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The Progressive Collapse Challenge

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posted on Aug, 29 2005 @ 12:07 PM

Originally posted by Shroomery

Originally posted by HowardRoark
In addition, the aircraft impact took out a fairly significant number of the columns thus increasing the demand on the undamaged columns.

About 3-10 of the 47 columns is fairly significant to you ?
Don't try and twist the facts.

Let’s just assume, for the sake of argument, that 6 of the core area columns were cut or severely damaged by the impact, that represents 13 percent of the load bearing capacity of the core.

If half of the columns on one face were cut or severely damaged by the aircraft impact, that represents 13 per cent of the structural load bearing capability of the exterior columns. . Since the core and the exterior columns split the total load of the building, 13 % of the structural strength was lost due to the impact.

Now. Let us just assume, for the sake of argument, that the average demand to capacity ratio for the building columns was 0.80.

Thus, if you reduce the capacity of the system by 13 %, the DCR changes to 0.92.

Now in reality, this is an oversimplification, but it does illustrate that the loss of the even a few columns was enough to bring the building very close to the point of instability and total collapse.

Then, as the fires caused the exterior columns to buckle inward, those buckling columns were no longer supporting their loads. Once this started, the building was doomed.

posted on Aug, 29 2005 @ 12:18 PM

Originally posted by HowardRoark

Originally posted by Shroomery

Originally posted by HowardRoark
In addition, the aircraft impact took out a fairly significant number of the columns thus increasing the demand on the undamaged columns.

About 3-10 of the 47 columns is fairly significant to you ?
Don't try and twist the facts.

Let’s just assume, for the sake of argument, that 6 of the core area columns were cut or severely damaged by the impact, that represents 13 percent of the load bearing capacity of the core.

If half of the columns on one face were cut or severely damaged by the aircraft impact, that represents 13 per cent of the structural load bearing capability of the exterior columns. . Since the core and the exterior columns split the total load of the building, 13 % of the structural strength was lost due to the impact.

Now. Let us just assume, for the sake of argument, that the average demand to capacity ratio for the building columns was 0.80.

Thus, if you reduce the capacity of the system by 13 %, the DCR changes to 0.92.

Now in reality, this is an oversimplification, but it does illustrate that the loss of the even a few columns was enough to bring the building very close to the point of instability and total collapse.

Then, as the fires caused the exterior columns to buckle inward, those buckling columns were no longer supporting their loads. Once this started, the building was doomed.

The nist found no evidence that fires above 600c were sustained for any period of time. The steel met the standards which required it to be submitted to 1100c for SEVERAL hours before any weaknesses would form. The nist's has completed several tests with ther "FDS" system.

Plus, all the central colums were encased in 1' of concrete in every direction. It seems very unlike that a lightweight aircraft such as a 747 (realativly speaking of course, most of the plane is made of light weight carbons and aluminums) would be able to break through 1' of concrete, blast through a huge steel beam, or even cause significant damage.

The spikes of energy im talking about are on the first graph, they're huge and they go through the lines above and below it. Showing a tremendous initial shock before the building fell.

[edit on 29-8-2005 by senseless04]

posted on Aug, 29 2005 @ 12:35 PM
Q: Referring to the column shortening in WTC 1, is the elastic strain reported at room temperature?
A: No. The values reported are for elevated temperature. The history is traced, including degradation of properties.

Q: For test 1 of the fire resistance tests of the floor systems at Underwriters Laboratories, you show unrestrained rating of one hour. Was that an analytical conclusion or a tested result?
A: We show in each case an unrestrained rating when we actually did a restrained test. What we are showing there is not the result of an actual unrestrained test, but the temperature criteria in the standard for a restrained test.
C: Right, one of the major significances of the series of these tests is that test 2 was an unrestrained test and showed superior performance.

