Looking for WTC ‘Achilles' Heel

Originally posted by The All Seeing I
Let me rephrase this... do we have any architects and structural engineers or students of these disciplines in the house,

Yes.

who can explain how one goes about designing a building that will collapse when distressed?

We don't. We design buildings to stand, not collapse. We even add in a "Factor of Safety" of at least 1.5. Most times 2-3. I know for a fact retaining walls have a FOS of 2-3 designed into them, so I would assume a 110-story skyscraper would have at least the same amount if not more.

...and how specifically was this designed into WTC 1, 2 & 7.

It wasn't and can not be. Or Controlled Demolitions Inc. would be out of business.

Again how does one design such a building, to collapse into it's own foot print.

And how do you determine what the 'Achilles' heel(s) will be?

Not being a demolitions expert (actually, demolitions experts are not structural engineers....they are just family run businesses...ask CDI...I did) I would say that the columns are the "Achilles heel" since they are what hold up buildings.

I'll answer the OP's question:

The Achilles' Heel is always the extensive cabling in high rise buildings.
You need LOTS of cables for a demolition job, the already existing ones can be used as endpoints for the ultra-modern thermobaric demo-charges you bring in and hang INSIDE the core and outer columns, and they will shatter like glass when the charges are ignited.

There will be no build-in procedures for demolition, eventually planned by architects or engineers. They will never cooperate with that.

But military planners, or uncontrolled secret agencies' planners will be very thankful for the kilometers of pre-laid cables covering all columns throughout the whole building they planned to destruct, when ordered to do so.
If the planning covers many years, as we may suspect in the WTC cases, it will be quite easy to install double safety pairs of cables, during the former years, under the cloak of extra online-time safety for IT businesses.

Here is a video asking questions. Why was the upper 50% of the South Tower for 36 hours put without energy and the security camera's thus were not working properly? Btw, this happened exactly in the weekend before Tuesday, September 11, 2001.
And if you are gonna look really into this subject, you will come up with photographs of a darkened upper part of the South Tower in the weekend before 9/11.
They needed no more than 3 days to place these charges via the small access/maintenance holes in the columns.
And thermobaric explosions are accompanied with extremely low frequency sounds, to be heard in the famous Rick Siegel video of the day of 9/11, filmed on two piers across the Hudson river.

Unusual activities at the world trade center before 911:



And this is the thread where I posted all my thermobaric bomb links:
www.abovetopsecret.com...&colorshift=yes
and where Insolubrious posted his VLF recording technique of some WTC collapse videos.

I took a look at the NIST study you linked to. Page 25 notes that with each of the four tests completed that "Failure to support load" "(3) Did not occur.". Therefore, the study actually does not do a lot to prove your point about the endurance of the trusses.

If you look at the test results these trusses used thicker layer of fire
proofing materials - these trusses were expected to provide 2 hours
fire rating. Much of the initial fire proofing was 1/2 " - 3/4" thickness
In 1996 Port Authority Chief Engineer order that fire protection be
upgraded to 1 1/2". This could only be done when tenant vacated spaces


Whole thing was rendered moot by aircraft impacts which blasted off
the fire proofing - the older method of encasing steel members in
concrete/terra cotta masonary proved much better to stand up to
impacts. 90 West St, built in 1907, was slammed by debris from south
tower collapse and was gutted by fires which burned for 2 days - yet
building survived with little structural damage. It was rebuilt.

The building was severely damaged in the September 11, 2001 attacks when the south tower of the World Trade Center collapsed directly across the street. Scaffolding which had been erected on the facade for routine maintenance did nothing to stop the fiery debris from raining into the building and tearing a gash deep down its northern face. Two office workers were killed when they were trapped in an elevator. The firestorm raged out of control for several days; the building, which had housed businesses including Hanover Capital, Frost & Sullivan and IKON Office Solutions, was completely gutted. It is believed that 90 West's heavy building materials and extensive use of terra cotta inside and out helped serve as fireproofing and protected it from further damage and collapse, as opposed to the more modern skyscraper at 7 World Trade Center, which suffered similar damage and collapsed later that day.

