"As the joists on one or two of the most heavily burned floors gave way and the outer box columns began to bow outward, the floors above them also fell. The floor below (with its 1,300 t design capacity) could not support the roughly 45,000 t of ten floors (or more) above crashing down on these angle clips. This started the domino effect that caused the buildings to collapse within ten seconds, hitting bottom with an estimated speed of 200 km per hour. If it had been free fall, with no restraint, the collapse would have only taken eight seconds and would have impacted at 300 km/h.1 It has been suggested that it was fortunate that the WTC did not tip over onto other buildings surrounding the area. There are several points that should be made. First, the building is not solid; it is 95 percent air and, hence, can implode onto itself. Second, there is no lateral load, even the impact of a speeding aircraft, which is sufficient to move the center of gravity one hundred feet to the side such that it is not within the base footprint of the structure. Third, given the near free-fall collapse, there was insufficient time for portions to attain significant lateral velocity. To summarize all of these points, a 500,000 t structure has too much inertia to fall in any direction other than nearly straight down."

any comments?

Domino effect new catch phrase ah! it used to be pancake effect.

? :lol:

lol...yeah, what the hell does that mean?? 95% air?? im in a huge debate on an lsu website about 911...if anyone wants to help me out, the address is www.tigerdroppings.com....just register and go to the menu on the left of the homepage that says, "Political Talk" Come on guys, I need some help!! Ive only been researching 911 for like 3 months. I live in Baton Rouge, LA and almost 95% of the people on this board are BIG TIME bush supporters....will someone help me out?? If you do join me, let me know on here what your screen name will be on there:(

No mention of the steel grid that made up the core of the building. Hilarious.

It really bugs me how people appear to treat the floors above the impact and fire zones like they are nothing more than a huge box or bag of boulders waiting to dump their load downward once the bottom falls out beneath them.

As Roxdog alludes to, beneath the aluminum and concrete, we have a steel infrastructure all interlinked, rigid and incredibly strong, especially at the core.

The only thing 'loose' in the towers was office furniture. Somehow I don't think they had the crushing capacity to bring about those explosive collapses.

Even with failures of parts of the perimeter wall and inner core, it wouldn't cause a whole floor to make a 10 foot freefall drop backed by the mass of all the floors above.

Weak spots would groan and give and any floor collapsing would be irregular and at fairly slow speed. When you look at the heavy steel in the WTC 1 & 2 debris piles, do you see bent and deformed steel or do you see steel that looked like it 'snapped' or 'fractured' in a quick release?

You clearly see example of this with the South Tower (WTC2) when it's whole upper section leans in unison and appears about to completely topple off the solid base below it. This makes sense because of course it's essentially a giant steel framed box clad in aluminum, glass and concrete and has no damage above the fire and impact zones. It's strong, rigid and should remain relatively intact.


Strangely though, the rug gets pulled out from under it, counteracting the topple and both the top portion and below begin to disintegrate before our eyes.

Either that steel was really gypsum board, or someone triggered some massive core demolitions before the topple couldn't be stopped and the planned cover story for the collapse of WTC2 was lost. With two thirds of WTC2 still standing and the core lined with strategically located radio-controlled explosives, waiting to be discovered post 9/11, the mysterious 'they' had to blow the stuffing out of that building.

MM

He is saying that 5% of the volume of the building was made up of support structures, etc, and the other 95% by volume was air. I don't know whether that figure is accurate for the towers, but by volume, the towers were made up of mostly air. (open space)

is anyone going to help me on www.tigerdroppings.com?? PLEEEEAASSSEEEEEEEEEE!!!
i dont know all the answers, so i need help...please go register!!

I just checked out that site.

You only have 2 people showing any interest (if you want to call it that).

It's more of a name calling session that makes the average JREF thread look quite mature.

I advise you to abandon that forum and leave them to their primary interest..sports.

They have no real interest in 9/11.

MM

good idea...my blood pressure is rising!! thanks for checking it out

This description totally misrepresents what actually happened. The TV footage of the South Tower does not show intact floors dropping like dominoes onto the ones below them. Instead, it shows each floor being blown to smithereens, one after the other, starting from the top, with detonation squibs appearing many floors below the level of destruction too low down to be due to air being compressed by floors dropping on top of one another.