Q: I want to ask about the floor performance. The way I understood your description of the collapse scenario, the behavior of the floor systems was not a central issue. Can you connect the floor results with that?
A: The results reinforce each other. The results of the fire test versus the load test support the finding that the floors were not a driving force in the collapse.

Q: Do we know for the pieces of steel that did not meet the requirement [referring to yield strength] what temperature they reached?
A: Indications are that the metal we tested did not see any kind of high-temperature excursions, and there was no damage to the paint on those pieces. They did not get above 250 ºC.

Q: The web is usually the strongest part of a column. I am puzzled by a data point on your slide showing the web of the columns lower than specified. What was the value of the flange?
A: I will address that in my presentation tomorrow.

Q: Do the 27 emergency responders from WTC 1 interviewed refer specifically to those people themselves as opposed to people that they know, other people that didn’t survive?
A: Yes, that is correct.

C (NIST): We have brought fire and structural communities together and developed models to analyze fire-structural interaction. We will need to make the models more robust before the private sector can adopt them for routine practice.

posted on Aug, 29 2005 @ 12:41 PM
The nist does say this.

The residual velocity and mass of the engine after penetration is sufficient to fail a core column in the event of a direct impact

"a" core column. not 3, not 10, "a" so, we may have had 2 core colums in each tower taken out.

All truss seats have sufficient capacity to support the weight of two floors for temperatures up to 700 ºC

As a result of thermal weakening (and subsequent to impact), the East wall carried about 5 percent more gravity loads and the core carried about 2 percent less loads. The other three walls carried between 0 and 3 percent less loads.

^ WTC 2

As a result of the thermal weakening (and subsequent to impact and prior to inward bowing
of the South wall), the North and South walls each carried about 10 percent more gravity
loads, and the East and West walls each carried about 25 percent more loads. The core
carried about 20 percent less gravity loads after thermal weakening.

^ WTC 1

wtc 2 fell first, if anything wtc 1 showed that it had SIGNIFICANTLY more stresses applied to it than tower 2.

[edit on 29-8-2005 by senseless04]

posted on Aug, 29 2005 @ 01:54 PM

Originally posted by senseless04
The nist found no evidence that fires above 600c were sustained for any period of time. The steel met the standards which required it to be submitted to 1100c for SEVERAL hours before any weaknesses would form. The nist's has completed several tests with ther "FDS" system.

Originally posted by senseless04
Q: For test 1 of the fire resistance tests of the floor systems at Underwriters Laboratories, you show unrestrained rating of one hour. Was that an analytical conclusion or a tested result?
A: We show in each case an unrestrained rating when we actually did a restrained test. What we are showing there is not the result of an actual unrestrained test, but the temperature criteria in the standard for a restrained test.
C: Right, one of the major significances of the series of these tests is that test 2 was an unrestrained test and showed superior performance.

The WTC floor systems were neither fully restrained, nor fully unrestrained.

Q: I want to ask about the floor performance. The way I understood your description of the collapse scenario, the behavior of the floor systems was not a central issue. Can you connect the floor results with that?
A: The results reinforce each other. The results of the fire test versus the load test support the finding that the floors were not a driving force in the collapse.

This interview is from 2004, the draft report issued in 2005 indicates that the driving force in the collapse was the loss of fireproofing. Furthermore:

Full Floor Subsystem
Finding 35: Floor sagging was caused primarily by either buckling of truss web diagonals or disconnection of truss seats at the exterior wall or the core perimeter. Except for the truss seat failures near the southeast corner of the core in WTC 2 following the aircraft impact, web buckling or truss seat failure was caused primarily by elevated temperatures of the structural components.

Finding 36: Analysis results from both the detailed truss model and the full floor models found that the floors began to exert inward pull forces when floor sagging exceeded approximately 25 in. for the 60 ft floor span.

