Was "Global collapse truly inevitable"?

[ozeco41]

In several recent posts (e.g. this one) the NIST claim that "Global collapse was inevitable" was questioned. I commented in this post that NIST could well be correct but for the wrong reasons. However I recently had opportunity on another forum to start to explain why "global collapse was in fact inevitable". That explanation was in response to two specific questions from a member who is a recognised "trolling truther". Emphasis on "trolling" and the fact that he deigned to ask some reasonable questions was why I responded at some length. Those two questions were:

What sheared or caused the perpendicular steel columns to fail? AND
What would have caused the core column flooring systems to fail?

Those two issues are central to understanding why the "Global collapse was inevitable" so the following is my version of the first steps of a reasoned comprehensive explanation - edited to remove material which was specific to another forum.

The acronym "ROOSD" meaning "runaway open office space destruction" may be new to some members here. I didn't invent the acronym but I find to be convenient shorthand in what follows.

A Reasoned Explanation of Why Global Collapse of WTC1 & WTC2 Was Inevitable - Part 1

Rational Step #1 - Defining the Context - where are we at and what are we discussing.

The issues are all part of the explanation of the "Global Collapse" AKA "collapse progression" stage of the fall of both WTC1 and WTC2 - at this stage we don't need to separate the two. I will be explaining that stage of collapse as "Three Mechanisms in Parallel" with one of them identified by the convenient label of ROOSD. The other two don't have recognised labels.

For our purposes here there were two distinct stages of WTC1 & 2 collapse viz:
1) "Initiation" which strictly speaking started at the point of first damage from the aircraft impact and ended when the "Top Block" of the tower started to fall. (Sometimes called "release" meaning "all four corners falling". I use the simpler version "top block falling". There can be subtle differences between the two but they are of no concern to us here.)

2) "Progression" AKA "global collapse" that period of whatever seconds from "top block starts falling" to "collapse front reached bottom of fall". Again there are some bits of pedantry in that but it is good enough for what we need here. And a damn sight tighter than we usually see posted.

We are discussing "Progression" - what happened after "Top Block" started to fall. I am going to explain three mechanisms which made up that overall "progression". Those three mechanisms were separate processes but closely related in time and interdependent. ROOSD was the leading process, the other two resulted from and were dependent on ROOSD. The three mechanisms are:
1) Failure of the OOS floors by the process labelled "ROOSD" - the process where whatever fell down the "open office space" could and did shear off the floor joist connections to columns;
2) Failure of the perimeter wall of columns by a process of "Peel Off" and falling away; AND
3) Failure of the core where the most likely main component was "Beam Strip Down".

Those three mechanism combine to a sufficient explanation for the "collapse progression" stage which is the stage we are discussing. I will try to present every necessary step of logic and indicate the status of evidence without detailing the evidence at this stage.

Rational Step #2 -- "Progression" Starts
As the top block starts to fall it is still a structural integral entity. Somewhat tilted and with the base slightly displaced. Evidence for "starts to fall" and "somewhat tilted" is in readily available video records. Evidence for "base slightly displaced" is from video evidence plus simple reasoning.

At at that point of time AKA that stage of the collapse sequence all columns in the failure zone - the zone affected by impact and fire damage - all columns have failed. AND they are all already misaligned - top and bottom parts not lined up OR they are inescapably in the process of failing and becoming misaligned.

Now the truth of those three assertions is obvious to me, many other people also see it immediately but many don't and some deny it even after being provided with explanations. And those come from both sides of the truther - debunker great divide.

So if it is obvious to you, skip the next couple of paragraphs - down to "Shortcut>>>> ". If it is not obvious read on.

A) The "Top Block" is falling must mean that for whatever reason more than enough columns have failed to reduce the total supporting strength to below what is needed to hold up the top block. Not enough strength remaining to hold up top block means it is inevitable that the top block falls.

So some columns must have already failed because the top block is falling - what about the others? The others are not strong enough to hold up the top block and the top block is falling means that, whatever strength may remain in those columns they are already failing - they must be already bending or buckling or (whatever failure mode)...because the top block is falling -- the space those columns occupy is getting shorter -- they must already be buckling or bending.

So that should prove two of those assertions:
A1 Some columns already failed; AND
A2 the rest already failing and those ones cannot escape from failing.

B) What about "misalignment'? Much the same logic proves misalignment. The "Top Block" is falling must also mean that the top parts of already failed columns are not aligned with their bottom parts. "Bypassing" has been the word of choice on some forums. So the failed columns are either already bypassing OR are in a situation where bypassing is inevitably coming into effect. The first claim self evident. The second one logically follows from the preceding reasoning for failure. If there are columns still trying to resist but losing they are losing because there aren't enough of them. So any lone column trying to remain in line holding load will be overwhelmed and pushed out of line. The circular logic of that last "yes but" claim is inevitable - if the column is not pushed out of line it will be hit with such force that it is pushed out of line.

Shortcut>>>> Rejoin discussion here.
Status at this point: The top block is falling, all columns failed and all columns are misaligned. Those two "failed' and "misaligned" are critical to what follows. And they are the key to answering these two as first step: AND
One more big step and we can answer those two.
(additional point - and we have proved my earlier claim that 'Evidence for "base slightly displaced" is from video evidence plus simple reasoning'.)

