Why did building 7 fall?

Could someone please qualify what is actually meant by the obscure words "....not like the others"? What the expert could have meant was it was not set to pull like the others, or look exactly the same as 1 and 2 when dropping. That stands to reason.

Every building has to be judged as to shape and materials used. WTC 7 was a much different shape than WTC 1 and 2. WTC 7 definitely was pulled, and it is obvious if people look at the roof line, as it is the first to start to begin to collapse in the center and swiftly pulls the balance of the building in on itself on all 4 sides.

WTC 1 and 2 were square and much taller. WTC 7 was highly elongated, not as wide, and much shorter. WTC 7 had to have charges set differently to pull in on itself in order to to land in its footprint, than 1 or 2, both of which dropped straight down into their own footprints due to being square, not highly elongated, and so tall.

WTC 7 dropped first in the center and then pulled the 4 walls inward due to normal demolition vacuum effect, while using weight, mass, and gravity to rapidly build velocity momentum, with least resistance from strategic supporting columns primarily in the center of the building and secondarily in the rest of the building. It was a different look when it dropped. WTC 1 and 2 did not look to drop exactly the same way, because they did not have the rectangular elongation to do that. They looked somewhat different while they were dropping. However, what is not different and indicative of controlled demolition implosion, is they all 3 very obviously imploded into themselves, in less than 10 seconds, into their own footprints. That is because implosions are designed to act as a vacuum for the buildings to pull in rather than topple or explode outward, and allow nature and physical structure to do the lion's share of energy expending.

The link is videos of controlled demolition implosions gone drastically wrong charging only at the base. The videos confirm what I explained a day or so ago, to someone asking why the WTC buildings were not blown from the bottom. I explained there would either be a shorter building or toppling from what was not blown. I just located these visual aids last night:

www.youtube.com...

The link below are progressive photos of a controlled demolition implosion done correctly. Please note the building was stripped before implosion leaving much, much less clean up to do, and more debris in the footprint where it belonged. Please also note where the majority of the debris lands as happened with WTC 1, 2 and 7. Contrary to what people may believe, there was far more debris in the footprints of those buildings than elsewhere:

www.controlled-demolition.com...

Originally posted by Aim64C
It's an interesting design. It allows for a lot of damage to be sustained before a collapse can occur, but it ensures that, once a collapse begins, it is global.

Jeez this again. There is NO proof that the towers global collapse was inevitable. That's just another silly baseless myth. You talk like you know it as fact, hilarious! There is NO proof the inner core sustained ANY damage. Unless the central core was completely compromised, no collapse. You could take away the outer mesh and still no global collapse. If you don't believe me you need to research more, and I don't mean looking at 911myths or anywhere similar.

It was a unique design for a building, but it doesn't mean the design was that new. The design was based on well known principles. The mesh design can sustain damage and not collapse, if you knew anything about engineering you would know this. To say it's collapse was inevitable is absurd.

Originally posted by OrionStars

WTC 7 definitely was pulled, and it is obvious if people look at the roof line, as it is the first to start to begin to collapse in the center and swiftly pulls the balance of the building in on itself on all 4 sides.

I strongly disagree.

As a non-expert, I see nothing in the collapse of WTC 7 that tells me if it was a controlled demolition or not. Correct me if I am wrong, but I see nothing that tells me you are any more qualified then I am.

I have many reasons, however, to doubt that it could have been intentionally destroyed by explosives. In fact, I think it's rather implausible.

Cheers.

Originally posted by deltaboy

Originally posted by ZeuZZ


How anyone can look at WT7 fall down that quickly and not suspect it was controlled demolition is beyond me.

How fast do tall buildings usually naturally falls?

Depending on the size of the building (weight, mass, and design) - minutes not seconds, due to very heavy resistance from primary load bearing beams and everything else in the way like floors, internal walls, bathroom fixtures, office fixtures, forming debris, air etc. They will topple and/or start breaking apart, not rapidly drop straight down into their own footprints from the least resistance.

WTC buildings were not pancake effect by any stretch of imagination. Which is one of the reasons Thomas Eagar besmirched his integrity and professional standing, by saying it was. He, above any layperson, should have known better than to say what he knew was untrue.

