Merged Applicability of Bazant's model to the real world

[ozeco41]

...This is precisely the point. Tony will not allow chaotic collapse as it's far too disturbing for his deluded 'theory' ...

...plus he is relying on a rigid top block to justify the trigonometry. And no way was that damaged top block rigid to that extent.

...Interestingly, any CD by whatever means (and let's hope he limits his own possibilities to high explosive cutter charges) would leave column ends bevelled, thus precluding axial impact. The column ends would be bound to slide off each other when they meet. Duh...

...that leads to the trap he sets himself in that the removed bits have to end somehow. The underlying problem of jumping in to metrication or calculation before you have thought through what you are trying to measure or calculate. Motto "think it through first". Plus get the thinking right of course.

...Quite. I was looking forward to Tony's diagrams showing the columns twisted into a flat horseshoe with little curls at each end, and able to provide 180° impact. Horizontal tangents would be involved He can't have this, of course, so CD is the only other possibility? Er, no.

...remember that we are only showing that there was another option as well as CD. We have not (at this stage) rebutted CD. But there's no need to be too shy about it. Tony is further away from establishing the CD case than we are from rebutting it.

 

[carlitos]

The math is nothing more than straightforward trigonometry and I think what I showed is more than enough for anyone familiar with trig. I'll explain a little further.

The horizontal shift is the difference between the hypotenuse and the adjacent side of a right triangle. In this case the width of the building is the hypotenuse and its projection onto the adjacent is what we get using the cosine of the angle. In other words, when the width is tilted down we want to know how much its horizontal distance changed.

The building width was 207 feet or 2,484 inches.

Cosine (1 degree) = adjacent/hypotenuse

.99985 = adjacent/2,484 inches

adjacent = .99985 x 2,484 inches = 2,483.627 inches

hypotenuse - adjacent = 2,484 - 2,483.627 = .373 inches

For 3 degrees

Cosine (3 degree) = adjacent/hypotenuse

.99863 = adjacent/2,484 inches

adjacent = .99863 x 2,484 inches = 2,480.597 inches

hypotenuse - adjacent = 2,484 - 2,480.597 = 3.403 inches

This would be the horizontal shift at the opposite side of the building from the hinge of any tilt which was the north face in the case of WTC 1. The core columns would experience even less of a shift as the width there was 60 to 147 feet less. In the case of the core at 3 degrees the shift would have been just .082 to 2.417 inches. This shows the columns would not miss each other due to the tilt.

Thanks. I was thinking vertical, not horizontal. I completely missed your reference to the width of the building there. My bad. On the bright side, I got to brush up on my trig in time for tutoring season to start this week!

ETA - Just to clarify, I was thinking of the "top section" tilting, and how much horizontal movement one end of the column would have as a result of the tilt. For a given length of column, horizontal shifting of one end of a column with 1º tilt would be more pronounced than the ratios you show above, and more akin to what I was calculating. Like one inch per 57 inches or so. Imagine a 1/89/90 triangle, with the 1º on the top, and measure the short side. Hope this makes sense.

Question - wouldn't hinging / rotation / tilting impart some momentum such that, during initial failure, the rotating / hinging top section would continue to move beyond the initial observed hinging / rotation / tilt?

 

[pgimeno]

The hinge areas of fully buckled columns are not shaped in a way which would cause a load to just slip off without impact. Additionally, the impact itself causes deformation which tends to flatten even fully rounded surfaces. Your claim here has no basis.

Do you have an estimation of the tilt after 1 floor already? It's important for you to hold this.

Now the entire 12 story upper section of WTC 1 weighed about 69 million lbs., so even with the conservative use of pinned end conditions and a temperature of 650 degrees C the buckling load for just the four corner core columns is 160 million lbs. or about 2.3 times the weight of the entire upper section. This says Bazant's model has no basis in reality whatsoever and this is why I have told anyone who thinks these columns would buckle easily that they are dreaming. It isn't happening ever.

Why are you neglecting to consider the effect of creep in that analysis?