Rational Step #3 -- "Progression" Continues
The critical issue we now face is "What hits what".

Since the lateral displacement of the Top Block is small it follows that:
A) What lands on the OOS areas of the lower tower will be mostly the OOS of the upper tower;
B) Similarly what lands on core will be mostly core; AND
C) The perimeter will tend to land on or near the perimeter.

The ROOSD process is self perpetuating once there is sufficient accumulated load of floor and other debris. The issue of how it gets started is more complex and I will leave it aside for now. I can explain if anyone needs the explanation and they have got past these preliminary but foundation matters.

So:
1) ROOSD is the key. Once sufficient mass is falling down the OOS "Outer Tube" the process is self sustaining.

So "Mechanism #1 - ROOSD" strips down the floors of the OOS.

2) ROOSD leaves the outer perimeter unbraced in the "radial" direction outwards from core. Those perimeters fall due to instability and probably some impact forces during the ROOSD collapse.

So "Mechanism #2 Perimeter Peel Off"

Neither of those should be contentious. The new territory is probably:

3) What happens with the core? Recall that we have shown that:
(i) the Top Block core is falling AND
(ii) All the columns are out of alignment.

So what hits what? It must be the horizontal beams. And those beams have strength appropriate to a "one floor" load. They are hit with their portion of the full weight of Top Block. Massive overload == beams shear off.

The situation is analogous to the OOS floor joists - overwhelming weight as a part of a multi-storey Top Block hits floor beams/joists designed for one floor plus a bit of safety. And it hits with dynamic impact. Forces 10-20 or more times the design load are available. Shearing is inevitable.

So "Mechanism #3 Core beams strip down"

Sure the difference with the core is that there will be a much more confused mess of bent or out of alignment columns plus assorted debris. Very confusing BUT it doesn't affect the underlying reality. Horizontal beam on horizontal beam is the dominant impact mode and the loads are overwhelming.

So those are the basic premises or foundations. Any claim has to rely on those factors. Any counter claim has to show those factors to be in error.


Rational Step #4 -- Preliminary Answers to those two original Questions and Concerns

The perimeter columns were left standing with bracing removed. They would fall over for one of several reasons -- impacts from the descending ROOSD process, instability or vibration following ROOSD descent OR simply Euler buckling due to unsupported column of hight/slenderness far in excess of critical length. The key causal issue is "Removal of Bracing" - the rest follows automatically.
The word "column" is confusing. The core beams failed because the core of the Top Block fell on the core of the lower block with the columns already out of alignment. So the beam on beam contact applied loads of multiple storeys to beam connections designed for one storey loads. The failure almost certainly shear at the beam columns connections.

We are merely starting to address this issue. Broadly stated the problem with discussion to date is that most comments and concerns expressed from the truth movement side are about specific issues. And those issues are not linked to either a legitimate context or any defined underlying foundations. Hence my effort to clarify the underlying realities. Once we get those basics clear THEN we are in a position to address members specific issues by reference to a known foundation and context.

What I have posted is the start - the bare minimum framework which any claim or concerns must comply with. (Provided I have it right. )

Even at this starting level there is enough to show the weakness of some truther claims. AND the weakness of many debunker arguments. On these issues there ain't a lot of difference in the quality of the arguments. And both sides do a lot of "Authority Parroting" ( there I go - lèse-majesté again. Fortunately it is no longer a capital offence. I'm new to DebatePolitics so members may not yet realise that I hold no fear of Authorities such as NIST or Bazant on the things that they get wrong. :lol: )

Understanding these 9/11 challenges is complex. They will never be explained or agreement reached by two way "JAQing off" I enjoyed writing this post - In this case modifying it for DebatePolitics. Let's see if it helps anyone, maybe casts a new light for some others.


PS Remember - it is only "Step One" AND Zero apology for the length of this post. If we really want to understand WTC collapse we need to get serious. And serious explanations will take a few (??) words.

 

[Thoreau72]

That's an awful lot of typing for such obvious sophistry.

I guess the term would be "verbose sophistry"

 

[mike2810]

That's an awful lot of typing for such obvious sophistry.

I guess the term would be "verbose sophistry"

and that is the best you can come up with to refute what was posted.:lamo

like you using web sites that give no information about the author(s).

 

[SanderO]

Ozzie,
Excellent summary.
I have some suggestions and one area to suggest an alternate

Peel off is PO
Beam Strip Down is BSD


Now for my conjecture (may be a disagreement) *my latest theory)

The top was not a block when it is moving at release. What we see as a block is the entire cage of the perimeter held by what was left of the hat truss with little or no OOD flooring or core attached. By the time of release.. the insides had already dropped.

Why do I suggest this?

When column was swiped by a part of the plane it was like a guillotine.. severing it and separating the top from the bottom. The upper column was carrying floor loads from the floors connected to it and from the column bearing on it. Lets look at what might have happened to as a consequence of severing a core column.

1. All loads above have lost path to bedrock that were going through the severed column. Those loads are then *seen* by the columns adjacent. Simply supported beam connected to two columns..... remove one column and beam and load drops or has to be cantilevered.