Finding 37: Sagging at the floor edge was due to loss of vertical support at the truss seats. The loss of vertical support was caused in most cases by the reduction in vertical shear capacity of the truss seats due to elevated steel temperatures.

and

Finding 52: The primary role of the floors in the collapse of the towers was to provide inward pull forces that induced inward bowing of exterior columns (south face of WTC 1; east face of WTC 2).
Finding 53: Sagging floors continued to support floor loads as they pulled inward on the exterior columns. There would have been no inward pull forces if many of the floors truss seats had failed and disconnected.

Q: Do we know for the pieces of steel that did not meet the requirement [referring to yield strength] what temperature they reached?
A: Indications are that the metal we tested did not see any kind of high-temperature excursions, and there was no damage to the paint on those pieces. They did not get above 250 ºC.

That is only the test on the piece that they found. There is no reason to suppose that the fires in the towers did not behave as every other structural fire in the history of mankind has behaved, i.e generate significant amounts of heat.

As for the ASTM 119 test of the truss assembly:

Conditions of Acceptance - Restrained Assembly Test
In obtaining a restrained assembly classification, the following conditions shall be met:

• The specimen shall have sustained the applied load during the classification period without developing unexposed surface conditions which will ignite cotton waste.

• Transmission of heat through the specimen during the classification period shall not have been such as to raise the average temperature on its unexposed surface more than 250 ºF (139 ºC) above its initial temperature.

Conditions of Acceptance – Restrained Assembly Test
In obtaining an unrestrained assembly classification, the following conditions shall be met:
• For specimens employing steel structural members (beams, open-web steel joists, etc.) spaced more than 4 ft on centers, the temperature of the steel shall not have exceeded 1300°F (704°C) at any location during the classification period

• nor shall the average temperature recorded by four thermocouples at any section have exceeded 1100°F (593°C) during the classification period.

wtc.nist.gov...

full report

A couple of notes on these tests:

1. There are some questions as to the “scalability” of the tests. While the smaller scale tests will generally indicate the overall behavior, it is not the same as a true full scale test. The tests are generally conducted on either half scale or shorter full scale sections of trusses. No tests have been conducted on 60 foot trusses.

2. The tests assume a single heat source, under the floor section. It does not involve heat applied to both the top and bottom of the floors system as would occur in a fire where multiple floors are burning simultaneously.

3. The fireproofing was undamaged at the start of the test.

posted on Aug, 29 2005 @ 01:59 PM

Originally posted by senseless04
Plus, all the central colums were encased in 1' of concrete in every direction. It seems very unlike that a lightweight aircraft such as a 747 (realativly speaking of course, most of the plane is made of light weight carbons and aluminums) would be able to break through 1' of concrete, blast through a huge steel beam, or even cause significant damage.

Where did you come up with that crap?

Concrete?

Not hardly.

Sprayed on fireproofing is hardly the same thing as concrete.

Furthermore, the fireproofing was sprayed on after the sheetrock shaft walls were installed. Thus when these walls were breached by the debris, it would have exposed unsprayed surfaces of the core area columns.

posted on Aug, 29 2005 @ 02:04 PM

Originally posted by senseless04
The spikes of energy im talking about are on the first graph, they're huge and they go through the lines above and below it. Showing a tremendous initial shock before the building fell.

Dude, those “spikes” of energy ARE the building collapse. The time scale on that first graph is such that even a thirty second signal appears as a spike.

How can you possibly claim that they occur before the collapse?

Look at the second graph, your spikes lasted 20 seconds. That was the impact of the building with the ground.

posted on Aug, 29 2005 @ 02:11 PM

Originally posted by senseless04
The nist does say this.

The residual velocity and mass of the engine after penetration is sufficient to fail a core column in the event of a direct impact

"a" core column. not 3, not 10, "a" so, we may have had 2 core colums in each tower taken out.

Oh, that’s right; the towers were hit by a single engine plane. How stupid of me.

There was sufficient mass of debris to cause damage to a number of core columns and beams.

The debris blocked the stairwells and cut a number of elevator cables.

