: 9/11 Structural Engineer's poll

" If this was a top down collapse, wouldn't there be a momentary pause as the columns at each floor absorbed the additional weight from above before buckling?"

No, because this is a dynamics problem not statics. The floors moving down have tremendous momentum and have already collapsed together so they basically act as a huge hammer with stored energy. By the same token each floor below also has mass and some spring so the floor being impacted bears the brunt of the impact, progressively. Thus progressive collapse.

RE: 9/11 Structural Engineer's poll

2
It was not a top down collapse. The middle collapsed due to the impact damage and fire, causing the entire top section to fall on the bottom part. The only progressive collapse mechanism in play was the top section collapsing from the bottom up, and the bottom section collapsing from the top down, as the two came together.

RE: 9/11 Structural Engineer's poll

(OP)

Quote:

BadgerPE
I have never been a believer of the controlled demo argument, but I paused a bit with this theory because I never considered that possibility before.


It is somewhat intriguing when you first start looking at it (i.e. why it failed). In my case, it came up right at a time when I was working on several dynamic loading problems.

RE: 9/11 Structural Engineer's poll

is it at all "odd" that it pancaked so nicely ? wouldn't one side of the building (obviously) receive more damage than the other ? wouldn't the fuel fire be concentrated on that side too ? maybe the 767s penetrated deep into the building, and so distributed the damage. if so that was a lucky day for us; can you imagine the additional damage if the towers had toppled ?

another day in paradise, or is paradise one day closer ?

RE: 9/11 Structural Engineer's poll

rb1957: your answer "may" be in here somewhere...Link

"It is imperative Cunth doesn't get his hands on those codes."

RE: 9/11 Structural Engineer's poll

Most videos show that the first tower to collapse had its upper section severely tilted. However, I suspect the floorings tended to collapse vertically. One probable error the terrorists made was that they impacted the buildings too high on the structure; in both cases, the planes impacted in the middle of the upper half of the buildings. Had they come in from a different direction, they could hit below the 40th floors, which probably would have resulted in a toppling. I think we dodged a much worst catastrophe that could have happened.

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RE: 9/11 Structural Engineer's poll

The alternative to that is that 40+ stories lower, the structure of those buildings was much more robust and the fires would have been easier to fight... so perhaps the collapse would have been avoided entirely.

RE: 9/11 Structural Engineer's poll

jgKRI,
The tower which collapsed first was the second to be impacted, and at a lower level. The additional load of the building above accelerated the collapse.

RE: 9/11 Structural Engineer's poll

"so perhaps the collapse would have been avoided entirely"

rumor had it that Bin Laden had some structural engineering, so may be those impact points were specifically chosen...

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RE: 9/11 Structural Engineer's poll

Quote (hokie66)

The tower which collapsed first was the second to be impacted, and at a lower level. The additional load of the building above accelerated the collapse.

I don't know enough about the buildings (and I'm also not an SE!) to state either way what could or would have happened had a plane impacted that much lower- my post was intended as food for thought only.

My understanding is that a major contributor to the collapse was how difficult it was for firefighters to work effectively that high- if the fires had been on the 30th floor instead of the 90th floor, it seems to me the fires would have been significantly easier to fight. Firefighters could have possibly used the roofs of adjoining buildings, the floors with active fires would have been easier to reach, etc.

Again, just food for though. I'm not an expert and don't claim to be. It is certainly possible that a lower impact would have caused the building(s) to topple which could have caused much more damage.

RE: 9/11 Structural Engineer's poll

IR, I've studied a lot of structural engineering.

I wouldn't have the slightest idea where to select impact points for maximum effect-- at least not without drawings and a lot of time.

I'd imagine that the instructions given were incredibly rudimentary.

RE: 9/11 Structural Engineer's poll

Quote (Lomarandil)

I wouldn't have the slightest idea where to select impact points for maximum effect-- at least not without drawings and a lot of time.

There's also the simple fact that flying a jet airliner at 500 mph is not a precision act.

If you instructed someone to hit a building at a specific floor, to do so in the real world would be very difficult.

