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Pilots For 9/11 Truth Forum _ North Tower _ Collapse Hypothesis

Posted by: billsmith Apr 19 2009, 09:11 AM

theThis is not exactly an integrated collapse theory ut it contains a few components that could fill in a few blanks.
We were arguing on a forum a week ortwo back about the fireproofing upgrade in WTC1- apparently only on the floors where the plane went in or ones that showed excessive amounts of fire. I call this 'extra fireproofing' rather than a 'fireproofing upgrade'.
You see I think some of the core columns had nano thermite sprayed INSIDE them. Drill a hole, charge the column and spray on however many layers you like. Fill it even. The extra fireproofing may have been to stop the jet fuel igniting the thermite prematurely as nano-thermite ignites at only 430 degrees C. The extra-thick fireproofing may also have acted as 'lightproofing' against the characteristic bright glare of the ignited thermite.
THis might have ocurred in an entire column from bottom to top- all 1300 feet draining the molten steel down into the basements. If this happened with many selected columns there might be hundreds or even thousands of tons of molten steel in the basements which could explain why it stayed molten for months and why there was so little steel on the ground outside after the
collapse.

The steel that poured out of WTC2 might point to a similar process going on there.. Also this would explain the hundreds of tons of thermite that would have been needed to provide such an even distibution of unreacted thermite chips in the WTC dust.

Posted by: lunk Apr 19 2009, 05:34 PM

I think that the twin towers were built with the intention of bringing them down in the future.
Though this sounds like a far out possibility, the technology was there at the time of construction. It has been eluded to, in this forum, that if the central cores were made out of steel box beams, the buildings would have had a great deal more oscillation in the wind then they had ever recorded. In fact, because they were only held at the base, and were 110 stories tall, supposedly constructed mainly of steel, the oscillations of the towers would have been much greater than recorded.
This leads one, to the possibility that the cores, of the buildings were reinforced concrete "tubes"
If they were, the reinforcement (re-bar) could have been coated with thermite or something similar, before the towers were even built.

Nano-particles have been around
long before nano-technology.

Posted by: billsmith Apr 20 2009, 05:46 AM

QUOTE (lunk @ Apr 19 2009, 11:34 PM) *
I think that the twin towers were built with the intention of bringing them down in the future.
Though this sounds like a far out possibility, the technology was there at the time of construction. It has been eluded to, in this forum, that if the central cores were made out of steel box beams, the buildings would have had a great deal more oscillation in the wind then they had ever recorded. In fact, because they were only held at the base, and were 110 stories tall, supposedly constructed mainly of steel, the oscillations of the towers would have been much greater than recorded.
This leads one, to the possibility that the cores, of the buildings were reinforced concrete "tubes"
If they were, the reinforcement (re-bar) could have been coated with thermite or something similar, before the towers were even built.

Nano-particles have been around
long before nano-technology.


\Yeah....the miltary always get the best stuff first.
Still I think we have to look seriously at the possibility of the hollow columns being filled or partially filled with nano-thermite. In the real world the only way steel will stay molten for months (despite them pumping what one fireman described as 'a lake of water' ) is if there is a hell of a lot of it- like thousands of tons, Plus it explains how the dust had such an even distribution of live thermite chips. THere had to be tons of the stuff, but no problem if you use the space inside the columns.

Posted by: lunk Apr 20 2009, 10:19 AM

It would be difficult to get into every column with 100rds of tones of anything.

There is another heat source that will heat up steel for weeks,
that leaves elevated levels of tritium, and tends to vaporize steel,
and liquefy concrete.

I don't think any amount of thermite can do this.

The thermite wasn't the only cause of the demolition, just a part of it.

Posted by: billsmith Apr 20 2009, 10:36 AM

QUOTE (lunk @ Apr 20 2009, 04:19 PM) *
It would be difficult to get into every column with 100rds of tones of anything.

There is another heat source that will heat up steel for weeks,
that leaves elevated levels of tritium, and tends to vaporize steel,
and liquefy concrete.

I don't think any amount of thermite can do this.

The thermite wasn't the only cause of the demolition, just a part of it.


Not really. They would have to ensure that the coulmns had any holes covered over wirh small welded plates. Then it would simply be a matter of drill a hole and pump the nano-thermite in. Even one 12 foot section would hold an awful lot.

If all this steel was melted down into the basements which appears to be possible that would also explain the huge rush to get rid of the steel that was left before nybody noticed how little there really was on the surface.'China' became the explanation but myself?....I think that 'China' was really in the basements.I think it might even still be there. Who has the equipment for detecting a large magnetic anomaly ?

Posted by: lunk Apr 20 2009, 11:07 AM

We have evidence of thermite in the dust,
elevated levels of tritium in the ground water,
guns encased in molten concrete from building 6!
metal spheroids in the dust, this could be the condensate of vaporized steel.

Thermite will melt steel but is not hot enough to vaporize it.

Thermite charges could be more easily be fastened to the outside of a beam.
as compared to the complex task of drilling and pumping, resulting in the same effect.

Even the design of the core has been questioned.
The cores could have been made of concrete,
this would have made it very difficult to get the thermite next to the re-bar inside the concrete, after it was poured.

This leads me to believe that for the amount of un-reacted thermite left in the dust, must have been coated on the re-bar at the time of construction.

And begs the question, when was the type of thermite found in the dust made? Was the technology to make nano-thermite around in the late 60s, before the twin towers were built?

Posted by: JimMac May 19 2009, 03:30 AM

QUOTE (lunk @ Apr 20 2009, 11:07 AM) *
Thermite charges could be more easily be fastened to the outside of a beam.
as compared to the complex task of drilling and pumping, resulting in the same effect.

Even the design of the core has been questioned.
The cores could have been made of concrete,
this would have made it very difficult to get the thermite next to the re-bar inside the concrete, after it was poured.


I'm about to make some comments related to construction, so pls allow me qualify my experience for clarity. I'm a builder (retired), i've never built high-rise, but its not a foreign language. Now it happened that a civil engineer friend quizzed me a few weeks ago on that same concrete column proposal, he sent me a link asking 'what did i think'. I told him I thought the guy running the site, (CB) was a psych-ops project, disinfo. Becuase on first impression the site looked hinky, so i did a thorough check on all his sites, internic registrations, etc (he's located in California), and it didn't pass the smell test. A few days later, by coincidence i came across the source of the image the site author used, and it originated with the BBC, on a 9/11 NEWS program explaining what might of happened in the 'collapse'. Someone had created an artists impression of concrete columns and some kind of steel tubes inside. It was very strange. I'm 99.9 percent sure no construction elements like that existed at WTC and I'm doubly sure the image was created for that broadcast.