Also you have to consider the probability that the floors in the impact zone also transmitted some of the impact force directly to the core beams.

posted on Aug, 29 2005 @ 03:48 PM
Whew! I have been following this thread (Even though I dropped off of it several pages ago) to see how genuine the "Debunkers", or in this case, the proponents of demolition theory, are with their arguments and presentations of such. I will tell... you are wasting your time here. All GOOD engineers quickly recognize the over and under-lying causal relationships that take place in any given failure and seek to rectify the specifics of where the causality originated and terminated during the failure event and how they might be inter-related. That's not the case with those folks that want to believe that the WTC towers were purposely demolished. Oh no, not at all.

These folks would have us believe that their poor attempts at tying unrelated and singular events together are the sole proof that the buildings were blown up. Example: Problem -- How many pancakes does it take to shingle a doghouse? Solution: Seventeen because ice cream has no bones! My point here is that there is NO WAY to establish any causality between any of the events nor does the solution actually relate to the problem in a logical manner. Just in the same manner that a janitor in the basement hearing explosions, or some windows broken while others are not, or how big was the stupid 40 ton press and what happened to it do NOTHING to either support or deny the claims being made here. This whole "Challenge" is nothing more than a disingenuous attempt to obfuscate the REAL science and physics behind this type of event.

The proof??? Well, the simple fact that the challengers recommend that this test be completed using anything from pancakes to straws to toothpicks. Well, really??? I was not at all aware that ASTM had certified that pancakes, straws and toothpicks all have the same tensile strength and density as steel!?!? Incredible! I guess that I can now inform my customers that they no longer need to purchase nor pay an annual licensing fee for material libraries for their analysis packages! Last I had chacked, there were literally THOUSANDS of values just for the different types of steel!

I think that it is safe to assume that those folks who want to believe that the WTC buildings were purposely demolished --REGARDLESS OF THE REASONS-- are going to continue to do so despite ANY level, quantity or quality of scientific data that is presented to them -- PERIOD! Sound science does NOT support their assertion, not has it at any given point in this or any other debate. They simply believe that this is the case because a.) they choose to, b.) it supports some warped desire thay have to attach a conspiracy to this event and c.) it supports their agenda, be it political or social.

As a result, please put it to rest. There has to be hundreds, if not thousands, of threads just like this one all over the internet and NOBODY has definitively proven that this was deliberate demolition. I think that it is time to simply agree to disagree and no longer waste server space going over the same old arguments over and over and over again. Thanks!

posted on Aug, 29 2005 @ 03:59 PM
Your absolutely right I think.
I used to be a diehard conspiracy theorist (and still am in some aspects) but after actually researching the event fairly I had to admit that a few years of my life had been wasted in propogating someone else's lies. I didn't want to either, but common sense and science prevailed.

I think it's just hard for some people to let go of something they cling so dearly too, especially if it is practically the only thing in their life (not saying that applies to anyone here necessarily, but it obviously does to some people out there!).

Bit of a bummer if you lose your missus and all your friends over it only to find out it was all for nothing ay! LOL

posted on Aug, 29 2005 @ 07:42 PM
I say, regardless of the outcome (we'll know for sure one way or the other in the future). We get rid of the cia, and kick some director ass for having had trained osama bin laden and his lackeys to begin with.

If they hadn't trained him to fight the russians, he wouldnt have been capable of bringing down the towers. Castro was a similiar circumstance. The CIA is real good apparently at pissing people off.

oh, and NIST evidence refutes the offical story.

[edit on 29-8-2005 by senseless04]

posted on Aug, 29 2005 @ 08:28 PM
So I gather with all this lamenting, and mutual commiserating, that you debunkers are admitting defeat - that neither you, nor anyone else, can reproduce even a simplified progressive collapse and meet the challenge.

So it seems that on that day in September 2001, the laws of physics were circumvented just for a one-time-only amazing performance. Admission price: Your SOOOOOOOUUUUUL~~ BWAHAHAHAHAHAAAAA!!!