RE: 9/11 Structural Engineer's poll

Especially in a place like Manhattan, with lots of other tall buildings around.

RE: 9/11 Structural Engineer's poll

From what I understand, the fire heated up the angle seat brackets that supported the steel floor trusses and thus deformed enough for the trusses to 'fall off.'

Floor pancaking initiated and thus the effective length for the vertical elements became ever longer. Without intermediate restraints (floors) the vertical elements buckled, which initiated the total collapse of the building.

It is interesting however, that it did fall within it's own footprint. I would have imagined that it be very unlikely when global buckling is involved?

RE: 9/11 Structural Engineer's poll

Quote (Trenno)

It is interesting however, that it did fall within it's own footprint.

I see this thought a lot in conspiracy videos and discussion..

Does anyone really think that phrase is accurate? I certainly don't. Buildings as far away as 500+ feet from either tower were damaged by debris, and not just shards of glass; ton-scale sections of the facade, floor sections, and other parts of the structure were thrown that far.

'Within it's own footprint' to me implies that the debris fell entirely within a 208 ft. x 208 ft. square centered on the original foundation. It certainly doesn't fit with the fact that big pieces of the building fell in places that were offset from the building by 35%-40% of its total height.

As a disclaimer, I most certainly do not support claims that there were bombs or other nonsense involved. A 30 story section of that building falling 800 or 900 feet contains a LOT of energy, which had to go somewhere.

RE: 9/11 Structural Engineer's poll

What the CTs are not talking about random debris, but that the bulk of the debris is contained almost completely within the plaza, so there was no toppling. Essentially, the roofs of the two towers fell within the confines of the plaza, as even the adjacent streets were relatively easily cleared for the rescue and salvage operations.


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RE: 9/11 Structural Engineer's poll

(OP)
Good pics IRstuff. I think when conspiracy theorists go on about "falling in its own footprint", it is a clumsy way of noting the fact it fell straight down (even if some of the debris fell outside the footprint).

I guess they thought it should have come down like a tree. (Which would not have made much sense.)

RE: 9/11 Structural Engineer's poll

Well, I have to admit that I was puzzled by the North tower, since its top was leaning over quite a bit, so I had expected some sort of off-axis impulse train that would have caused the north tower to collapse and tilt to the south east, but the rest of the tower pretty much collapsed vertically in reality.

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RE: 9/11 Structural Engineer's poll

There was some tilting of the top of both towers, toward the side which was impacted. The South Tower, 2WTC, collapsed first because although it was impacted last, the damaged area was lower.

RE: 9/11 Structural Engineer's poll

So Building 7 fell due to an office fire. I read somewhere, a critical transfer element failed and thus lead to the progressive collapse.

Anybody able to elaborate?

There's been a recent push in the Aus standards (Link) for Structural Robustness - certainly gives a good argument to minimise transfers when debating with the Architect!

RE: 9/11 Structural Engineer's poll

(OP)

Quote:

(Trenno)
So Building 7 fell due to an office fire. I read somewhere, a critical transfer element failed and thus lead to the progressive collapse.

Anybody able to elaborate?

Basically (as I have said elsewhere in this thread), WTC 7 was a bit odd in terms of it had a number of cantilevers (and other systems) to redistribute the vertical load. The building's layout (in plan view) overshot it's foundation (which was placed years prior the building being built). The result was that a lot of vertical load had to be redistributed from some of the upper floors down to the foundation. (A pic: https://en.wikipedia.org/wiki/WTC_7#/media/File:Wt...) Perhaps this made the building more susceptible to the fire that brought it down.

As far as the actual "trigger" goes (i..e. what initiated the collapse).....the frequently mentioned culprit is a girder that was forced off its seat by thermal expansion of some beams that framed into it. This loss of bracing caused "Column 79" to buckle......and down the rest came.

I've read some "Truther" arguments that say the girder could not have been physically forced off its seat by the thermal expansion involved. While that may be true.....I ran some calculations that show very little movement was required to over stress the seat with the day to day gravity loads it would see.

