RFC: Bazant and Zhou Simple Analysis refuted

[Newtons Bit]

NONE of the columns ever saw a tension load anywhere. The weight (downforce) on them was greater than any tension a wind load could develop.
Think of bolt preloading.

I dunno about that. I'm pretty sure that an analysis of P/A -Mc/I with a 0.6D + 1.0W combination (using the combinations the designers used) would likely generate tension.

 

[Newtons Bit]

The following picture is a good example that shows the welds were not stronger than the member itself:

Notice how the plates have separated, this is due to the large shear flow in the welds (basically bending in that area) that exceeded the strength of the weld.

 

[rwguinn]

I dunno about that. I'm pretty sure that an analysis of P/A -Mc/I with a 0.6D + 1.0W combination (using the combinations the designers used) would likely generate tension.

Somebody shows the numbers, I back down.
I'm easy that way.
Just remember, Mc/I will be for the structure. C is 100 feet, but I is really, really Big ((208^4)/12)

 

[Norseman]

This quote is from Major Tom's site:

Example 9

I haven’t seen any other picture like this. There certainly seems to be a hole blown right through the steel on the long side of the box column.

The damage appears to be made by an explosive device placed about 3 feet up from the end.

Original context

Your are aware that what you claim to be hole blown by a bomb is just the hole after a coupon removed for further metallurgic analysis. Did you notice the blackened edges, that is a sure sign that the hole was made after the column was recovered from the pile. Had it been made in the collapse it should have been rusty like the rest of the column. This type of cuts you can se in many of the pictures of steel saved for further studies by FEMA and NIST. You can read about getting coupons in this FEMA report:
http://www.fema.gov/pdf/library/fema403_apd.pdf
And about oxygen cutting of steel here:
http://11-settembre.blogspot.com/2007/04/real-world-tests-cut-through-steel.html. And it also gives you the explanation that your article about Angle-Cut Columns is missing.

But from the article I guess you know this. Great you understood that Jones thermate idea was wrong, both in the process you invented your wrong idea about how the towers collapsed instead. And of course Jones had be disinfo. But the problem you got is that you, like Steven Jones, do not know what you are talking about, that is very evident.

By the way, do you really believe that FEMA would put a picture of a column showing sure signs of bomb damage in this report:
http://www.fema.gov/pdf/library/fema403_apd.pdf
See Figure B-6.

 

[bje]

As for Silverstein's comment on that History Channel show, I showed proof here that he was on that show.

Silverstein NEVER made any such comment. Get real.

 

[Major_Tom]

Norseman, That photo is a one of a kind and for that reason I don't believe in it myself.

I've never seen another like it and for that reason it is not representative of the weld attacks I am describing.

I look for patterns and this is not a pattern.

I'd appreciate further feedback on that photo from others with some technical knowledge.

So someone actually reads the material on my site. Good.

The info about Mr Jones on my site is from much personal experience in corresponding with him.

 

[GregoryUrich]

You have repeatedly been told that Bazant's model is a simplification that is extremely conservative in favor of no global collapse: yet in that model there is more than enough energy in the falling mass to bring the collapse to the ground.

Major Tom, is there anything about this that you do not understand? If not, then do not bring it up again. You seem to think you gain points by mindlessly repeating your favorite mantras here. That's not how learning works.

The Bazant model has one major assumption in favor of survival of the structure:

1. Equal distribution of impact into columns.

However, there are at least 7 major assumptions in favor of collapse continuation.

1. No energy is absorbed by the upper section.
2. The falling energy is overestimated.
3. The strength of the structure is underestimated.
4. The spring constant is overestimated.
5. No energy is absorbed during elastic or plastic deformation of the initial collapse.
6. No energy is absorbed by floor flexion.
7. No energy is absorbed by plastic deformation of the floors.

When I quantify these with reasonable approximations I get an overload factor of 0.56. Thus, when you take these into account there is not enough force to overload the structure. Without quantifying these you are just taking Bazant's word that his hand waving is valid.

It may very well be that when you take uneven distribution of impact into account that global collapse is inevitable but Bazant's "simple analysis" proves nothing!

 

[GregoryUrich]

This quote is from Major Tom's site:

Original context

Your are aware that what you claim to be hole blown by a bomb is just the hole after a coupon removed for further metallurgic analysis. Did you notice the blackened edges, that is a sure sign that the hole was made after the column was recovered from the pile. Had it been made in the collapse it should have been rusty like the rest of the column. This type of cuts you can se in many of the pictures of steel saved for further studies by FEMA and NIST. You can read about getting coupons in this FEMA report:
http://www.fema.gov/pdf/library/fema403_apd.pdf
And about oxygen cutting of steel here:
http://11-settembre.blogspot.com/2007/04/real-world-tests-cut-through-steel.html. And it also gives you the explanation that your article about Angle-Cut Columns is missing.

