Merged Why WTC7 should not have collapsed

[leftysergeant]

It requires absolutely no knowledge of engineering issues to know the removing and destroying all the physical evidence from a crime scene fatally compromises any investigation.

Leaving the steel where in situ during the investigation was not an option that anyone with a room-temp or higher IQ would entertain. Stop bringing it up.

The steel was examined at Fresh Kills. Did you hear Astineh-Asl complaining that there should have been more than he saw?

 

[Mobyseven]

I think it's you who doesn't understand if you think that is a reasonable comparison. 200 ft and 3 feet are the difference. The match car would be damaged at 200 feet and the car not very from 3 feet.

*facepalm*

If I dropped a car, an actual size car, 3', then that car is not going to be a happy bunny. Indeed, dropping a car from three feet up is going to send you in for quite a few repairs.

But if you really think that a car won't be very damaged from three feet, scale, take it up a bit further. I can throw (yes, throw) a matchbox car out of a third story window and it won't get too damaged (perhaps a few scratches). What would happen to a car dropped from the same height?

 

[Heiwa]

It's not non-responsive at all. Heiwa starts with no assumptions about the weight, composition or strength of the structure, none about the temperature, extent or duration of the fires, none about the thermal properties of the materials involved, and makes no calculations; he simply advances a line of reasoning which he claims leads to the conclusion that progressive collapse cannot occur. In the absence of any data or calculations, this can only be assumed to be a perfectly general result. Since progressive collapse does occur, it is also a completely wrong result. Having thus summarised Heiwa's arguments, I can conclude that they are not worthy of further consideration. This is called attacking the argument.

In effect, Heiwa is saying, not that WTC7 should not have collapsed, but that nothing can ever collapse. It's a perfectly reasonable response to say that this conclusion is insane.

Dave

Hm, do I say nothing can collapse? Where? No, I just say when a local failure occurs for any reason, you have to analyse the consequences of this local failure. Other parts may get damaged. What happens then? Just do the analysis step by step and record the results in a simple manner. NIST is not doing that in its WTC7 reports and it is the same people that wrote the WTC1/2 reports that are now back in action. Same method - plenty of words, little logic. Typical when you do not know what you are talking about.

 

[Grizzly Bear]

Same method - plenty of words, little logic. Typical when you do not know what you are talking about.

Dare I say you're having an irony moment?

 

[JihadJane]

Leaving the steel where in situ during the investigation was not an option that anyone with a room-temp or higher IQ would entertain. Stop bringing it up.

Please give reasons why the WTC 7 debris pile could not have been forensically dismantled.

Who, BTW, said it should have left in situ during the investigation?

The steel was examined at Fresh Kills. Did you hear Astineh-Asl complaining that there should have been more than he saw?

Correct me if I'm wrong but I think the steel was taken to scrap yards not Fresh Kills. Only a small portion of it was "examined".

 

[boloboffin]

No astrophysicist is arrogant enough to claim that they cannot be wrong.

Well, the reason they might be wrong isn't because it's all a dark velvet cloth with holes poked through it.

 

[Travis]

Column 79 is assumed to fail first due to a local fire. Read the report.

So you are saying you don't feel that the loss of lateral support when the girder connecting column 79 and 44 failed had anything to do with column 79's collapse?

But the penthouse was also supported by other columns and they could not fail due to failure of columnn 79 (unless assisted of course).

So what do you think caused the bent in the penthouses right above column 79 that preceded the collapse of the east penthouse?

 

[Cuddles]

there's no evidence that column # 79 failed.

So the new construction on the WTC site has been slow because the columns from the old WTC are still standing? Don't you think it's just a little bit stupid to claim that a column didn't fail when it's rather obvious that the entire building, columns included, is no longer there?

Explain to me the similarities of a high rise building and a table.

"And that, my liege, is how we know the Earth to be banana-shaped."

Sorry, seemed appropriate for some reason.

 

[Stellafane]

No astrophysicist is arrogant enough to claim that they cannot be wrong.

