Merged Applicability of Bazant's model to the real world

[ozeco41]

They are not full scale (and simplified in structure), but are performed from an FEA system...

http://the911forum.freeforums.org/progression-attributes-of-enik-s-core-simulation-t406-45.html#p12213

Thankyou.

As you are aware I agree with the concept - my approach, as usual from a global perspective, that the falling load was obviously "overwhelming" once the "global collapse" was established - i.e. had fallen a "few" floors. There are questions which I leave unresolved as to how the very first impact has sufficient effective mass. That in turn brings in the questions about when and where the top block started to disintegrate and whether any or all of the top block outer columns fell inside the lower outer tube whilst the top block still retained some integrity.

All of those in what I would call the "transition" from the initial downwards movement of the top block and the later, fully established, global collapse mechanism.

PS I also updated my reading of the reference thread on the911forum - I must be getting old - I had forgotten that the material was there.

 

[femr2]

There are questions which I leave unresolved as to how the very first impact has sufficient effective mass.

Yes. One aspect of the ROOSD study is determining metrics for that initial mass.

From a very simple 1D model, about three complete floor assemblies would propogate in around the right time (14.5s), but that was certainly not a definitive test. (especially in terms of propogation timing behaviour through MER floors)

That in turn brings in the questions about when and where the top block started to disintegrate

Indeed.

and whether any or all of the top block outer columns fell inside the lower outer tube whilst the top block still retained some integrity.

Do you mean outer core columns ?

All of those in what I would call the "transition" from the initial downwards movement of the top block and the later, fully established, global collapse mechanism.

I would suggest the *transition* phase should start before downwards movement.
And add for clarity that ROOSD does not specifically account for core behaviour.

 

[leftysergeant]

And add for clarity that ROOSD does not specifically account for core behaviour.

Nor need you account too specificly for it, outside of the failure point at which collapse was initiated. Once the floors started failing, collisions and mechanical resonnace handle the core columns pretty effectively, though more slowly.

 

[femr2]

Nor need you account too specificly for it

I do not agree.

Once the floors started failing, collisions and mechanical resonnace handle the core columns pretty effectively, though more slowly.

Too much conjecture in there for my liking I'm afraid.

 

[ozeco41]

Yes. One aspect of the ROOSD study is determining metrics for that initial mass.

From a very simple 1D model, about three complete floor assemblies would propogate in around the right time (14.5s), but that was certainly not a definitive test. (especially in terms of propogation timing behaviour through MER floors)...

Yes - see my later comment on "transition".

...Do you mean outer core columns ?

No, I did mean the top block outer columns - the question is "Did the top block integral with its outer columns wedge inside the lower tower outer tube?" Or from the opposite perspective - "Were the top block columns peeled off in the transition to global collapse?". For simplicity I had visualised the former. There is also the "half and half" possibility. I am not persuaded that the top block remained intact right down to ground level. The type of detailed research that you and like minded persons undertake could give the answers - you may already have them. I don't know.

...I would suggest the *transition* phase should start before downwards movement....

I comprehend and respect that you will have sound reasons for that. I selected the short time of the initial downwards movement as my boundary between "initial collapse" and "global collapse" because it gives a definable stage where there is limited if any axial load bearing by columns. So the "initial collapse mechanism" - whatever it was including natural and unnatural causes - leads to that initial drop. So that point defined for me the start of the global collapse OR potentially a transition period - I have never formally defined either the transition or the end point of transition. So the bottom line is that I am open to another boundary for "transition start" if it fits more detailed research into collapse initiation.

...And add for clarity that ROOSD does not specifically account for core behaviour.

Understood. My own explanations are essentially qualitative but backed by professional judgement and reasoning which shows the critical loadings to be "overwhelming". That much has sufficed for discussions with lay persons on the global arguments of "demolition or not". You will be familiar with my approach from other discussions and how it differs from your own. So I have a "qualitative" plus "ball park quantification" explanation for floor area collapse which is compatible with/analogous to ROOSD. I have a separate explanation for the core but based on similar principles. Plus some minor add-ons for the various overlaps core to OOS resulting from misalignments.

 

[leftysergeant]

I do not agree.


Too much conjecture in there for my liking I'm afraid.

We see parts of the core standing after the floors are gone. They are wobbling randomly. Mechanical resonnance. It tears things apart pretty quickly.

