29 Structural & Civil Engineers Cite Evidence for Controlled Explosive Demolition

[Christopher7]

I got it from two lines before the freefall phase quote you like so much. It says that just before the final collapse, and after the core columns had collapsed, all perimeter columns were laterally unsupported on three out of four sides.

I read pg 1A 45 and 9-1 602 again. It does not say that. Post the paragraph you are referring to or admit that you are lying again. The exterior columns were supported in the horizontal and vertical planes in both directions.

It went from not not falling to freefall in almost 2 seconds. Buckling is an unstable phenomenon. Asymmetric loads cause buckling, which creates more asymmetry etc. Now your hunches as to how long that takes are not really useful. I prefer numbers.

The slight movement was at the kink and does not constitute falling. The north west corner and west wall went from no movement to free fall acceleration.

...leaving them free to buckle in any perpendicular direction. Read the quote from the report above.

In or out

Do you have a source for this claim? Where were the hot spots?

NIST L pg 22-26 The data collection on fire progression was complete when this report was published.
http://wtc.nist.gov/progress_report_june04/appendixl.pdf

Note that on pg 26 is says the fire on floor 12 had burned out by 4:45PM.

Didn't you see the math? The model shows exterior colums buckling between at least floors 7 and 14. (figures 12-62 and 12-63), meaning these columns were unsupported over about that length before buckling. Normally the columns are unsupported over the length of one storey, but at that point a length of 7 storeys or more.

When the global collapse began, none of the exterior couumns were supported by the floor slabs on any floor.

Load bearing capacity for columns is proportional to the inverse square of the unsupported length.

Source?

That is, if I increase the unsupported length by a factor of 7, the load bearing capacity will decrease by a factor 7². Asymmetry in the loading can further decrease this dramatically, as you will see as soon as you stand on an empty soda can.

Your premice that the exterior columns were unsupported for 7 floors is incorrect. When the global collapse began, none of the exterior couumns were supported by the floor slabs on any floor. Furthermore, you are assuming no lateral support in the horizontal plane of the wall. This is also incorrect.

Now assuming that the loadbearing capacity is 1% of its orignal value,

That's a false assumption because it's based on faulty assumptions.

The load berring the opposing force to the collapse is 1% of the weight of the top part of the building. The top part will then be pulled down by a force of 99% of its own weight, causing it to fall at 99% of g.

No. The columns will buckle but equating 99% of the weight to the speed is popycock. Show the formula and math before making claims.

But that is not the way NIST said it happened. NIST said the all the core columns collapsed over 7 floors progressing from east to west and they had all collapsed before the onset of 'global collapse'. That did not happen in the video.

What? No they had all buckled, not collapsed.

Same thing. When a column buckles, it collapses.

that is, the insides of the building were not supported anymore, and therefore also not structurally connected to the perimeter anymore.

Wrong. The interior columns were still connected to the exterior walls thru the floor beams. NIST states the core pulled the exterior walls down.

The horizontal progression of column failures across the core between floors 7 and 14, prior to global collapse, does NOT happen in the NIST video!

They say the model collapsed at free fall acceleration but it can't buckle the walls as shown and fall at free fall acceleration.

I'm sure this made sense to you when you wrote it down, but I'm not sure where you get this bizarre disconnect from.
The exterior columns clearly buckle in the model, and the top part falls at freefall acceleration in the model, and does so while the columns are buckling.

Impossible. The top part cannot fall at free fall acceleration and do any other work like buckling all the exterior columns. Buckling is not instantaneous and cannot result in free fall of the building.

Okay it wasn't shaky. Doesn't change much though. It's not exact data. It's data that's as good as it gets. They fit a curve through the data and see that the acceleration is not distinguishable from freefall,

Correct.

meaning that the load bearing capacity of the supporting columns is not distinguishable from zero in the context of having to support two thirds of a building.

The weight exceed the load bearing capacity of the perimeter columns and the buckled.

 

[Architect]

I'm sorry, are you claiming that I'm not an architect? Do you want to put your money where your mouth is?

Chris,

I've told you already, the Mods have had sight of my relevant bona-fides including ARB and RIBA registration details, and Chillzero took steps to contact me at work to verify identity.