RE: 9/11 Structural Engineer's poll

7 has always been a bit of an enigma to me, but it helps to hear a more technical explanation (not a structural guy). I've witnessed chain-of-event situations in mechanical failures, albeit on a much, much smaller scale and complexity, that defy imagination at first glance, and then make perfect sense once the root cause analysis is performed.

What doesn't help is Larry Silverstein going on national TV and saying "that we decided to pull it". I read somewhere that he came out smelling like a rose on 7, to the tune of $500 Million to the good, after insurance settlements.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

RE: 9/11 Structural Engineer's poll

I saw a purported video of the collapse of building seven. A friend who is a retired demolition contractor said that it showed a textbook case of controlled demolition. The penthouse subsides first and then the entire building starts to drop as a unit.
The problem is, the video was taken from some distance away and I have never been assured that it is in fact a video of building seven and not some other building.
Would someone use a video of a different building to make a point on the internet?
As for Larry Silverstein; Could he have meant evacuate it?
At some point it would make good sense to acknowledge that the fires could not be extinguished and "Pull" out first responders.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: 9/11 Structural Engineer's poll

Verbatim - "I remember getting a call from the fire department commander, telling me that they were not sure they were gonna be able to contain the fire, and I said, 'We've had such terrible loss of life, maybe the smartest thing to do is pull it.' And they made that decision to pull and then we watched the building collapse." –Larry Silverstein

It could be taken either way, but it's a very curious way to state "we decided to get everyone out". When he says "pull IT", IT is a very strange way to refer to people. Sounds like he's talking about an object, like maybe a building.

And then there is the underlying detail that buildings are not simply "pulled" on a moments notice. Weeks of preparation = planning and foreknowledge. Mind-boggling implication.

My opinion, the jury is still out on the whole damned day. I may be callous, but for all of the good that there actually is in the world, mankind is capable of terrible, unthinkable, incomprehensible evil. For most of us, to think of something other than the accepted narrative, to ponder what the alternative really entails, simply overloads cognitive reasoning. I'm not 100% convinced one way or the other. I'm a naturally suspicious person, and too many things don't add up, but the "evidence" that most of the nut-job conspirists put out for public consumption doesn't hold a lot of water, either. One thing I am convinced of, is that if there is another side to this, it will never see the light of day.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

RE: 9/11 Structural Engineer's poll

Or maybe he meant to say "pull out" and just mis-speaked.

RE: 9/11 Structural Engineer's poll

BTW - nobody was in 7 at that time. It had already been evacuated, so the "loss of life" comment is also unclear. 7 had no casualties that day.

Food for thought ~

Craig Bartmer, a former officer of the NYPD [1]:
"I walked around it (Building 7). I saw a hole. I didn't see a hole bad enough to knock a building down, though," said Bartmer. "Yeah there was definitely fire in the building, but I didn't hear any I didn't hear any creaking, or I didn't hear any indication that it was going to come down. And all of a sudden the radios exploded and everyone started screaming 'get away, get away, get away from it!' It was at that moment ...I looked up, and it was nothing I would ever imagine seeing in my life. The thing started pealing in on itself ...Somebody grabbed my shoulder and I started running, and the shit's hitting the ground behind me, and the whole time you're hearing "boom, boom, boom, boom, boom." I think I know an explosion when I hear it ...Yeah it had some damage to it, but nothing like what they're saying ...Nothing to account for what we saw I am shocked at the story we've heard about it to be quite honest."

In his book dealing exclusively with the mystery of WTC 7 collapse, David Ray Griffin has devoted an entire chapter to disregarding of the testimonial evidence by NIST. He quotes a journalist, Peter Demarco of the New York Daily News [2]:
There was a rumble. The building's top row of windows popped out. Then all the windows of the 39th floor popped out. Then the thirty eighth floor. Pop! Pop! Pop! was all you heard until the building sunk into a rising cloud of gray.