[edit on 2005-8-29 by wecomeinpeace]

posted on Aug, 29 2005 @ 08:43 PM

Originally posted by senseless04
Other than that 1 huge piece (which is the top of the building by the way)...

I was of the impression that the top of the building fell on WTC6...but I could be mistaken.

posted on Aug, 29 2005 @ 08:45 PM
WCIP, you must have missed all my posts earlier that clearly met the first challenge.

Progressive collapse is real, look back a few pages and you'll find the link to a dissertation on progressive collapse.

The challenge called for many things not related to progressive collapse, so not meeting the challenge really has no bearing on the existence of progressive collapse.

Here's a number of papers written on progressive collapse from google scholar.

Here is a course on progressive collapse.

training.bossintl.com...

It is ridiculous to deny the existance of progressive collapse.

It is a real phenomena.

posted on Aug, 29 2005 @ 09:01 PM
Howard,

Though I understand that you're focus on trivial details here is crucial for you to maintain the appearance of debunking the major issues of the WTC collapses, and distracting from the fact (and the whole point of this thread) that we challenge you to prove the gravity theory via progression collapse reproduction, you could at least understand what's being said.

Originally posted by HowardRoark

Originally posted by senseless04
The nist does say this.

The residual velocity and mass of the engine after penetration is sufficient to fail a core column in the event of a direct impact

"a" core column [per engine]. not 3, not 10, "a" so, we may have had 2 core colums in each tower taken out.

Oh, that’s right; the towers were hit by a single engine plane. How stupid of me.

The fact is that we don't know how many core columns were damaged, just as we don't know much about the WTC's over-engineering. I think it's pretty clear from the impact videos of the South Tower that the severing of core columns was not a major contribution to collapse, since in this case they must've been almost completely missed judging by the impact angle, and yet the South Tower fell much faster than the North, which suffered a direct blow.

Futhermore, you're posting NIST's conclusions as evidence in the very thread that is asking for proof that what NIST did was legitimate scientific research.

And the removal of fireproofing from steel columns does not compromise the strength of steel itself.

Neither fire lasted even a whole hour, they both quickly lost intensity after the depletion of jet fuel around 15 minutes or so after the impacts, and there is a lack of evidence of them ever being that hot to begin with. What happened to the fireproofing is trivial in light of such information, especially considering for what extreme conditions the fireproofing was designed. Bare steel would've held up well enough in such conditions on its own. Steel without fireproofing isn't aluminum, after all.

Originally posted by kozmo
There has to be hundreds, if not thousands, of threads just like this one all over the internet and NOBODY has definitively proven that this was deliberate demolition.

With all due respect, no one has proven the hogwash that NIST or FEMA has put forward, either. In fact, the whole point of this thread is to prove the gravity-driven hogwash. For such great minds, you guys tend to forget this fairly often.

Actually, NIST doesn't even tell us how they got their results, exactly, and such agencies refuse to release into public domain the critical information, blueprints, etc. that would be required to recreate their work.

Which brings us back to the point of this thread in particular:

Has anyone yet to recreate the sort of progressive collapse outlined on the first page? I'm allowing the wind speed to be adjusted proportionately, and even for computer simulations, given that the procedures needed to recreate them are included.

The only person I know of that's attempting my challenge at the moment is Shroomery, who doesn't even support the gravity theory. Most of the official story lackies here have attacked the challenge for its sense of humor instead (using pancakes, mud, etc. to show that the author doesn't care in the slightest what materials are used, because, again, it isn't like it's an actual requirement to actually use those materials
).

Originally posted by AgentSmith
I used to be a diehard conspiracy theorist

I used to believe Osama actually did it. Who'd have thought.

Originally posted by senseless
I say, regardless of the outcome (we'll know for sure one way or the other in the future). We get rid of the cia, and kick some director ass for having had trained osama bin laden and his lackeys to begin with.

