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then what?
Right.
A plane going 500 mph and fire.
Then the force of the moving mass of 200 or 300 767s crushed the rest of the building which was not designed to withstand said force.
then what?
If it's within the range they gave in the same sentence - 1,300F - everything seems plausible. That's about 700C.I imagine it depends on the amount of sulfur.and what percent of steel strength is lost at those temp ranges?
Let me give you a hint...NIST calls it 'progressive collapse'.....
here's a pic:
The section of the Ronan Point building that collapsed was not part of the support structure of the building. Rather, the collapsed balconies were short cantilever sections supported by the building's main structure. This contrasts with the collapse of a large structural section of the Murrah Building, and the total collapses of the World Trade Center syscrapers.
If one researches the history of total progressive collapse of buildings one will find that, in regard to the structural failure of large steel-framed or steel-reinforced-concrete-framed buildings it is a recent phenomenon, apparently starting with the Oklahoma City Bombing, and then rearing its ugly head again in the 9/11/01 attack.
Source: Link
What do you mean? There's nothing after that. The building has collapsed. There's your hint.
Here's a hint: When a 30 floor building falls on a 70 floor building, it all comes down.
the problem with the progressive collapse theory is that it doesn't work...the probability is really. really low...
...you've seen the buildings collapse thousands of times I'm sure....when the building kinks while falling, you have energy transfer to the side of the kink so much of the mass isn't coming down on the inner support columns at all...that's significant because it effects the rate at which the building should have collapsed versus the time it did collapse....not to mention that the complete progressive collapse of a steel structure building has only occurred twice, on 911 and during the Oklahoma City bombings....coincidink?
And the Ronan Point building is a pretty poor comparison. There was a gas explosion in the corner of the 18th floor, nowhere near the core. That's a fail.
The Murrah building didn't completely collapse. Quit muddying the water with bull .
Now as for this energy transfer business -- it was 20 and 30 floors of falling office building. Nothing was going to stop or deflect that.
I was just using the Ronan building as a point of comparison to what the official NIST explanation of the collapse of the towers...I didn't just pull it out of my ass....
...anyway....
LinkIn the 20th Century, steel melted at 1535 degrees Celsius (2795 F) (see http://www.chemicalelements.com/elements/fe.html), but in the 21st Century, it melts at 800 degrees C (1472 F).
This might be explained as a reporter's mistake — 800 to 900 C is the temperature for forging wrought iron. As soft as wrought iron is, of course, it would never be used for structural steel in a landmark skyscraper. (Descriptions of cast iron, wrought iron, steel, and relevant temperatures discussed at http://www.metrum.org/measures/castiron.htm or http://911review.com/articles/jm/cache/castiron.htm.)
But then lower down, the BBC page repeats the 800 C number in bold, and the article emphasizes that the information comes from Chris Wise, "Structural Engineer." Would this professional individual permit himself to be misquoted in a global publication?
Eduardo Kausel, an M.I.T. professor of civil and environmental engineering, spoke as follows to a panel of Boston area civil and structural engineers: "I believe that the intense heat softened or melted the structural elements — floor trusses and columns — so that they became like chewing gum, and that was enough to trigger the collapse." Kausel is apparently satisfied that a kerosene fire could melt steel — though he does not venture a specific temperature for the fire ( http://www.911review.com/articles/jm..._whenfell.html).
I feel it coming on again — that horrible cynicism that causes me to doubt the word of the major anchor-persons. Please just think of this essay as a plea for help, and do NOT let it interfere with your own righteous faith. The collapse of America's faith in its leaders must not become another casualty on America's skyline.
In my diseased mind, I think of the floors of each tower like a stack of LP (33-1/3 RPM) records, except that the floors were square instead of circular. They were stacked around a central spindle that consisted of multiple steel columns interspersed with dozens of elevator shafts (see http://www.skyscraper.org/tallest/t_wtc.htm, http://www.civil.usyd.edu.au/wtc.htm and http://www.GreatBuildings.com/buildi...de_Center.html).