Heh, then you're not familiar with Norman Lockyear or Allan Sandage. In any case, there's a huge difference between "I might be wrong" and "this is all based on infinite malleability and guesswork."

 

[Hokulele]

No astrophysicist is arrogant enough to claim that they cannot be wrong.

You haven't met very many astrophysicists, have you?


(Grrr, Stellafane beat me to it.)

 

[JihadJane]

So the new construction on the WTC site has been slow because the columns from the old WTC are still standing? Don't you think it's just a little bit stupid to claim that a column didn't fail when it's rather obvious that the entire building, columns included, is no longer there?

What kind of logic is this?

 

[leftysergeant]

Please give reasons why the WTC 7 debris pile could not have been forensically dismantled.

Who, BTW, said it should have left in situ during the investigation?

And where are you proposing that this examination should have taken place and when? In the immediate area of the collapse? I think not. Investigators knew where the steel was taken. There is no evidence that i have seen that anything was recycled without the investigators having a chance to look at it, aside from a small percentage that was stolen.

 

[WildCat]

*facepalm*

If I dropped a car, an actual size car, 3', then that car is not going to be a happy bunny. Indeed, dropping a car from three feet up is going to send you in for quite a few repairs.

But the General Lee was always fine in the Dukes of Hazzard!

 

[leftysergeant]

Hm, do I say nothing can collapse? Where? No, I just say when a local failure occurs for any reason, you have to analyse the consequences of this local failure.

You are looking at this with too narrow a view. When one floor slab fails due to expansion, it does stop pushing against the column due to expansion, there is still another floor slab pushing against it with no resistance.

That is one of the problems with twoofers. They look at what they see and do not think about what they do not see.

 

[cmcaulif]

3D-beam structures with say 60 vertical columns as primary parts carrying the loads to the base and with horizontal beams as secondary parts with loads on them connected to the columns at regular intervals do not collapse, if you remove one column.

Try it yourself with a table with say 10 legs. Remove one leg and the table does not collapse. Try it with a table with only three legs and remove one leg. Nothing happens if you have secured the legs to the ground!

Or try my famous model test at http://heiwaco.tripod.com/nist.htm (and scroll down a little). It is just 4 legs and all are supposed to fail, due to heat. But nothing happens.

May we see your dimensional analysis which proves that your model is representative of the actual tower?

Scale models of fires is difficult enough Dr. Quintiere actually advanced this field while at NIST, but scaling of structural strength is even more difficult. I'm interested in seeing how you manage it.

Furthermore, to asses the progressive collapse potential of a structure, engineers do not rip a leg off the nearest table and declare their structure fit. One analytical method is the so called push down analysis, a dynamic energy based method in which a critical column is removed suddenly, resulting in a net acceleration. Elastic and plastic strain energy will then have to dissipate the resulting kinetic energy to prevent damage from propagating to other parts of the structure. If you are interested in more detail, I can provide a good reference.

NIST chose to take a numerical approach, and since many truthers seem to have some unreasonable disdain for finite element, I'll just remind you that FEA is just an approximate method for solving differential equations. In the case of LS-DYNA, a program for dynamic analysis with explicit time integration, its solving DE's using a central difference scheme.

Bottom line, NIST has provided an approximate, although accurate solution to an extremely complex physical problem. Pulling legs off tables without any thought of scale or physics won't do.

 

[DGM]

Try reading.

People that argue that we can build buildings that can withstand anything that nature (or anything else) could throw at it have no clue as to the economics of building it in the first place. I agree with you that NIST's recommendations (the newest) are good on paper but who will pay the price?

Have you written a response (forgive me if I missed it)? PM me a link if you have. Thanks.

 

[dudalb]

Jihad Jane pretty much showed where she is coming from with this little statement in another thread:

In my opinion political literacy is far more important to understanding 911 than scientific literacy.

My jaw just fell open at that foolishness. Just a fancy way of saying "My Mind Is Made Up, Don't Confuse Me With Facts".

 

[Stellafane]

Jihad Jane pretty much showed where she is coming from with this little statement in another thread:

In my opinion political literacy is far more important to understanding 911 than scientific literacy.