Good luck getting that done with guys like these all over the place:

[edit on 29-8-2005 by bsbray11]

posted on Aug, 29 2005 @ 09:14 PM

Originally posted by LeftBehind
WCIP, you must have missed all my posts earlier that clearly met the first challenge.

No, I didn't miss it, and it was addressed by bsbray11, myself and others, although you continue to reappear periodically and repeat the claim that it wasn't. *shrug* In fact, I personally feel that bsbray11 was being very generous in granting that your partial collapse of a structure with it's base removed had met even the 1st criteria.

It is ridiculous to deny the existance of progressive collapse.

The challenge requires more than just say-so. That's the whole idea. A new theory in structural engineering has appeared on Earth since September 2001...wait...it's not even a "theory" yet, it's a hypothesis. The challenge simply seeks a reproduction of the supposed effects of that hypothesis. Just think, billions of dollars are now being spent on coming up with ways to prevent buildings exploding into concrete dust and bits of steel when structural support elements are weakened, and all based on a hypothesis that cannot be reproduced in the real world or even via simulation. Go science. Yayyyy.

The scientific method has four steps

1. Observation and description of a phenomenon or group of phenomena.

2. Formulation of an hypothesis to explain the phenomena.

3. Use of the hypothesis to predict the existence of other phenomena, or to predict the results of new observations.

4. Performance of experimental tests of the predictions by several independent experimenters and properly performed experiments.

If the experiments bear out the hypothesis it may come to be regarded as a theory or law of nature. If the experiments do not bear out the hypothesis, it must be rejected or modified.

[edit on 2005-8-29 by wecomeinpeace]

posted on Aug, 29 2005 @ 09:38 PM

Originally posted by wecomeinpeace
No, I didn't miss it, and it was addressed by bsbray11, myself and others, although you continue to reappear periodically and repeat the claim that it wasn't. *shrug* In fact, I personally feel that bsbray11 was being very generous in granting that your partial collapse of a structure with it's base removed had met even the 1st criteria.

None of the contents were adressed, none of the glaring problems with this challenge have been adressed, and none of my calls for positive proof of demoliton have been addressed.

You people seem happy to dismiss me with insults, while ignoring the points I bring up.

If it is generous to insult me and say that my points arent worth debating, he can keep it to himself.

If a scientific paper about progressive collapse isn't proof, than what would you accept.

I think that the paper is held to higher standards than this test.

Like I said before, what do any of the challenges except the first one have to do with progressive collapse?

Edit: Here is the abstract for the paper on progressive collapse.

Progressive collapse of multi story buildings could result in catastrophic consequences, and one needs to understand such phenomena for preventing their occurrence. The analysis of progressive collapse should include the flow and sequence structural failures. There is no finite element code that can be used without modification to simulate dynamic collapse problems that contain strong nonlinearities and discontinuities. This research consisted of the following activities: Develop an analytical definition of progressive collapse based on structural behavior; define the primary criteria that cause progressive collapse; and establish an analytical/numerical procedure to study such behavior in multi story buildings. Since those three activities are closely linked, the research was carried out interactively on all three issues. An appropriate analytical procedure was established, and several behavioral and failure criteria were applied. The analytical definition of progressive collapse was studied by iteratively adjusting both the analytical procedure and collapse criteria. With the analytical concepts presented above, a revised concept of external behavioral criteria was adopted and applied. Stress (or strain), buckling and connectivity were selected as behavioral and failure criteria that controlled the numerical process through externally written routines. This enabled effective partitioning of structural degrees of freedom, and the application of variable boundary conditions. The revised technique demonstrated the feasibility of the analysis of progressive collapse. This approach enabled to start understanding the cause and effect of progressive collapse, and to a parameter identification approach for building assessment and a collapse warning system. As a by product of this study, the approach could support considerations of optimal sensor placement and effective signal processing for developing an effective progressive collapse warning system.

The paper:

www.ptc.psu.edu...

