Merged Why WTC7 should not have collapsed

[cmcaulif]

Do you understand that progressive collapse is a dynamic phenomenon?

It may very well by possible that 7 could do without one column under gravity. However, when a column fails, and progressive collapse begins, failures may propogate vertically, horizontally, or both simultaneously. Kinetic energy is the major player at work, and that energy goes into damaging the structure.

Of course the load redistibutes, onto a damaged structure(load misalignment, damaged connections, possibly broken leading to greater column instability). if strain energy at the local failure site cannot arrest the collapse the scenario gets worse(again, see 'push down analysis'). This is not to mention fire damage, which, if you would like to begin to understand, from an analytical standpoint, see:

A.S.Usmani, J.M.Rotter, S.Lamont, A.M.Sanad, M.Gillie. Fundamental principles of structural behaviour under thermal effects Fire Safety Journal, 36, 721-744, 2001

I'm pretty sure theres a free copy on google somewhere, and yes, they give the buckling load of a beam as a function of temperature, due to thermal expansion.

 

[JihadJane]

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.

leftysergeant, are you able to provide any reasons as to "why the WTC 7 debris pile could not have been forensically dismantled"?

The engineering/fire failures of 911 have massive implications for thousands of steel high-rise buildings all over the world. This is why experts in the field at the time called for an immediate halt to the removal and destruction of the evidence.

I don't understand your focus on the "immediate area of the collapse" as a necessary site for all the investigation. It is normal in such disasters for the evidence to be carefully mapped and then taken elsewhere for investigative reconstruction. The USA is a big place with apparently unlimited amounts of money to spend on protecting its interests. I expect it would be possible for the richest country in the world to fund proper investigations to ensure the safety of the thousands of Americans who work in high-rise, steel-framed buildings.

NIST investigators had no part in choosing the pitifully small selection of steel that was available to them for analysis. The rest of the steel had been melted down before the NIST investigations began.

 

[JihadJane]

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

Quote:

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".

I hope you have managed to close it again!

JREF and its scientist participants seem to have a very narrow focus when it comes to 911.

Physical evidence forms only a small part of the possible evidence pointing to US State complicity in the 911 atrocity. Many 911 sceptics recognise that attempting to prove demolition theories is unnecessary or even an obstacle to discovering the truth about what happened and why, e.g.:

"Demolition theories are not the best evidence of complicity":

http://www.oilempire.us/demolition.html

In my experience the two main obstacles to considering the possibility that the 911 Shock and Awe event was not as officially described are:

1) A assumption no-one in government would sanction the death of those they are charged to protect, even for reasons of political expediency.

2) An assumption that a false flag operation would take hundreds or thousands of people to pull off and that some of these many participants would surely blow the whistle.

Both these assumptions are based on political illiteracy. Scientists can be as politically illiterate as anyone else.

 

[Heiwa]

Do you understand that progressive collapse is a dynamic phenomenon?

It may very well by possible that 7 could do without one column under gravity. However, when a column fails, and progressive collapse begins, failures may propogate vertically, horizontally, or both simultaneously. Kinetic energy is the major player at work, and that energy goes into damaging the structure.

Of course the load redistibutes, onto a damaged structure(load misalignment, damaged connections, possibly broken leading to greater column instability). if strain energy at the local failure site cannot arrest the collapse the scenario gets worse(again, see 'push down analysis'). This is not to mention fire damage, which, if you would like to begin to understand, from an analytical standpoint, see:

A.S.Usmani, J.M.Rotter, S.Lamont, A.M.Sanad, M.Gillie. Fundamental principles of structural behaviour under thermal effects Fire Safety Journal, 36, 721-744, 2001

I'm pretty sure theres a free copy on google somewhere, and yes, they give the buckling load of a beam as a function of temperature, due to thermal expansion.

Of course it is a dynamic phenomenon. Luckily it is arrested when it runs out of energy. So you have to check the available energy at every step of local failures and where it can be applied and how it is lost and absorbed. NIST does not do it!

Read http://heiwaco.tripod.com/nist3.htm why WTC1 could not have collapsed as the available energy was consumed by local failures up top.