-----
While the 9/11 Commission ignored WTC 7 altogether in its report, NIST (National Institute of Safety Technology) did file several reports on their studies of the collapse of WTC 7. While NIST went to lengths in its tortuous analyses to state that it found no evidence of a demolition job in WTC 7, it was not honest in its study because it entirely ignored testimony of witnesses from both the inside and outside of WTC 7. With regard to the Twin Towers both the NIST as well as the 9/11 Commission had ignored witness testimony because eye witnesses to the event, numerous survivors from within the buildings, as well as those who watched things from very close quarters, stated unambiguously and consistently that bombs kept going off in all buildings.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

RE: 9/11 Structural Engineer's poll

Explosions are NOT indicative of bombs, per se. If you were to torch your house, you'd probably hear quite a few explosions, unrelated to the actual bombs in your basement. Cans of solvents, cleaners, etc. make fairly large bangs when they get cooked.

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RE: 9/11 Structural Engineer's poll

Agree with you IRstuff, there are other things that could have produced popping noises. However, even if there were a lot of spray cans, etc lying about in the buildings, would that have the force and energy to blow out windows of the type used in commercial highrises? Doubtful. A couple cans of air freshener or furniture polish just wouldn't do it. And there would be no reason for all of these aerosol containers to begin spontaneously bursting on floors of the building which had no fire. I remember a television interview of several fire dept personnel that day or shortly after that mentioned "bombs going off all over the place". They had been on the lower floors of 1 or 2 just prior to collapse, I don't remember which.

As a kid I used to have great fun throwing aerosol cans into the burn barrel and waiting for the ensuing explosion. Although they were better than black cats and cherry bombs, they were still pretty tame. The sound certainly would not carry through multiple floors of a finished building, nor would the concussion of what little shockwave they generate. Small quantities of solvents, household chemicals, etc are all relatively low energy. They just don't have the speed and energy content to propagate the kind of shockwave that commands your attention.

It's a very interesting subject. I love discussing it, but the first reaction of most people is anger when it is suggested that anything other than the official government narrative could have a spark of merit.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

RE: 9/11 Structural Engineer's poll

Are these people saying that the explosives were planted just prior to the collisions? That alone is challenging, since a typical demo is done with the building stripped, so that the specific members that need to be blown are readily accessible.

Are these people also saying that somehow, the rather imprecise process of crashing a jet into a building resulted in exact correlation with the a priori placed explosives? Or are they saying the explosives were placed on every single floor and that someone, somehow, was able to set up the specific explosives corresponding to the actual crash locations of the planes?

Or are they saying the explosives were planted when the buildings were built, in anticipation of this event 28 years after the construction? I kind of like this last scenario; it shows how deep the government conspiracy extends winky smile

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RE: 9/11 Structural Engineer's poll

3
I've always believed strongly that the 'explosions' people refer to are the rapid failure of brittle elements of the structure such as windows, parts of the facade, and perhaps of the structural elements themselves.

In response to the veracity of eye witness testimony, I have three responses:

1) The average American has never heard anything actually explode, outside of a Michael Bay film. When a building is coming down, there's going to be a lot of things failing in a lot of different ways, generating a LOT of noise. There's lots of very large, very heavy things crashing into other large, heavy things with a lot of impact energy. That can be very loud, and can do things like make the floor of a building vibrate in a very unfamiliar way. Without understanding what is happening around them, what is the average person going to call an event which is extremely loud- maybe the loudest sound they have ever and will ever hear- combined with a building moving around them in ways they never thought possible? What vocabulary do they have to describe this event? 'Explosion' is one of the few terms that everyone knows.

2) The average American has what I describe as net-negative understanding of engineering (incorrect conclusions based on inaccurate assumptions because some complex engineering topics appear simple to the uninitiated), meaning that they have no idea how fragile something like a building can be when the right forces or stimuli are applied. They assume that buildings and bridges are monoliths that are impervious to damage and will last forever no matter what they are subjected to. We, as trained engineers, obviously know this is not the case. They don't understand things like the simply massive amount of energy contained in a fully loaded jet traveling at 500 mph, or that very large steel structures are often only strong when loaded the way they were designed to be loaded.