As for the re-bar, can you be thinking of re-bar perhaps in the 4 inches of light-weight floor concrete? If so, I don't think they used re-bar in the floors. I saw a drawing somewhere, and seems they used just steel decking panels with 'V' channels. All re-bar does is prevent concrete expansion (cracking), its not structural in any way in floors, so it would have added a lot of excess weight. They mixed in a serious amount of asbestos for light-weight properties.

As for the unexploded chips Neils Harrit and crew found in the dust, he holds out the observation that its most likely a military contract-lab designed exotic chemical compound, probably circa mid 1990's.

The simplest answer is probably more likely, they installed the explosives sometime over 3 months, after the new owner took the building over, and revised the insurance policy to collect 5 billion. If you read Hoffman's proposed blasting scenario, there about a hundred tons of (mostly) building 'upgrade' materials used ( installed as upgrades and building/tenant improvements). When the amazed Danish TV host asked Neils Harrit how did they possibly get all that material into the area, Harrit replied, 'on Pallets'.

As for how and when, I think http://www.ask.com/bar?q=Scott+Forbes+elephant+in+the+room&page=1&qsrc=2106&ab=0&u=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DbrSXmZVVCMI

Posted by: lunk May 20 2009, 12:20 AM

Hmm, concrete columns, covered up as steel beams...
original plans hidden from the public, the possibility of
the concrete cores having been built with thermite coated re-bar,
the whole construction of the twin towers, predetermined
to be demolished, at the push of a button in the then distant future,
before their construction even began...

There are a lot of posts here, discussing these concepts,
and a lot of evidence, ...er... not denying it.

Posted by: JimMac May 20 2009, 04:27 AM

QUOTE (lunk @ May 20 2009, 12:20 AM) *
Hmm, concrete columns, covered up as steel beams...
original plans hidden from the public, the possibility of
the concrete cores having been built with thermite coated re-bar,
the whole construction of the twin towers, predetermined
to be demolished, at the push of a button in the then distant future,
before their construction even began...

There are a lot of posts here, discussing these concepts,
and a lot of evidence, ...er... not denying it.



Ok Lunk, i'll formally be the first to deny it. (wink)

But let's not drown the potential for good discussion in argument, for argument's sake. You have this notion that the Port Authority pre-designed a demolition ( with a button) back in 1966. I think such a notion belongs (dare i say it) in a latter-day James Bond movie, but then I've had some very wild ideas myself. So let's press on to see what we can agree on. We can hash out structural concrete elements later.

Meanwhile, take a look at this ground zero photo from the pinned resources in this forum. I just noticed something interesting on the core column (the column cut on the angle); notice where it appears NOT fully melted, at the back 9" to 12" inches or so, on both long sides and the 12" furthest away side of the column it seems was not cut (but ripped). It looks like the uncut metal was later sheared off by force, and on a somewhat irregular line generally following the angle of the partial (24" to 26" length) column side cut.

To me this visual (unless mine eyes deceive) suggests they might have cut (some of) the core columns partially but not sliced clean through, in order to weaken them and maybe used a charge (or not) to kick them out on collapse initiation. The uncut metal would probably be enough to hold the column in place (tacked). What do you see?

Cheers!
Jim

Notes: core column size at base has beenhttp://physics911.net/thermite as 12"wide x 36"deep x 2" thick


Posted by: JimMac May 20 2009, 05:05 AM

One aspect of this demolition that I now have a much more clear appreciation for is the concrete floor removal. This aspect has always fascinated me greatly, even intuitively before i understood what i was in fact truly seeing. After looking at the videos of the collapse a few hundred times, with a particular focus on the particle-slurry blown OUT of each floor in stages, i finally got the Zen of what they were trying to accomplish. In time lapse, they were disassembling the building, layer by layer, as you would build it, only backwards.

First they harvested all the concrete and asbestos flooring (together with gypsum wall board ) in one fell swoop pulverized it and blew it out into the neighbour's property. That was about 53% of the mass of the building removed in 1/10th of second per floor. How ingenious. To do this they needed the core to hold, until the moment after the floor-wide (evenly, uniformly broadcast) explosion, fully expelled an acre per floor of 4" concrete and harmful asbestos (the real super big demo permit problem) into the air; at which point the core column structure could be made to fail. (had to be made to fail, section-by-section, floor-by-floor a 1/4 second above that action. (separate, independent wave of explosions for the core, how tricky is that!...to keep the trailing wave of explosive materials intact surviving the first wave of explosions.)

If the concrete flooring was 53% of the mass of the building, and the concrete was 40% lightened by asbestos fiber, think about how much asbestos went into the air that day, blown off the property in 10 seconds.

As far as commercial crime goes, this must go down as the biggest AND most clever in history, making Capone and the Joker both look like pikers.

Posted by: lunk May 20 2009, 08:34 AM

I remember hearing a report of somebody overhearing a discussion of the towers being brought down a year before it happened, in a graveyard.

Controlled demolition can take months in preparation.

I think it is reasonable to conclude that the planes had nothing to do with the collapse of the towers, other than to create a smoke screen, to hide the initiation of the demolition.

This was a top down demo. However, an explosion was heard from the sub-floors, prior to the first plane impact, by the janitor.

Engineers like to build things with at least 3X maximum load capacity.
So, the towers must have been somehow weakened before the collapse.

I have been trying to find out if there was more steel in the construction,
than was taken away after the demolition. I have not yet seen much data on this.

As there are many signs of mini nuclear devices having been used, too, which would have boiled away some steel.
And spherical iron remnants were found in the dust,
could this be from something hotter than the thermite reaction?

Then I heard about the theory of the concrete core.
This would explain why, the total amount of steel taken from the site of the WTC, was not fully reported, as it would be considerably less, if the cores were really made from concrete and re-bar.

The evidence of thermite doesn't mean that that was the only demolition material used.

Posted by: JimMac May 20 2009, 03:23 PM

QUOTE (lunk @ May 20 2009, 08:34 AM) *
I remember hearing a report of somebody overhearing a discussion of the towers being brought down a year before it happened, in a graveyard.

Controlled demolition can take months in preparation.


Have you read Jim Hoffman's plausable demo theory? (i'm starting to sound like a broken record )
Please check it out here: http://911research.wtc7.net/essays/thermite/blasting_scenario.html
QUOTE
This was a top down demo. However, an explosion was heard from the sub-floors, prior to the first plane impact, by the janitor.


Agreed, sublevel exposions 6 to 8 sec before the first aircraft impact were heard and felt by several witnesses in the bsmts of WCT1 and not only by janitor William Rodriquez. Some men were even injured, thrown to the ground etc. But who knows what these were about. For example, Rudy Gulianni and crew were looking for gold reserves which had reportedly been stored in a vault. I think at least one Canadian bank lost a few hundred million (hearsay is). So how much gold was stored? In how many vaults? How much was recovered? We will never get these answers. But, we have to always keep in mind this was a criminal operation. I'm guessing that the demo management was not oblivious to the bullion treasure vaulted in the bsmt.
QUOTE
I have been trying to find out if there was more steel in the construction,
than was taken away after the demolition. I have not yet seen much data on this.