But from the article I guess you know this. Great you understood that Jones thermate idea was wrong, both in the process you invented your wrong idea about how the towers collapsed instead. And of course Jones had be disinfo. But the problem you got is that you, like Steven Jones, do not know what you are talking about, that is very evident.

By the way, do you really believe that FEMA would put a picture of a column showing sure signs of bomb damage in this report:
http://www.fema.gov/pdf/library/fema403_apd.pdf
See Figure B-6.

Unless you have some evidence that the photo in question is representative of a coupon cut, your statement is nothing but conjecture. Notice that the steel is deformed (inward) around the hole--definitely not a typical feature of an oxy-acetylene cut.

 

[Furcifer]

I'd appreciate further feedback on that photo from others with some technical knowledge.

The edge of the hole in the column does not look like it was cut by an oxy torch. While hard to tell exactly, it appears jagged. Unless the person who cut it was very inexperienced, the hole would be more symmetrical, striated (from the cutting process as the torch blows the oxidized metal into the hole it creates) and flush to the face of the column if it were taken as a coupon. There's obvious fatigue in the metal about the hole, suggesting one of two things in my opinion. Either it was struck by another smaller piece of steel and punctured or, the more probable of the two, there was another piece of steel welded to the column in that location, which was struck at a perpendicular angle to the face of the column and pushed inward, fatiguing the metal, then it was struck again at an angle parallel to the face of the column ripping it and the weld from the already fatigued metal. This two step process is the most likely of the two as it accounts for both the inward deformation, the observed fatiguing and the jagged edge around the hole protruding outward from the face of the column.

 

[Major_Tom]

I am glad we have so many people participating in this discussion that know something about welds.

Consider the following images.

These are copies of extremely high resolution photos taken by Aman Zafar from his balcony.


If we place the images over one another and fade out the building, we discover something rather interesting.

It is easy to place one image directly over the other with precision by using the building with the dome and it's window grid.


The following graphic accurately depicts the core column locations and relative sizes of core column cross sections on the first floor of WTC 1.

You would be looking at this graphic from the lower left side to compare it with the photos.

The closest columns seem to be 701 and 801.

Note that Dave, being highly observant, said those columns could be either from the 700, 800 rows or from the 500, 600 rows.


From the above images they certainly look like the 700, 800 rows.

What do you think?

 

[Major_Tom]

I'll give a close-up of those columns from the same picture to help judge.

Remember that the lateral braces are separated by 12 to 13 feet.

 

[Newtons Bit]

The Bazant model has one major assumption in favor of survival of the structure:

1. Equal distribution of impact into columns.

However, there are at least 7 major assumptions in favor of collapse continuation.

1. No energy is absorbed by the upper section.
2. The falling energy is overestimated.
3. The strength of the structure is underestimated.
4. The spring constant is overestimated.
5. No energy is absorbed during elastic or plastic deformation of the initial collapse.
6. No energy is absorbed by floor flexion.
7. No energy is absorbed by plastic deformation of the floors.

When I quantify these with reasonable approximations I get an overload factor of 0.56. Thus, when you take these into account there is not enough force to overload the structure. Without quantifying these you are just taking Bazant's word that his hand waving is valid.

It may very well be that when you take uneven distribution of impact into account that global collapse is inevitable but Bazant's "simple analysis" proves nothing!

Care to quantify your quantifications?

 

[Myriad]

The tangent of the quotient of the apparent (pixel) width on the photo of the tower wall on the left divided by the apparent width of the tower wall on the right gives us the angle between the photograph and the plane of the left wall of the tower. (This assumes the photo is taken from an infinite distance, so that the angle of the convergence of the sight lines to the edges of the tower can be taken as zero; given that the photo is taken from a great distance compared to the width of the tower, the angle of convergence of the sight lines is negligibly small so the assumption introduces only a very slight inaccuracy.) Measuring from the image of the intact tower, that's about 34 degrees.

The cosine of that angle, then, represents the foreshortening of distances parallel to the wall on the left. That factor is .827. That is, the apparent width of that wall is .827 of what it would be if the tower were turned, in place, so that that wall were face on.

The factor for vertical foreshortening, at the height of the close-up image, is negligible due to the distance of the camera and the elevation that the photo was taken from.

Now we can examine the leftmost columns (the highest standing framed structure) in the close-up. Knowing the floor to floor height of the towers (11.98 feet), and measuring on the close-up the spacing of the mean interval between the floors and the mean center-to-center horizontal spacing between the columns, (41 and 45 arbitrary length units, respectively; this is the least precise step in the process) and correcting for the horizontal foreshortening factor derived above, the spacing between the column centers works out to 15.9 feet.

Therefore they cannot be 700-800 row columns, and as they are too far to the left to be 900-1000 row columns, they must be 500-600 row columns.

(Measurement errors, and some vertical foreshortening that was not taken into account, no doubt accounts for why my calculated center-center column spacing is off by a few inches from the figure given for the 500-600 rows. However, even without taking the much more significant horizontal foreshortening into account, it's clear that these cannot be 700-800 row columns, because their centers, even foreshortened, are farther apart than the floor-to-floor height, but the 700-800 rows were spaced closer together than the floor-to-floor height.)