Do you think that column will bear the load the same way as a perfectly aligned column?

 

[GlennB]

Interestingly, any CD by whatever means (and let's hope he limits his own possibilities to high explosive cutter charges) would leave column ends bevelled, thus precluding axial impact. The column ends would be bound to slide off each other when they meet. Duh.

...that leads to the trap he sets himself in that the removed bits have to end somehow. The underlying problem of jumping in to metrication or calculation before you have thought through what you are trying to measure or calculate. Motto "think it through first". Plus get the thinking right of course.
.

Of course (after a 'liquid lunch') I've got this back to front.

My mistake was comparing natural collapse to CD, finding them similar, and taking this as evidence that Tony is wrong. Tony is comparing CD with an impossible 'natural collapse' which involves horseshoeing columns with neat knobs on the ends making 180° contact with each other in the vertical plane. I should know better than to post after a good meal with a few beers.

The fact remains that we still await Tony's explanation (with diagrams) of how clean axial column impact can ever occur, in order to explain how the 'jolt' could ever happen and thus lead us to become suspicious about its absence.

As a building engineer-dude-thingy undoubtedly Tony has skills in CAD software and could knock this kind of thing up in a jiffy.

 

[bill smith]

Originally Posted by Tony Szamboti
... It is looking more and more like the only possible way to have the 98th story fail is to blow the core column splices with some sort of device. In reality we shouldn't even be discussing whether Bazant's model has any credibility, because it is not hard to show it doesn't.

Tony if explosive devices were used to break those splices would that be enough to cover the volume of columns we see whirling through the air ?

 

[ozeco41]

Of course (after a 'liquid lunch') I've got this back to front.

My mistake was comparing natural collapse to CD, finding them similar, and taking this as evidence that Tony is wrong. Tony is comparing CD with an impossible 'natural collapse' which involves horseshoeing columns with neat knobs on the ends making 180° contact with each other in the vertical plane. I should know better than to post after a good meal with a few beers...

..remember his second error which is in presuming the "top block" is rigid.

Better still have one on me - my "shout".*

* Aussie slang to English translation available if meaning not clear in context.

 

[Tony Szamboti]

Originally Posted by Tony Szamboti
... It is looking more and more like the only possible way to have the 98th story fail is to blow the core column splices with some sort of device. In reality we shouldn't even be discussing whether Bazant's model has any credibility, because it is not hard to show it doesn't.

Tony if explosive devices were used to break those splices would that be enough to cover the volume of columns we see whirling through the air ?

Although I would have to see which columns you are talking about, I tend to believe a covert controlled demolition would have used as few charges as possible and generally don't think there were columns blown out of the towers by charges.

 

[Tony Szamboti]

Utter bull flops in a great stinking pile.

The only way you are going to get points B and C to collide is the ensure that the upper section falls straight down.

Aint gonna happen.

We're talking about an office building here. Weight is randomly scattered across all the floors above the break. A nasty great aluminum structure was just rammed into the building, further randomizing the load in such a way that there were great masses of material in someplaces, far less in others.

And then there were the fires.

They cause steel to expand, you know, right? This is going to misallign the surviving columns even further.

Of course, because of the impact of the aircraft, some big chunks were missing out of both blocks.

I see no way that that sucker is going to fall down with any precision onto its old footprint.



Here in our time/space continuum, you can cause railroad tracks to buckle by sticking nickels between the ends of the tracks while they are cold and letting the sun hit them. A friend of mine killed about a hundred or so people that way once. Put a trainload of armored vehicles and their crews down a slope into a river.

Now, if just sunlight can make steel expand enough that it will buckle, what is a few hundred pounds of burning paper and plastic and kerosene or diesel going to do?

There was almost nothing missing from the core at the 97th and 98th floors of WTC 1. See the NIST report for that eye opening little reality.

It has been shown that the geometry of the upper section proves the columns would not miss each other.

 

[BasqueArch]

Although I would have to see which columns you are talking about, I tend to believe a covert controlled demolition would have used as few charges as possible and generally don't think there were columns blown out of the towers by charges.