Nor will anybody ever I suppose (see the data). However, take a step back and look at ground zero photos, and in particular the size of the rubble pile. Look at the visual evidence. There is a giant rubble pile of mostly steel (no concrete) which stands a few levels above grade on the day after 9/11 (see fireman flag raising photo). Including the below-grade 7 sub-levels, the rubble pile was about 10 stories high, mostly steel and other metal parts, material that survived the floor-by-floor pulverisation (which we clearly see in the 10 seconds of demolition to have occured). Perimeter columns were blown outside the building footprint (as we cleary see in the take-down). So what is left is a one acre pile (in height 100' plus) of mainly steel column debris. That's a lot of steel debris, steel mainly related to the 47 core columns, each formerly standing 1360 high plus the miscelaneous debris of 99 elevator cores and whatever else survived the waves of exposions downward.

QUOTE
As there are many signs of mini nuclear devices having been used, too, which would have boiled away some steel.

Evidence of a nuclear exposion is news to me. I submit this idea of nukes is evidence of more psych-ops ideas that do not fit the reality and are intended to obfuscate the picture. Look at the towers coming down, floor by floor. Does this look like a nuclear blast to you?

QUOTE
And spherical iron remnants were found in the dust,
could this be from something hotter than the thermite reaction?


Steve Jones and Neils Harrit have published a scientific paper which address the tiny spheres and how they were created. They did lab experiments and simulated their creation. Its not a mystery.

QUOTE
Then I heard about the theory of the concrete core.
This would explain why, the total amount of steel taken from the site of the WTC, was not fully reported, as it would be considerably less, if the cores were really made from concrete and re-bar.


This theory is bunk. You should investigate Christoper Brown and his web site. http://algoxy.com/conc/core.html. This guy really disturbs me, because he a fraud and he is the source of this mis-information on the net. I can't believe how many people get sucked into his BS. BTW..the images he used are borrowed from a BBC news documentary which is also bunk. My guess is Chris Brown is on the dark-ops payroll, under the '9/11 obfuscation' chart of accounts.

Other than footings, concrete was not used as a structural element in WTC construction. Footings would have been gigantic and require truck load upon truck load of pre-mix.

Posted by: lunk May 20 2009, 06:07 PM

I was really disturbed when I first watched building 7s demise, on youtube.
Before that I thought only 2 towers were brought down by airplanes, on 9/11.
Then suddenly, I knew, the entire event was, a planned in advance, demolition.

After that I started to notice the huge disinformation campaign, to derail any
serious investigation, which only makes sense, if it was a planned demolition.

The other thing that I have noticed is the number of 9/11 spokes people who seem to come out of military intelligence, which is where the disinformation would be coming from, for all these things to have happened.
So I have to view anyone in this category as suspect.

Ah, yes, the nuke theory:

http://video.google.com/videoplay?docid=-4731051210315608217

-elevated levels of Tritium in the ground water after 9/11.
-radiation hot spots found around the demolition.
-recorded sounds of long, huge, rumbling, explosions during the demolition.
-power outages, possibly caused by electro-magnetic pulses (EMP), from mini-nukes.
-molten concrete, that "flowed like lava" in building 6 encasing guns in the police museum.
The giant hole in the roof of building 6 that went all the way down inside, that had no debris in it?!



The proven use of thermite, by prof. Jones,
belittles these implications, who seems to deny anything nuclear.
...Even going back to the days of cold fusion!

I found all this, extremely disturbing.

Sort of made me want to turn my mind to music:

http://www.youtube.com/watch?v=VwtGpdSTaAI

lunk

Posted by: JimMac May 20 2009, 08:06 PM

QUOTE (lunk @ May 20 2009, 06:07 PM) *
Ah, yes, the nuke theory:
lunk


Editing this post...got my photo links mixed up

(Wrong photo pasted...looking)

Posted by: lunk May 20 2009, 09:58 PM

I guess the question is,
that we know, that thermite was used,
but if they used that, then we must conclude,
that it was a planned controlled demolition.
If this is the case, what was to stop them from using
other demolition devices?

...and not tell us.

Posted by: JimMac May 23 2009, 02:40 AM

I did find the WTC drawings online. On bsmt level five, bottom level, the drawing schedule has a detail for footings. The elevations (hand written) are hard to read, but the detail is to scale. The concrete footings were specified to be about 40" in height above the grade of the finished floor, and apparently bear on solid bedrock below, at what elevation i don't know. So in other words the footings would be anchored to the bedrock with ties. The steel columns were fastened to the footing somehow, no detail on that, probably on another drawing. Anchor bolts, shoe-plate, whatever they used it would be common practice for 1966.

On the same detail, the architect spec's the use of fire brick on the steel column surface, 5" thick. The brick work is just ordinary masonary brickwork, only using fire brick, as you would in a chimney. They probably plastered over that to create a finish.

There are no details on the relative height of the footing, but i am guessing that it was about 6 to 8 feet in height, or more. That being the case, they probably dumped a few thousand truck loads of material into the hole after the footings were built, and brought up the grade, compacted the fill then poured a 6" to 8" floor (on top of the fill material and of course also around the base of each footing, leaving 40" of footing above grade to support steel colums). There were lots of concrete pads specified in the same drawing. Mechanical room stuff probably, and maybe even a future bank vault, one beefed up floor area room was specified as 'records room'.

What does this have to do with anything? i'm not sure. But that's what I found. If you want the drawing links, i'll post them later. (closed all browsers at the time and didn't bookmark)

Posted by: lunk May 23 2009, 11:24 AM

The whole WTC was built in a "bathtub" was surrounded by a waterproof retaining wall, or the hudson river would flow in.
..Not sure about building 7, was that outside the "bathtub"?

Posted by: Sanders May 25 2009, 03:03 PM

While I do believe that the "powers that be" had probably decided to switch America's #1 enemy from the Soviet Union to "radical Islamic terrorism" for numerous and very broad reasons around the time the Trade Towers were being built (Zbiggy Brzezinski talked Carter into funding the Mujahedeen to lure the Soviets into the Afghan war in '79 I think), and I know that the Trade Towers were a Rockefeller endeavor, but I really find it hard to believe that the towers were constructed with demolition built-in. Maybe they were, I have no idea, but when I get an urge to do something I want to do it now. I can't imagine planning something 30 years in advance ... and how sure could they have been that it would have worked, 30 years later??? And what advances in technology would they have forgone to rely on 70's technology? - I am highly skeptical of that theory, for the record.

Posted by: tnemelckram May 25 2009, 05:37 PM

QUOTE
. . . (I) really find it hard to believe that the towers were constructed with demolition built-in.
. . . . . . . .
I am highly skeptical of that theory, for the record.