3) Ask any cop, or accident investigator, or anyone else who deals with witness testimony on a daily basis and they will all tell you the same thing: witness testimony is unreliable as often as not. People see things that aren't there, recall events in the wrong order, see faces they think they recognize, on and on.. not because they mean ill or are unintelligent, but because the human mind is not a perfect receptor and processor of information, and it often 'modifies' memories to make things fit within the person's understanding of the world. This is a fact, based on years of psychological study. If you don't believe it, there is ample reading about it. Add a massive adrenaline hit to the mix (which, biologically, does things like make lights brighter as pupils dilate and sounds louder as the brain goes into full fight or flight) and people's recollections of simple events can very quickly become unreliable.

RE: 9/11 Structural Engineer's poll

(OP)
Look and (especially) listen to any controlled demo and then compare it to the collapses on 9/11. You'll see and hear the differences pretty quick.

By the way, sorry to say a 17 story building collapsed today in Tehran (from fire):

https://www.youtube.com/watch?v=sPGr4D1-zDI

Condolences to the families of the firefighters who died.

RE: 9/11 Structural Engineer's poll

Quote (ornerynorsk)

My opinion, the jury is still out on the whole damned day. I may be callous, but for all of the good that there actually is in the world, mankind is capable of terrible, unthinkable, incomprehensible evil. For most of us, to think of something other than the accepted narrative, to ponder what the alternative really entails, simply overloads cognitive reasoning. I'm not 100% convinced one way or the other. I'm a naturally suspicious person, and too many things don't add up, but the "evidence" that most of the nut-job conspirists put out for public consumption doesn't hold a lot of water, either. One thing I am convinced of, is that if there is another side to this, it will never see the light of day.

This is an unbelievable paragraph. You go from broad speculation that suggests demolition to complaining about conspiracy theorists and their "evidence". Your comment regarding an evil world fits squarely into "evidence".

You give off the vibe that you get your second medical opinions from your plumber.






"It is imperative Cunth doesn't get his hands on those codes."

RE: 9/11 Structural Engineer's poll

IRstuff, I don't think anyone is disputing that it wouldn't be a challenge. Challenging, yes, impossible, no. In addition, 7 was never hit by a plane. Pre-planted 28 years in advance? Not sure I've ever heard that one, but let's just say highly unlikely :>). Yes, I know . . . . sarcasm.

Good points, everyone. As I said before, I am not 100% convinced one way or the other, though I do steer toward the official version. After all, 100's of people would be privy to the operation were it an actual conspiracy. I really don't see that many people being able to keep a secret of that scope and magnitude, even under the threat of death. Is that kind of evil possible in our own government? You better believe it.

Anyway, once we fear to play the devil's advocate, if even for the sake of casual discussion instead of actual discovery, we all become yes-men. Bought and paid for. The danger lies in summarily dismissing ideas which venture outside of what we consider to be normal, particularly where there are some unmitigated outliers that muddy the lens and absolute proof is not necessarily possible. But, it's really not normal to intentionally fly airplanes into buildings then, is it?

So, how many of you take the Warren Report at face value??? surprise Haha. Really, let's not go there.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

RE: 9/11 Structural Engineer's poll

MacGruber22, I'm not sure what is so unbelievable about not being convinced 100% one way or the other. Kudos to you if your mind is made up. I like to think from more than one angle. I was not aware that this thread was exclusive to the "Yep, that's exactly the way it happened" club.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

RE: 9/11 Structural Engineer's poll

(OP)

Quote:

(ornerynorsk)
I was not aware that this thread was exclusive to the "Yep, that's exactly the way it happened" club.

It isn't. I (for one) welcome alternative p.o.v.(s).

I especially would like to hear the commentary of a impact guru (on some of the things I have said and his/her comments in general).

RE: 9/11 Structural Engineer's poll

Thanks WARose. I love hearing both sides, as well. It really does deserve to be discussed from all angles, if for no other reason than to respectfully exhaust all possibilities for the memories of the 2996, all those who have died from related causes, all those who have yet to die as a result of exposure to dust and debris, and all of those who had their loved ones mercilessly ripped from their lives. That miniscule shred of uncertainty demands at least some attention.