 

[femr2]

I did mean the top block outer columns - the question is "Did the top block integral with its outer columns wedge inside the lower tower outer tube?" Or from the opposite perspective - "Were the top block columns peeled off in the transition to global collapse?". For simplicity I had visualised the former. There is also the "half and half" possibility. I am not persuaded that the top block remained intact right down to ground level. The type of detailed research that you and like minded persons undertake could give the answers - you may already have them. I don't know.

Yes, it's been looked at in detail at the911forum. Will dig out links, but ...

Upper block perimeter *kick-out* resulted in the perimeter of at least the North and West faces descending outside the lower perimeter, and, yes, would act to help *skin* the OOS flooring from upper perimeter, releasing upper block OOS flooring rapidly (on perimeter side at least)

Behaviour (top of head) is not so clear for East and especially South perimeter due to lack of visual material.

Major_Tom will have more specific detail on perimeter kick out behaviour than I can recall without delving into previous analysis.

So the bottom line is that I am open to another boundary for "transition start" if it fits more detailed research into collapse initiation.

The current discussion on the OOS thread here is aimed at that point, as-in how early smoke/dust ejection behaviour relates to interal movement.

I have a separate explanation for the core but based on similar principles. Plus some minor add-ons for the various overlaps core to OOS resulting from misalignments.

Again, for these more focussed discussions, it may be a good idea to perform them at the911forum, where narrow scope and tight thread focus are very much encouraged.

 

[femr2]

We see parts of the core standing after the floors are gone. They are wobbling randomly. Mechanical resonnance. It tears things apart pretty quickly.

As per other elements of the event behaviour, I'm more interested in detailing specific behaviour encompassing the period of time pre-initiation to post core remnant descent.

*It wobbled about, then fell down* is not going to satisfy. Suggest this thread is not the place for that discussion.

 

[ozeco41]

...The current discussion on the OOS thread here is aimed at that point, as-in how early smoke/dust ejection behaviour relates to interal movement...

Understood. And agreed - shift from external visible movement to internal invisible to direst observation movement if the latter is supportable by evidence/argument.

BTW that shift does not destroy the utility of my "external visible movement" criterion for simpler lower level discussions.

....Again, for these more focussed discussions, it may be a good idea to perform them at the911forum, where narrow scope and tight thread focus are very much encouraged.

Yes - agreed.

 

[ergo]

Because once it gets going,

wait for it....

the forces being applied to the intact structure below the descending mass is so large that the connections keeping the OOS floor assembly attached to the perimeter and core are easily overcome and very rapidly destroyed.

... The inevitability argument.

It's hard to believe you're taken for anything other than a official collapse theory apologist as you borrow so much from Bazant.

It's also bizarre that you suggest that 80 to 90 levels of floor to column connections would have popped around the perimeter and around the core pretty much all at the same time and at the rate of 0.16 of a second per floor. Have you actually sat down and thought about this time frame? If you live in or know of an apartment building, consider what that would mean for your apartment building, for it to collapse at the rate of 6 floors per second. Then consider this for a steel-framed highrise.

And then ask yourself, where is the office furniture? Where are these large floor pans, which would obviously not pulverize? Where are the crushed people?

Take some time and look at how each floor truss was actually connected to the core and perimeter before responding to this point.

Well, we know the connections had to have been strong enough for the trusses to pull in the perimeter box columns for the collapse initiation. Surely the bolts would have popped with the degree of floor sagging and strain that NIST proposes. But no, they didn't, according to NIST. They were strong enough to pull in an entire row of thick steel box columns until those columns themselves snapped. Not the bolts. The columns.

Interesting.

 

[Newtons Bit]

Well, we know the connections had to have been strong enough for the trusses to pull in the perimeter box columns for the collapse initiation. Surely the bolts would have popped with the degree of floor sagging and strain that NIST proposes. But no, they didn't, according to NIST. They were strong enough to pull in an entire row of thick steel box columns until those columns themselves snapped. Not the bolts. The columns.

The bolts needed 6,000lb of capacity to do what they did. I've done the math.

Perhaps you ought to go study some basic mechanics before you start implying that something is impossible.

 

[ozeco41]

I missed commenting on this:

...Upper block perimeter *kick-out* resulted in the perimeter of at least the North and West faces descending outside the lower perimeter, and, yes, would act to help *skin* the OOS flooring from upper perimeter, releasing upper block OOS flooring rapidly (on perimeter side at least)...

Actually in the broad picture it matters not if the upper block perimeter falls outside - when the lower tower perimeter will act as the "knife edge" to shear off the outer ends of the top block floors OR if the upper block perimeter falls inside when it will act as the descending "knife edge" to cut off the outer ends of the lower tower floors. Either way you get the concentration of load to shear off those first few floors and the resulting falling mass sufficient to start the global collapse which, once started, is unstoppable.