I have evidently informed Shyam Sunder (and his boss) accordingly. No reply so far, so I assume they agree with me (or were busy with more lies about WTC7?).

 

[Grizzly Bear]

Of course it is a dynamic phenomenon. Luckily it is arrested when it runs out of energy. So you have to check the available energy at every step of local failures and where it can be applied and how it is lost and absorbed. NIST does not do it!

Read http://heiwaco.tripod.com/nist3.htm why WTC1 could not have collapsed as the available energy was consumed by local failures up top.

I have evidently informed Shyam Sunder (and his boss) accordingly. No reply so far, so I assume they agree with me (or were busy with more lies about WTC7?).

BUMP for you: http://www.internationalskeptics.com/forums/showpost.php?p=3984318&postcount=100

You are applying a general standard scenario to the collapses. I would really like to know what standards you're using and what considerations you've made.

 

[Cuddles]

What kind of logic is this?

Just plain, regular, normal logic. You know, the kind that starts with a couple of propositions and then leads to a conclusion. It's really not that complicated. Here, I'll give you a hand:

1) Column 79 existed at some point.
2) Column 79 no longer exists.
C) Column 79 failed.

See? Not difficult at all. It follows that anyone who claims there is no evidence that column 79 failed does not have a clue what they are talking about.

 

[JihadJane]

Did she fall or was she pushed?

Just plain, regular, normal logic. You know, the kind that starts with a couple of propositions and then leads to a conclusion. It's really not that complicated. Here, I'll give you a hand:

1) Column 79 existed at some point.
2) Column 79 no longer exists.
C) Column 79 failed.

See? Not difficult at all. It follows that anyone who claims there is no evidence that column 79 failed does not have a clue what they are talking about.

Many thanks for your patient explanation...however, I think you are being a little unfair to Column 79.

If, as as been hypothesised, means other than gravity and fire were used to bring down the building, is it really fair to call Column 79's subsequent non-existence a "failure"?

It would be a bit like training an athelete to run the 100 metres, shooting her in the knee just before the race and then declaring she has failed as an athelete because she didn't make it to the other end.

 

[Drudgewire]

JREF and its scientist participants seem to have a very narrow focus when it comes to 911.

We have a very narrow focus when it comes to horses too. There are ones which are real, proveable, and backed up by science.

And then there are ones with horns and/or wings which are imaginary and aren't believed in by sane people.

 

[phunk]

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.

Except that is not reality. When 79 failed, it didn't magically disapear. It was still attached to all of the floors above and below the area that failed, and when it started to move downward, it pulled on all of those floors, and they in turn pulled on the other columns they were connected to.

 

[cmcaulif]

Of course it is a dynamic phenomenon. Luckily it is arrested when it runs out of energy. So you have to check the available energy at every step of local failures and where it can be applied and how it is lost and absorbed. NIST does not do it!

Finite Element, an energy method, relies on knowing the energies in the system. The basic fiite element equation is

[k]{u} = {f}

where [k] is the stiffness matrix, {u} is a vector of (nodal) displacements, anf {f} is the vector of forces at each node. Finding the displacement infolves inverting the [k] matrix, but if their is some kind of instability or runaway failure, this matrix becomes singular and the the equation wont work. SO other methods, many of which explicitly use energy as a criteria for convergence of the solution, are used for failures like buckling and post buckling.

NIST did do this.

I do however feel that they are far too relient on FE, and since there is always difficulty in matching a model to reality (that is, making sure all of your assumptions are physical). I think some sort of 'check' calculations are needed.

I'm not finished my study of the report but I haven't found any checks, I'll likely write them to request that they include some.

Read http://heiwaco.tripod.com/nist3.htm why WTC1 could not have collapsed as the available energy was consumed by local failures up top.

stop linking your site, it doesn't make sense

I have evidently informed Shyam Sunder (and his boss) accordingly. No reply so far, so I assume they agree with me (or were busy with more lies about WTC7?).

So since there was no correction or retraction, they agree with you? yeaaaa

 

[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?