I agree.

You give good reasons why it would not be feasible or desirable to pre-position demolition apparatus.

Perhaps the best possible compromise view is that the planning or design of the building contemplated that some day, eventually, these massive constructions would have to be razed. So their structure in some way was designed to accommodate that, or there was some planning for where to place charges. But it is far fetched to think that apparatus was built in.

Who knows what advances in demolition the future might bring? *Some say* that the planes, "hot jet fuel fires" and suspension of the laws of physics and other sciences actually demolished the buildings in a novel and unexpected way that the designers could not have foreseen.

Posted by: JimMac May 25 2009, 07:19 PM

QUOTE (tnemelckram @ May 25 2009, 05:37 PM) *
I agree.

You give good reasons why it would not be feasible or desirable to pre-position demolition apparatus.

Perhaps the best possible compromise view is that the planning or design of the building contemplated that some day, eventually, these massive constructions would have to be razed. So their structure in some way was designed to accommodate that, or there was some planning for where to place charges. But it is far fetched to think that apparatus was built in.

Who knows what advances in demolition the future might bring? *Some say* that the planes, "hot jet fuel fires" and suspension of the laws of physics and other sciences actually demolished the buildings in a novel and unexpected way that the designers could not have foreseen.


(Trust me on this), Architects do not give the slightest, faintest thought to how their crowning achievements will be one day be torn down. On the contrary, they imagine them to provide a sense of immortality to their creators. And if the impossible idea were somehow to apply in the case of WTC, they would need to bring in a team of demo engineers to advise at the planning stages. And to build such a structure using 'explosive' and therefore dangerous materials, even if it was done covertly, would be next to impossible. The idea is beyond far fetched. It just didn't happen.

Its true that professional people did think for at least a decade on how to demolish the buildings (legally on behalf of the Port Authority) but the covert action that eventually did occur was planned well in advance, maybe even five to ten years in advance by the people that eventually gained control of the buildings with that purpose in mind. They had a plan when they set up Larry Silverstein as the new owner, because he is a front man asset. He has backers.

Here's an interesting little tid bit from wiki: In 1989 Larry Silverstein proposed to members of the Israeli government that a Free-Trade zone should be created within the Negev region of Israel. The project ultimately failed, however it enjoyed popular support amongst leading Israeli political figures. (Silverstein was very connected)

Posted by: JimMac May 25 2009, 07:44 PM

Another tid bit to the history of WTC is that the Federal Reserve Bank of NY took a lease for something like 40,000 Sq Ft (area from recall) back in the early days of leasing the building, because it was a dog to lease. The open space floor plan was a novel and exciting idea, but it was hard to find tenants to take advantage of the large floor areas in the beginning. Y'all know who is the controlling mind of the NY Fed Reserve.

Posted by: guillaumedock May 26 2009, 11:28 AM

QUOTE (lunk @ Apr 20 2009, 04:19 PM) *
It would be difficult to get into every column with 100rds of tones of anything.

There is another heat source that will heat up steel for weeks,
that leaves elevated levels of tritium, and tends to vaporize steel,
and liquefy concrete.

I don't think any amount of thermite can do this.

The thermite wasn't the only cause of the demolition, just a part of it.

Received loud and clear. If you look downwards, such a source of energy would have a circular footprint.
If you don want that source of energy to be contained in each tower, that will leave the corners. So you
use your special source of energy, and for the corners you use good old thermite. Guess where on the
towers the flowing molten metal was seen? On the corners, yep.

Now, the question I have been asking myself is this... was the source of energy placed within the bedrock,
creating a cavity into which a part of the core fell, while the perimeter columns stood on the bedrock, thus
shearing and tearing the horizontal beams? Or was the source at the basement above the bedrock... not
sure of that.

However it seems that parts of the core descended a few levels.

If those columns are indeed corner columns (501,508,1001 or 5008), from structural data, we know there is a column
width transition from the 9th to the 10th floor, and no transition till the 60th or something floor. As I see a transition in
the photo, this means that this is the boundary between the 9th and 10th floors. Yet the large tridents mark the 6th
floor. Checking other pictures to guard against misleading perspective, it seems to me that this part of the core
sunk about 3 levels, either because the core fell into a cavity, or because its base was vaporized or knocked out.

Posted by: JimMac May 26 2009, 01:46 PM

QUOTE (guillaumedock @ May 26 2009, 11:28 AM) *
Now, the question I have been asking myself is this... was the source of energy placed within the bedrock,
creating a cavity into which a part of the core fell, while the perimeter columns stood on the bedrock, thus
shearing and tearing the horizontal beams? Or was the source at the basement above the bedrock... not
sure of that.


http://www.flickr.com/photos/mapplegate/1380111770/

Posted by: guillaumedock May 26 2009, 02:10 PM

QUOTE (JimMac @ May 26 2009, 07:46 PM) *
http://www.flickr.com/photos/mapplegate/1380111770/

Does this picture help one hypothesis or the other?

Posted by: JimMac May 26 2009, 06:53 PM

QUOTE (guillaumedock @ May 26 2009, 02:10 PM) *
Does this picture help one hypothesis or the other?


Well, its a core column. I thought it was helpful. I guess you must decide. If you look closely, I think we see the top of a footing there too. (So far, I have not seen a pic of an actual footing in place, but that's kinda beside the point. )

Can you reconcile this photo with the idea that a small nuke blew a hole in the bedrock?

Posted by: lunk May 27 2009, 02:43 AM

I wonder just how far ahead this demolition was planned.
at least months, perhaps a year, or maybe more.

Why were the twin towers built in the first place?
For world trade?
I guess.
But was there a need, for these buildings then?

The more I think about it the more it seems that they were built to withstand aircraft, so they wouldn't come down unexpectedly.

How long does aluminum and rust last? Forever?
I think it would have an unlimited shelf life,
made with those ingredients.

Posted by: guillaumedock May 29 2009, 05:20 AM

QUOTE (JimMac @ May 27 2009, 12:53 AM) *
Well, its a core column. I thought it was helpful. I guess you must decide. If you look closely, I think we see the top of a footing there too. (So far, I have not seen a pic of an actual footing in place, but that's kinda beside the point. )

It's not a core column. Core columns were box columns until approximately the 2/3rds of the tower. This does not show a box column but an I-beam.
The perspective is also misleading. It's a column of the WTC, all right, but not of the core of the buildings. It's next to the boundary of the WTC area.


The last core column was removed in the "last column" ceremony.


Now can we reconcile the above last column picture with the idea that "a small nuke blew a hole in the bedrock"?
Well, if a small nuke created a (half-filled) cavity, and if the top of that cavity collapsed shortly after, you'd get a depression but not
necessarily a gaping hole. So the columns could sink a few stories but not disappear. Would that be possible, or helpful
for the demolition?

