The 9/11 Forum

How do you know this? A-A Astenah[sic] stated that the welds in the core were just construction welds.

From STJ911 angle cuts to Bazant buckling, I have heard so much crap and misinformation stated about core columns which flatly contradicts observed facts that I couldn't possibly give much weight to the above statement.


Core box columns were found for the most part very straight and separated into lengths of about 36n where n=1, 2. 3 (and even 4?)

Eight years after the event and most self-proclaimed experts probably aren't aware of that.


What is a 72' box column section? It is a straight piece where the weld held so well that nobody looking at the piece would even be aware of the location of the weld along it unless they where to told where to look.


This is why almost nobody can see all the core box column welds that held perfectly within the rubble.


What is a 98' straight box column? It is 2 consecutive welds holding perfectly while being subject to extreme abuse.



Please consider all the 36n where n=2, 3, 4 lengths of core column sections you can find in the rubble, perfectly straight, before you believe the WTC cores were tack or construction welded.


For example, in the photo below can anyone show me where some surviving core box column welds are? (You can't see them unless you know where to look).

http://www.sharpprintinginc.com/911_old/Photo_archives/north_tower_debris/FDNY_US_R_0288.jpg


Some of the welds were pretty strong, no?

Or the photo



The speared object is longer than 36 feet. Does that seem like a tack weld to you?


(On another subject: Look at the piece of flooring in the foreground in the photo above. How did it get so far from the base of either building?)

Major_Tom --- All core columns members were 36 feet long, not longer. The box column memberss were through welded at the factory. In only one photos did box column mmber factory welds fail. The welds which did fail, copiously, were the on-site construction welds between the box column members; but not those for the wide flange rolled members (H-members) used further up, at least not so often.

I doubt the "speared object" is over 36 feet long, but even so, it doesn't prove a thing all by itself.

By the way, you really ought to learn who A.-A. A. is and why his early exploration of Ground Zero is still considered important. As for Baaant buckling, this is a well understood phenomena, see Bazant/Credolin for an advanced treatment. See the NIST steel collection for examples from WTC. So far I fear you are just displaying ignorance in a most unpleasant manner.

David B. Benson wrote:Major_Tom --- All core columns members were 36 feet long, not longer. The box column memberss were through welded at the factory. In only one photos did box column mmber factory welds fail. The welds which did fail, copiously, were the on-site construction welds between the box column members; but not those for the wide flange rolled members (H-members) used further up, at least not so often.

I doubt the "speared object" is over 36 feet long, but even so, it doesn't prove a thing all by itself.

By the way, you really ought to learn who A.-A. A. is and why his early exploration of Ground Zero is still considered important. As for Baaant buckling, this is a well understood phenomena, see Bazant/Credolin for an advanced treatment. See the NIST steel collection for examples from WTC. So far I fear you are just displaying ignorance in a most unpleasant manner.

Six floor hinging would not have been possible in the core due to the horizontal bracing and the reason I know the welds retained 60% of the strength of the columns in bending is that I did calculations based on the sizes of the welds discussed.

Here is a dumbed-down version of my last post for DDB:

What is the distance between flooring on average?

Please look at the speared piece.

How many flooring connectors exist along it's length?

Not over 36 feet long?


Note to others: You will most always see 3 flooring connectors along a 36 foot box column (3x12=36)

You can estimate the length of a beam by counting the number of flooring connectors visible along it's length.

You will notice that there are either 3 or 6 or 9 connectors along the length of columns in the rubble.

In the case of 6 or 9 consecutive connectors, you can estimate the location of a weld that held by using the following pattern:

http://www.sharpprintinginc.com/911/index.php?module=pagemaster&PAGE_user_op=view_page&PAGE_id=13&MMN_position=182:182

I doubt the "speared object" is over 36 feet long, but even so, it doesn't prove a thing all by itself

It's not all by itself. Please look at photos of the rubble around the cores again, but this time open your eyes.

So far I fear you are just displaying ignorance in a most unpleasant manner.

Please review the photos presented again remembering that the distance between floors is 12 feet and then repeat to yourself:

"I fear I am displaying ignorance in a most unpleasant manner" 10 times.




I don't claim to be an expert at this. How shameful for you to be proven wrong again and again by a quite ordinary person while you fancy yourself an expert.





Tony, counting floors along intact and unbent columns shows that many of these "construction" welds were undamaged. There are many examples.