The saying "They don't build 'em like they used to" is probably the best
epitath for the towers. Newer construction materials and techniques
designed to build cheaper don't provide same level of resistance to
impact/fire like older techniques. Glass curtain walls vs concrete/stone
infill , tube construction vs internal columns, masonary fire protection vs
spray on, trusses vs solid I beams for floor support - contrast Empire State vs WTC

reply to post by thedman


Let me ask. Do you think we work in death traps now? I work in building restorations and your input as a fireman would help me in my field. Thanks in advance. This is not a trick question or anything, and I'm not being sarcastic in any way. Your input would help.

Personally, I think if architects and engineers started to build with planned obsolescence in mind as is sometimes (perhaps mostly) done in modern manufacturing, they would surely plan, as a building neared it's "best before date", that the entrances would first seize up thus preventing people from getting into the building just prior to the collapse.

That of course didn't happen on 9/11. I doubt if the buildings were designed with controlled demolition in mind either because when they were built, controlled demolitions were done with cranes and wrecking balls mostly. Using explosives was just starting to be done in a limited sort of way.



[edit on 1-1-2009 by ipsedixit]

Let me ask. Do you think we work in death traps now? I work in building restorations and your input as a fireman would help me in my field. Thanks in advance. This is not a trick question or anything, and I'm not being sarcastic in any way. Your input would help.

Problem is not that these buildings are "death traps" as you alluded to
its just that modern construction techniques are designed to economize
on materials and time. Because of this - using trusses instead of
solid beams they are less forgiving of extreme events than older
buildings where the engineers unsure of the loads in days before
computers overbuilt. As the old battalion chief who taught us building
construction remarked "A truss is perfectly adequate under normal
conditions" then quickly added a fire in a building was not a normal condition. In NJ after number of incidents involving truss collapse the
state passed law required all building using truss construction for roof
or floor supports be marked in prominent place to warm FF. We are
taught that in truss constructed building you have a limited amount of
time to operate in the building - you are told have 20-25 minutes to knock
down main body of fire if cant to get your ass out. Even then have to
watch for any signs of structural instability or collapse.

Originally posted by thedman
We are
taught that in truss constructed building you have a limited amount of
time to operate in the building - you are told have 20-25 minutes to knock
down main body of fire if cant to get your ass out. Even then have to
watch for any signs of structural instability or collapse.

No offense, but why were there firefighters in the towers to begin with if this is the case? Obviously it would take more than 20-25 minutes to just walk up 80-some flights of stairs.

And according to NIST, the trusses aren't what failed. The trusses sagged but were still strong enough to pull the outer columns inward causing the columns to buckle. Does this coincide with your training?

[edit on 1/2/2009 by Griff]

No offense, but why were there firefighters in the towers to begin with if this is the case? Obviously it would take more than 20-25 minutes to just walk up 80-some flights of stairs.

Answer is were not aware of the dangers of the web truss floor supports
as were many engineers. Only in wake of WTC collapses did fire
investigators and structural engineers become aware of long span truss
construction. Fire commanders did not understand the effect the fires
would have on the web trusses and figured would have much longer inside building

At 9:30 Chief Joseph Callan in North Tower notices building becoming
unstable as walls begin to crack, windows blown out of frams and orders
all personnel to leave building. Because of poor communications nobody hears the orders.....

Inside WTC 1, New York City Fire Department's Assistant Chief Joseph Callan realized the building was in trouble even before the first building, building two, collapsed. Interviewed Nov. 2, 2001, Assistant Chief Callan told New York City Fire Marshal Michael Starace, "Approximately 40 minutes after I arrived in the lobby, I made a decision that the building was no longer safe. And that was based on the conditions in the lobby, large pieces of plaster falling, all the 20 foot high glass panels on the exterior of the lobby were breaking. There was obvious movement of the building, and that was the reason on the handy talky I gave the order for all Fire Department units to leave the north tower. Approximately ten minutes after that, we had a collapse of the south tower, and we were sort of blown up against the wall in the lobby of the north tower, and we gathered together those of us who were still able to."

Should read this - very log article yet highly informative



Fire service is always playing catch up with changing materials and construction - only after tragedy do we learn

reply to post by thedman

The document you linked is one of the most interesting I have read on the subject of the collapse of the towers. In the fire chief's view, the collapse of the WTC towers was due to the fires. He states that the buildings were not sufficiently damaged by the planes and probably could have stood indefinitely if not for the fires.