Also, if you absolutely want a gaping hole... you could have a gaping hole that covers only a few core columns.
There were 48 core columns. Is there a picture of 48 core columns standing on their foundations after the event?

Posted by: dMole May 29 2009, 06:27 AM

QUOTE (guillaumedock @ May 29 2009, 03:20 AM) *
The last core column was removed in the "last column" ceremony.

What "force" bent that column? Has anyone done a "free-body diagram" yet? Breaking, ultimate, and yield strength(s) anyone?

http://upload.wikimedia.org/wikipedia/commons/f/f1/Stress_v_strain_A36_2.svg

T = F x r

http://hyperphysics.phy-astr.gsu.edu/HBASE/torq.html#torq

This thread has already gone borderline "Alt theories" and it might get moved soon.

EDIT: Euler buckling (of columns):

http://freewikimedia.com/en/wiki/Column.html

EDIT2: Oh yeah, engineers mostly like to refer to torque T as a "moment" +/- "arm" for whatever their reasons... (The boldface denotes vector quantities, as was standard in my collegiate literature back then anyway)

Posted by: JimMac May 29 2009, 12:53 PM

QUOTE (guillaumedock @ May 29 2009, 05:20 AM) *
It's not a core column. Core columns were box columns until approximately the 2/3rds of the tower. This does not show a box column but an I-beam.


Hello, guillaumedoc, I just saw this post now, or I would have replied sooner. Your statement is interesting; i did a little study on just that subject this week after I saw a newspaper article stating that this column was a perimeter column. I didn't think so, which led me to investigate. http://mcluhan12.angelfire.com/index2.html. I have a thread running on this issue too.

Posted by: guillaumedock May 29 2009, 06:30 PM

QUOTE (JimMac @ May 29 2009, 06:53 PM) *
Hello, guillaumedoc, I just saw this post now, or I would have replied sooner. Your statement is interesting; i did a little study on just that subject this week after I saw a newspaper article stating that this column was a perimeter column. I didn't think so, which led me to investigate. http://mcluhan12.angelfire.com/index2.html. I have a thread running on this issue too.

Hello,

Are you still referring to the picture at http://www.flickr.com/photos/mapplegate/1380111770/ ?
It's neither a core column, nor a perimeter column of the towers. Perimeter columns
were resting on the famous "tridents" which were resting on box columns which were
resting on foundations ; not on I-beams. Actually, I don't think it's a column from the towers
themselves, but from the complex (i.e. a basement column) since it is shown to be next to
the bathtub wall, which the towers were not.

Posted by: guillaumedock May 29 2009, 06:33 PM

QUOTE (dMole @ May 29 2009, 12:27 PM) *
What "force" bent that column?

Hello dMole, are you talking of the ceremony column? Seems straight to me.
It was also standing straight before being removed, see for instance Meyerowitz's
book "Aftermath".

Edit. Page 269 of the book, states that the "ceremony column" is column #1001 of the south tower, expressly retained for a ceremony.

Posted by: JimMac May 29 2009, 06:37 PM

QUOTE (guillaumedock @ May 29 2009, 06:30 PM) *
Hello,

Are you still referring to the picture at http://www.flickr.com/photos/mapplegate/1380111770/ ?
It's neither a core column, nor a perimeter column of the towers. Perimeter columns
were resting on the famous "tridents" which were resting on box columns which were
resting on foundations ; not on I-beams. Actually, I don't think it's a column from the towers
themselves, but from the complex (i.e. a basement column) since it is shown to be next to
the bathtub wall, which the towers were not.



Did you look at the web page mini-study I did? If you did, and still make the above statements, then we would be in full disagreement. http://mcluhan12.angelfire.com/index2.html

Posted by: guillaumedock May 29 2009, 06:46 PM

QUOTE (JimMac @ May 30 2009, 12:37 AM) *
Did you look at the web page mini-study I did? If you did, and still make the above statements, then we would be in full disagreement.

Yes I did. I agree that it's not a perimeter column. However it is neither a core column as point ( B ) of the study claims. It is IMHO a column of the subbasement level of the WTC complex. So we are in partial agreement and in partial disagreement.

Posted by: JimMac May 29 2009, 08:14 PM

QUOTE (guillaumedock @ May 29 2009, 06:46 PM) *
Yes I did. I agree that it's not a perimeter column. However it is neither a core column as point ( B ) of the study claims. It is IMHO a column of the subbasement level of the WTC complex. So we are in partial agreement and in partial disagreement.


Ok, i'm not sure if you are construction savvy or not, but when you have a structural element of this massive size there is a load bearing reason. And, if you notice on the floor plan of sublevel5 where this column starts, there are no interior floor columns that do not form part of the core 48 (or 47) col array. So please tell me where you see it positioned, because it does not show on the floor plan. (unless you accept it as one of the core columns).

Back to you.

(btw, thanks for taking the time to sort this out, because i do believe its important)

Posted by: Christophera Feb 22 2010, 02:55 PM

QUOTE (JimMac @ May 18 2009, 06:23 PM) *
This theory is bunk. You should investigate Christoper Brown and his web site. http://algoxy.com/conc/core.html. This guy really disturbs me, because he a fraud and he is the source of this mis-information on the net. I can't believe how many people get sucked into his BS. BTW..the images he used are borrowed from a BBC news documentary which is also bunk. My guess is Chris Brown is on the dark-ops payroll, under the '9/11 obfuscation' chart of accounts.

Other than footings, concrete was not used as a structural element in WTC construction. Footings would have been gigantic and require truck load upon truck load of pre-mix.


Dude, most likely that the reverse of what you post is true. Or, that you are on the payroll not I. I am a US Citizen working to protect the US Constitution.

This is substantiated by the fact that I have filed a United States Code, Title 18, part I, chapter 115, 2382 filing at United States District Court with substancial evidence.

http://algoxy.com/psych/9-11title_18.disclosure.html

Now, show us how you will work to protect the Constitution. Or . . . have it be true that you are working against it.


Posted by: SanderO Jun 27 2010, 08:22 PM

http://img16.imageshack.us/img16/6861/terminal.gif

terminal velocity revealed.

The twins were mostly air. Each 12 feet from floor to floor has 4" of concrete slab and 11'-8" of air with some office contents within the 11'8" as well as some ceiling /floor structure and ducts. But it was 97% air... except for the columns of course, in the core and partitions.

If one considers the collapsing floors the total height of the slabs was 36' and the other 1430 feet was air.

We can see that the facade was largely found outside the footprint and appears to have peeled away being pushed by the collapsing floors or explosions (less likely). The core frame seems to have survived the collapse a bit, some of it standing 70 stories before collapsing or in some cases toppling over. The lateral supports and the core floors likely collapsed ie, crushed by the massive weight of material falling from the top sections.