Now, let's be quite clear. Are you claiming that I'm not an architect, and are you willing to put your money where your mouth is?

 

[H'ethetheth]

I read pg 1A 45 and 9-1 602 again. It does not say that. Post the paragraph you are referring to or admit that you are lying again. The exterior columns were supported in the horizontal and vertical planes in both directions.

You might try reading the pages I actually pointed to. Look on page 588. PDF 250, line 4. I pointed it out twice before.

The slight movement was at the kink and does not constitute falling. The north west corner and west wall went from no movement to free fall acceleration.

To quote a certain someone: Wrong! Read this. It's on the page you say you just reread:

In stage 1, the descent was slow, and the acceleration was less than that of gravity. This stage corresponds to the initial buckling of the exterior columns in the lower storeys of the north face, as seen in figure 12-62. By 1.75 s the north face had descended 7 ft.

Bolding mine.

In or out

Yes, they are free to buckle inward or outward. That's what "normal to the wall" and "perpendicular" mean.

When the global collapse began, none of the exterior couumns were supported by the floor slabs on any floor.

Sorry, this contradicts a lot of what you've said before, and is in agreement with what I've been trying to tell you. I'm not sure what to say about this.

Source?

I got it from my structural mechanics textbook, but wikipedia agrees.

Your premice that the exterior columns were unsupported for 7 floors is incorrect. When the global collapse began, none of the exterior couumns were supported by the floor slabs on any floor. Furthermore, you are assuming no lateral support in the horizontal plane of the wall. This is also incorrect.

Read the quote again:

As the interior columns buckled across the building, the exterior columns were left laterally unsupported normal to the east, south and north faces.

That's a false assumption because it's based on faulty assumptions.

Look at figures 12-62 and 63. (pdf 250 & 251) What the hell does that look like to you? To me it looks like buckling over 7 floors.

No. The columns will buckle but equating 99% of the weight to the speed is popycock. Show the formula and math before making claims.

You may have heard of Brannigan's Newton's 2nd law?

F= ma.

The gravitational Force on the top of the building is mg. Normally, the columns counter this force, so the total net force is zero. However, due to loss of support, the columns now only supply 1% of the required mg. This makes the total net downward force equal to: (mg -0.01 mg).
Plug this force into the 2nd law:

(mg -0.01 mg) = m a

Then solve for a. That yields a = 0.99g

Wrong. The interior columns were still connected to the exterior walls thru the floor beams. NIST states the core pulled the exterior walls down.

Well, beside the fact that you really have to read the quote from p. 588, I can assure you that this will not help any tendency of the perimeter to buckle. The floors provide an asymmetrical load, which is bad for buckling. Read the wikipedia article on buckling.

The horizontal progression of column failures across the core between floors 7 and 14, prior to global collapse, does NOT happen in the NIST video!

Maybe I have better eyes than you. You linked to a movie of the physics based model. At the end of the movie, like on figures 12-62 and 12-63, the perimeter columns buckle over a huge height in the lower part of the building.

Impossible. The top part cannot fall at free fall acceleration and do any other work like buckling all the exterior columns. Buckling is not instantaneous and cannot result in free fall of the building.

No but it can at about 99% of freefall for some distance, and people can't analyse accelerations on such avideo with an accuracy much greater than +/- 1%. This last claim is only from limited second hand expercience, so I'm willing to be proven wrong, by the way.

Also, the claim that it should be instantaneous is bizarre. As several people have pointed out, it took 1.75 seconds before the building accelerated at g.

 

[FineWine]

Kiss my what?

Intellectual cowardice and acute snobbery.

ETA: My response to Here
http://www.internationalskeptics.com/forums/showthread.php?postid=4402841#post4402841
It seems you are the one with a truth problem.

You knock down strawmen but refuse to deal with critical issues like; free fall acceleration cannot occur in a progressive collapse or the NIST video does not match the collapse videos.

You have nothing of value to offer, just the usual JREF hand wave and insults.

You are unable to understand tfk's lucid posts. You keep raving the same debunked nonsense. Your performance is embarrassing, as usual. How does humiliating yourself promote the aims of your insane and dishonest movement?