And the conclusion:

A newly developed external criteria screening (ECS) technique to analyze progressive
collapse was described in this paper. Necessary definitions and approached were described for
material and geometric nonlinearities for analyzing progressive collapse.
A matrix reformation and stiffness reduction technique was described to achieve element
elimination effects in the proposed analysis procedure. Matrix partitioning and variable
boundary conditions (VBC) techniques were developed to improve solution convergence and
stability problem. Such problems might appear in applying a stiffness reduction factor technique
that is more advantageous, and that leads to relatively shorter computing time.
A section of a steel frame structure was selected as the numerical model. The behaviors and
time histories using stress/strain failure criteria were compared with those obtained with a
general finite element analysis. The behavior of the structural model with a linear material
behaved differently than that with a nonlinear material. Structural behaviors with different
nonlinear material models were similar. The structural responses obtained with a general finite
element procedure were different from those obtained with the modified approach, as presented
here. Behavior comparison between those obtained with the developed procedures and those
derived with a general procedure is meaningless for the differences of structural system.
In this study, buckling was considered as a contributing failure criterion, together with a strain
failure criterion. A new solution that can analyze local buckling failure was implemented and
inserted into ANSYS, as an external module. The collapse started much earlier when buckling
was considered than if only a strain criterion was considered. This behavioral difference can
indicate that collapse might progress very differently when buckling is considered.

[edit on 29-8-2005 by LeftBehind]

posted on Aug, 29 2005 @ 09:55 PM
I just found a project at the University of Melbourne that will cost \$19,500, to accurately model progressive collapse. Hardly the simple challenge you present it as.

www.vpac.org...&_internships/e-research_projects/round_six_expertise_grants.php

Progressive collapse denotes an extensive structural failure initiated by local structural damage, or a chain reaction of failures following damage to a relatively small portion of a structure. There have been many examples of progressive collapse in the past (Ronan Point 1969, Oklahoma Bombing 1995, World Trade Center 2001, etc.) which caused severe casualties, economical and social consequences. Progressive collapse due to a terrorist attack or an accidental explosion could occur to almost any conventionally designed building under sufficiently large and widespread loading. The prediction of possible progressive collapse under specific conditions may provide very important information that could be used to control or prevent progressive collapse. However, to date, no adequate tools exist that can perform a progressive collapse analysis with acceptable reliability.

You still expect us to do this on our own time and resources?

posted on Aug, 29 2005 @ 10:06 PM
I wrote:

I'm trying to visualize what you just said.. you tilt the building and remove the bottom floors (25~ feet).. (I'm assuming by nicely timed explosions.). The weight of the building falling this distance (the now removed bottom floors) is enough to tear the rest of the building apart?

So in theory, if trusses and columns of the WTC were to be weakened by the fires on a number of floors, and one essentially dropped one level, the weight of the upper floors falling down onto the lower floor would be enough to completely destroy the next floor, in essence, causing the famed "pancake theory" of all the floors repeating this process of falling/breaking apart?

Not all structures will collapse when tilted and dropped 25 feet...A re-enforced concrete smoke stack will lay over like a tree, As will some steel structures....However, I'm Confident the WTC would collapse,,

Your 2nd paragraph is correct. ..in my opinion,

I recall seeing some smaller buildings near the WTC collapse on the morning news. I also recall a documentary (was it the discovery Channel) which detailed the construction of the WTC towers,,,and how they fell. ....complete with video of point of failure and collapse.

[edit on 8/29/2005 by QuietSoul]

posted on Aug, 29 2005 @ 10:12 PM

* Is it possible to do a demolition wirelessly?

* How do they know if all the charges go off or not?

* What happens if a charge fails to go off and the buildings falls anyway?

* Would it be possible to rig up a building so that the sounds of the explosives going off would not be noticed from a few blocks away?

* How would you place a cutting charge on a box column if you only had access to one face of that column?