He gives the straight and non-sensational facts on the fire temperatures (between 600-700 degrees centigrade) and says interesting things about the dynamics of superheated gases and weird effects caused by water from sprinkler systems.

He's dead set against long floor trusses and points to them as the cause of collapses in other buildings. He suspects them as the source of the collapse in the WTC. He suggests collapses of the floor trusses on the upper floors of the building leading to failure of lateral support for the exterior columns and the core columns, leading to buckling and failure of these vertical supports and the catastrophic collapse of the towers.

It's an idea. It reads well, but I don't believe it. Too much speed. Too much symmetry.

Thanks for posting the link though. There is a lot of food for thought in the document. I do appreciate having had a look at it.

Originally posted by ipsedixit
He's dead set against long floor trusses and points to them as the cause of collapses in other buildings. He suspects them as the source of the collapse in the WTC. He suggests collapses of the floor trusses on the upper floors of the building leading to failure of lateral support for the exterior columns and the core columns, leading to buckling and failure of these vertical supports and the catastrophic collapse of the towers.

This is also what Dr. Quintiere (former chief of fire engineering at NIST) thinks happened. BTW, this is the opposite of what NIST claims as the collapse mechanism. NIST claims the trusses are not what failed and were even strong enough to pull the exterior columns inward.

So my question becomes: Which is it? Strong trusses or weak trusses?

Originally posted by Griff

This is also what Dr. Quintiere (former chief of fire engineering at NIST) thinks happened. BTW, this is the opposite of what NIST claims as the collapse mechanism. NIST claims the trusses are not what failed and were even strong enough to pull the exterior columns inward.

So my question becomes: Which is it? Strong trusses or weak trusses?

I think NIST discounts that the trusses failed cuz they aren't seen through the windows. If the connections failed on the ext, then they would be seen hanging, right? Int, all bets are off.

Are you sure about Dr Q's thoughts? I didn't think he went into such detail, and merely stated that NIST was too conservative in their analysis and underestimated the fires.....

Originally posted by Griff
So my question becomes: Which is it? Strong trusses or weak trusses?

Doesn't it really have to be weak trusses, or rather trusses weakened by fire, since they were the structural elements most exposed to fire and also most vulnerable because of their smaller dimensions, anyway?

All of the vertical elements, besides being much thicker than the trusses, were only being heated on one side.

I like the fire chief of the linked document. He may be cutting the administration all kinds of breaks in his analysis and to some extent, "blowing smoke" but it's not Disney style technicolor dream smoke.

I can hardly wait to hear their explanation of what happened to the lower 85 or so stories of ever increasingly stronger, undamaged building that just kept failing to support a lighter and lighter load until the building vanished entirely.



[edit on 3-1-2009 by ipsedixit]

A lot of this banter is silly when it comes to such tid for tats.

If i could rephrase the OP title for a moment to
"Looking for the OS ‘Achilles' Heel"

Without a doubt the Achilles Heel would be WTC7

...and ae911truth i think has added the final nail in the OS coffin with this expose
"WTC7: Nist Finally Admits Freefall":

Part I


Part II


Part III



[edit on 19-1-2009 by The All Seeing I]

[edit on 19-1-2009 by The All Seeing I]

To me the Achilles' heel of the towers was the hat trusses, which were bridge structures built atop the core at the top of the towers and linked the core structurally to the outer curtain walls.

Once the cores failed in the impact areas, the hat trusses went with them and the curtain walls were now unsupported and fatally destabilized. The buildings, which were now a partial core surrounded by the mesh outer walls and only held together by the weak skein of the floor trusses, then basically unzipped.

That said, there was lots of help at all stages, IMO.

edit to add: griff you had a thread on this failure mechanism over a year ago--it was a very important insight.


[edit on 20-1-2009 by gottago]

...and how does this theory apply to WTC7?

or do we just ignore WTC7... write it off as irrelevant?

I find it very strange how those who buy the OS, fail to see that their story/theory does not sufficiently explain why all 3 buildings fell into the path of greatest resistance at free fall speed into their own foot print.

The Achilles Heel must be the same for all 3, for we see the collapse behavior is the same for each. The prominent CT is the only explanation that makes sense of this phenomenon.

