Top-Down Demolition

Some people like to claim that demolitions must start from the base of the building.

For anyone not familiar with electronics, here's a video showing that a top-down demolition is possible:




Really, charges can be set off in whatever order desired. There's nothing physically limiting anyone from setting of detonator caps in any sequence they want, if they have the software for it.

It comes down at a rate comparable to free fall, and you hear "boom, boom, boom".

[edit on 25-9-2007 by bsbray11]

nice find Bsbray! I have been looking for top down demolition examples for a while and this has to be the best. I am guessing this video has just hit the net? Recent demolition was this? It is very reminicent of the twins coming down on small scale, particularly like how the top falls down into itself and the rolling clouds spinning backwards, the top looks almost like its falling with little to no resistance - freefall. I also notice how there is a slight vaccum drawing the smoke back in and down and the top falls into itself, very much like the twins also. Thanks for posting.

So the question is, did they plant explosives on every (or many) floors and reconfigure the order of detonation once the aircraft hit? Or did the aircraft have to hit exactly the right floor in the first place so as to allow the detonation sequence to work (and to ensure no accidental denotation before everyone was ready)?

Actually, that last point might be worth discussing? If there were explosives planted in the towers, and assuming that were on at least some of the upper floors, how did they ensure that the aircraft impacts didn't set the explosives off early?

[edit on 25-9-2007 by Essan]

well, as you see, this building is more like a bare structure of a building not solid.is not compareable with a full solid, massive heavyweight like the WTC towers, pulling-down-wise..

[edit on 25-9-2007 by anti72]

Originally posted by Essan
Or did the aircraft have to hit exactly the right floor in the first place so as to allow the detonation sequence to work

The floors that "collapsed" first weren't necessarily the floors with either the most fire or most impact damage. So getting "the right floor" wasn't as exact of a science as it seems like it would have been. It just has to be hit somewhere, apparently.

how did they ensure that the aircraft impacts didn't set the explosives off early?

How do you know they didn't, at least where they actually impacted? It's not like that part of the structure wouldn't be destroyed either way at that point.

Originally posted by anti72
well, as you see, this building is more like a bare structure of a building not solid.

How do you quantify "more like a bare structure" and "not solid" in terms of physics and engineering? Because the building was obviously solid, and the "bare structure" is all that EVER holds up ANY building anyway!

The explosives, by themselves, do not bring the building down. The building to be demolished has some controlled vandalism done to it. This vandalism weakens the stucture. Or would, if steps were not taken to counter the weakening. At demolition time, the steps to counter the vandalism are overcome, by explosives. Then, the building comes down.

Picture an I beam standing by itself. Call it 10" wide across the flanges, and 1/4" thick. Procure 2 plates of steel, 10" X 12" X 1/4, and 4 plates of steel 10" X 3" X 1/4"

Weld the little plates to the ends of the big plates, so you get a plate 10" X 12" X 1/4 in the middle and 10" X 12" X 1/2 at the ends. Weld that to your I beam.

You now have the architectural equivalent of an arterial bypass. You can cut out the I beam between the steel plates you added to the sides of the I beam. Leaving a 6" gap in the I beam.

That's where you put the demolition charges.

To bring these structures down under control "they" would have to do this patch and vandalize routine to structural members of the buildings in hundreds of places, maybe thousands, per building. You would think someone would have noticed so much work going on for so long.

Explosives are the star of the show in a controlled demolition, but not the primary cause of the collapse. If you want to claim these were controlled demolitions, you have to demonstrate that the 99% dull boring time consuming stuff was done, not pretend that the 1% "whooo-doggy did you see that" did it all.

Originally posted by bsbray11
It just has to be hit somewhere, apparently.

I feel that "somewhere" was the top-most mechanical floors. It would make sense to have, say, thermate in the cores to split the core there (silently) and then when the building starts to fail, set off the explosives (whatever they were) down the structure. It's the only explanation of the south tower tilt IMO. Since the plane hit the south tower near the mechanical floors, a pivot point (when the core was severed) developed. That's why it had to go first.

Because the building was obviously solid, and the "bare structure" is all that EVER holds up ANY building anyway!

Oh no, the building's not "solid".





BTW, BsBray, nice find.

Originally posted by Researcher
To bring these structures down under control "they" would have to do this patch and vandalize routine to structural members of the buildings in hundreds of places, maybe thousands, per building.

This is assuming that conventional methods were used, and conventional high explosive charges like RDX were used. Just like if you hired a company to do it publicly. What if thermobarics were used? What if a specialized form of thermite was used to pre-cut columns before they were cut? What if thermobarics had been laid into the floors between the concrete and floor trays around all four sides of the major box columns, every 3 floors in staggered intervals? And btw, there weren't many I-beam columns. The columns were mostly box columns ~2-3 inches thick all the way around.

good find but for the record even I have been willing to admit that a top down is possible. the floors above the impact zone could have added the extra weight to make it go smoother.

i just still dont think it was a cd but thats just me, everyone knows WHY i dont think so so i wont even go there. but to say a top down is IMPOSSIBLE is just ignorant.

also, just for clarification, make sure what you are calling a thermobaric is what the rest of the world thinks is a thermobaric...cuz what youre describing for a hypothetical device doesnt sound like a thermobaric to me. but i may not have read it close enough either i guess.

good find overall

but in the spirit of open discussions ill just say to researcher...while a building tagged for CD is usually prepped the way you describe, it CAN be done without the prep work or any prep at all, just requires more explosives. they usually prep a building so that they can use less explosive which is cheaper (though the man hours probably eat that up quick) and so that the overpressure poses less danger to surrounding buildings. if youre not worried about the overpressure, load it up with HE and have a heyday.

