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9/11 documentary
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jonnyboiFull MemberPosted 6 years ago
According to a new report by Middle East Eye, Prince Bandar bin Sultan – Saudi Arabia’s most famous arms dealer, longtime former ambassador to the US, and recent head of Saudi intelligence – was among those detained as part of Crown Prince Mohammed bin Salman’s (MBS) so-called “corruption purge” that started with the initial arrests of up to a dozen princes and other top officials last weekend.
If confirmed, the arrest and detention of Bandar would constitute the most significant and high profile figure caught up in the purge – even above that of high profile billionaire investor Prince Alwaleed Bin Talal – given Bandar’s closeness to multiple US administrations and involvement in events ranging from Reagan’s Nicaraguan Contra program (including direct involvement in the Iran-Contra scandal), to making the case for the Iraq War as a trusted friend of Bush and Cheney, to directing US-Saudi covert operations overseeing the arming of jihadists in Syria.
So you now agree that the twin towers collapsed due to aircraft impact and subsequent uncontrolled fire and you wish to talk about the people involved in that? or are you going to disprove science with politics?
CharlieMungusFree MemberPosted 6 years agoThere were huge lateral forces when the plane hit the building; shook the whole tower. Took the resultant fire to take it down though.
yes, i meant in the collapse
amediasFree MemberPosted 6 years agoso the towers in fact collapsed in quite an unpredictable way?
No, but see below
So… it was predictable?
Yes, but see below
One would expect that given all possible collapse scenarios, the one that occurred was quite likely?
It couldn’t really have collapsed any other way, that does NOT mean that the collapse was predictable or likely. Just the manner of collapse.
You seem to be mixing up probability of collapse Vs probability of a different manner of collapse. (or maybe I’m mixing up what you’re getting at?)
I doubt anyone would have predicted it would collapse. But if you’d told people to predict the manner of collapse if subjected to excessive structural damage of the type that we now know occurred then “down, roughly into it’s own footprint” is the answer you’d likely have got.
jonnyboiFull MemberPosted 6 years agoThe issue is that there appeared to be minimal lateral forces.
should there have been, why?
amediasFree MemberPosted 6 years agoyes, i meant in the collapse
as above then, are you aware of some significant lateral force that we’ve all missed?
jonnyboiFull MemberPosted 6 years agoCharlieMungus – Member
yes, i meant in the collapse
referenced above, but copied again
Nearly every large building has a redundant design that allows for loss of one primary structural member, such as a column. However, when multiple members fail, the shifting loads eventually overstress the adjacent members and the collapse occurs like a row of dominoes falling down.
The perimeter tube design of the WTC was highly redundant. It survived the loss of several exterior columns due to aircraft impact, but the ensuing fire led to other steel failures. Many structural engineers believe that the weak points—the limiting factors on design allowables—were the angle clips that held the floor joists between the columns on the perimeter wall and the core structure (see Figure 5). With a 700 Pa floor design allowable, each floor should have been able to support approximately 1,300 t beyond its own weight. The total weight of each tower was about 500,000 t.
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.
aracerFree MemberPosted 6 years agoStill not huge enough to shift the CoG outside the footprint. In fact I suspect even if you had a succession of airliners crashing into the tower during the 10s it took to collapse that still wouldn’t have been enough to prevent it collapsing straight down.
Before anybody asks, no I haven’t done the maths and I CBA.
CharlieMungusFree MemberPosted 6 years agoIt couldn’t really have collapsed any other way, that does NOT mean that the collapse was predictable or likely. Just the manner of collapse.
Yes, i did mean the manner of collapse. That if someone said a plane would explode in there and the subsequent fire would cause a collapse, you would reasonably say, Yeah, it will pretty much fall on itself
Unless you’re aware of some significant lateraa force that we’ve all missed?
Only ones i can imagine would be the unpredictable nature of one thing falling on another. tends not to be just vertical forces at play
amediasFree MemberPosted 6 years agoOnly ones i can imagine would be the unpredictable nature of one thing falling on another. tends not to be just vertical forces at play
No, it really is just the vertical bit you need to worry about in this situation.
The force is gravity, and the mass is mahooosive, any lateral reaction forces from bumping into stuff on the way down are many orders of magnitude smaller, consequently you cna pretty much disregard them, hence…
“Yeah, it will pretty much fall on itself”
5plusn8Free MemberPosted 6 years agoOnly ones i can imagine would be the unpredictable nature of one thing falling on another. tends not to be just vertical forces at play
Yeah but the mass under the influence of gravity swept everything in one direction, there was considerable deflection mass – lots of stuff being ejected in the videos, but the general trend is going to be in the direction of the insanely dominant accelerating force of gravity.
Stevet1Free MemberPosted 6 years agojivehoneyjive – at times with your various forum posts very occasionally you touch on some almost credible (albeit tenuous) points. But with all the nonsense spouted on topics like this you’re discrediting anything you say I’m afraid. I wish you well, the world needs cynics but you need to pick an appropriate target, this is on a par with faked moon landings and lizard Royal families.
amediasFree MemberPosted 6 years agoThis is one of those situations where the numbers are BIG, and humans are generally speaking, terrible at envisioning BIG. We think we can, but we can’t, hence why we need maths to prove stuff to us once it gets outside of the realms of what our brains can deal with.