Can the load be cantilevered and just hang there and all the floor loads carried on the surrounding columns?

yes - they can be carried by surrounding columns
but NOOOOOOOOOOOOOOOOO they beams won't perform as cantilevers (my best guess)

What happens? All the floor loads resting on the connecting bracing (beam) cause the brace to bend and break at the beam stub and dump the floor sections down? How many floor sections? I suspect all of them up to the hat truss area.

What happens to the column(s) line above the severed section?

They still have floor loads connect to them and loads bearing down on them.

THOSE COLUMNS HAVE BEEN TURNED INTO HANGERS (tension) AT THE MOMENT THEY WERE SEVERED. Now were have another problem

The bearing connections column on column were not engineered for tension. All the local loads are for an instant hanging from the hat truss. Those connections fail... especially the ones closest to the hat truss seeing the greatest loads.

This effectively causes a complete local failure of the columns (hangers now) and floors above the severed columns

OOO
OXO
OOO

All the 4 floor areas between Xs and

What else happens?

The O columns lose all their bracing an more easily can be pulled off alignment. This induces Euler buckling.

Since there were MULTIPLE columns severed it is LIKELY that a fair amount of the core region from the strike zone to the hat truss collapsed If this involved the PERIMETER of the core it would ALSO involve the OOS flooring adjacent.

Is this consistent with the observed movements? YES

There was asymmetries. There was additional weakening of the unsevered columns from heat... and being asymmetrically braced rotation was induced by the remaining continuous columns carrying the hat trues loads. That is the strike side of the core was LESS subject to heat weakening and the far side failed first and was the direction of the tilt.

What say you (who does not like details)?

 

[ozeco41]

and that is the best you can come up with to refute what was posted.:lamo

like you using web sites that give no information about the author(s).

Totally predictable. Part of the ongoing falling level of forum discussion of 9/11 matters. Current standards are well below what we enjoyed in the heyday era of 9/11 discussions 2006-7-8. And trolling standards have also fallen in parallel with mainstream genuine issue discussion.

The two main reasons obvious viz:
A) All the significant genuine questions long since answered so no serious discussion is needed;
B) Most of the genuine truthers have long since got their answers and moved on. Only the die hard denialist core left plus a few stragglers arriving late to the party. And the inevitable trollery.

So on most forums which still have active 9/11 sections the activity is dominated by:
1) Pure trolling and counter trolling (Do a count of active threads on JREF); OR
2) Recycling of long rebutted canards and the rituals of standard response rebuttals.

From my perspective "counter trolling" is "counter productive" - feeding the egos is what keeps them trolling; AND
recycling of long euthanased canards IMO is no more than trolling.

Judge for yourself where I rank suggestions from the idiotic fringe like "mini-nukes". Since those posting them make to pretence at reasoned argument in support I see no point in responding. Just more noise into the already poor "noise to signal" ratio IMO. Others clearly don't share my opinion. Their call - it's a free world.

And, meanwhile, the remnants of genuine discussion tend to be on secondary or sideline issues e.g.
3) Discussion of thermXte in dust which is a red herring from the S Jones desperation ploy to re-establish the "market prominence" he was losing to Gage. He lost. Gage remains #1 con-man on 9/11.

My SOP's over last four or so years include a "two posts rule". If I see a person, who normally trolls or posts idiocies, make a reasoned claim, statement or question I may respond with reasoned consideration. If they continue to post reasoned discussion I stay engaged. If they revert true to form then I post a final comment. The usual score is "two posts" maximum. i.e. few of them give two or more consecutive rational posts.

So, if HD makes a reasoned counter claim I may respond. Otherwise I'll save energy.

 

[Cyrylek]

That's an awful lot of typing for such obvious sophistry.

I guess the term would be "verbose sophistry"

The term currently accepted by the scientific community is "lotsa bul*****".

But I suspect this may be an attempt at an intentional parody.

 

[ozeco41]

Ozzie,
Excellent summary...

Thank you. My intention should be obvious. I thought it appropriate to have on the table here a hard line comprehensive and coherent hypothesis supported by reasoned argument. If anyone can prove it wrong or better it -- great. We all benefit.

However your suggestions come from a diametrically opposite position to me:

...I have some suggestions and one area to suggest an alternate...

I understand what you say and it is reasonable contemplation of possible alternates. But I was not presenting conjectures - I presented hard edged facts. My post was built strictly on objective facts which have evidential support available and are linked by appropriate logic and focussed towards a clearly defined objective. "Global collapse was inevitable". In the context of this internet discussion they remain facts, logical argument and legitimate conclusion until someone shows me where I am wrong.

Take my central example:
The top block is falling and I say:

At...that stage of the collapse sequence all columns in the failure zone...have failed. AND they are all already misaligned - top and bottom parts not lined up OR they are inescapably in the process of failing and becoming misaligned.

Three assertions of fact which cover the three possibilities - viz "have failed already"; "have not failed (yet)" OR "are in transition - cannot turn back"

There are no other options that I can see. And hence one of the reasons why the original audience ran away. Also a reason for HD to run away. (Sideline but it would also scare one of our colleagues who insists that things can only be true if they are "observables" and measured with high precision. You know the reference. :3oops

The two questionable items being "yet" and "inescapably" both of which I can demonstrate if anyone is interested in reasoned discussion.