Adherents of the official account deny what their own eyes see because they know that gravity alone cannot explain what happened. According to their own scenario, even supposing the floors HAD dropped, their destruction started too high up for their acquired kinetic energy to pulverise to dust most of the concrete in the floors below them. All the bogus, convoluted arguments the 9/11 truth deniers use are being applied to an imaginary scenario in order to make it sound credible! Strictly speaking, neither tower 'collapsed', because this word implies most of the matter in each floor impacted onto the contents of lower floors and reached the ground, whereas in fact it was being turned to huge clouds of dust. This is why the tremors recorded when each tower was destroyed were less than that recorded for the Kingdome building, even though the latter was one-quarter the height of the the towers. A large proportion of their mass was being turned into dust and never hit the ground. It was also why the debris pile was only about 2% of the height of the towers - far too small for half a million tons of steel and concrete in a 1000ft building - and why the debris generally was so small in size - far too small to have resulted from the impact of falling material. No building can leave - simply by falling down - so little debris because it turned mostly to dust! WTC7 DID collapse in the conventional manner of a controlled demolition, and it left a considerable debris pile. WTC1 and WTC2, however, were NOT conventional controlled demolitions.

Also the accounts of the FDNY personnel

http://www.flcv.com/firemen.html

Insist on the fact that the the south tower (WTC2) did not collapse on itself. They say it exploded.

More to the point many of them identify a sound like some kind of high pitched engine noise like an incoming missile but much louder, as well as six to ten loud explosions, before each tower begins to disintegrate.

I am begginning to think that something far more interesting, than thermite could have been the cause. Possibly something a bit sinister, especially when you add the other anomolies of the 1400 cars with strange damage up to half a mile away.

And the fact that lots of the aluminium cladding can be found on the rooftops of the other nearby buildings but much less structural steel which it was attached to. How did so much aluminium survive. When so much steel did not?
The dismantled steel should have been a massive pile, tens of stories high.
If you watch the construction video Building the WTC There was so much steel required that they couldn't even store it near the site and had to have a very well organised deliver just in time system.

When they were constructing these towers huge trucks loaded with steel were turning up every day for several years. Where did it all go?

It would be interesting to know what the weight of scrap steel exported to China was compared with the estimates of the total weight of that used for construction.

so UK you're becoming a space-beam-er? A shame, you added much scientific insight to the towers discussions.

Thanks but I am not a scientist, I am an Electrical and Electronic Engineer.

No I'm not a space beamer.. :D

I just think that thermite/thermate is a red herring, and would require far too much preperation over much too long.
There has to be some kind of solution which fits all these anomolies. I don't believe that a so called beam from space so big could be generated because it would be impossible to have a source of many megawatts/gigawatts so far from earth that would be so powerful that it could disintegrate a building from such a distance.

There has to be some new weapon which causes steel to disintegrate, or bend like chocolate but doesn't kill people if they are not too close and doesn't leave a detectable nuclear fallout.

Don't forget the dissapearing massive press in the WTC basement, and the fact that many experts claim that the 9-11 dust was molecular. Also the fact that the towers vaporised from the top down, and lots of paper survived unburned.

Many bizzarely bent massive steel beams were found with unexplainable features. No one has even attempted to explain how that has happened other than to say it is not something ever seen due to gravity and the paint doesn't suggest heat

If you listen to this presentation Douglas Beason It is clear that direct energy weapons are now in use in the military as they have been declassified since 2001. Not only that but the crudest examples required a massive power supply and more up to date, will now fit in a Humvee ?

Why put all that in space when it could be located for instance in WTC7? With a good view of both towers, and a huge substation in the same building...
Come to think of it from the top full floor of WTC7 you would get a good view down into the amazing holes through the middles of WTC6 and WTC5 which were next to WTC7

Finally if one is looking for a single unifying conspiracy, for the WHOLE of the events at the WTC on 9-11, there has to be a good reason for WTC7 to be destroyed at the end of the day. It seems to me that the only reason that building needed to go was to destroy equipment or evidence. Demolishing that one was a great risk as it could have easily led to embarrasing questions if the media wanted to show it, due to the building not having been hit by a plane or having WTC1 collapsing on top of it.
Meanwhile it stood tall enough to have a good view of the top half of the towers where the pulverisation starts, and it is close enough to them so that if such a means was employed that less power would be lost by transmitting over a long distance. Also it demolished in a different way suggesting a different method of destruction.

I was reading that today, interesting though. But, that leaves me with who not to believe, NIST says this, MIT says that, PM says whatever....stories don't line up, and these are scienetists? Conflicting stories are altering the past.

i don't believe in thermite anymore either. the government agents all love talking up thermite aswell. i think they are leading a lot of people down a garden path. which when it is debunked will blow our only chance. i'm not in the exow camp either. i'm not sure yet but i think they may have got creative.

I disagree it isn't interesting, it is complete disinformation.

1 ) any failing support clips would require energy to force them to break. This would slow down the collapse of each floor not speed it up

2 ) watch any video clip of the collapsing towers, the floors are not crashing down onto floors below, they are exploding to dust. The concrete of the towers changes into fine dust. If pure gravity was used to collapse the towers you would see large lumps of concrete on the ground and the dust would have cleared in around a single day, and the debris pile would have been an estimated 8 to 10 storeys of solid material there was hardly anything there.

