WTC 1 & 2. What happened after collapse initiation?

We have just left casablanca, and are in some nasty swells now.
The cans are sliding back and forth in my frigde.

Friction is greatly overrated.
 
Seems? Evidently when two bodies (structures) A and B come in contact, the force F of body A on the other body B, produces an opposite reaction force, Fo of body B on body A. Google on Isaac Newton for more info. F = Fo = equilibrium.
Depending on the properties of A and B, F may damage or deform B or Fo may damage or deform A. There are plenty of possibilities but quite easy to analyse what happens after this initiation contact.

After each damage or deformation of A or B you have to redo the analysis, step by step, to see what happens then with the forces involved. Luckily there is always equilibrium to simplify the analysis. Normally some of the new forces that develop after initiation contact produce friction forces, so you have to include those in a complete analysis.

NIST and Bazant suggest without any evidence that A destroys B. NIST suggests that B lacks strain energy to absorb the energy transmitted by A to B without any calculations to back up the suggestion. Bazant suggests that A crushes down B, while A remain intact. Neither has heard about friction!

It seems neither NIST nor Bazant has any knowledge of structural damage analysis (like many participants on this thread). Reason is that very few universities teach the subject. Bazant has written 400+ scientific papers but none about structural damage analysis. He has still a lot to learn.

I on the other hand that have investigated and analysed 100's of steel structural damages due to contacts (ship collisions - also groundings and ships colliding with quays and fixed objects) have some experience. Structural damages occur every day so it is not a new phenomenom! On the contrary.

Some 13 (?) years ago some Japanese made a complete damage analysis of a serious contact A against B using Finite Element Models + plenty of computer capacity. The destructions followed the A+B contact would in reality take 5 seconds, but the analysis split this events in 5000+ sub-events (how the further damages developed and were arrested) and it took the computers three weeks to do the full analysis.

When the analysis was done they actually arranged a real A + B contact and found good agreement between theoretical analysis and the real thing.

Interesting stuff. I wrote a positive review about that project in a serious English engineering monthly journal published by the Royal Institute of Naval Architects in London.

And you can do calculations to back this...assertion up?

Just to keep this question fresh.
 
Heiwa,

If I were to use your logic, wouldn't a CD have also been arrested by friction?

How do you think the towers came down and weren't arrested by friction? Do you seriously believe that the buildings could have possibly been wired with enough high explosive to not only take out the columns but also acres upon acres of floor space?

Don't you think someone would have noticed?
 
1. the core was not hollow and the majority of the mass of the buildings was the steel....

not really hollow, isnt it?

I gather you were referring to the columns themselves being uniformly solid in cross section? Regardless that assumption is false, neither the columns nor the core as an assembly were 'solid'

You can get a better sense of the column cross sections by observing this image: LINK

Good day...
 
ok its not the majority, around 100 000 tons per tower and one tower weighed around 300 000 tons.
[qimg]http://911research.wtc7.net/mirrors/guardian2/sixty-state-street/wtc-core.gif[/qimg]
not really hollow, isnt it?

You see those X's, those are penetrations in the floor slab.
 
I gather you were referring to the columns themselves being uniformly solid in cross section? Regardless that assumption is false, neither the columns nor the core as an assembly were 'solid'

You can get a better sense of the column cross sections by observing this image: LINK

Good day...

hollow columns yes. but a hollow core? no.

the floors was alot more hollow than the core....
you cant say the core was hollow, thats nonsence.
 
would you say the WTC Cores was hollow?

They were mostly air, yes.
Elevator shafts, ventilation shafts, stairwells, restrooms, storerooms, corridors connecting these etc. What else could they be? Do you really think the designers would fill the voids with structurally useless yet expensive concrete?

If you're looking for an escape route from your embarrassment then you can move the goalposts and say "aha! but they were not completely hollow, so I'm right really". Feel free.
 
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Is it really relevant? I would say 'partially hollow' is obviously the best description, but I would suspect by area and volume they were more than 50% empty space.

considering that the floors, has even more than 50% hollow, i would say it is very missleading to say the core was hollow.

but once again, when it is a conspiracy-denier then its ok to tell such vague and missleading stuff.
 
considering that the floors, has even more than 50% hollow, i would say it is very missleading to say the core was hollow.
Picking over the semantics of what is said is irrelevant, people often misspeak and often do not say exactly what they are thinking.

Dictator Cheney said:
but once again, when it is a conspiracy-denier then its ok to tell such vague and missleading stuff.
I am afraid I don't understand what you're saying here.
 
considering that the floors, has even more than 50% hollow, i would say it is very missleading to say the core was hollow.

but once again, when it is a conspiracy-denier then its ok to tell such vague and missleading stuff.

While I have no intention of putting words into e^n's mouth and he is free to correct me if I have misinterpreted him, but the way I understand his 50% area is that more then 50% of the core flooring was empty space. It's also quite obvious that there was vastly more than 50% of the core volume that was empty space.

What area of the floor sections was empty space?
 
While I have no intention of putting words into e^n's mouth and he is free to correct me if I have misinterpreted him, but the way I understand his 50% area is that more then 50% of the core flooring was empty space. It's also quite obvious that there was vastly more than 50% of the core volume that was empty space.

What area of the floor sections was empty space?

in the core you have a good number of walls, rooms, doors, floors, stairs.

on the floor there was no walls other than the outer perimeters and the walls that surounded the NOT hollow core. a huge very huge free space without walls or columns. that was so special about the design.
 
in the core you have a good number of walls, rooms, doors, floors, stairs.

on the floor there was no walls other than the outer perimeters and the walls that surounded the NOT hollow core.

So the core was solid you claim? After all it is either hollow or solid and you say it wasn't hollow, so I guess you are claiming it was solid?

a huge very huge free space without walls or columns. that was so special about the design.

You mean apart form the all the walls that separated the offices and rooms and such? I guess you'll next claim that they were just sheetrock anyway, but guess what, so were the ones in the core, in fact one group of surviors carved their way through a wall from a lift shaft to a bathroom to escape. The majority of the mass in the towers was in the floor sections, both as the trusses and concrete and the live load itself, the desks, chairs, books, tables, carpets, people, and so on, all the things the core section (of which over half was hollow tubes and the rest near empty rooms or stairwells, which are just hollow tubes with flimsy bit of metal inside) didn't have. Think about this really carefully. If you'd been in the towers and wanted to survive, would you rather have been out in the floor section with all the other floor sections above you and very little to stop then dropping ontop of you, or in the core where there was very little above you?
 
oh radicalism hits us.
hollow or solid
with us or againt us.
nothing between...
 
Yes DC, with all those stairwells and elevators, there is a lot of floor penetration in the core.
Whereas the floor outside the core is uninterrupted.
Is that what you are trying to say?
 
oh radicalism hits us.
hollow or solid
with us or againt us.
nothing between...

Well then oh great font of wisdom, what exactly is the state between hollow and solid? Sorta hollow? Hollow but for a few bits that aren't? Not really quite hollow cause I can't possible admit that I'm wrong?
 
Yes DC, with all those stairwells and elevators, there is a lot of floor penetration in the core.
Whereas the floor outside the core is uninterrupted.
Is that what you are trying to say?

oh and a penetrated floor makes the core hollow......
yeah sure.
 
Definition of hollow:

not solid; having a space or gap or cavity.


Are you saying that the core had no spaces, gaps or cavities? Are you saying it was solid?
 

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