Now if you want to critique my argument then falsify those assertions of fact. Show me where it is wrong but:

Now for my conjecture (may be a disagreement) *my latest theory)

...you show some interesting thinking but it is OT for this thread.

What say you (who does not like details)?

Two things:
1) Good thinking but not relevant to my very focussed reasoned OP argument; AND
2) Please desist. I object to false argument based on misuse of irrelevant or insignificant details. That is a long way from "does not like details".

 

[Menard_K]

"A) All the significant genuine questions long since answered so no serious discussion is needed;"

REALLY? ......

Please note that as a statistics & probability problem, the total destruction of two 110 story
steel framed skyscrapers is VERY suspicious!

There are so many alternatives to total "collapse" ..... scenarios where the buildings may have
been seriously damaged, but not destroyed. it is the least probable of all outcomes that BOTH
towers should suffer total collapse.

The uniformity of the destruction + the completeness of the destruction is very much a factor here.

 

[ozeco41]

"A) All the significant genuine questions long since answered so no serious discussion is needed;"

REALLY? ......

Yes.
Note that the statement was in the context of technical issues. Please list any "significant genuine questions" which you consider have not been answered and provide your reasoned explanation as to why they are not answered. No. beterr dtill you have queried the statemtn 'global collapse was inevitable"
A) Do you still question that claim? If so you have two oprions before you in this thread:
B(i) Respond to my OP post with rational reasoned considerations;OR
B(ii) Put forward your own explanation as to why global collapse was not inevitable - obviously within this thread the reasoning and presentation would need to be better than mine. Go for it. We could both learn something.
OR
C) Withdraw your claim disputing the inevitability of global collapse.

Please note that as a statistics & probability problem, the total destruction of two 110 story
steel framed skyscrapers is VERY suspicious!...

False reasoning. As a "statistics & probability problem" the destruction is not the least suspicious. The probability is 100% - the events happened. Please show how the "two 110 story steel framed skyscrapers" were not totally destroyed - or tighten up the expression of your statement to say what you mean.

There are so many alternatives to total "collapse" ..... scenarios where the buildings may have
been seriously damaged, but not destroyed. it is the least probable of all outcomes that BOTH
towers should suffer total collapse.

Same wrong statistics. None of the alternates happened - past events - probability 0%. The buildings did collapse - probability from perspective of 2013 is 100%. I suspect that you are not stating what you mean.

The uniformity of the destruction + the completeness of the destruction is very much a factor here.

Sure - but given your tendency for mendacious or foggy statements I would need to define what you mean by "uniformity" and "completeness" before responding to your ill defined comments. Follow my explanation with Part 1 in the OP. It will show - probably at the equivalent of Part 2 (and if we get there) - why destruction was both "uniform" and "complete" within the way I use the words. And if you follow through discussion we may see if your meaning for those two words agrees with mine. If it doesn't there will be two options and one of them I can deal with if we reach that stage.

 

[Menard_K]

Yes. Note that the statement was in the context of technical issues. Please list any "significant genuine questions" which you consider have not been answered and provide your reasoned explanation as to why they are not answered.
False reasoning. The probability is 100% - the events happened. Please show how the "two 110 story steel framed skyscrapers" were not totally destroyed - or tighten up the expression of your statement to say what you mean.
Same wrong statistics. None of the alternates happened - past events - probability 0%. The buildings did collapse - probability from perspective of 2013 is 100%. I suspect that you are not stating what you mean.
Sure - but given your tendency for mendacious or foggy statements I would need to define what you mean by "uniformity" and "completeness" before responding to your ill defined comments. Follow my explanation with Part 1 in the OP. It will show - probably at the equivalent of Part 2 (and if we get there) - why destruction was both "uniform" and "complete" within the way I use the words. And if you follow through discussion we may see if your meaning for those two words agrees with mine. If it doesn't there will be two options and one of them I can deal with if we reach that stage.

100% probability that the "collapse" of the twin towers was the product of some additional source of energy, be it black powder or atom bombs, or? .... the "collapse" had to have had help from some source of energy that was not simply the potential energy of the mass of the structure. The speed, & regularity & the fact of total destruction tells the story.

 

[SanderO]

100% probability that the "collapse" of the twin towers was the product of some additional source of energy, be it black powder or atom bombs, or? .... the "collapse" had to have had help from some source of energy that was not simply the potential energy of the mass of the structure. The speed, & regularity & the fact of total destruction tells the story.

This statement about the necessity to supply additional energy for total destruction has been made many times and many assume it to be true with demonstrating it to be true.

Let's take an example of a fire in a wood building. A match begins a fire which burns without any additional energy input or fire fighting and over time the entire house is consumed by fire or collapses in what everyone would call total destruction. Sometimes the masonry parts are all that is left standing. The point of this example is to show that the statement about additional energy input is an unproven assumption and may likely be false.

How would that be determined?