[edit on 20-1-2009 by The All Seeing I]

Originally posted by The All Seeing I
...and how does this theory apply to WTC7?

or do we just ignore WTC7... write it off as irrelevant?

well that's pretty much the MO of NIST, dragging out their investigation for years until it becomes a footnote easily overlooked, and it has worked like a charm--less than 10% of the public even knows that WTC7 fell on 9/11.

I find it very strange how those who buy the OS, fail to see that their story/theory does not sufficiently explain why all 3 buildings fell into the path of greatest resistance at free fall speed into their own foot print.

LOL! That's the first time I've ever been accused of buying the OS! Take a look at my posting history on the 9/11 board; you'll find out quite otherwise. For example, I discovered and posted a patent issued in 2000 for fibre-optic detonators. Don't jump to judge someone by a slanted interpretation of one post.

Read what I wrote above carefully--it answers what you asked for, and I think it's a very sound analysis. Also note the last sentence about "lots of help."

The Achilles Heel must be the same for all 3, for we see the collapse behavior is the same for each. The prominent CT is the only explanation that makes sense of this phenomenon.

There is absolutely no logical reason that the flaw has to be the same for all 3 bldgs. WTC was demolished quite differently and obviously. It was a classic CD; the towers were a much more complex and difficult job.

[edit on 20-1-2009 by gottago]

gottage... sorry to offend, was not my intention.

My objective was to speak to the insanity of the subject at hand, not any specific individual... your post as well as many others, whether they be truthers or debunkers, triggered me to point to the lunacy of leaving WTC7 out of the equation.

Seems to me that the answer has been staring us straight in the face, ever since the moment they collapsed. All of the articulating and stretched rationalizations over the cause being something other then a CD... has for years gone beyond the point of ridiculous. It's like a parent who is in denial over their kid being a crystal-meth dealer/addict, all of this effort to avoid the hard ugly truth.

reply to post by The All Seeing I


Actually with time passing I hope we all have a clearer, more dispassionate view of the events, but that is just a hope; at least I know I see the event with more clarity, though several fundamental questions remain:

*Why did WTC7 fall in the afternoon, when it would have been perfect to drop it soon after the north tower fell? Why so sloppy and obviously CD? The treatment of it aftward by NIST--the 7-year stall--shows that this was the part of the plan that went very wrong.

*How did the towers fall? The major question--I think it was a complex undertaking and included several discrete components, some of which we might not even know about yet.

*Just who were the perpetrators? Though I think I have a fairly good grasp on that, and think it's a pretty unsavory assortment of bedfellows.

Returning to the original question of the fatal flaw, I really do think the question of the hat trusses is central to understanding the collapse of the towers, and what was targeted. They were the crucial element linking the core to the exterior and allowing them jointly to share and redistribute the loads and stresses between the two elements. Once you destroy them--the linkage between core and exterior--the buildings had to fail. But no way in 12-13 seconds, in an explosive collapse. That was pure theatre: "Shock and Awe," if you will. Check out the etymology of that phrase and it gives you some clue to the culprits, IMO.

ah i see your perspective is more from a demolition crew's point of view.

I could see planning a strategic approach that would initiate this domino-unzipping effect. Main advantage being to get more "bang (collapse) for your buck (investment-in-time & materials)"... while at the same time being in a position to direct blame to a pancake theory.

My angle on proposing a hunt for an Achilles Heel for all 3 buildings was to challenge the OS flock to reassess their blind faith. If the best explanation is fire, then this in itself is the Achilles Heel in the OS theory... as well as the weakest lamest argument among all prevailing theories on both sides of the fence.

When exhausted and under pressure people sitting-on-a-lie are most likely to slip up and blow their own cover-story. Word-substitution mistakes are more characteristic of problems in planning speech caused by a person rushing through word/phrase/descriptor preparation and/or omitting a sub-process in substituting fact with fiction:

Three significant slip ups that reconfirm what we have come to understand to be the reality:



1. Roemer slips that a missile...plane hit the pentagon

2. Bush slips that explosives were set off at the WTC towers

3. Rumsfeld slips that United 93 was shot down in Pennsylvania.

.......................

oops i meant to post this to Psychology101 to Psychology911

but i suppose it fits here as well... if you consider all of these slip ups come from "heels"

[edit on 7-5-2009 by The All Seeing I]