Originally posted by ANOK

Jeez this again. There is NO proof that the towers global collapse was inevitable. That's just another silly baseless myth.

How so? Lots of structural engineers and scientists have shown that it was inevitable. Many hundreds of thousands of others do not disagree.

Why should we accept your assertion, ANOK? Do you possess the necessary expertise to demonstrate your claim to us all here?

Cheers.

Originally posted by jthomas

I strongly disagree.

You are entitled to do so.

This link is to a video that shows the center roofline sagging first and the two ends pulling in as I described. One has to scroll down to get to the video of WTC 7:

911research.wtc7.net...

Originally posted by OrionStars

Depending on the size of the building (weight, mass, and design) - minutes not seconds, due to very heavy resistance from primary load bearing beams and everything else in the way like floors, internal walls, bathroom fixtures, office fixtures, forming debris, air etc.

Minutes?

DO share your sources and calculations to back up your claim, will you?

Cheers.

Originally posted by OrionStars

Originally posted by jthomas

I strongly disagree.

You are entitled to do so.

So, please support your claim.

P.S. How's the video coming on WTC 2 showing its top leaning 23 degrees for 15 minutes?

reply to post by deltaboy

Originally posted by deltaboy

Soooooooo... which means we can't compare to any pass events of another naturally falling tall building because it has never been done before so we just considered it a demolition instead eh?

Of course, we can compare past events of collapsing structures under various circumstancs of cause to effect, naturally and unnaturally. Comparisons and a great deal of them should be done. Since you brought it up, why don't you find some visual aids of buildings having collapsed naturally, present them to the forum, and we can more aptly compare the results of natural collapsing?

Some of us have already presented visual aids, of different structures, collapsing unnaturally. Since you brought it up, that now leaves it up to you to present substantiation for your points of argument for comparisons to naturally collapsed buildings.

Originally posted by jthomas

I strongly disagree.

You are entitled to do so.

So, please support your claim.



Claim of what? That you are entitled to your opinion? Don't you want to be entitled to your opinion or what? If not, I will stop making that claim to you. All you have to do is say you do not want that claim directed at you any longer, and I will certainly be more elated to comply.

Originally posted by jthomas

Minutes?

DO share your sources and calculations to back up your claim, will you?

Cheers.

I do not have to. Anyone who knows the very basic laws of physics knows I am correct. Resistance always hinders velocity and momentum regardless of weight, mass, or amount of gravity. That's a given.

Originally posted by Aim64C

They used very mesh-like construction mechanics to allow for more complete distribution of the force in the event of a few columns being damaged.

Why do people continue to make such weak arguments by choosing words which give distorted connotations? Meshlike strongly implies something easily destroyed. The WTC buildings were never designed to be easily destroyed under some extremely high stressful conditions, i.e. fire, earthquake and even Boeing aircraft impacts. They were designed to specifically withstand those conditions to high stress levels.

You are getting all your information from disinformation presentations. I know this because you parrot the same I have seen at least 500 times before in over 6 years time.

You clearly do not indicate you remotely understand the construction of the WTC buildings. You clearly do not indicate you understand the basic laws of physics. You clearly do not indicate you have done research to compare natural and unnatural disaster collapses, to those having been pulled by controlled demolition implosions.

You are strongly implying your intent in discussion is to tangent people away from topic. You engage people for the sake of arguing to argue, and never validly attempt to prove yourself correct and your opponent in error. That is not debate. That is deliberate detraction.

*sigh* Okay, I will get out my pen and paper and draw some pretty, colorful picture to prove my point. I might even make it animated and make some cool flashing lights and sounds.

Perhaps that will effectively convey the message.

However, let me point out through words, first, that a mesh framework is incredibly strong for its weight, and usually far more durable than a more solid construction.

However, as I said, because each and every part of the building is connected to the rest of the building - if one part is capable of collapsing, it means that there is a total structural failure. It is not like a normal column-and-platter construction that allows few sections to collapse, while the rest of the building remains - because most buildings, even some steel framed ones, do not have this meshed architecture.