We've been subjected to occasional calculations of the gravitational PE of the towers. These are based on M x ht using assumed mass in a very simplified manner. The question one might ask is can any building/structure collapse resulting in what you refer to as total destruction? In this thought experiment we know that all materials are subject to gravity and would fall down. What makes a building or a structure is that it is composed of materials joined together and with lots of air so the structure can be used by occupants or house equipment. A partially built steel frame would fall were it not for the connection which hold the steel together... and then the rest of the building is CONNECTED to the steel frame... some with a structural role and some simply to protect from the elements such as the envelope. The floor in a multi story structure is its own structure system which is intended to support the occupants and things placed on the floor. The floors are CONNECTED to the frame. The frame of course has structural properties such that it does not deform of fail under the loads placed on it. This includes the CONNECTIONS.

Those who are familiar with the ROOSD concept understand that the floor system (all identical aside from the mech fls) can only support so much and when that capacity it exceeded it will fail. Since the floors are one atop the other once ROOSD failure begins all floors below will be seeing the same and then some loads over capacity and fail as well. This sort off fails is at the local level of any portion of the floor and the global level wherever the floor collapse is taking place. Once started ROOSD insures by definition that the floor collapse with be total... ie total destruction of the floors.

But what does that look like? The pancake conception is misleading because the floors do not drop as a stake of records does. The ROOSD destruction also involves the breaking of the floor plates into increasingly smaller pieces because the floors and then the floor pieces are subject to multiple mechanical collisions. Each collisions destroy or breaks the colliding elements into smaller chunks. One might think of this as a plate dropped on the floor shatters... then pick the pieces up and drop them from the same height and they shatter to smaller pieces. And this analogy is off because there would be more plates and pieces dropping each time.

Apparently people find it hard to accept that the dropping of the floor plate mass of ROOSD can destroy the floors... rendering them into very small grain sized remains. The concrete of the slabs would not fail well in such multiple collisions of such mass.... especially at the bottom or end of the collapse when the crushing mass was close to the mass of all the scores floors above. What happened to the fluted decking or the wire mesh and rebar and the joists? Why wouldn't this survive? I think much of it did and much of it was mechanically ripped apart and also ground up in the vertical avalanche... just as the furniture and people were. What can survive as recognizable with what amounts to hundreds of thousands of tons of materials including steel falling on top of it? And grinding it around in a chaotic vertical avalanche? We should be surprized when and if something DOES survive in recognizable fashion.

Can the energy of destruction of the floors and the contents be calculated? There were billions of collisions... I suspect it is theoretically possible, but practically not. It's much more complex than calculating how every part of two cars will fail or in an auto accident.. despite know the weight of the cars and the relative velocity at impact.

The only means to arrest ROOSD would be if a given floor or area floor was able to support the superimposed load which fell on it. This is not going to happen in the open office space system of multiple floors.

There is clearly enough PE of gravity turned to KE to run ROOSD once started to conclusion - total collapse destruction of the floors. Understanding the destruction of the floors from slabs to *sand* is a more complex problem but one can see how mechanical interactions in stone tumblers turn extremely hard materials to dust by mechanical interactions.

Accepting that there is adequate stored PE to destroy the floor system once the ROOSD starts... where is the energy that did in the columns?

This again is gravity but working not to crush but acting in more complex and perhaps subtle manner. We all know that it is gravity will causes something not properly balanced to fall. When the center of gravity moves outside the neutral axis a column or a wall becomes unstable and tips over driven by gravity. Balance an 8' long 4x4 on its end. It stands up. Apply some lateral force at the top and it will tip and fall. Add some weight to one side... it will also tip and fall. Apply lateral force at the bottom and it may also tip and fall. Once the CG is no longer aligned with the neutral axis the 4x4 will topple.

The columns in multi story steel frame sit one atop the other. The twins at 38 stacked up of 36' length. If you attempted to do even a scale model you would find the full column would be very unstable... in fact it would topple from the smallest eccentricities driven by gravity. Euler has done studies of column performance related to their material and slenderness ratio. When too slender the column buckle under its own weight... gravity Gravity = weight.

Important to note is what these 38 part column looked like and how they managed to stand 1300+ feet tall. By themselves they were far in excess of the slenderness ratio to self support. They were held in alignment by lateral bracing. This prevented buckling by reducing the unsupported length to 12'.

Next important thing to note is the nature of the connections of columns to each other and to the bracing. Columns bearing one atop the other need only good bearing of the surfaces to transfer the loads to the one below. This is why steel bearing on masonry uses non shrinking structural grout under the steel where it bears on masonry. So the columns resting one on the other only need even full contact bearing. In erection the twins had some plates welded to hold the column ends in alignment until the floor beams were connected. And the were connected at 3 points 4' 16' and 28 from the end and these beams supported the floor plates. Core column ends were not laterally braced!

Final thing to note is that the collapsing floors removed the bracing which both reduced the supported length to 12' and held the columns in vertical alignment. Without the bracing the columns were subject to being relatively easily pushed out of alignment from flex as the connections were not strong enough to turn the columns into a single *strand* or fiber or member.

When the ROOSD process got going it progressively and rapidly not only destroyed the integrity of the floor plates, but it removed or stripped away the bracing which was essential to holding the columns in proper alignment and keeping the slenderness ratio as a stable value. The growing rapidly gravity driven ROOSD mass was sewing the seed of the column failure.