There are indeed people who mention that all mass indeed pancaked into the basement and that the peeling-out effect is only the perimeter columns wedged outwards or snapping and that the dust hides the view and only makes it look like everything is ejected horizontally.

But I've never seen a single picture of that rubble pile, it seems to be in a book called aftermath, could anyone provide scans of that? I think if it really was the case then it would be the first thing that debunkers would show, what do they have no, imo. only the small meteorite, but if those pictures exist I really would like to see them.

No, buildings don't collapse like that.

There are indeed,
but if so many thousands of tonnes of concrete and steel plunged to earth in just over ten seconds, how did they find some people alive in the rubble?
If either tower had come down complete the resulting pile would have been a huge filthy pyramid at least 10 storeys high and weighing one million tonnes.
The force of the collapse would have destroyed the bathtub, some say caused mahattan to flood, possibly causing an artificial earth tremor which would have caused adjacent structures to collapse.

But it didn't, the minor seismic events recorded during the collapse of the towers was so trivial it was compared to the kind of blasting in a nearby open cast mining operation. The energy should have been akin to a huge nuclear explosion of megaton proportions or an earthquake.

The only explanation is that most of the towers were pulverised and the dust was blown around Manhattan.

I estimate that if it hadn't, they would be carting the rubble and twisted steel off site for a much longer period of years.

It is interesting in the fact that the stories conflict, one place says this, another says that.

I agree that it would slow it down A LOT, not speed it up as well.

I think what alot of people go over is that core of the building. The whole core was definitely not "melted" and the force of outer floors falling wouldn't be enough to just take it out. The core was TOTALLY distroyed and again, PM, NIST, and MIT don't explain what happened to the core.

The reason that all the scientists have conflicting explanations in my view is because the method used is so new that it is not recognised as being common science that can easily be explained.
They all are very highly respected and learnéd people from different disciplines but they are all trying to explain different aspects of 9-11 while ignoring other parts.
They all have egos and favourite theories, but they should all practice what they preach and take a step back and find alternative theories which encompass all the anomolies at the WTC.
THERE HAS TO BE A SINGLE OVERARCHING THEORY WHICH MEETS THE FOLLOWING POINTS

What it CAN'T be ;
1 ) there can't be massively powerful weapons in space :rolleyes: because they would be too easy to detect by rogue states, the power required to destroy something as massive as this would require a significant space vehicle which would be massive in volume ( even if only a reflector ) , and be visible by a layman with binoculars on a clear night.
2 ) there can't have been a small nuclear device because the explosion and fall out would have been detected by other governments and widely reported. And the seizemic records would indicate such a device.
3 ) thermite is impractical due to the inaccesibility and size of the core columns and there would be so many manhours involved installing, it would be noticed, also it only accounts for cut columns, not concrete pulverised to dust and surviving steel girders which seem to have been cold bent like pieces of cheese without any stress.
4 ) aviation fuel, because it doesn't burn hot enough in open air to cause steel to loose it's structural strength, and besides most of the fuel load was spent as the planes crashed, and people were walking about close to the fires so they can't have been all that hot. And all steel was connected to massive beams which would draw the heat away cooling the hot area.
5 ) pancake collapse, the building explodes it doesn't collapse. The debris doesn't consist of layers of floorpans and concrete, and the 47 core columns were not left standing.

What it HAS to involve ;
1 ) steel and concrete turned to dust which blows away in the wind
2 ) some process which can make massive steel girders soft enough to bend without heating them enough to blister their paint
3 ) some process which causes a large press to dissapear in the basement levels, possibly this process might react with iron but not with aluminium.
4 ) some process which causes the unusual effects with cars within half a mile having melted engine blocks and missing door handles and axles while other parts of the same cars especially the fuel tanks! were untouched. ( could the cars with melted engines have heavy iron engine blocks? )
5 ) some process which could also cause explosions all over the buildings as witnessed by many members of the FDNY
6 ) some method of scooping out big holes right down to the ground floors in WTC5 and WTC6 leaving very little debris inside the holes.
7 ) some process which causes a building to collapse as if in free fall, without any resistance from the supporting structure.
8 ) some device which is highly accurate. Capable of being aimed at some structures but not at others. Only the WTC buildings were destroyed. All other tall buildings suffered mainly light damage.
9 ) detailed planning so that the bathtub survived the incident. The buildings were collapsed in a specific sequence to avoid too much collateral damage not the order in which the planes hit. Workmen even pulled down one of the remaining buildings with cables so it fell away from the bathtub walls. How is it that the skeleton of an 8 storey building demolished with controlled demolition could have damaged the retaining walls when 2 x 110 storey buildings destroyed on the same day in 2001 didn't?