For a single section (we'll say a single floor, with a floor space of ten-by-ten feet) to collapse, you would have to sever nearly every vertical column that intercept the horizontal mesh, AND sever the horizontal mesh at the extremities of the dimensions of the floorspace.

The advantage of this is that a single support column can be damaged or completely removed, and it barely effect the entire structure. This is because the load is shifted to the next available support - in a very diverse support environment with many different load 'paths'. So, multiple support columns can be removed, damaged, etc, and the structure still remain standing.

However, there is a catch 22. Due to the mesh support - if any one segment is capable of collapsing, it means that the load bearing capability of the next-available support(s) has been exceeded. That support will fail - and all of the load then transfered to the next-available support. Since the last support segment failed (this is additive of the mass that the failed segment was supporting) - it is very likely that this segment will also fail - and the load transfered.

It should be noted that this is a horizontal shifting of loads - not vertical. What we see happen is a sequential failing of each individual support segment (at a very rapid rate - so fast it is nearly instantaneous). This is because, unlike concrete, steel does not crumble so well under torsion (twisting/bending). This ensures that all of the mass of the collapsing structure is transfered to the next support segment, instead of 'breaking off' - like in your column-and-platter constructions.

It is both a strong and vulnerable structure design. It can endure a lot... but once it is done, it throws in the towel in a big way. It is an acceptable trade-off because this building is not designed to be a bomb shelter or anything that is supposed to take damage.

It is designed as a place of business that will have people moving through it and conducting their business. It can easily withstand many forces of nature, because of the way its support system works.

The people who designed the building designed it to withstand some damage from natural disasters, accidents involving an aircraft lost in the fog (not intentionally trying to hit it - and much smaller craft that do not have more strict flight plans), and the occasional fire. An airliner-turned-cruise-missile was not exactly on their drawing boards - nor is something like that even economical to engineer into your buildings.

"Hey guys, let's increase the amount of material we have to use by 30% and decrease the maximum height of this structure by 10% in order to secure it against an airliner 40% larger than the ones that exist to day slamming into the side of it at 300+ knots! Then try and pass the budget by the owners!"

In the business world... it ain't gonna happen, since the likelihood of such an event occurring is incredibly small. It is like putting a cup holder on the side of a TV.... all it does is increase the cost to produce the TV and make customers go "why would I need that?" "Because you might be sitting a foot from your 40-inch television and need to put your soda in the cup holder!" "... Why would I be sitting that close to my TV? To count the number of pixels it takes to render Bart Simpson's Head in episode 32 at 2:51?"

You clearly do not indicate you remotely understand the construction of the WTC buildings. You clearly do not indicate you understand the basic laws of physics. You clearly do not indicate you have done research to compare natural and unnatural disaster collapses, to those having been pulled by controlled demolition implosions.

*eyebrow perks* ... I wouldn't be lecturing on "research" or "understanding" when arguing that the external mesh of the WTC had concrete in it.... considering that completely goes against the principle of the external mesh being able to flex and absorb shock (in the sense of earthquakes)....

To the contrary, I am an engineering major, studying for aerospace engineering. This would include such simple things as structural analysis and design concepts. I assure you, I don't just understand the laws of physics, I can emulate stress analysis (static and dynamic) as well as fluid dynamics (aerodynamics) in my mind. I can't necessarily punch out numbers for you - but I can tell you what is going to happen simply by looking at your experimental setup.

I am also employed in the United States Navy as an Aviation Electronics Technician. So I am no stranger to the engineering field - as I hang out with the guys who perform maintenance on structures that undergo some of the most extreme sets of conditions in the world.

But all that is just here-say. I am not completely willing to send you evidence of that, as it involves personally identifiable information - which is not a good idea in today's world - so you'll just have to take my word. If you do, fine. If not - then I'll do my best to continue explaining concepts to you.

Originally posted by Aim64C
However, as I said, because each and every part of the building is connected to the rest of the building - if one part is capable of collapsing, it means that there is a total structural failure. It is not like a normal column-and-platter construction that allows few sections to collapse, while the rest of the building remains - because most buildings, even some steel framed ones, do not have this meshed architecture.