If I were a betting man, I would bet that there are plenty of folks on Eng-Tips who share at least some doubt, as well, but aren't comfortable being on the "wrong" side of the discussion. That's OK, though, for some us that is our comfort zone. If it causes someone to question and think, to open a door and peer into those otherwise verboten places, whether or not they participate, that's what separates us from the animals.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

RE: 9/11 Structural Engineer's poll

(OP)

Quote:

(ornerynorsk)
If I were a betting man, I would bet that there are plenty of folks on Eng-Tips who share at least some doubt, as well, but aren't comfortable being on the "wrong" side of the discussion.

In any failure, there is going to be some doubt/questions. In this case especially because we are talking a situation [with regards to WTC 1&2] involving two very complicated processes: impact and dynamic buckling. Even most structural engineers don't deal with those topics on a day to day basis.

RE: 9/11 Structural Engineer's poll


ornerynorask - you are more than welcome to have any opinion you want here or anywhere else. That doesn't mean you get to be sheltered from strong criticism of your generalizations and reliance on allusion/doubt as evidence.

Quote (ornerynorsk)

It really does deserve to be discussed from all angles, if for no other reason than to respectfully exhaust all possibilities for the memories of the 2996, all those who have died from related causes, all those who have yet to die as a result of exposure to dust and debris, and all of those who had their loved ones mercilessly ripped from their lives.

That is called a red herring argument. Now, there is obviously a place for pathos in many argumentative situations. However, it is not substitute for evidence and analytical rigor that is required to evaluate the mechanics of such a complicated building collapse. In your search for an alternate cause to the collapse, you may find better footing by sticking to challenging the specific investigative engineering findings in the previous reports.

"It is imperative Cunth doesn't get his hands on those codes."

RE: 9/11 Structural Engineer's poll

The bigger challenge with the conspiracy theories is to what end?

Precipitating a war with people with a penchant for suicide bombing and general fanaticism doesn't seem like a plausible goal.

And unless you're one to believe that the the Illuminati or some other group are actually running the world, the probability of achieving any particular desired outcome is very low, so where's the return on investment?

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RE: 9/11 Structural Engineer's poll

Although, I do suppose that it's quite odd that these guys haven't even come close to anything similar in the last 16 years. That just seems really surprising, given how vulnerable much of our infrastructure is. The more complex something is, the easier it is to gum up the works. I can think of a number of things that would be reasonably spectacular, but would involve much in the way of equipment or planning.

Given how leaky our borders are, it's unclear to me why all sorts of odds and ends haven't snuck their way into the country. Moreover, there are lots of supplies that are already in-country that could suborned into lethal objects.

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RE: 9/11 Structural Engineer's poll

To what end, indeed. But, that is the kind of response from someone who isn't a thrill seeker in that department. Conspiracy theorists live in the moment of the argument; enjoying the tactics of deflection and purposeful confusion. It is fun to be ornery and a contrarian for some people. The end game doesn't ever come to fruition, because it doesn't matter.

"It is imperative Cunth doesn't get his hands on those codes."

RE: 9/11 Structural Engineer's poll

(OP)

Quote:

(IRstuff)
The bigger challenge with the conspiracy theories is to what end?

Precipitating a war with people with a penchant for suicide bombing and general fanaticism doesn't seem like a plausible goal.


The explanation I have typically heard is to perpetuate American global hegemony (and secure resources) by getting us into several wars in the Middle East. Frequently cited as the smoking gun for this plan are documents by PNAC [Project for the New American Century] written years in advance. (Some of which call for regime change in Iraq.)

Obviously the theory has a few holes in it.....one of the main ones being the government didn't claim that a single hijacker's nation of origin was Iraq. So if that was the plan.....it was poorly executed.

But your question "....to what end?" is very applicable to conspiracy theorists themselves. The fact of the matter is: quite a few of them I have run into over the years (regardless of the particular conspiracy) have a agenda in mind. If you look at everyone they suspect, it is (in fact) people ideologically opposed to their beliefs. So they are starting with a desired outcome and working backwards from there. The goal typically is some sort of political/societal change they want. And these theories serve as some sort of rallying cry/banner for them to that end.

RE: 9/11 Structural Engineer's poll

I am all for considered criticism of just about everything- the law, the government, engineering disasters, whatever.