Just one photo from the WTC2 core



If "F" is one floor, you can guess where the welds which held are located. They are all over the place but you won't recognize them unless you know where to look (as DBB has just demonstrated).

I can't see the stills well enough to pick out floor connections. Indeed, I'm yet to be convinced those are core box column members (although probably are) and not perimeter column members.

And I don't claim expertise in PI.

For Tom: review NIST's steel collection photgraphs to see that most are kink bluckled in 3 floor column members. Only one is longer and serverely buckled due to aircraft impact.

I'd suggest a stronger pair of glasses and access to your local public library to view video clips.



I wouldn't rely on filtered and pre-chosen selections of core columns provided by the experts at the NIST. I look at the as-is conditions and locations of debris as found in the rubble from multiple viewpoints.

If you get the glasses and look at the photos, you will see what everyone else here can: The ideas in your latest posts are a bit off.

<b>Major_Tom</b> --- I do need new glasses, but I don't think that is the problem; the resolution on this monitor is not good enough.

Looking carefullly through the available photos and videos is certainly worthwhile. As before, I'll leave you to interpret the evidence. But do remember that this is a low bandwidth communicatiion medium and we have not established a common terminology.

David B. Benson wrote:Major_Tom --- I do need new glasses, but I don't think that is the problem; the resolution on this monitor is not good enough.

I hate to state the obvious, but perhaps viewing the images in a viewer with a "zoom" facility would help you out here ?

May I ask what hardware you are using ? To have any hope of valid opinion on discussion of any of the visual details presented on this site we're really going to have to get you going with a few basic techy facilities.

Browsers these days allow you to 'zoom' the page. I use control+mouse-wheel in Firefox...

I don't want to pollute this thread with this kind of discussion though, so perhaps we should start a new one with platform specific help on how to get, view and process images and video.

femr2 --- Thank you! I didn't know that about Firefox. Later I'll give it a try.

I just had an idea for another model design the other day. It would involve the third law because the falling mass would be crushable unlike the stack of washers I used here:

http://www.youtube.com/watch?v=LXAerZUw4Wc

When I originally started that model I intended to use larger washers. There is a size that is almost 2 inches in diameter and about 1/4th of an inch thick. But the hardware stores don't stock very many of them. I would have had to go to 20 stores to get enough, so I used smaller washers.

But now I am thinking that by using the big washers so a stack could be made with the washers separated by folded pieces of paper. Cut the paper into 1/2 inch strips and fold them so little boxes could act as supports between the washers. Since the paper at the bottom of the stack would have to support more weight either thicker paper or multiple strips could be used. So the paper would act as the columns of the WTC that could be bent and crushed.

So a small stack of washers, also separated by paper "columns" could be dropped down the dowel to test the effect of the impact. So if 5 washers separated by paper were dropped on 25 similarly separated washers then the bottom of the falling portion would experience the same CRUSHING EFFECT as the top of the stationary portion. This would slow the mass of the top of the falling portion.

The only problem with this is that the washers would all be the same mass. There would not be the tapering of mass effect as in a real skyscraper.

So if the collapse was ALWAYS ARRESTED in such a test then what would that say about the WTC. Curious that so many engineering schools haven't come up with something that simple. This would be better than toothpicks since the "paper columns" would have to be made stronger toward the bottom. A lot of experimenting would have to be done with the strength of the paper though. It would have to support itself for at least a week to be sure it was similar to a skyscraper.

psik

psikeyhackr wrote:I just had an idea for another model design the other day. It would involve the third law because the falling mass would be crushable unlike the stack of washers I used here:

http://www.youtube.com/watch?v=LXAerZUw4Wc

When I originally started that model I intended to use larger washers. There is a size that is almost 2 inches in diameter and about 1/4th of an inch thick. But the hardware stores don't stock very many of them. I would have had to go to 20 stores to get enough, so I used smaller washers.

But now I am thinking that by using the big washers so a stack could be made with the washers separated by folded pieces of paper. Cut the paper into 1/2 inch strips and fold them so little boxes could act as supports between the washers. Since the paper at the bottom of the stack would have to support more weight either thicker paper or multiple strips could be used. So the paper would act as the columns of the WTC that could be bent and crushed.

So a small stack of washers, also separated by paper "columns" could be dropped down the dowel to test the effect of the impact. So if 5 washers separated by paper were dropped on 25 similarly separated washers then the bottom of the falling portion would experience the same CRUSHING EFFECT as the top of the stationary portion. This would slow the mass of the top of the falling portion.