So the matter to examine is how did the floors break free from their supports. Or perhaps were the crushed by collapsing material from above. What caused the upper sections to collapse, ie be freed from their support (columns)? Were the columns exploded away? Were they displaced by explosions? Were they cut but incendiaries? Did the buckle from extreme heat (from whatever source) or did the structure torque and twist as a result of damaged columns and a progressive failure? Or a combination of the above? Regardless, it seems that once that sort of mass was free to fall, it would have enough energy to make it down to the ground at free fall only slowed by the time it took to destroy the floor and/or its columns connections. That time is very small when one considers hundreds of thousands of tons of material dropping on a 4" thick slab. That slab would hardly slow the collapse at all.

The gif above shows that terminal velocity was reached after a few seconds at about the 85th floor and appears to be in excess of 60 mph.

Posted by: gepay Sep 27 2010, 03:44 PM

QUOTE (JimMac @ May 23 2009, 10:19 PM) *
(Trust me on this), Architects do not give the slightest, faintest thought to how their crowning achievements will be one day be torn down. On the contrary, they imagine them to provide a sense of immortality to their creators. And if the impossible idea were somehow to apply in the case of WTC, they would need to bring in a team of demo engineers to advise at the planning stages. And to build such a structure using 'explosive' and therefore dangerous materials, even if it was done covertly, would be next to impossible. The idea is beyond far fetched. It just didn't happen.

Its true that professional people did think for at least a decade on how to demolish the buildings (legally on behalf of the Port Authority) but the covert action that eventually did occur was planned well in advance, maybe even five to ten years in advance by the people that eventually gained control of the buildings with that purpose in mind. They had a plan when they set up Larry Silverstein as the new owner, because he is a front man asset. He has backers.

Here's an interesting little tid bit from wiki: In 1989 Larry Silverstein proposed to members of the Israeli government that a Free-Trade zone should be created within the Negev region of Israel. The project ultimately failed, however it enjoyed popular support amongst leading Israeli political figures. (Silverstein was very connected)


There is much circumstantial evidence that Silverstein knew in advance. The price for his participation is evident in the destruction of WTC 7 which Silverstein had constructed. That and his portion of the 5billion of the terrorism insurance plus the government carted away all the debris on their tab.
Cui bono. Plus helping with "never again' . see Bibi Netanyahu's statement about how good 911 was for Israel. There is much actual evidence for Mossad help - the hifiving Israeli 'movers' filming the towers destruction- the noisy diversionary Israeli 'art students. etc

then there are all the benefits to the Bush admin and the neocons. This operation required help from elements of the CIA, the military, the FBI, etc. although I agree with the statement = "there's no disaster so bad that it can't be made worse by the government coming to help." This ineptness and turf battles and the left hand not knowing what the right hand is doing was used by the covert moles in the US government to be able to use the resources available to the above agencies to bring this off without being caught in the act. Although there was Israeli help , even the Mossad can't put the US airForce on hold down.

The WTC towers were huge buildings. They required a very complex demolition. My guesses would be it appears that seconds before impact, some of the core columns were weakened in the basement. Then a nanothermite thermobaric device(s?) were used to destroy the floors and the outer perimeter. The towers exploded like popcorn and threw tons of steel away from the foot print. This was after the top floors above the impacts were destroyed in a conventional demolition. You can't have 20 or more stories of a building 1/4 of mile up in the air tumbling onto some of the most pricey real estate in the world. Then the core columns were cut. And yes, the elevators had recently undergone upgrading that year by a business, Ace Elevator, that is not now in existence. The elevator operators all left that 911 day and didn't help with the rescue as they had in the first WTC bombing. And we have heard of the Bush connections to the security of the WTC. The tremendous heat left in the rubble is the smoking gun anybody who has a skeptical ounce of perception needs to know this was not done by radical islamic terrorists.

Posted by: SanderO Sep 27 2010, 06:55 PM

With all due respect the theories presented above about the destruction of the twin towers show a lack of clear understanding of their structure and a failure to properly describe the observation of the collapse.

First one needs to understand that as much as 40% of the core survived the collapse of the floors outside the core with 501 standing 0ver 70 stories and this included all the columns on the north side of the core perimeter. Many stood over 50 stories before collapsing. All this can be seen in videos if you bother to look for this.

This means that the core columns were not destroyed to enable the collapse of the lower section - ie below the plane strikes.

Next, each tenant floor was designed to support 100# per square foot with a healthy safety factor of perhaps 6. But it's likely that they would not collapse - total failure unless there was 1,000#/SF.

When the upper section in WTC 1 was destroyed or collapse it's weight mostly came down on the 92nd floor - uppermost undamaged floor from the plane strike and fire. The floors system alone weighed over 100#/SF so this meant that a sizable fraction of 1700#/SF descended on the 92nd floor over a few seconds as the top section was destroyed. This included the dynamic load where some of the mass was dropping 225 or more feet. Bottom line is that the typical outside the core floor such as 92 collapse from the falling debris and this over load condition continued right down to the ground. The top 17 floors weighed north of 80,000 tons and discounting the core and the perimeter the floors alone weighed over 50,000 tons and this does not include walls and furnishings etc. No floor system in the towers could support this load.

The collapse we saw was the progressive and very rapid at about 60 mph of the floors. In the process of collapsing the mass acted like a chaotic avalanche and pushed in at the core and out at the facade. The facade peeled and was pushed away by the avalanche of the floors. The core which was mostly shafts had much of the lateral support beams destroyed by the debris from the collapse above. The boom boom boom boom etc was the rapid sequence of one floor crashing to the next heard in the beginning of the collapse.

The plane strike did not push the top off the columns which held it up. Neither did office fires etc provide enough heat to weaken enough of the steel core columns to cause them to buckle and then fail releasing the top to plunge done destroying the floors below. No columns were crushed, certainly from the lower section.

It's possible that only a 14 of the perimeter core columns were "attacked" over three floors (each column was made of 3 story sections so there were 37 of them one atop the other obviously with the lower ones being the strongest. Only 24 of the core columns supported the floors outside the core, the remaining 23 in the center did little except carry the antenna and frame the shafts and support the few corridors and floor areas in the core. But even the center 3 columns did not carry the antenna alone (each tower was designed to carry an huge antenna). The hat truss was a three dimensional space frame which distributed the antenna loads to the stronger perimeter core columns and even out to a few facade columns. So attacking the for corner columns 501, 508, 1001 and 1008 and the ones which supported the hat hat truss 505, 506, 1005, 1006 and 701, 801, 708 and 807 at three floors and the joint where the connected to the columns above supported another three floors would likely be enough to "release" the tops, get them off axis and descending permitting the first 6 and then the remaining 11 floors to impact floor 92. And to finish the job that mass continued down growing by 3000 to 500 tons per floor destroyed. By the 50th floor the pressure was 50,000 PSI and by the time the collapsing floors hit ground the force was 100,000 PSI.