*cough*

 

[Newtons Bit]

Finite Element, an energy method, relies on knowing the energies in the system. The basic fiite element equation is

[k]{u} = {f}

where [k] is the stiffness matrix, {u} is a vector of (nodal) displacements, anf {f} is the vector of forces at each node. Finding the displacement infolves inverting the [k] matrix, but if their is some kind of instability or runaway failure, this matrix becomes singular and the the equation wont work. SO other methods, many of which explicitly use energy as a criteria for convergence of the solution, are used for failures like buckling and post buckling.

NIST did do this.

I do however feel that they are far too relient on FE, and since there is always difficulty in matching a model to reality (that is, making sure all of your assumptions are physical). I think some sort of 'check' calculations are needed.

I'm not finished my study of the report but I haven't found any checks, I'll likely write them to request that they include some.



stop linking your site, it doesn't make sense



So since there was no correction or retraction, they agree with you? yeaaaa

Technically speaking, [k]{u} = {f} can be based on non-energy mechanics

It can also be solved through simultaenous equations and using something like Gauss Elimination rather than inverting the k-matrix (which is much simpler to program). NIST didn't actually do this, they used programs that other people have developed that do this. Just a minor quibble.

 

[Heiwa]

Except that is not reality. When 79 failed, it didn't magically disapear. It was still attached to all of the floors above and below the area that failed, and when it started to move downward, it pulled on all of those floors, and they in turn pulled on the other columns they were connected to.

OK, so now the beams are pulling. Good! Column 79 has only failed between, say floors 0 and 10 and is hanging, via the beams (intact), to other columns above, that in turn are intact to floor 0.

It is very easy to with my 3D-beam model what happens. Remove column 79 between floors 0 and 10. The top, intact part of column 79 is now hanging freely above floor 10 (bottom part missing) and is supported by the beams in four directions at every floor 10-49 to adjacent columns.

The total load on column 79 at floor 10 is now carried as tension in the 39x4= 156 beams connected to it to adjacent 4 columns (and further on to other columns).

No way that the 156 beams will pull the 4 adjacent columns down causing global collapse. Actually - the first local failure that may occur is that one of the 156 beams' connections fails.

If all 156 beam connections fails, column 79 drops down from floor 10 to floor 0. End of demolition.

This exercise is standard when checking the redundancy of a structure. NIST failed to do it.

 

[Newtons Bit]

Except that is not reality. When 79 failed, it didn't magically disapear. It was still attached to all of the floors above and below the area that failed, and when it started to move downward, it pulled on all of those floors, and they in turn pulled on the other columns they were connected to.

You're getting it.

 

[cmcaulif]

Technically speaking, [k]{u} = {f} can be based on non-energy mechanics

Of course, but since for FE, one arrives at this equation not by considering equilibrium of forces, but minimum potential energy...

It can also be solved through simultaenous equations and using something like Gauss Elimination rather than inverting the k-matrix (which is much simpler to program). NIST didn't actually do this, they used programs that other people have developed that do this. Just a minor quibble.

Well you have me there

Still cant use that equation for failures though.

 

[Newtons Bit]

No way that the 156 beams will pull the 4 adjacent columns down causing global collapse. Actually - the first local failure that may occur is that one of the 156 beams' connections fails.

Calculations please. Or a model.

 

[Newtons Bit]

This exercise is standard when checking the redundancy of a structure. NIST failed to do it.

Actually, this is one of the methods to verify that a structure has sufficient strength to resist a column failure. The WTC7 designers did not do such an analysis, nor did they consider column failure in their design (as the building codes at the time did not require it).

Buildings that are not explicity designed to resist column failure are not implicity guarenteed to resist column failure.

 

[kookbreaker]

Calculations please. Or a model.

Dude! He said 'no way'. What more do you need?

 

[Mobyseven]

Hello? Hello?

Anybody in this thread still want to volunteer their car for a three foot drop, while being confident that it won't damage the car?

How about a three storey drop that a matchbox car can survive?

 

[uruk]

Read http://heiwaco.tripod.com/nist3.htm why WTC1 could not have collapsed as the available energy was consumed by local failures up top.

So you are saying that all that falling mass would not damage and weaken the structure below?

Does impact mean anything to you?