You can see the *spire* columns survived the floor collapse but has almost all bracing stripped away. You can also see them topple in the unbraced direction... like ladders falling over. The buckling from Euler forces will cause the columns to break at the weak end connections. Make a stack of small columns and apply vertical pressure at the top.. when the forces it too great the stack of columns will not crush, but *spring apart* into the segments it was made from. Even with some glue on the ends the failure will manifest at the weak end to end connections. If the glue was stronger than the stick material the excess pressure will eventually buckle the column at the weakest location usually close to mid height. (look up how columns work)

So now we've established that it gravity which drove the floor destruction leaving too unstable core columns and then gravity which drove their buckling and breaking into their original lengths. So what happened to the facade? The facade can be likened to a thin walled container made from separate panels with bits of glue connecting them together. Like the core for load bearing they simply had to have *clean meeting* end to end conditions and they had a 4 bolts to connect one column to the other as there were no high lateral forces to resist. They were similarly connected each other with spandrels bolted together. The facade was effectively 4 huge very thin walls of a square tube. The tube required the floor plates to hold their square shape. Wind pressure could easily bow the center of the facade inward. To much bowing would break the connections.

Is it conceivable that ROOSD would strip away the floor plates (lateral bracing) and the facade could stand as a hollow tube? Unlikely for normal wind conditions. Deflection would break the connections.

Why did the facade fail as we saw? It broke apart into pieces as small as a single 10'x36' panel and as large as assemblies of hundreds of them which fell way as massive sheets. The latter appear to be what we would expect from a too thin wall toppling over... once falling it has no internal stress and the panel connections maintain it as a huge sheet. The facade likely was pushed outward by the growing collapsing ROOSD mass. Note how thin walled milk cartons tend to bulge outward when filled with milk or sq yard cartons for containing sand are bulging to the just about breaking.

The facade was caging the collapsing ROOSD mass like a silo cages the grain poured into it. A square is not as strong as a round shape and did not do well to contain the growing ROOSD mass. It bulged outward and enough to break the weakest connections and then send those no longer connected sections (assemblies or panels) toppling over the side. Single panels tended to drop down close to the footprint. Large assemblies tipped away like a wall falling or a flag pole toppling. The force to get them going was a combination of the instability of gravity re Euler forces and ROOSD bulging mass.

We see lateral forces manifest when we pour sand... it spreads laterally into a cone shape. We see lateral forces exerted by liquids against the wall of the container... and we see lateral forces exerted against the walls of a silo from the stored grain, and sand on the boxes it is placed in for conveying to construction sites. Those lateral forces come from... Gravity.

So it is clear that gravity can completely dismantle the twin towers once ROOSD starts. ROOSD does not explain the pulverization or soft materials into such fine grain. That is a caused by the mechanical interaction of millions or billions of energetic gravity driven mechanical collisions or the fractured components of the vertical and partially/temporarily caged avalanche.

Once ROOSD started no additional energy is required.

What was the energy that stared ROOSD?

 

[SanderO]

Ozzie,

Your approach makes perfect sense and those who have followed the *debates* trying to explain the destruction know well that the truth movement has completely failed to put together a coherent explanation to explain the observed destructions. Virtually all of their arguments are absurd concepts drawn from a misreading of the debris/results of the destruction such as Woods asking where did the towers go? Of course she fails to note that they removed over 1MM tons of rubble and countless tons was carried aloft and disbursed as dust.

The real truth seekers have assembled a credible physics and engineering based explanation of a cascading progressive destruction.

Why has the Chief Truth Guru Gage (CTGG) not critiqued ROOSD? Even Szamboti concedes ROOSD.

I think most honest truth seekers understand it is the initiation process leading to ROOSD which is in contention by the Szamboti as the only truther who tries to shoe horn initiation into a CD only cause. His smoke and mirrors have fooled no serious physicist and even some dumber engineers and architects.

Most truthers cling to what they see as anomalies. But this isn't even explained on how they are related to CD. They can't explain X so X is evidence of CD. Pretty shabby thinking.

It is truly a waste of time to rehash explanations which are already on the web at 911FF for analysis of and data on femr2's and Tom's websites for example.

Unless you enjoy jousting with uniformed or willfully ignorant there is no reason to beat a dead horse.

However, I do think that the laymen does have a difficult time in understanding the physics and engineering involved in the destruction of the WTC. To them it's like quantum physics... comprehension is inaccessible. Despite trying to make these explanations accessible, I too am ready to throw in the towel as unless someone wants to learn their willful ignorance will always find ways for them to cling to beliefs and see them as facts - or *truth*.

Boy did the truth movement put a hurting on the meaning of the word -truth-. Nice legacy for the CTGG.

 

[Thoreau72]

Hot damn! The conversation is so profound that we are down to matches and wood to explain what happened. :doh

Demonstrating again that truth is stranger than fiction. Men pretending to have a rational and "oh so intellectual" discussion about the unnatural events at WTC are reduced to matches and wood fires. :lamo

That's nothing but humorous. A fellow on another site the other day attempted to explain the DELTA Group's findings with an example of steel wool and a lighter. He was as unable to put that high school experiment into context as it related to WTC as Sander is unable to put his matches and wood example into context.

So it goes, when one attempts to defend the official story.