My jaw just fell open at that foolishness. Just a fancy way of saying "My Mind Is Made Up, Don't Confuse Me With Facts".

"In my opinion political literacy is far more important to understanding 911 than scientific literacy." That quote could serve perfectly as the rallying cry of the Truther Movement -- and ultimately, its epitaph as well.

 

[Heiwa]

May we see your dimensional analysis which proves that your model is representative of the actual tower?

Scale models of fires is difficult enough Dr. Quintiere actually advanced this field while at NIST, but scaling of structural strength is even more difficult. I'm interested in seeing how you manage it.

Furthermore, to asses the progressive collapse potential of a structure, engineers do not rip a leg off the nearest table and declare their structure fit. One analytical method is the so called push down analysis, a dynamic energy based method in which a critical column is removed suddenly, resulting in a net acceleration. Elastic and plastic strain energy will then have to dissipate the resulting kinetic energy to prevent damage from propagating to other parts of the structure. If you are interested in more detail, I can provide a good reference.

NIST chose to take a numerical approach, and since many truthers seem to have some unreasonable disdain for finite element, I'll just remind you that FEA is just an approximate method for solving differential equations. In the case of LS-DYNA, a program for dynamic analysis with explicit time integration, its solving DE's using a central difference scheme.

Bottom line, NIST has provided an approximate, although accurate solution to an extremely complex physical problem. Pulling legs off tables without any thought of scale or physics won't do.

FEA or simple 3-D beam analysis is an excellent tool when designing and analysing structures. What is lacking in the NIST report is an analysis of the intact structure before any failures and the static and dynamic design loads used in the design. Then we would know the forces, moments and stresses in all primary (columns) and secondary (beams) parts and thus get a feeling of the whole structure (and the weakest links/parts).

I assume the FoS were >3, i.e. the static (+ dynamic) stresses were less than 1/3 of the permissible stresses in all parts and connections.

The beauty with such a model is that it is simple to simulate failures and to see what happens, i.e. to find out the redundancy, e.g. to remove (complete failure) one complete column and disconnect the attached beams and allow the attached beams just to be attached at their other ends. The (remaining) load on the beam is then only transmitted to the intact, adjacent column. A complete new situation/structure has developed.

What happens then?

You will then find - by analysing this model - that adjacent intact columns will not be overloaded and collapse. It is basic. Evidently you remove one supporting beam of an adjacent column but as there are still three other beams at each level, there is enough support, the stress in the adjacent column will increase a little but due to initial FoS the stress is still below permissible values (redundancy). Or simply - each column (primary structure) is quite independent of adjacent columns and the failure of one column and removal of beams attached to it cannot produce a progressive, global collapse.

NIST has made big noise about thermal expansion as a contributing factor but it is all nonsense.

It is easy to check thermal expansion with an intact model, e.g. just allow the sun to shine (heat) on one side with the other in the shade. Evidently the structure will deform like a banana but the stresses remain the same. You can do the same with internal parts at various floors to simulate a fire.

 

[Heiwa]

You are looking at this with too narrow a view. When one floor slab fails due to expansion, it does stop pushing against the column due to expansion, there is still another floor slab pushing against it with no resistance.

That is one of the problems with twoofers. They look at what they see and do not think about what they do not see.

You don't know anything about structural analysis, do you? A horizontal beam (secondary structure) is not pushing against a column (primary structure). The load on the beam is simply transmitted as shear to the column via the connection beam/column and produces compression of the column. Remove the beam and no load at all is transmitted to the column.

Thermal expansion do not cause progressive collapse of complete structures! If that were the case, the easiest way to demolish a steel structure would be to arrange fires around some primary parts (columns) and then just wait for thermal expansion to do the job. However, it does not work!

Try my simple model test at http://heiwaco.tripod.com/nist.htm .

I find it interesting to note how the American public ignores basic facts of structures, fires, redundancy, etc, or just does not want to hear about it and accepts the crude propaganda of NIST & Co that the WTC demolitions were natural consequences of fires, etc.