[edit on 26-9-2007 by Damocles]

isaw a video where a worker in the WTC said tht in the weeks leading up to 9/11 there was lots of construction work going on all over the WTc's and people where being moved about from floor to floor because of it could this of been "them" planting the explosives? and aslo could the attack in the basment before 9/11 been a ruse so they could plant yet more explosive under the pretense of rebuilding the carparks?

but this dude was adament about the building works why would he lie what whould he gain form it?

and in tht video it looks just like the WTC fell the way the top seems to float down still intact



[edit on 26-9-2007 by N.B.A.Y.S.O.H]

Originally posted by Essan
So the question is, did they plant explosives on every (or many) floors and reconfigure the order of detonation once the aircraft hit? Or did the aircraft have to hit exactly the right floor in the first place so as to allow the detonation sequence to work (and to ensure no accidental denotation before everyone was ready)?

They would have to logically. In the event of catastrophic failure a controlled demolition would be a lot safer than a uncontrolled collapse. Imagine the carnage if the thing went over on it's side.

Originally posted by Damocles
also, just for clarification, make sure what you are calling a thermobaric is what the rest of the world thinks is a thermobaric...

Well, what I really had in mind was anything that detonates with slower overpressures but that last a few times as long as they do in HEs. I was under the impression that that was what made the SMAW-NE more effective at knocking things out. Just an example of somewhere else to look instead of constantly at conventional cutter charges, even if the stereotypical example would need heavy modifying. And I wouldn't know whether it was actually used or not.

And I know you never personally claimed that top-downs were impossible, but a lot of people have been parroting it since some guy that works for PROTEC wrote an article saying demolitions aren't done that way. The point I wanted to make is that this guy was talking out of his ass, and there's nothing physically stopping anyone from rigging charges to go off in whatever order they damned well feel like, regardless of what's "usually" done (each and every demolition is a special case, anyway, especially for high-rises). A lot of people won't hear of it unless you're (a) judged by them to be an "expert", and (b) agree with what they already believe (and it seems condition "a" is dependent upon this ). But there it is, the first post of this thread proves the obvious, that people can do whatever they want with technology, regardless of what debunkers insist from their computer chairs.

[edit on 26-9-2007 by bsbray11]

And btw, there weren't many I-beam columns. The columns were mostly box columns ~2-3 inches thick all the way around.

Irrelevant. The point of my post was to describe the method in generic terms, not specific terms.

So the question is, did they plant explosives on every (or many) floors and reconfigure the order of detonation once the aircraft hit?

Two major kinds of detonators: Electronic and compressed air. Everybody going to compressed air because it can't be set off by static.

Order and times of detonation determined by configuration of hoses in a compressed air system. Fixed timing unless physically reconfigured.

Electronic detonators could conceivably be reprogrammed. If you anticipated the possibility and had everything tied to a network and could reprogram during a crisis and knew the network would survive and if...

Yeah.

ok, yer def on teh right track for thermobarics, i just wanted to make sure you hadnt fallen into the trap some others have of reading the "thermo" part and going with thermite/mate (cuz its hot).

problem with it being a thermobaric is that for it to be able to overpressureize a full acre of area (sq not ^3) is that it would have to be a BIG thermobaric and then we wouldnt be having this discussion cuz we'd have noticed live and in color (it would have had to make the fuel explosion from the impact look like a firework display)

and as to the rest of the post about "experts" i agree 100%. (now u really understand what ive been dealing with in any of these discussions lol) but i think when the PROTEC guy was saying "well thats how its done" was more in the spirit of tradition. normally you blast from the bottom so as to let the weight of the building do the work for you and you get to use less ordinance to do it.

but that doesnt change the fact youre right about being able to do it however you want...its just a matter of work and ordinance. to do it top down takes more of both...if you have unlimited resources, doesnt matter.

reply to post by Researcher



wanna post some info on compressed air detonators? the military doesnt use them so ive not worked with them and im always interested in learning something new.

cuz asking anyone with military demo about major types of detonators they'll say electric and non electric and the non electric are preferred as being safer and more reliable.

so id love to learn new things

"wanna post some info on compressed air detonators? the military doesnt use them so ive not worked with them and im always interested in learning something new."

Would if I could but I can't. Saw them on a TV show about demolition. Asked our ordnance guys what the heck was that, looked like air hoses going to the charges. Yup, that's what they are.

We need tighter control of the timing. Thank you for not asking why.