 

[psikeyhackr]

Hot damn! The conversation is so profound that we are down to matches and wood to explain what happened. :doh

Demonstrating again that truth is stranger than fiction. Men pretending to have a rational and "oh so intellectual" discussion about the unnatural events at WTC are reduced to matches and wood fires. :lamo

As the top block starts to fall it is still a structural integral entity. Somewhat tilted and with the base slightly displaced. Evidence for "starts to fall" and "somewhat tilted" is in readily available video records. Evidence for "base slightly displaced" is from video evidence plus simple reasoning.

The NIST says the top of the south tower tilted 20 to 25 degrees. Frank Greening says it tilted 25 degrees in FOUR SECONDS. Richard Gage says 22 degrees.

The 30 story top block of the south tower would have been about 360 feet tall. So 180 feet from the center to the bottom. The sin of 20 degrees is 0.34. 180 * 0.34 = 61.6 feet. So either the bottom moved horizontally 60 feet or the center did or some combination of the two.

But where was the Center of Mass?

Funny how that doesn't even get questioned in TWELVE YEARS.

Judging from the video it does look like the bottom moved at least 20 feet. How many columns would have to shear for that to happen?

psik

 

[SanderO]

The NIST says the top of the south tower tilted 20 to 25 degrees. Frank Greening says it tilted 25 degrees in FOUR SECONDS. Richard Gage says 22 degrees.

The 30 story top block of the south tower would have been about 360 feet tall. So 180 feet from the center to the bottom. The sin of 20 degrees is 0.34. 180 * 0.34 = 61.6 feet. So either the bottom moved horizontally 60 feet or the center did or some combination of the two.

But where was the Center of Mass?

Funny how that doesn't even get questioned in TWELVE YEARS.

Judging from the video it does look like the bottom moved at least 20 feet. How many columns would have to shear for that to happen?

psik

none... if you consider the connection between columns off setting to not be shearing.

The CG did move to the SE, but the insides of the top were also coming apart and dropping onto the structure below as the tilting was taking place.

What most seem to not realize is that the perimeters of all three towers were like rigid cages and more so with the twin towers. By the time those cages were moving / tipping dropping the insides were likely pretty much collapsed or in the process of collapsing. We see basically the cages not the entire assembly with intact floors descending.

HD, I gave a simple analogy to illustrate a basic concept... that sufficient PE energy CAN be and in the case of the house and the WTC buildings sufficient to completely destroy a structure. You're stubborn in your beliefs as any religious fanatic or scientologist.

 

[psikeyhackr]

none... if you consider the connection between columns off setting to not be shearing.

What the Hell does that mean?

The CG did move to the SE, but the insides of the top were also coming apart and dropping onto the structure below as the tilting was taking place.

What most seem to not realize is that the perimeters of all three towers were like rigid cages and more so with the twin towers. By the time those cages were moving / tipping dropping the insides were likely pretty much collapsed or in the process of collapsing. We see basically the cages not the entire assembly with intact floors descending.

HD, I gave a simple analogy to illustrate a basic concept... that sufficient PE energy CAN be and in the case of the house and the WTC buildings sufficient to completely destroy a structure. You're stubborn in your beliefs as any religious fanatic or scientologist.

Do you ever say anything besides vague BS that you can't back up with anything and then expect other people to provide evidence.

At least anybody that wants to can find the sin of 20 degrees.

psik

 

[SanderO]

What the Hell does that mean?



Do you ever say anything besides vague BS that you can't back up with anything and then expect other people to provide evidence.

At least anybody that wants to can find the sin of 20 degrees.

psik

The connections of column to column were not the same as shearing the column. Columns rested on (bearing) one below and the splice was a some short welded with plates easily broken in flex... enabling the upper column to move laterally... no shearing of the massive section... it was already effectively sliced!

mass came down mostly on top of the structure below.. do you doubt that?

 

[psikeyhackr]

The connections of column to column were not the same as shearing the column. Columns rested on (bearing) one below and the splice was a some short welded with plates easily broken in flex... enabling the upper column to move laterally... no shearing of the massive section... it was already effectively sliced!

mass came down mostly on top of the structure below.. do you doubt that?

So provide your evidence of how a connection was made. You demand that other people provide evidence. But it would still have to be sheared. How many columns were there? What provided the force to cause it to happen?

The impact of the plane only caused the building to deflect 15 inches. How could fire and gravity make it move horizontally 20 feet?

Do the physics. Don't just make excuses. :lamo

psik

 

[SanderO]

So provide your evidence of how a connection was made. You demand that other people provide evidence. But it would still have to be sheared. How many columns were there? What provided the force to cause it to happen?

The impact of the plane only caused the building to deflect 15 inches. How could fire and gravity make it move horizontally 20 feet?

Do the physics. Don't just make excuses. :lamo

psik

The connections can be seen in the debris... what's left of them... and in the construction photos.;.. or visit a site which has a similar system of column splices 4' above the floor (bracing elevation). Those connections are meant to to little more than hold them in place until the bracing is installed.

Do you understand a moment? The damage was asymmetrical..

 

[psikeyhackr]

The connections can be seen in the debris... what's left of them... and in the construction photos.;.. or visit a site which has a similar system of column splices 4' above the floor (bracing elevation). Those connections are meant to to little more than hold them in place until the bracing is installed.