But I thought David Chandler had conclusively proven and Gage and AE911 to this day confirm that multiton "girders" had been explosively expelled hundreds of feet.

Why are they wrong.
Have you told them?

 

[Tony Szamboti]

Anyone here who actually thinks the shape of the column would prevent a deceleration during impact will disabuse themselves of that silly notion by taking a couple of one inch diameter metal spheres, placing one on clay, balancing the other on it, and then measuring the indentation.

Next place one sphere in another location on the clay and drop the other one onto it from about 12 inches up.

There will be a hard impact which will drive the bottom sphere into the clay and produce an indentation in the clay of a significantly larger size than it was with the static load of the two spheres. The greater diameter indentation is produced by the upper sphere applying a significantly greater load than it does statically. This amplified load can only occur due to a deceleration much greater than gravity.

 

[Tony Szamboti]

But I thought David Chandler had conclusively proven and Gage and AE911 to this day confirm that multiton "girders" had been explosively expelled hundreds of feet.

Why are they wrong.
Have you told them?

I agree with them that there were upward and outward plumes and focused high speed ejections indicative of charges and that there might be some smaller items thrown outward as seen in one of David Chandler's videos.

However, in general I don't think there were large structural sections blown outward by charges.

I have expressed my thoughts on this yes.

 

[ozeco41]

Although I would have to see which columns you are talking about, I tend to believe a covert controlled demolition would have used as few charges as possible....

...generally true that Tony. But bear in mind that with any demolition the usual practice is to err on the side of safety. Safety in ensuring that the demolition works. So more charges/more weight of charge is the "play it safe" side. And military practice would tend to overkill even more than civilian.

...and generally don't think there were columns blown out of the towers by charges.

...keep in mind the distinction between cutting and kicking charges. To achieve column break would require some "kicker" device. But they could be directed "inwards" if the objective was to keep the demolition covert. So no obvious bits of column flying outwards to be seen on video after the event. Hiding the blast of air movement being a different challenge.

Cutting of core columns is the obvious place for covert demolition. But, without the luxury of knowing in advance exactly which columns if any the aircraft would cut and which would be missed and need "help", you would need to err on the side of safety. There are a couple of other problems to overcome naturally.

I have for some time regarded cutting of floor joist lower chords as a key to any covert demolition - it would mimic the outer column "pull in" effect. Certainly whenever I answer the challenge "How would you do it Mr Military Engineer?" my disclaimer is "couldn't do it without getting caught" then - cut some core and cut some floor joist lower chords is the outline plan to closest match what happened. But, as the military engineer,I would prefer to cause the same collapse without all the complications caused by the initial "cover plot" of the aircraft impacts. But what is the point of creating that type of collapse top down without the cover of aircraft impact? May as well simply blow the guts out of the base levels.

 

[BasqueArch]

I agree that there were upward and outward plumes indicative of charges and that there might be some smaller beams thrown outward as seen in one of David Chandler's videos.

However, in general I don't think there were large sections blown outward by charges.
I have expressed my thoughts on this yes.

Have you expressed your thoughts on this to Chandler and posted this on AE911. What do Chandler and Gage and AE911 posters respond.
ETA: Why are you right and Chandler wrong.

 

[ozeco41]

...It has been shown that the geometry of the upper section proves the columns would not miss each other.

Tony why not stop appealing to authorities. "it has been shown"

The reality is that the top block was moving downwards. That means that there was no significant core on core axial contact. You were right on that premise in your "Missing Jolt" paper. The "error" or "oversight" being that there are two ways that axial column on column contact can be avoided. One way is to cut out a bit of column. Your preferred explanation for obvious reasons.

The other way is that the column ends by-pass each other. And a little thought will show why that will happen despite all your attempts to assert otherwise.

Try this as a thought experiment. What happened to the outer columns of the top block?

We know that the outer columns of the lower tower were peeled off without being end for end buckled. And don't try to fight that one - the claim is absolutely neutral to whether some explosives were used to disconnect the floor joists OR the falling weight did it unassisted

So what happened to the outer columns of the top block? Did they try to fall outside the lower tower? "Inside?" "A bit of both?" Then what do your thoughts on that say for your insistence that the top block remained rigid and unchanging in its geometry?