Careful, considerate investigation and analysis is what keeps things like building design, auto and airline safety, and a million other engineering endeavors on a constant path of improvement.

But there eventually becomes a point where the evidence points at a specific chain of events, and further speculation in the face of evidence becomes not only wasted effort, but counter productive.


With regard to the conspiracy, none of us will ever know who knew what or at what time. It is entirely possible that some government employee at some level knew this attack would happen and failed to act, or aided in the conditions that allowed it, or whatever.

But ultimately the political side and the physical events that took place are separate elements. Even if it's found 10 years from now in an email that the director of the CIA planned the whole thing- that does not change the fact that the preponderance of physical evidence points to the fact that planes hit the buildings and the buildings collapsed as a result.

So many conspiracy 'theories' I have heard or read insists that GEORGE BUSH KNEW IT ALL or whatever and that because of that 'fact' it must have been a mythical nuclear warhead in the basement.

RE: 9/11 Structural Engineer's poll

Quote (IRstuff)


The bigger challenge with the conspiracy theories is to what end?

Precipitating a war with people with a penchant for suicide bombing and general fanaticism doesn't seem like a plausible goal.

I like the theory about how they planted the explosives in the WTC when they built it. It is the early seventies, and of course, you must explain to a bunch of architects, engineers and construction workers why they must not under any circumstances, discuss what you are doing. It is so obvious that somebody is going to crash giant airliners into the building, and we need mass carnage, and we need to blame it on the Iraqis.

--
JHG

RE: 9/11 Structural Engineer's poll

The long games are always the best winky smile

One might argue that it was in anticipation that the balance of power in that corner of the Middle East would shift to Iraq, since we allowed the Shah of Iran to be deposed in 1979 and then propped up Saddam as a counter to the Shite ascendency, but knowing full well that Saddam was not that controllable and would need to be deposed through some justifiable pretext. It was certainly clear by the first Gulf War that we had lost control of Saddam, who was hell bent on fighting the Iranians. So, it was around 1991 that WTC 1 and 2 were prepared and set up for what would happen 10 years later.

Sounds like the making of a rousing conspiracy thriller, eh?

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RE: 9/11 Structural Engineer's poll

IRStuff,

Was the spelling in that last post on purpose?

A.

RE: 9/11 Structural Engineer's poll

On purpose, in the sense that I knowingly spelled it way, but I had intended the meaning to be for the other spelling.

Nevertheless, it's not necessarily incorrect, since the Iranians were very well equipped by the US during the Shah's reign; we sold them fairly high-end military hardware, since they were ostensibly our surrogates in that region. At the start of their first Gulf War, the Iranians supposedly had a fairly large number of F-4s, F-5s, and F-14s in their force structure. They had just missed out on getting delivery on a large number of US F-16s due order termination because of the revolution.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
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RE: 9/11 Structural Engineer's poll

All I know those buildings fell at free fall gravity speed with little resistance and 40 stories of reinforce concrete elevator shafts were turn into dust.

RE: 9/11 Structural Engineer's poll

Bobby,
What gave you the idea that the elevator shafts were reinforced concrete? These were steel framed structures, including both the exterior and interior walls.

RE: 9/11 Structural Engineer's poll

BobbyEngineer007,

No need to be bashful or passive. Come out and say what you want to say.

"It is imperative Cunth doesn't get his hands on those codes."

RE: 9/11 Structural Engineer's poll

You can't 'know' that the towers fell at 'free fall gravity' speed because they didn't fall at free fall speed.

Watch video, count the seconds. It didn't happen.

RE: 9/11 Structural Engineer's poll

(OP)

Quote:

(hokie66)
What gave you the idea that the elevator shafts were reinforced concrete? These were steel framed structures, including both the exterior and interior walls.

Quite true. This is something the Truthers have been pushing for years. But they have mistaken a sheet rock perimeter as RC walls. (As incredible as that sounds.)

I looked in on an argument once where they [the Truthers] were claiming the elevator shaft(s) in the buildings were (also) hermetically sealed.

Another reason to hope you get to your floor fast. wink

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