Logic and experience tells us that if you bump into stuff you get deflection*, but in everyday situations we’re not encountering stuff BIG enough, or realising the BIGness of the difference between things.
Plug the numbers in and it becomes a lot clearer!
*yes some of the rubble gets spat out sideways, but the bulk of the mass goes in the same direction.
CharlieMungusFree MemberPosted 6 years agoThe force is gravity, and the mass is mahooosive, any lateral reaction forces from bumping into stuff on the way down are many orders of magnitude smaller, consequently you cna pretty much disregard them, hence…
I can accept the difference in magnitude, but the chaotic nature of bumping into stuff, especially the building itself, lots and lots of times makes the straight down seem very unusual
amediasFree MemberPosted 6 years agomakes the straight down seem very unusual
It’s not though.
This really is a case of your perception vs reality. There may be lots of stuff in the way for it to bump into in a chaotic fashion, but the horizontal forces are still orders of magnitude smaller than the one going down, so down it goes, and remember its not a rigid structure, even if some part of it gets a punt sideways, it’s not transferred to the mass as a whole.
You really need to get your head around the fact that there are no external lateral* forces during the collapse. Once you get your head round the fact that there is no force acting laterally on the mass then you can see why there’s no reason to expect lateral movement of the mass as a whole.
*The only lateral forces are horizontal components of reaction forces due to the down wards motion, and these are tiny by comparison.
whitestoneFree MemberPosted 6 years agoThe chaotic nature at the small scale (say the size of a brick or book) is going to largely cancel out. Within the core of the building there’d be so much material and so little time between a floor collapsing and the material of that floor impacting the next that lateral forces would be minimal. At the edges there’d be less constraint so you’d get material ejected but it would be relatively constant on all four sides so the resulting lateral forces would still be too small to have any significant effect.
As noted earlier, the largest lateral force the buildings had to cope with were the plane strikes: 280 tonnes at 400-500 knots vs 450,000 static tonnes.
5plusn8Free MemberPosted 6 years agoI can accept the difference in magnitude, but the chaotic nature of bumping into stuff, especially the building itself, lots and lots of times makes the straight down seem very unusual
Assuming every level was blown to get it to drop – would this look any different? All the concrete is gonna break up and be sent in all directions but will get normalised into the downward direction.
CharlieMungusFree MemberPosted 6 years agoforces are still orders of magnitude smaller
Except they are not. They are of the same magnitude, they may be smaller. Unless you reckon the angle of the ‘bump’ is very small. It would just be a factor of Cosine of the bump angle, wouldn’t it?
5plusn8Free MemberPosted 6 years agothere is always a gravitational force on the mass, the deflection forces get cancelled/minimised/deflected again or the part gets destroyed/broken again, when they hit something else, the gravity force is still there.
It’s lie leaves blowing int he wind, there is turbulence, collisions and stuff getting ejected sideways, but the majority of the mass is going in the direction of the prevailing wind.CharlieMungusFree MemberPosted 6 years agoAssuming every level was blown to get it to drop – would this look any different? All the concrete is gonna break up and be sent in all directions but will get normalised into the downward direction.
Not sure how it works, but by blowing it, isn’t bumping reduced because the thing it might bump into has gone?
jivehoneyjiveFree MemberPosted 6 years agoIn isolation, many of the theories regarding the towers collapse as a result of plane impact and fire do seem perfectly reasonable, all we’re ever likely to have on that front is informed conjecture from either camp
That said, when looking at cases which bear some similarities, it’s not unreasonable to question not only the mode of collapse, but the factors which led to it.
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CharlieMungusFree MemberPosted 6 years agothe deflection forces get cancelled/minimised when they hit something else,
except at the edges, where they will tend to be in the same direction.
and only if collapse is uniform5plusn8Free MemberPosted 6 years agoNot sure how it works, but by blowing it, isn’t bumping reduced because the thing it might bump into has gone?
So you have concrete and steel layers, an external skin, and inner cores columns. The layers (the floors) are tagged onto the inner core columns. If you cut all the columns or de-tag them from the columns its gonna go down right. But there is still most of the existing mass.
sbobFree MemberPosted 6 years agojivehoneyjive – Member
In isolation, many of the theories regarding the towers collapse as a result of plane impact and fire do seem perfectly reasonable, all we’re ever likely to have on that front is informed conjecture from either camp
Not really.
I saw the plane impact the building, I saw the fire, I saw the collapse.
They didn’t collapse before the plane impact and fire, did they?5plusn8Free MemberPosted 6 years agoexcept at the edges
lots of stuff got ejected sideways, have you seen the videos.
whitestoneFree MemberPosted 6 years agoThe Windsor building in Madrid is a different construction to that of the WTC. The Windsor building is/was a traditional stanchion and beam construction so each floor has multiple columns supporting it. The WTC were an inner core and outer skin joined by very lightweight lattice beams.