...Behaviour (top of head) is not so clear for East and especially South perimeter due to lack of visual material...

...OK So I stay with my preliminary hypothesis of "it doesn't matter - either way gives enough mass falling onto the OOS to initiate global collapse".

 

[Dave Rogers]

Perhaps because what you wrote is unintelligible. Eg: "...the downward force on Block C..." implies something pressing down from above. Block C is the upper block.

What is obvious to eight-year-olds and other people who understand everyday physics...

...is that gravity is an attractive force acting on all bodies, and that in everyday experience it is a downward force. Anybody with the most rudimentary understanding of physics will understand that gravity can be described as "the downward force on Block C..." with perfect clarity. Only someone utterly ignorant of the most basic principles of physics would draw the conclusion that "the downward force on Block C..." necessarily implied something other than gravity.

There's very little point arguing with someone this ignorant. He needs a remedial physics course before he's even capable of understanding the replies.

Dave

 

[leftysergeant]

It's also bizarre that you suggest that 80 to 90 levels of floor to column connections would have popped around the perimeter and around the core pretty much all at the same time and at the rate of 0.16 of a second per floor.

Either your visualization or the construction of that sentence is utterly bizarre. I do not recall anyone's having said that the fllors popped loose from both ends simultaneously. I see no way that they could have. They would have fallen at different angles. That there was office furniture on the floors would also have changed the way in which they fell, because, even compacted, they would have occupied space.

Have you actually sat down and thought about this time frame? If you live in or know of an apartment building, consider what that would mean for your apartment building, for it to collapse at the rate of 6 floors per second. Then consider this for a steel-framed highrise.

Stop listening to Sophia Shafquat's brain going klunkity-klunk inside her skull. Why do you think this rate is impossible? There are factors which would increase the speed of the collapse over time. The first few failures may have been slower, but so what?

Even if you postulate CD, you would have the floors falling that far that fast. There is no reason to assume that it takes more than a millisecond or two for the connections on one end of a floor truss to fail once that staggering great load slams into them. If you widsh to make such an issue of the rate of failure, you need to show some arresting factor and attach a supportable numerical value to it.

And then ask yourself, where is the office furniture?

Most of it these days is particle board. It would be pretty finely ground up in that swirling mess of stuff.

Where are these large floor pans, which would obviously not pulverize?

A lot of them are seen in the rubble pile, twisted almost beyond recognition. There are a few of them sandwiched between the slabs of the "meteorite" in Hangar 17.

Where are the crushed people?

Put a large bug of some sort in a gallon jar half-full of marbles and aquarium gravel and shake it like mad for about twenty seconds. You'll get the idea.

Well, we know the connections had to have been strong enough for the trusses to pull in the perimeter box columns for the collapse initiation.

We also know that the perimeter columns were bloody hot, probably expanding a bit, so that they would have to bow either inward or outward to some degree. The pull of the floor trusses determined that that would be inward.

Surely the bolts would have popped with the degree of floor sagging and strain that NIST proposes. But no, they didn't, according to NIST. They were strong enough to pull in an entire row of thick steel box columns until those columns themselves snapped. Not the bolts. The columns.

Actually. if you look at the ends of the perimeter columns, it is obvious that the columns themselves did not break. The bolts that held them together broke. Or bent. Or pulled out of their holes. Whatever. If I am wrong here, maybe one of the engineers will correct me, but it looks to me, from the pictures I have seen of them, that the perimeter column bolts were longer than those that held the trusses in their brackets.

It has been my experience that it is a lot easier to break a bolt that is longer in comparison to its diameter than it is a short one of the same diameter. It looks to me like the perimeter column bolts were far longer than the truss bracket bolts, thus should have failed first.

 

[Tony Szamboti]

The bolts needed 6,000lb of capacity to do what they did. I've done the math.

Perhaps you ought to go study some basic mechanics before you start implying that something is impossible.

The truss connections at the perimeter were indeed strong enough to pull a perimeter column inward before breaking. You are correct there. In fact, there was more strength than just the bolts when the gusset plates and strap anchors are considered along with the bolts.

However, the issue isn't about one set of bolts or one truss connection. NIST needs to disconnect nine out of ten trusses at the perimeter to get the overload needed for the sag they predict. The problem is then that they only have one truss connection to pull about twenty perimeter columns inward, and that can't happen before the connection breaks. That is the real dichotomy in their theory.