That is not correct but the following is:

www.journalof911studies.com...

"Why Indeed Did the WTC Buildings CompletelyCollapse?
By Dr. Steven E. Jones Physicist and Archaeometrist
The views in this paper are the sole responsibility of the author

11. Steel Column Temperatures of 800°C Needed: A Problem in the Argument of Bazant and Zhou

A Mechanical Engineering professor suggested that I review a paper by Zedenek P.Bazant and Yong Zhou, which I did.

Quoting:The 110-story towers of the World Trade Center were designed to withstand as awhole the forces caused by a horizontal impact of a large commercial aircraft. Sowhy did a total collapse occur? (Bazant and Zhou, 2002, p. 2.)

Correct – the WTC Towers were designed to withstand forces caused by large commercialaircraft – we can agree on that. MIT’s Thomas Eagar also concurs “because the number ofcolumns lost on the initial impact was not large and the loads were shifted to remaining columnsin this highly redundant structure” (Eagar and Musso, 2001)."

[edit on 18-12-2007 by OrionStars]

reply to post by Aim64C


I fail to see a substantial connection between aviation and building industry structural engineering. But then I also fail to see any substantial connection between electrical engineering and the other two fields of engineering as well.

When you state what do, regarding the WTC buildings, you display a distorted understanding of design and construction of the WTC. That is basically what I stated in a prior post.

Granted, a little flex play is necessary, and the WTC was designed to do just that. But when the 100 mph winds the WTC buildings experienced from time over the years, too much flex is not a good thing at all.




[edit on 18-12-2007 by OrionStars]

havnt finished the whole thread yet but i had to address this one:

Originally posted by adjay
and your statement that someone using a cell phone could have triggered the charges is an outright falsehood.

actually, its an outright fact. step one for any responder who suspects a bomb is to cut off all radio coms in the area depending on the strength of the local transmitters. ask anyone with ANY experience using explosives.

Please prove this "fact".

FM 5-34 Engineer Field Data Ch. 6 Demolitions Page 1 Table 6-2 Premature Detonations by induced currents.

theres a nifty little chart there for minimum safe distances to transmitters of various sizes.

i wont go find a copy online as id hate anyone to accuse me of linking to a fabricated source so i leave it to you to find it on your own so you can trust the validity of the information.

any radio transmitter CAN set off an electronic blasting cap. so unless your demo guys on 911 were using time fuse to a none-electric cap to detonate detcord....but that doesnt matter. the FACT is that defcon was 100% right when he said that a cell phone CAN set off the charges (depending on the manner in which they were primed of course)

Originally posted by adjay
Blasting site safety signs are no proof that using a mobile phone can set off a charge.

well, you think they put them there just to inconveinience people who happen to use cell phones in the area? hmm...

Radio frequencies used by mobile phones are very high, between 380 and 1990 MHz.

the frequence has nothing to do with it, its about the wattage.

I believe the minimum safe distance for a ~1W mobile phone and blasting circuitry is ~3M,

30m actually. its in the chart i mentioned in my last post.

There are also many different ways this could be avoided altogether, RF jamming being one of them.

oh theres a great idea. we dont want the radio signals to detonate our charges so we'll pump MORE RF energy into the air around our blast site.

im at a loss........

OK for the record and in the spirit of fair discussion i do have to agree with BSB to a point.

YES its possible to shield the primary detonator from RF interference in the sense that many things are possible.

we all know i dont think there were any HE devices involved..

BUT IF (and this is a huge friggin if) it was a CD the MOST LIKELY scenario is that the individual charges were linked by detcord and the detcord was set off by a blasting cap somewhere else and that cap was set off by either hardwire, timer or remote. set up a reciever and put everything but its antanea in a farady cage type shield.

individual recievers on each charge is unlikely becuase each one is just one more possibility of failure which means things dont go as planned and leave behind evidence that someone who's "not in on it" could find.

set yer charges up, link them with detcord ring mains, prime those in a central area to be set off on command and the detcord will set them off with much more surity than an individual reciever.

i still dont think thats what happened but in the spirit of fair discussion i have to back BSB on this one. it IS possible, i just find it unlikely based on all the other evidence.