Yeah, if they paly favorites, who can you trust and who is right?

Great post!

thanks man,
I kept away from all speculation on that post and just put facts. None of my own theories. Just the bare facts.. ;)
I want the science guys to stop going off on their own sometimes irrelevent tangents and deal with these important points all together.. If they worked as a team it could all be solved much easier. :angry:

There has to be one single process which is the answer to all these effects. Just one.

I have to disagree.

It is important to understand that the structure comprised four main elements which were designed to act as a whole; the outer envelope (half the dead load of the floor plus redistribution of wind loads), the inner core (half the dead load of the floor plus resistance to the overturning moment), the hat trusses (redistribution of loads betwixt core and envelope), and the floors (dead load plus bracing core and evelope).

Think of it as a huge girder, or space frame, where even the modest elements are necessary for the overall stability of the structure.

The core was never designed as a tall, free standing structure as this would involve all sort of laterall forces, torsion, and the like. We know that a certain amount could stand on its own, per construction photographs, but there was simply no way that we were going to see tens of floors standing after the main collapse.

Your model also assumes that the floor supports sheared neatly, with little or no damageto the core structure. This is simplistic; damage is almost certain. Likewise we would expect falling debris to impact and cause further damage, especially given that we can see from videos that the towers did not fall symmetrically.

Finally, small portions of the lower spires did survive as free standing structures over no more thana few floors, before we see columns peeling off and the entire section failing. This was as much as 20 seconds after the outer section fell.

A few floors? You better look again and retract that.

Voila




A fair height, to be sure, but proportionately quite modest.

Now, do you disagree with any of the other points made?

You said a few floors. That building to the left of it is over 40 stories tall and it's in the foreground. If it was not in the foreground it would look even smaller in comparison to that spire. That is NOT a few floors. You need to retract.

I think you're making it seem like the buildings were flimsier than they really were.

That really doesn't take us too far forward. Can you be more specific? Do you have aproblem with the much simplified girder analogy? Are you suggesting that the core was designed in such a way as to be self supporting over the full height of the building? Are you suggesting that the impact of the upper floors - whether by fire induced collapse of CD - would not have caused damage to the core? Do you think the floors would have sheared off without any significant damage?

You don't know how to admit when you're wrong. You need to retract.

Whatever works for you. Now, what was your answer to the above?

Retract first.

Photographic evidence suggests that part of the central core on one of the towers stood for between 15 and 25 seconds to a height somewhere around 50% of the total, the exact details being obscured by dust. There was nothing to suggest the degree to which this was intact or damaged, and it collapsed to one side very quickly.

Now, I await your answer to my query with interest.

I think you know it's closer to 50 percent, which is not a few floors. That's not a retraction. You're too proud to say you're wrong, but whatever.

No, but that's not what you said at first. This is what you said.

But we did see tens of floors standing after the collapse. It was swaying back and forth, but it was standing. Then all of a sudden it just dropped straight down.

I hope you don't act like those other jokers who were here a few days ago.

Inasmuch as I'd already corrected it prior to your post, I look forward to your retraction.

We appear to have a difference in terminology here. You are not, I assume, suggesting that the swaying structure was in any meaningful way stable and would agree, I am sure, that this was merely part of the collapse process?

Likewise you would agree that the "spire" of the other tower fell in a much shorter period of time?

Incidentally, could you clarify "straight down" please?

Should I take your word for it? You should never have said 30 percent in the first place.

If the swaying was part of the collapse process, then it should have toppled when it fell, which it didn't.

Hard to tell how fast the towers fell because of all that pulverized material in the way. How did most of the contents other than the steel get pulverized?

Straight down is straight down.

I'm sorry, but you're going to have to clarify what you mean by that.

Framed structures do not topple in the style of (say) a telegraph pole because the joints exceed design capacity very quickly, leading to break up. Thereafter gravity does all the work and it collapses downwards as a series of sections. I have a simplified digital sketch on my computer, but can't see a simple way download it.

The result is this:

YouTube

Now the point I'm making in my earlier post, which you've yet to give a detailed reply to, is that the core cannot stand as a stable freestanding structure because it was designed as part of a composite structure where each element relied on the others to provide overall stability. We also need to bear in mind the damage which would clearly have occurred to it during the principal colapse sequence.

Are there any aspects of that which you would disagree with?

OMG! Please don't embarrass yourself by downloading it.

My, what a helpful response.

Now, are you going to respond to the substantive points put to you in the post or not?

Naw, that's ok. I'm bored with this. Just let me know when you get that sketch downloaded.

How disappointing. I had assumed that you were interested in and able to comment on the issues at hand. Do let me know when you change your mind.

I did comment. You are the one who ducks out of answering questions. Where is your sketch?