 

[femr2]

The inevitability argument.

Sigh. I have spent much more time than I'd like trying to show you how sustainable propogation occurs, and the regional context, namely the OOS floor region.

I asked you numerous questions about simplified scenarios which you seem to have chosen to ignore, but I think it's worth repeating to ensure that you don't keep walking down the same road with blinkers on...


Hammock...with extra information on how this relates to the towers...please don't view this as silly. Take the time to answer these very simple questions...

1) Two trees

One tree represents the vertical load bearing core columns.

The other tree represents the vertical load bearing perimeter columns

2) Hammock #1

A nail is hammered into each tree and the ends of the hammock are tied to each nail.

The hammock represents the OOS floor assembly.


Our hammock is only designed to hold an absolute maximum of the weight of 2 Homer Simpsons.

Q1) When one Homer gets into the hammock, his weight is being held off the ground by the trees, yes ?

Q2) The hammock (through it's connection to the nails) is supporting the weight of one Homer, yes ?

Q3) What happens if three Homers get into the hammock ?

a) The string at either end breaks, or the nails pop out of the tree, resulting in one or more ends of the hammock (and the three Homers) falling to the ground.

or

b) The trees snap in half and the hammock (and three Homers) fall to the ground.

It's hard to believe you're taken for anything other than a official collapse theory apologist as you borrow so much from Bazant.

I'm looked upon as a *twoofer*, *nutjob*, ...

Which makes this discussion kinda ironic don't you think ?

And then ask yourself, where is the office furniture? Where are these large floor pans, which would obviously not pulverize? Where are the crushed people?

What was not crushed during descent was pulverised when the masses impacted the ground with enourmous available KE.

Well, we know the connections had to have been strong enough for the trusses to pull in the perimeter box columns for the collapse initiation.

I do not agree with the NIST IB scenario.

 

[femr2]

Tony,

From prior discussion it is clear that your WTC 7 *jolt* statement relates to the data blip at the 10s mark in this graph generated by David Chandler...

I have repeatedly shown you the following WTC 7 velocity trace...

...highlighting the following:

a) An eight storey drop equates to 12.75*8=102ft.
b) 102ft drop of the NW corner equates to ~14.8s on my provided graph.
c) There is a slight behavioural change at that point in time, but no significant *jolt*.
d) Change in the trend of velocity does not occur until around the 16s mark.
e) At 16s the NW corner has descended ~200ft.

Your response was rather silly...

Obviously, the upper section had to go through the eight floors of rubble before hitting the intact structure below and it was not literally meant that a jolt occurred immediately at the end of the eight story drop.

I'm sorry but that was either an incredibly silly mistake or a feeble attempt at something more underhand.

After the NW corner has descended 102 ft the bottom of the *upper block* is already through your *rubble layer*.

102 ft of *removed building*, 102 ft of descent.

The trend of the velocity does not change until the NW corner has descended another 100 ft.

That's another 8 storeys.

Tony, please... make your position clear.

At what point in time (specifying upon which graph) are you stating that the "deceleration of 14 mph" occurred, and what are you stating caused it ?

(And please stop mixing up your units.)

 

[pgimeno]

A lot of them are seen in the rubble pile, twisted almost beyond recognition. There are a few of them sandwiched between the slabs of the "meteorite" in Hangar 17.

Here's an example. In the high res version the pan is clearly visible near the right edge, behind the rebar. To the right of the bucket being held high there's another pan.

http://www.navy.mil/view_single.asp?id=2485

But what point is there on feeding this troll who has already filled 26 pages of openly declared willful ignorance in another thread (and not the only one) and has filled 4 pages of utter offtopic so far in this thread in two days as soon as someone started answering him?

There's more than enough material for Stundies, and he already won one.

http://www.internationalskeptics.com/forums/showthread.php?t=187582#post6406462

Really, he explicitly refused to learn. Trying is pointless.

 

[leftysergeant]

To address whetehr the perimeter columns of Block C fell inside or outside the perimeter columns of Block A, I think this rather supports their falling inside:

(Sorry to link you to a Chandler Video, but he did do one service in slowing this down a bit.)

We can see in his video that there is no debris falling outside the building as dust puffs out. That puts the perimeter columns inside the tube as they descend.

 

[femr2]

To address whetehr the perimeter columns of Block C fell inside or outside the perimeter columns of Block A

My post related to WTC 1, but I think it's reasonable to assume that at least two faces of each upper block descended outside the lower perimeter, with the other two inside.

There may have been more than two for WTC 1, but I'll need to check.