What was the explosion heard in the basement? If it was anywhere near the main freight elevator it was likely to destroy /weaken the 3 columns under the antenna (which led the descent of the top) These columns were not directly connected to the perimeter, but it they dropped they could pull some of the core perimeter inward via the lateral support beams. Careful examination of the collapse of the top of WTC 1 show the outer perimeter of the roof being pulled in as it descends indicating that the center was "hollowed out" some what.

Most of the steel columns were broken apart at their weakest point - the joints which held them together, though some were bent from the collapse itself.

There are still many mysteries about the destruction of thew twin towers but once those tops broke free the collapse was natural and predictable and required no explosives or incendiaries. The towers were 96% air by volume in the floor area outside the core and only slightly more when the columns are considered (but they did not get crushed).

Whomever did it understood the structure and its weak points and that was the open column free long span floor system. If they could overload that the floor collapse would take the columns with them or leave them too tall to stand unsupported. Plane strikes would and could not attack enough floors to set the avalanche going nor could local floor collapse from a few damaged floor trusses. NIST liedf and deceived. But they did not bother to explain the collapse after their bizarre collapse initiation fiction.

That's where the new investigation must focus - collapse initiation.

Posted by: amazed! Sep 28 2010, 04:36 PM

There will be no new investigation.

Not of this event, and not of the assassinations of MLK or JFK. Ain't gonna happen, and there is a reason for that.

Posted by: SanderO Sep 28 2010, 05:03 PM

I think you are correct. A new investigation will air some very dirty laundry and that would be unacceptable.

Posted by: mrmitosis Sep 29 2010, 02:19 AM

QUOTE (SanderO @ Sep 28 2010, 05:03 PM) *
I think you are correct. A new investigation will air some very dirty laundry and that would be unacceptable.


http://labvirus.files.wordpress.com/2010/01/ssrn-id1084585.pdf

^^^

I only learnt about this Cass Sunstein character earlier today. It seems that Obama is determined to carry the torch passed over from the previous administration (as if there were ever any reason to believe otherwise).

SanderO, I'm not sure if I understand the nuances in your analysis, and I am sure that you understand the physics better than I do.

However, there are a couple of details which I suspect you have misinterpreted. For example, are you suggesting that once the collapse sequence had been initiated in the case of the North Tower, that the destruction which ensued can be explained without speculating about the use of explosives?

To my understanding, the damage caused to the towers resulting from aircraft impacts would in fact result in a decreased capacity for the upper portion to crush what lies beneath it. David Chandler explains it pretty well -

http://www.youtube.com/watch?v=28ds5sFvTG8&feature=related

In other words, not only was there insufficient energy available for the collapse to begin - there was not enough for it to continue, either.

Perhaps this is not what you are arguing, and perhaps I need to brush up on my own understanding of the forces involved. Apologies in advance if this is the case dunno.gif

Posted by: SanderO Sep 29 2010, 06:09 AM

I believe in this case Chandler is wrong. My explanation is based on the simple fact that there was more than sufficient mass in the upper section of the towers to destroy the FLOORS once that mass was dis associated from the columns. Chandler's basic physics concept is correct, but he is not actually describing what happened. He reduces the problem to a small block crushing a big one or essentially why would columns which supported X mass not supported it mysteriously on 9/11 after the plane strike?

But the fact is that those columns - the core - were not involved in the collapse of the floors. The columns would be the path of most resistance, but the floors fell, not on or through (crushing) the columns, but onto one another. The floors were connected to the sides of the columns and they had each been designed for a 100 #/SF load (mechanical floors more) and with the upper floors coming down on them this was exceeded by a factor way beyond the safety margin of the FLOOR design. The floors failed and did so chaotically and the failure progressed rapidly and became less stoppable as more and more floors added to the descending mass. Neither the core columns not the facade columns were involved nor could prevent the collapse of the floors.

This is basic statics and something that engineers who design structures understand and principles they use all the time. A floor slab, and in this case the trusses which support it, and the connections to the columns which support the trusses are designed to carry anticipated loads (in this case 100#/sf for the slabs) with a safety factor. The floors themselves weighed more than 100#/sf without adding the live load. So each floor could conceivable represent 200#/ sf of added load when it feel to the floor below. Some of the mass went over the side and some into the core so this is the upper limit of added mass contributed by each floor. But some of the core columns might fall outside the core and add to this mass. Regardless in a few seconds AFTER collapse initiation the conditions for floor collapse were met and the top floor supporting all that extra mass sagged past its elastic limit and shattered dropping down and presenting the floor below with even more extra mass and it failed quickly and so on to the ground. This was not pancakes as the over loading of the floors did not have to happen simultaneously over the entire floor area, but in a short period of time all the mass above came more or less straight down and overcame the entire area of each floor.

Proof that the core columns were not involved in the floor collapse is the spire which stood for a bit after the floors collapsed. Not all the core but at least 40% and up to 50 floors and 501 stood over 7o. The longest surviving core columns were the ones supporting the north (long span side) of the floors outside the core.

Also confirming that the columns were not involved is the fact that the facade columns were found un buckled and can be seen falling away in huge sheets of up to 150 tons flat and made up of 20 or more 10x36 facade panels. This strongly indicates that they peeled away after the floors had collapsed with the growing floor mass providing the horizontal force to push them away.

All the air in the building was rapidly displaced by the compacting crushing falling debris and this is seen by the huge cloud of dust which propagated away from the bottom after the collapse hit the ground. Some of the air pressure shattered the glass and carried smaller pulverized debris in streams of air laterally as the collapse progressed.

Some lighter elements were strung off the building such as the light aluminum skin of the facade columns and even some steel sections so it was not like pouring sand down a chute. It was a very chaotic and energetic even involving the collapse of hundreds of thousands of tons of material.

Getting this all started is where the engineering took place. But once it was started it was nature that destroyed the structure. This is analogous to the use of explosive to set of avalanches. Once they get started they are completely natural phenomena.

Posted by: mrmitosis Sep 29 2010, 10:00 PM

I'm well and truly out of my depth here, but perhaps I can paraphrase your argument as I understand it in dot form, respond briefly, and you can correct me if I have misinterpreted anything. (I hope you don't consider this too much of a tedious exercise.)

In essence, what I gather you are saying is that:

(i) the structural integrity of the tower floors was dependent on the strength of what was bracing them to the columns, and the M x A of what came crashing down onto them.

(ii) the scenario you describe was distinguishable from pancaking because the floors were not ripped from the columns as whole blocks, but in a more random (but close to simultaneous) fashion. Basically, the concrete was smashed apart and brought down by the descending material from above, which naturally accumulated as the collapse sequence gained momentum.