Do you understand a moment? The damage was asymmetrical..

I am not trying to make a big deal out symmetry or lack thereof. Provide a link to a post where I talked about the symmetry of anything.

What provided the energy to make the top of the south tower tilt and how much did it take? You still don't say how many columns had to shear for the tilt to occur. I don't care whether they sheard at the joints or not. How could gravity and fire do it?

Like I said: DO THE PHYSICS!

psik

 

[ozeco41]

Ozzie,

Your approach makes perfect sense...

Thanks - I've had a bit of practice - not just explaining WTC 9/11 collapses but through my engineering manager/trainer/coach roles over many years. Also back in 2007-8-9>> explaining WTC collapse when there was a lot of genuine interest in understanding and the denialist trolls who dominate today's discussion were very much in the minority. There isn't much interest in real discussion these days as evidenced by some of the responses.

You are aware of by "Rules of Engagement" for these matters - specifically:
1) I rarely if ever comment on the idiotic such as :

.... Woods asking where did the towers go?

- mini nukes go into that class obviously. So I ignore the manic fringe.

2) I ration denialist trolling to two responses max. specifically two situations: a) When a person who is a regular troll actually asks a reasoned question I often respond (The OP of this thread came from such a response on another forum) b) If the person continues in reasoned discourse I will continue to engage.

...The real truth seekers have assembled a credible physics and engineering based explanation of a cascading progressive destruction.

I've made my contributions but mostly on relatively obscure forums.

Even Szamboti concedes ROOSD.

but with serious limitations.

I think most honest truth seekers understand it is the initiation process leading to ROOSD which is in contention...

Sure - initiation is the clue - progression is relatively simple. Which is why I led off with "progression" in this thread. The concepts as I spelled them out at high school level in the OP are within the comprehension of anyone who can legitimately take part in these discussions. If we see nothing but evasive denialism on "progression" then there is no point me laying out "initiation" at the same level of understandability. It is a couple of grades more difficult and not for wasted effort in face of entrenched denialism.

Most truthers cling to what they see as anomalies. But this isn't even explained on how they are related to CD. They can't explain X so X is evidence of CD. Pretty shabby thinking...

You know my explanation -- most truthers cannot think and the fact that they cannot think is the the main reason they are truthers. That's the technical side. Then the political aspect of the need to hate authority esp Government. And as you know I also see hatred of Government as linked to "cannot think".

It is truly a waste of time to rehash explanations which are already on the web at 911FF for analysis of and data on femr2's and Tom's websites for example.

I disagree strongly. There is a lot of good material but it is hard to access. The preferable approach when dealing with a genuine truth seeker is that someone like you or I point them to the supporting evidence. Then again M_T's site is severely hindered by his persistent false generalising logic flaws and his insulting attitude towards anyone intelligent.

Unless you enjoy jousting with uniformed or willfully ignorant there is no reason to beat a dead horse.

Hence my personal ROE's - I will discuss with people who are willing to learn. I don't waste much time with game players.

However, I do think that the laymen does have a difficult time in understanding the physics and engineering involved in the destruction of the WTC. To them it's like quantum physics... comprehension is inaccessible.

True but - I've never had any difficulty explaining (asay) WTC Towers collapse to genuine honest people. The ones who are obsessed are a different challenge. But that challenge is in the field of psychology/psychiatry - not engineering or law. I'm not a psych of either flavour. I'll pass on the obvious pun.

 

[SanderO]

I am not trying to make a big deal out symmetry or lack thereof. Provide a link to a post where I talked about the symmetry of anything.

What provided the energy to make the top of the south tower tilt and how much did it take? You still don't say how many columns had to shear for the tilt to occur. I don't care whether they sheard at the joints or not. How could gravity and fire do it?

Like I said: DO THE PHYSICS!

psik

asymmetrical damage Loss of support on the SE caused a moment You don't get that?

 

[psikeyhackr]

asymmetrical damage Loss of support on the SE caused a moment You don't get that?

Who can get anything with your incompetent communication. Or is that deliberate to convince others that they are stupid.

The Moment of Inertia resists motion.

Moment of inertia - Wikipedia, the free encyclopedia

But the motion of the top of the south tower is wrong to have been caused by damage on one side creating a tilt.

Rotation of the WTC2 top.avi - YouTube

psik

 

[ozeco41]

asymmetrical damage Loss of support on the SE caused a moment You don't get that?

The issue with tilt and why didn't tilt continue and become topple over the side is complex. IIRC I did a "think it through" exercise on 911Forum a year or more back.

Put simply (and again IIRC) there are two dominating factors viz:
1) The downwards dynamic is an order of magnitude greater than the tilt/rotate dynamic - downwards wins the race; AND
2) There isn't a sufficiently strong "hinge point" because the process causing tilt is the same time weakening the hinge needed for tilt to become topple.

So, put even simpler, the hinge fails and the fall runs away faster than the tilt.

 

[psikeyhackr]

1) The downwards dynamic is an order of magnitude greater than the tilt/rotate dynamic - downwards wins the race;

Hello econ:

Where did you compute and report the horizontal velocity of the top of the south tower?

psik