The only problem with this is that the washers would all be the same mass. There would not be the tapering of mass effect as in a real skyscraper.

So if the collapse was ALWAYS ARRESTED in such a test then what would that say about the WTC. Curious that so many engineering schools haven't come up with something that simple. This would be better than toothpicks since the "paper columns" would have to be made stronger toward the bottom. A lot of experimenting would have to be done with the strength of the paper though. It would have to support itself for at least a week to be sure it was similar to a skyscraper.

psik

The floors were essentially the same mass and it was only the steel frame which varied in mass with height. If the washers represent the floor mass and whatever you put between them has a strength similar to the columns in the towers in relation to the mass they were supporting you are moving in the right direction. Of course, you should try to ensure you are following the similitude rules for a model if you don't want criticism. UC Berkely does a lot of model scaling of buildings for earthquake resistant design. You might want to see if you can follow their rules for similarity.

T_Szamboti wrote:The floors were essentially the same mass and it was only the steel frame which varied in mass with height. If the washers represent the floor mass and whatever you put between them has a strength similar to the columns in the towers in relation to the mass they were supporting you are moving in the right direction. Of course, you should try to ensure you are following the similitude rules for a model if you don't want criticism. UC Berkely does a lot of model scaling of buildings for earthquake resistant design. You might want to see if you can follow their rules for similarity.

As far as I am concerned we are debating something which should have been settled in about SIX MONTHS.

People are playing pseudo-intellectual ego games over this issue. I DON'T GIVE A DAMN ABOUT CRITICISM. I have never heard or read of Steven Jones discussing the distributions of steel and concrete in the towers. I asked Richard Gage about them in Chicago in May of 2008 and he got a surprised look on his face and gave me a LAME excuse about the NIST not releasing accurate blueprints. He's an architect heading an organization of architects and engineers. How much computing power is available to them today compared to when the WTC was designed? They should be able to come up with good figures without the NIST.

I understand the weight variation takes place in the columns not the floors and that the technical floors were very different. I am not saying my washers would represent the floors they would just be mass whose inertia would have to be overcome and accelerated for a top down collapse to occur. But I find it curious that I have never seen anyone specify the total weight of a floor assembly, the concrete plus the pans plus all of the trusses. From indirect information in the NCSTAR1 report I estimate it at 1100 tons.

I don't care about criticism because as far as I am concerned most engineers have already insulted themselves by letting this nonsense drag on this long.

I just noticed this a few weeks ago:

http://letsrollforums.com/9-11-hollywood-t19418p2.html

psik

Dr. G wrote:Another worthwhile analogy would be a tower made out of wooden dominoes weakly glued together at each end. Now suppose I douse some of the dominoes near the top of the tower with gasoline and set them on fire. After a while the gasoline-soaked dominoes would burn through and start to crumble. At some point the block of dominoes above the fire-affected zone would drop down on to the section below this zone. I feel confident in predicting that the motion of the upper block could initiate a total collapse of the entire structure.

Again, I have to ask, have I violated any of Newton’s Laws?

If the dominoes are weakly glued together the whole structure would be destabilized, and yes it
would COLLAPSE, the dominoes would not crush the lower structure from top to bottom, it is more likely that the structure would start to wobble and fall to the side.

Like i said in another thread, i would like to see clarity in language as this hopefully will bring
clarity in thought and communication.

If we have a piledriver, CRUSHING the lower structure, that is not a COLLAPSE.

Dr. G wrote:
Are you familiar with the verinage technique of building demolition? In this technique hydraulic rams, placed on an upper floor of a building, are used to push columns over causing the entire block of floors above the critical floor to drop onto the structure below. When done correctly this causes the entire building to collapse. Now you guys would tell me that this is impossible, so may I suggest you check out this video and follow the collapse sequence frame by frame.

Why would anyone deny this? Verinage shows why the towers could not possibly crush themselves.
How come they do not take on tenth of the building and drop it on the lower structure?

Perhaps because it would crush itself before doing much damage?

What we see in almost all the videos is the pyrrhus victory of the upper block versus the lower, it crushes most of the lower structure, but it also crushes itself on the lower structure and then most of it falls of.


Again, the buildings do not COLLAPSE, if this is the terminology that is being used today
then i would say change it!

If i faint, the joints in my body bends and i end up in a heap at the floor, i would say that i COLLAPSED.

However, if i end up under a falling tree, reduced to meaty pulp (sorry for being graphic!)
i would say....well my friends would say that i was CRUSHED, very different....