 

[Christopher7]

Okay so here's the thing. Let's say we have a building weighing a lot, and its support structure (hint: the colums) are not connected to each other over the full footprint of the building

The exterior columns were intact except for 7 on the south west side.

Yes, read what I wrote though. The columns were not connected to one another. The report says they were not supported horizontally. This is a very unfavourable situation for a column. The fact that the columns were all free to buckle between floors 7 and 14, means they weren't supported over at least that length.

Man, have you got that all wrong.
There were moment frames on every other floor. I don't remember all the details but the exterior walls were extremely well tied together.
Where did you get your info?

I got it from two lines before the freefall phase quote* you like so much. It says that just before the final collapse, and after the core columns had collapsed, all perimeter columns were laterally unsupported on three out of four sides.

I read pg 1A 45 and 9-1 602 again. It does not say that. Post the paragraph you are referring to or admit that you are lying again. The exterior columns were supported in the horizontal and vertical planes in both directions.

You might try reading the pages I actually pointed to.

This [pg 588] is not the page you referenced* [1A pg 45].

Look on page 588. PDF 250, line 4. I pointed it out twice before.

The text says "the exterior columns were left laterally unsupported nominal to the east, south and north faces."

It said unsupported, not disconnected as you originally stated.

You misinterpreted "laterally unsupported nominal to the east, south and north faces" as the exterior columns not being connected to each other.

You are NOT an engineer!

 

[FineWine]

That is not the page you referenced* [1A pg 45].


The text says "the exterior columns were left laterally unsupported nominal to the east, south and north faces."

It said unsupported, not disconnected as you originally stated.

You misinterpreted "unsupported to the east, south and north faces" as the exterior columns not being connected to each other.

You are NOT an engineer!

When you get around to addressing tfk's posts--he IS an engineer, as you know--wake us up.

 

[DGM]

Chris7:
I asked this question before and you blew it off. I'll ask it again because if you think about it, it is very relevant (and should spark some thought).

Why do you think the engineering world (as a whole) is ignoring what you think is an obviously bogus account of the demise of the WTC buildings?

 

[Christopher7]

When you get around to addressing tfk's posts--he IS an engineer, as you know--wake us up.

I have been addressing his posts and he is NOT an engineer. He has not a clue about framing.

 

[Christopher7]

Chris7:
I asked this question before and you blew it off. I'll ask it again because if you think about it, it is very relevant (and should spark some thought).

Why do you think the engineering world (as a whole) is ignoring what you think is an obviously bogus account of the demise of the WTC buildings?

Your question calls for speculation so you can respond with childish insults and endless, pointless arguments.

WTC 7 fell at free fall acceleration for about 100 feet.

The refusal to accept this fact is clear evidence that you-all reject any facts that counter the OCT.

 

[Christopher7]

So your claim that betting is illegal is only valid in California for sites outside Casinos and race tracks.
You might reflect upon the fact that this is the World Wide Web

Would you care to say whether or not you accept the fact that

WTC 7 fell at free fall acceleration for about 100 feet.

or will you run away form it like all the intellectual cowards who refuse to deal it?

 

[triforcharity]

Why are you the only one constantly bringing this up??? Why wouldn't EVERY OTHER ENGINEER in the world not be up in arms for this to be investigated??? Certainly many of them have reaad the report, and understand it more than you or I do. Don't you think that they might find this funny??

 

[DGM]

Just to add:
I would understand a little if we were talking about 29,000 engineers, but 29? Are you kidding me? If looked hard enough I could find that many that saw Elvis yesterday (or at least this year).

 

[Shalamar]

I have been addressing his posts and he is NOT an engineer. He has not a clue about framing.

Are YOU an engineer?

 

[Shalamar]

Your question calls for speculation so you can respond with childish insults and endless, pointless arguments.

WTC 7 fell at free fall acceleration for about 100 feet.

The refusal to accept this fact is clear evidence that you-all reject any facts that counter the OCT.

And yet, you are rejecting ALL The facts that counter the inane inside jobby job.

There are no facts that go against the official story.

If you have some, please, present them.