Quoting:The 110-story towers of the World Trade Center were designed to withstand as awhole the forces caused by a horizontal impact of a large commercial aircraft. Sowhy did a total collapse occur? (Bazant and Zhou, 2002, p. 2.)

This is rather misleading. Yes, the towers were designed to withstand an impact from the largest jet liner at the time, with a low airspeed (below 300 knots), and without the intent to hit the structure (an aircraft that had experienced some form of instrument failure and was lost in the fog).

However, the Iowa class battleships were also designed to withstand a torpedo hitting below the armored belt. It turned out there was a flaw in the design theory that caused the angled armored belt to buckle near the bottom and cause some serious problems. While the idea wasn't completely fool proof - other elements of design turned out to make the total implementation of the theory/concept a 'failed' design.

So, we often find that the drawing board and real life are two completely different things.

Correct – the WTC Towers were designed to withstand forces caused by large commercialaircraft – we can agree on that. MIT’s Thomas Eagar also concurs “because the number ofcolumns lost on the initial impact was not large and the loads were shifted to remaining columnsin this highly redundant structure” (Eagar and Musso, 2001)."

Also somewhat misleading. Elements of the core were damaged, as well as damage caused by heat to the rest of the un-compromised structure. Since the load is distributed most greatly to the next-available column, it is not too great of a stretch to say that an already partially damaged column that was then subjected to heat, could fail. This increases the load on the next column, and greatly reduces the amount of heat required to cause any one of its elements to fail.

See how there are so many factors to consider? It's not as simple as calculating the point where steel loses 30, 60, or 80% of its integrity due to thermal effects - there are so many things to consider and so many events that you cannot begin talking specifics of "It only reached 239.5 degrees... It needed to be 242!"

I fail to see a substantial connection between aviation and building industry structural engineering. But then I also fail to see any substantial connection between electrical engineering and the other two fields of engineering as well.

It's not always about direct field association. I bump shoulders with a bunch of guys who not only have an education in the engineering world, but also experience.

Have you ever looked at an airframe and wondered what kinds of forces it takes on in a day to day basis? Especially fighters - which can pull five or more Gs simply because the pilot thought about committing to a maneuver?

Plus, I study a lot of subjects in the general field of engineering - why - because I have this unquenchable appetite for knowledge.

When you state what do, regarding the WTC buildings, you display a distorted understanding of design and construction of the WTC. That is basically what I stated in a prior post.

Granted, a little flex play is necessary, and the WTC was designed to do just that. But when the 100 mph winds the WTC buildings experienced from time over the years, too much flex is not a good thing at all.

And where do you get this from? The only time flexing is a bad thing is when you want what you are building to maintain some sort of regular shape. Please, prove me wrong. And I mean prove me wrong.

Prove to me that I'm wrong about the structural characteristics of a mesh structure. Show me some data or some fancy animation. I'm working on my own sequence of pictures (and maybe an animation, since I am learning how to do that, anyway) to help demonstrate my point. I don't want an opinion of some 'expert', I don't want you telling me "your view is twisted and distorted" - the MINIMUM I want is an explanation from you. Explain the dynamics behind it - put it into words the best you can.

I'm not saying I will agree with it - but it will help me understand where it is you are coming from, and start getting rid of the visions of the Starship Enterprise sending photon torpedoes in to destroy the Twin Towers when I try and figure out what you're saying.

Which will be better for both of us, and probably everyone else on this forum.

reply to post by Damocles


Read my posts again, specifically the paper, the minimum safe distance for a 1W cell phone is 3 metres (10 foot). Read it in black and white, don't take my word for it.

oh theres a great idea. we dont want the radio signals to detonate our charges so we'll pump MORE RF energy into the air around our blast site.

im at a loss........

"Why not keep the suspect from detonating an explosive remotely..."

Better tell those bomb squad guys it's a bad idea before one gets hurt!

10/10 for foot-in-mouth.


EDIT: You're missing the point by a long shot. He said "no CD cos a cell would set it off", this is false because nobody knows how it was demolished, if it was indeed a CD. Those of you who can read, have no excuse!

[edit on 18-12-2007 by adjay]