Tom, thank you for your excellent and careful work with the superimposed photographs, that allow this question to be resolved with such a high degree of certainty.

Respectfully,
Myriad

 

[Heiwa]

The Bazant model has one major assumption in favor of survival of the structure:

1. Equal distribution of impact into columns.

However, there are at least 7 major assumptions in favor of collapse continuation.

1. No energy is absorbed by the upper section.
2. The falling energy is overestimated.
3. The strength of the structure is underestimated.
4. The spring constant is overestimated.
5. No energy is absorbed during elastic or plastic deformation of the initial collapse.
6. No energy is absorbed by floor flexion.
7. No energy is absorbed by plastic deformation of the floors.

When I quantify these with reasonable approximations I get an overload factor of 0.56. Thus, when you take these into account there is not enough force to overload the structure. Without quantifying these you are just taking Bazant's word that his hand waving is valid.

It may very well be that when you take uneven distribution of impact into account that global collapse is inevitable but Bazant's "simple analysis" proves nothing!

You should add one factor - time.

If I drop a bag of 20 kgs cement on my bed it bounces ... and then compresses the mattress.

If I pour the same cement, 20 kgs, from the bag on my bed (it takes a little longer) there is no bounce ... but the same compression.

 

[Gravy]

Norseman, That photo is a one of a kind and for that reason I don't believe in it myself.

Of course. That's why you wrote, "The damage appears to be made by an explosive device placed about 3 feet up from the end."

What you don't know about explosives could fill a website. Oh, it already has.

Major Tom, why don't you write to the FEMA/ASCE engineers and ask them why they went through the trouble of describing and showing that column in their report but never mentioned the bomb hole right next to their camera?

 

[Gravy]

From the above images they certainly look like the 700, 800 rows.

What do you think?

I think you're playing games. I think you're afraid to come to the point. I think you will never present a coherent theory that accounts for the observed collapse conditions, and you will never present a shred of evidence that the buildings collapsed due to anything but damage and fire.

I think you haven't thought things through, nor do you want to.

 

[Major_Tom]

Myriad, I'll look into your claims. Thanks for the input.

I know what you mean by the rectangles. Notice that the rectangles of the column pair with the cross-bracing behind the first pair are taller than their width, while photos from other directions strongly suggest that all surviving columns are from the same 2 column rows.

I'll try to bring more data to the discussion.

 

[rwguinn]

I think you're playing games. I think you're afraid to come to the point. I think you will never present a coherent theory that accounts for the observed collapse conditions, and you will never present a shred of evidence that the buildings collapsed due to anything but damage and fire.

I think you haven't thought things through, nor do you want to.

There is the other problem, Gravy:
Coming to a point means you have the capability of supporting the point.
Carbon steel can be pointed very nicely.
Jello, on the other hand...

 

[Myriad]

Myriad, I'll look into your claims. Thanks for the input.

I know what you mean by the rectangles. Notice that the rectangles of the column pair with the cross-bracing behind the first pair are taller than their width, while photos from other directions strongly suggest that all surviving columns are from the same 2 column rows.

I'll try to bring more data to the discussion.

Applying the same measurements and calculations to the other column pair (since they are clearly in the same plane, the same horizontal foreshortening applies), I get 10.6 feet column to column -- a match so close to the nominal spacing of the 700-800 column rows to make me certain that those columns are indeed from those rows. However, if there's another angle that shows that all the surviving columns must be from the same two rows, that would throw both my determinations into doubt, so let's check it out and see.

By the way, by "cross-bracing" do you mean the huge columns sticking at angles out of the top of the dust cloud? I've seen no evidence that any angled bracing members of that size, or any connected to, but extending beyond, the core, existed in the Towers. I rather suspect that what you're seeing there is column sections from the core above that have speared the lower core, or columns stripped of their horizontal connections and forced to the side but still momentarily attached to the standing core structures, or perhaps even columns in the act of falling (another photo from a different instant might determine the latter possibility one way or another).

Respectfully,
Myriad

 

[Major_Tom]

By the way, by "cross-bracing" do you mean the huge columns sticking at angles out of the top of the dust cloud?

No. Just the short horizontal members between column pairs.

I have seen no evidence of angled bracing anywhere except in the 4 corners where they had the cranes. Very short diagonal bracing which won't affect the present discussion.

We'll get to the bottom of this soon.

Note to those who were talking about how weak the welds are: These pieces were swaying unsupported and were about 40 to 50 stories high. Welds every 3 floors.

I think Realcddeal has a point.

As I mentioned before, there are many unbroken welds to be found in the rubble.

More info will be coming soon.



Myriad, for photos of the North Tower spire from 5 directions (4 of which are useful) and added graphics, please visit a photo album devoted only to this topic at

http://www.sharpprintinginc.com/911...toalbum&PHPWS_Album_op=view&PHPWS_Album_id=16