* If you put a cutting charge on one face of a 12 inch box column that was strong enough to sever that column, how far would the shrapnel fly?

* What does a steel beem look like after it has been cut by an explosive charge.

* What is the long term stability of the explosives used in demolition projects?

* "removing the bottom 25 feet or so" How does that explain your theory that damage to UPPER floors caused the building to collapse like a controlled demo?

* Have you ever worked with C4 or military-grade explosives before? How do they differ from conventional demolition explosives?

* Imagine for a moment that the WTC towers were indeed brought down with explosives, what kind of explosive would you surmise it was done with?

* If you severed 10% or less of the support columns near the top of a steel frame building whose core had a load-bearing redundancy of 500-600%, would the building then collapse down to the ground?

* If you severed some exterior columns and core columns on only one side of a building such that the building collapsed, will the building collapse tilt to one side or will it fall straight down in a symmetrical collapse. Will the entire floor where the columns were severed collapse symmetrically and simultaneously, the unbroken columns included?

* Conventional controlled demolition works by severing a building's supports and then letting gravity do the rest, correct? In your experience in the industry, have you ever seen a steel frame building completely collapse, all its support columns severed, all of its concrete exploded into fine powder and spread into a giant dust cloud several kilometers in width, and 80% all of its exterior columns being blasted outside of the building's footprint, just under gravity alone with no explosives to help it?

* If molten steel was found in the basement of a collapsed building where the foundation was, what technology or explosive could possibly cause this? Would the presence of molten steel be unusual for a building that collapsed under gravity alone?

* Have you ever seen the footage of WTC7's collapse? Does this look like a conventional controlled demolition to you or not?

* WTC7 exhibited a perfectly symmetrical collapse supposedly because of relatively small fires on a couple of levels. How do you summise this occured? Do you think in the future setting buildings on fire could be a cheaper method of demolishing buildings than the current method of using explosives?

* If you were contracted to demolish the WTC towers but had to make it look like it collapsed by itself from the top down, how would you do it?

Wireless? Yes, There are detonating cord and radio systems for initiating explosives.

Detonators (electric caps ) can be checked in advance with a specially built galvanometer. Modern initiating systems are very reliable....Sometimes, a cap will work but fail to detonate an explosive charge. Sometimes, a mangled charge (minus detonator) will get dug up in the rubble..

The sound of metal cutting shaped charges is incredibly loud and difficult to conceal.

Access to each side of a box column is needed....there are outrageous exceptions.

Most shaped charges are made of Metal (usually copper) tube that is pressed to look like this ^ . They have a core of explosive that detonates at a velocity of about 5 miles per second. The backside of these charges can send bits of metal shrapnel that can be found buried in solid steel hundreds of feet away. So, some kind of protection (cover ) is often needed..There is one brand of charge that does not have a metal backside....but it uses more explosive (more expense, more noise, more concussion)

Linear shaped charges work by sending a pencil-lead thin, focussed beam of metal particles (moving at about 10 times the speed of a rifle bullet) through a steel target. The cut is as neat and clean as though cut with a knife....much neater than a cutting torch.

The explosives used in shaped charges are stable for years.

Upper and lower segments of similar material are both diminished at the point of contact,

C-4 is made with RDX ..The same stuff that's preferred in linear shaped charges..Only linear shaped charges would be considered for demo of a big steel building by an expert.
Once again, there are outrageous exceptions.

10% No

One explanation does not fit all structures..This one is bigger than anything anyone has actually experienced, so I can't say how it should have looked.

Can't explain the molten steel.

I saw the footage. Yes ,, It looked like conventional explosive demolition. I saw a TV documentary about this event, the building's internal structure, the video of the collapse,and the points of structural failure. Personally, I was satisfied with its explanations.....But who can know for sure?

It has been an honor to answer your questions..but time wont permit me to continue....please, no more.

Thats all folks!

[edit on 8/29/2005 by QuietSoul]

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