If you don’t understand the difference then you won’t understand why one collapsed and the other didn’t. Of course I don’t remember a passenger jet aircraft striking the Windsor building, do you?
lots of stuff got ejected sideways, have you seen the videos.
Yes but it wasn’t all from one side so any force resulting from material being ejected from the north side would be largely counteracted by that being ejected from the south. Similarly for east and west.
5plusn8Free MemberPosted 6 years agoCharlieMungus – Member
Do they not collapse from the ground up?Well yeah but the demolition proponents say they were blown in order just in advance of each floor dropping. I am giving them latitude.
CharlieMungusFree MemberPosted 6 years agoHad we not established that mechanically at least, the aircraft impact was not relevant?
CharlieMungusFree MemberPosted 6 years agolots of stuff got ejected sideways, have you seen the videos.
There’s videos of the collapse????
amediasFree MemberPosted 6 years agoforces are still orders of magnitude smaller
Except they are not.[/quote]
The horizontal motion from ‘bumping into stuff’ is a small horizontal reaction component of the downwards momentum after collision, there is still the resulting downwards component of momentum + the force from gravity downwards, and that is still acting, the horizontal force stops after collision.
Take a single piece of rubble as an example, even if 100% of the downwards momentum were converted to 100% lateral, there is nothing pushing that bit of rubble sideways after it hit whatever it hit, but gravity is still pulling it downwards, overall path is down…
I’ll say this bit again:
There are no external lateral forces. There is an external vertical force, gravity.
NorthwindFull MemberPosted 6 years agoCharlieMungus – Member
Not sure how it works, but by blowing it, isn’t bumping reduced because the thing it might bump into has gone?
If you blow it into dust, sure. But that’s not what controlled demolitions do. In either situation the bulk of the building and the bulk of the strength and resistance to the falling material is still going to be there.
Perhaps you could do a massive demolition which did have a bigger impact on the strength and the rate of collapse- but people would have noticed when the building blew up like a melon with a grenade in it, rather than collapsing like a collapsing building. Or, you could strip out the contents and leave just a skeleton- like in a real demolition- but again that’d be kind of noticable.
CharlieMungusFree MemberPosted 6 years agoI’ll say this bit again:
There are no external lateral forces. There is an external vertical force, gravity.
No need to say that again I haven’t proposed any external lateral forces
Take a single piece of rubble as an example, even if 100% of the downwards momentum were converted to 100% lateral, there is nothing pushing that bit of rubble sideways after it hit whatever it hit,
nothing pulling it back either. I can assure you it’s not the lack of understanding of the basic mechanics of this which makes it problematic. It is the complexity of the interactions which make it difficult to unpick
5plusn8Free MemberPosted 6 years agoHad we not established that mechanically at least, the aircraft impact was not relevant?
I think it is likely it did cut a column here and there.
5plusn8Free MemberPosted 6 years agonothing pulling it back either.
Indeed which is why the cloud of whatever is significantly larger than the perimeter of the tower.
amediasFree MemberPosted 6 years agoNo need to say that again I haven’t proposed any external lateral forces
Yet you think there should be (bulk) lateral movement. How can there be lateral movement with no lateral force?
nothing pulling it back either
There’s nothing pulling it no…. but there is something pushing back against it….air resistance, which is why it decelerates horizontally, probably not *that* much there is no force acting on it any more pushing it further out where as vertically gravity is still acting on it vertically.
CharlieMungusFree MemberPosted 6 years agoLet’s try some probabilities
1)Probability that it would collapse ‘neatly’ given that it was a controlled explosion:
2)Probability that it was a controlled explosion, given that it collapsed neatly:
some estimates will do just to get started
CharlieMungusFree MemberPosted 6 years agoYet you think there should be (bulk) lateral movement. How can there be lateral movement with no lateral force?
Off centre mass would be a possibility. Think Jenga, no external lateral force, still results in bulk lateral movement
There’s nothing pulling it no…. but there is something pushing back against it….air resistance, which is why it decelerates horizontally, there is no force acting on it any more. Where as vertically gravity is still acting on it vertically.
This isn’t towers dropping in a vacuum!
air resistance acting in any significant way on a brick ejected laterally from the building?amediasFree MemberPosted 6 years agoOff centre mass would be a possibility. Think Jenga, no external lateral force, still results in bulk lateral movement
Nooooo! the Towers are NOT like Jenga.
re-read the earlier posts re: pivoting and rigid/load transferred structures. Jenga blocks are solid, the Towers were mostly hollow. The upper stack of a Jenga tower can pivot due to being a semi-rigid structure with good load transference. The Towers could not do that.
air resistance acting in any significant way on a brick ejected from the building?
you’d be surprised, but you’re missing the point. In the absense of an acting force the brick (or whatever) will continue horizontally at the same speed, it won’t get any faster, it would infact slow down due to air resistance, but the amount is not the point, the point is that gravity is STILL acting on it vertically so it will accelerate vertically.
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