 

[Justin39640]

Debunking by dominos

Trees fall over so the WTC would fall over.

heres a video i ran into
about 3/4 of the way in the kid lights a lady finger and watch what happens

falls straight down

 

[The Platypus]

Chris7:
I asked this question before and you blew it off. I'll ask it again because if you think about it, it is very relevant (and should spark some thought).

Why do you think the engineering world (as a whole) is ignoring what you think is an obviously bogus account of the demise of the WTC buildings?

They usually say its because they are all in on it, paid or threatened... Same thing with the demolition industry, scientific community, why they aren't on the media, why none of those involved have come forward, everyone that works for the gov't, or the airlines, etc...

As for the rest of is there is a slight variation. Every single one of us in the general public that doesn't buy their snake oil... we are brainwashed by the media and/or gov't, too dumbed down from flouride, chemtrails, etc..., in on it or paid off.

The whole world is wrong and crazy except them...

 

[Christopher7]

The slight movement was at the kink and does not constitute falling. The north west corner and west wall went from no movement to free fall acceleration.

To quote a certain someone: Wrong! Read this. It's on the page you say you just reread:
Bolding mine.

NCSTAR 1-9 vol.2 page 602
In stage 1, the descent was slow, and the acceleration was less than that of gravity. This stage corresponds to the initial buckling of the exterior columns in the lower storeys of the north face, as seen in figure 12-62. By 1.75 s the north face had descended 7 ft.

That's what NIST said but that's not what happened. NIST used a point at the top of the parapet wall on the roofline aligned with the east edge of the louvers* on the north face where the 'kink' developed. This area starts to descend before onset of global collapse as can be seen in this video:
*dark area in center of top 2 floors
http://nate.flach.s3.amazonaws.com/NIST_WTC7_video1.mov

Left click and hold on the 'button' and slide it back and forth slowly starting with the beginning of the collapse of the screenwall thru the onset of global collapse. [north west corner and west wall start to fall - entire building falling]

The word 'descent' is not synonymous with 'falling'. The columns under the 'kink' buckled and the roof line descended 7 ft in 1.75s and then jumped to free fall acceleration. The north west corner and the west wall went from not moving to free fall acceleration.

The top 30+ floors cannot fall at free fall acceleration and buckle all the exterior columns.

 

[Christopher7]

WTC 7 did not fall at free-fall acceleration for 100 feet.

So you think NIST is lying?

In Stage 2, the north face descended at gravitational acceleration, as the buckled columns provided negligible support to the upper portion of the north face.
This free fall drop continued for 105 ft

 

[TokenMac]

So you think NIST is lying?

In Stage 2, the north face descended at gravitational acceleration, as the buckled columns provided negligible support to the upper portion of the north face.This free fall drop continued for 105 ft

You seem to be ignoring some parts of your own post.

 

[beachnut]

The 29 people have bogus ideas on 911. Only those who can't think for themselves and or lack knowledge will fall for their nut case take on 911.
One common theme of those with no clue about 911 like Knesl is a lack of understanding of gravity and large structures.

Edward E. Knesl, civil and structural engineer, of Phoenix, Arizona
"We design and analyze buildings for the overturning stability to resist the lateral loads with the combination of the gravity loads. Any tall structure failure mode would be a fall over to its side. It is impossible that heavy steel columns could collapse at the fraction of the second within each story and subsequently at each floor below. We do not know the phenomenon of the high rise building to disintegrate internally faster than the free fall of the debris coming down from the top.

The engineering science and the law of physics simply doesn't know such possibility. Only very sophisticated controlled demolition can achieve such result, eliminating the natural dampening effect of the structural framing huge mass that should normally stop the partial collapse. The pancake theory is a fallacy, telling us that more and more energy would be generated to accelerate the collapse. Where would such energy would be coming from ?"

Gravity! He has no idea gravity is the primary energy source for a controlled demolition. He never once mentioned the 150 TONS of TNT energy due to gravity is why the WTC looked destroyed. Gravity dude.

Another "fall over like a tree guy" who is not a structural engineer who knows or designs high-rise buildings. What a bunch of nut case ideas shared by a few failures on 911. 7 years an not one of these x-perts has made it past the nut case CTer stage. It is sad this person with moronic conclusions had no calculation and no evidence to back up his failed ideas; just talk.