The part which does not square with my observation is the fact that such a small proportion of the steel columns remained standing and intact after the rest of the building came down. You mention that at least 40% of the core remained post-collapse, but from my perspective, I find it difficult to explain how ANY steel below the impact point could be destroyed so cleanly and rapidly, at least by virtue of tumbling concrete. As you say, this was the path of most resistance, and so an additional source of energy is required.

You also point out that there was enough bulk sitting above the point of impact to separate the floors from the columns, bringing those floors and the ones below down with them. I have no reason to dispute this, but I don't think this is what Chandler was referring to.

When he raises the matter of a "small block crushing a big block", I think he is drawing attention to the impossibility of this as an explanation (not the reality of it) as far as the building's core is concerned. Setting aside any of the mechanisms involved in separating the floors from the columns and trusses, how are we to explain the destruction of the columns themselves? The steel was sliced and diced neatly and uniformly, and a lot of it was visibly and forcibly ejected sideways as the structure fell. Something was breaking the steel apart and shooting it out horizontally - what was it?

On a slightly unrelated point, it's interesting that on every piece of footage I've seen, the camera shudders violently about 12 seconds before the north tower comes down, although we hear nothing on the audio track. Hmmm.

Posted by: SanderO Sep 29 2010, 11:00 PM

I break up the destruction of the towers into separate phases which blend into one another as opposed to discrete steps though parts of the collapse do involve discrete elements of the structure.

What we have is the plane strikes which damage some columns and then some fires which seem to cause local damage but are not hot enough to melt of seriously weaken enough steel for the tops to come down. That is where the engineered intervention comes into play and though I can propose various ways to accomplish that it would be speculation be cause I believe this involves the perimeter core columns and we can't see them.

What we see is the next phase where the top appears to be descending downward after tilting a bit with the antenna leading the descent. But descent is perhaps a bit misleading. The top IS descending but the bottom of the top "block" is not descending and it appears to be "disappearing" into the top of the bottom. It almost looks as the top is collapse at its bottom as it falls down through the plane strike zone onto the largely undamaged top of the lower section at about the 92nd floor. At the same time we see "ejections" all around the building at this impact zone between the top and the bottom. The upper part seems to hang together and it appears to be under little internal stress and in fact its initial descent accelerates at or close to free fall indication that there was nothing stopping its descent or nothing we could measure.

What is likely happening in the early stages of the collapse of the upper part is that it has been dislodged from the columns which supported it and naturally it drops, much like WTC 7 as it drops it brings the lowest floor say 93 in contact with floor 93 and the 94 is added and so on. These are not added a pancakes or uniform slabs and the collisions are energetic, not perfectly aligned contain dislodged steel columns and so forth which shatters the floors as the collide. Some of them crash through multiple floors related to the aircraft damage.

The destruction of the top takes about 4 seconds and the huge antenna moves ahead. It required the hat truss to distribute its loads to multiple columns and without that it is like a spear dropping through a grid of beams. The ones just below it were not very strong and the hat truss was used to assist those columns. It did other structural things such as act as an end plate stiffener for the square tube facade. But when the hat truss was compromised the antenna was "on its own" and down it went. In destroying the center of the core it also caused the lateral beams in the core to pull at the perimeter of the core and that in turn caused weakening and separation from the floor system.

As a static structure the loads were engineered to be travel to the columns and then down to the foundation. As columns and lateral beams were compromised and then unloaded others say increased loads and this also could progress to a runaway overloading and failure scenario.

In any case the top section came apart and descended on to the upper part of the lower section. When it did some of the material "splashed" over the side and pushed the facade columns away. Some of the facade columns in the initial moments of the descent were buckled and sprung from the building leaving the floors with no out board support. Some of the facade was displaced and in descending the meeting facade columns then severed the connects to the floor system. This was a chaotic event and 80,000 tons of concrete, steel and heavy HVAC equipment came tumbling down. The floor upon which this material began to fall was quickly overloaded... at least parts of it were and then all of it was. As parts were overloaded because of the somewhat random nature of the collapsing floors and mass from above they collapsed onto the floor below them 17 floors of material came "raining down" in those first few seconds.

As an area of floor saw the load exceeding its yield strength it shattered. This could be concrete breaking, or truss chords snapping or beam seats shearing, or bolts and welds parting. But it took perhaps 6 - 10 floor masses to destroy an intact floor which was designed for 100 PSF.

The floors began to fall down/ collapse inside the the top of the lower section. Pretty soon large areas of floors were failing at once dropping and some dropped in huge sections forcing the air outward breaking the glass and the the flimsy shaft walls of the core which had the express elevators arrayed the length of the long side of the core along with HVAC shafts.

The mass now plunged down floor by floor as an avalanche slow at first but eventually reaching a speed of over 60 MPH The gathering mass pushed against the facade and it toppled over in huge sheets as the bolts between columns and spandrels were not designed for that sort of shear load. The stripped off facade panels rolled over and sailed to the ground broke apart on impact.

A similar avalanche destroyed the floors and many of the cross beams which supported them in the core. Like the collapsing floors outside the core, the collapsing floors inside the core raced down leaving many of the columns behind. Some still connected to each other by surviving lateral beams. But these columns were unstable and had inadequate lateral support - too tall and thin to stand on the own and with the chaotic collapse around them they were jostled and began to oscillate, sway and buckle - breaking at the weakest points - the connections between one 36' long column to the next. The core columns in the lower sections show no signs of burning, melting, cutting, or explosions. They fell apart like pick up sticks. Examine the debris photos.

None of the facade panels achieved more than 34mph as it fell away from the towers. Chandler traces something which he clocks at 70 mpg - a point on / leading a dust plume taken from across the Hudson River at Liberty Landing. We can't identify this as a facade panel or know the weight of the projectile. I'm sure pieces were sprung violently in the collapse and there were things within the building such as refrigerant in the HVAC system which surely exploded in the collapse and there were 12 mechanical floors in 4 separate heights in the building. The only identifiable facade panels are clocked at much lower speeds which is supports the idea that they fell off or we pushed off by the collapsing floors.

To understand the design of the floor system imagine four legs of a table, but the top is not ON the legs but rests on little support blocks on the side of the legs. If you put too much weight on the table top the top might buckle or the blocks would break of the top would shear at the blocks. But whatever happened to the top it would not damage the leg except to perhaps push it over of pull it in. The floors were not designed to carry 17 floor masses.

So the collapse was completely natural, but the initiation was likely engineered and it need only involve perhaps as few as 14 - 36 foot tall columns in the upper section. That is speculation. The gravitational collapse AFTER initiation is basic engineering and physics.

The observed spire columns were the strongest and were the ones which supported the floors outside the core. All the weaker core columns in the center of the core did not survive in the spire. This tells us that the collapse was not the result of destruction of the perimeter core columns. The initiation of collapse likely involved those columns above the strike zone. But below it the gravitational collapse destroyed the floors, stripped the support from almost all facade columns which feel away and the the spire remained but too tall and thin to stand without lateral support

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