 

[ozeco41]

Anyone here who actually thinks the shape of the column would prevent a deceleration during impact will disabuse themselves of that silly notion by taking a couple of one inch diameter metal spheres, placing one on clay, balancing the other on it, and then measuring the indentation.

Next place one sphere in another location on the clay and drop the other one onto it from about 12 inches up.

There will be a hard impact which will drive the bottom sphere into the clay and produce an indentation in the clay of a significantly larger size than it was with the static load of the two spheres. The greater diameter indentation is produced by the upper sphere applying a significantly greater load than it does statically. This amplified load can only occur due to a deceleration much greater than gravity.

A very strained analogy. (Oops - that pun was unintended )
The key error you are making I think is an order of magnitude issue. The jolt you look for is one where the total falling weight is significantly affected. The worst case jolt produced by "end on end axial contact" of the two parts of one column is too small to measure as that column instantly buckles under the overwhelming load. At least one and probably two decimal orders of magnitude less than the jolt you are looking for.

Yes I am aware of multiple columns. Multiple possibilities but they would be spread in time. (If you can visualise that reality given your apparent fixed view that the structure is of rigid geometry. It isn't)

I cannot think of a perfect analogy..

However. Think if a small paint brush. Cut all the bristles but one leaving the one protruding. Then drop the brush on that one bristle. Alternatively try to push something with that one bristle.

 

[Tony Szamboti]

A very strained analogy. (Oops - that pun was unintended )
The key error you are making I think is an order of magnitude issue. The jolt you look for is one where the total falling weight is significantly affected. The worst case jolt produced by "end on end axial contact" of the two parts of one column is too small to measure as that column instantly buckles under the overwhelming load. At least one and probably two decimal orders of magnitude less than the jolt you are looking for.

Yes I am aware of multiple columns. Multiple possibilities but they would be spread in time. (If you can visualise that reality given your apparent fixed view that the structure is of rigid geometry. It isn't)

I cannot think of a perfect analogy..

However. Think if a small paint brush. Cut all the bristles but one leaving the one protruding. Then drop the brush on that one bristle. Alternatively try to push something with that one bristle.

It is quite a ways from a paint bristle analogy and unfortunately for your point of view the Verinage demolitions show what I am saying to be true.

Additionally, the columns don't buckle without the overload which can only be caused by high g deceleration. I can back up what I am saying with math whereas it sounds like you are arguing from incredulity here.

 

[Grizzly Bear]

Additionally, the columns don't buckle without the overload which can only be caused by high g deceleration. I can back up what I am saying with math whereas it sounds like you are arguing from incredulity here.

The 8 fold dynamic load that I've seen calculated is a maximum value. The floors had no where near the capacity to withstand a force of that extent so they failed well below that maximum. The 8g assumes the most perfect scenario possible - axial impact (end to end). If the columns bypass - as they did - you cannot exploit the maximum strength of the structure because the load is hitting at an angle. That's not incredulous, that's pretty basic when your trying to discuss how well a structural frame is going to hold something up.

Also buckling, isn't strictly limited to overloading. You should understand better many that it's a failure caused by instability, such as a high slenderness ratio, or an eccentric load. Both factors affect the total capacity of the columns, and in turn they affect how much it can carry.

 

[femr2]

Why is this thread being allowed to turn into yet another jolt thread ?

Applicability of Bazant's model to the real world.

 

[pgimeno]

Additionally, the columns don't buckle without the overload which can only be caused by high g deceleration. I can back up what I am saying with math whereas it sounds like you are arguing from incredulity here.

Where's creep in your math?

http://www.internationalskeptics.com/forums/showpost.php?p=5537049&postcount=1040

 

[AZCat]

Why is this thread being allowed to turn into yet another jolt thread ?

Applicability of Bazant's model to the real world.

Tony perseverates, the rest just follow.