With the central core bearing the weight of the building, the platters were tied together and stabilized by another set of steel columns at the outside rim, closely spaced and completely surrounding the structure. This resulting structure was so stable that the top of the towers swayed only three feet in a high wind. The architects called it a "tube-within-a-tube design."
The TV experts told us that the joints between the floors and central columns melted (or the floor trusses, or the central columns, or the exterior columns, depending on the expert) and this caused the floor to collapse and fall onto the one below. This overloaded the lower floor, and the two of them fell onto the floor below, and so on like dominos (see http://news-info.wustl.edu/News/nrindex00/harmon.html or http://www.911review.com/articles/jm/cache/harmon.html).
Back in the early 1970s when the World Trade Towers were built, the WTC was the tallest building that had ever been built in the history of the world. If we consider the architectural engineers, suppliers, builders, and city inspectors on the job, we can imagine they would be very careful to overbuild every aspect. If one bolt was calculated to serve, you can bet that three or four were used. If there was any doubt about the quality of a girder or steel beam, you can be sure it was rejected. After all, any failures would attract the attention of half the civilized world, and no corporation wants a reputation for that kind of stupidity — particularly if there are casualties.
I do not know the exact specifications for the WTC, but I know in many trades (and some I've worked), a structural member must be physically capable of three times the maximum load that will ever be required of it (BreakingStrength = 3 x WorkingStrength).
According to Engineering and Technical Handbook by McNeese and Hoag, Prentice Hall, 3rd printing, September 1959: page 47 (Table) Safety Factors of Various Materials, the mandatory safety factor for structural steel is 600%. That is, a steel structure may be rated for a load of only one sixth the actual theoretical limit.
Given that none of those floors was holding a grand piano sale or an elephant convention that day, it is unlikely that any of them were loaded to the maximum. Thus, any of the floors should have been capable of supporting more than its own weight plus the two floors above it. I suspect the WTC was engineered for safer margins than the average railroad bridge, and the actual load on each floor was less than 1/6 the BreakingStrength. The platters were constructed of webs of steel trusses. Radial trusses ran from the perimeter of the floor to the central columns, and concentric rings of trusses connected the radial trusses, forming a pattern like a spider web (see http://news.bbc.co.uk/olmedia/154000...ructure300.gif ). Where the radial trusses connected with the central columns, I imagine the joints looked like the big bolted flanges where girders meet on a bridge — inches thick bolts tying the beams into the columns.
In order to weaken those joints, a fire would have to heat the bolts or the flanges to the point where the bolts fell apart or tore through the steel. But here is another thing that gives me problems — all the joints between the platter and the central columns would have to be heated at the same rate in order to collapse at the same time — and at the same rate as the joints with the outer columns on all sides — else one side of the platter would fall, damaging the floor below and making obvious distortions in the skin of the building, or throwing the top of the tower off balance and to one side.
But there were no irregularities in the fall of those buildings. They fell almost as perfectly as a deck of cards in the hands of a magician doing an aerial shuffle.
Whoever J. McMichael is, he goes on and on in this diatribe written in November 2001 about melting steel. This has no value whatsoever.
Does he have a DVD for sale now?
The WTC fires ranged in temp from (800-1000'F) depending on your source....
...and the actual standard ratio for static (structural) loads is five, not three. That is, if a bridge is rated to carry 1 ton, it should be capable of bearing 5 tons without collapsing....
Going back to the fire at the WTC, we can see that reducing the steel structure to 60% its rated strength should NOT have weakened it to catastrophic collapse, because at 60% it would still support three times the rated load. The steel structure would have to be reduced to 20% of its rated strength to collapse.
Thus, even if the fire had heated the steel to 550 degrees C (1022 F), that would not have been sufficient to cause the towers to collapse.....
Is that the standard for the WTC? It wasn't a bridge.
Using numbers you got from a bridge.Going back to the fire at the WTC, we can see that reducing the steel structure to 60% its rated strength should NOT have weakened it to catastrophic collapse, because at 60% it would still support three times the rated load. The steel structure would have to be reduced to 20% of its rated strength to collapse.
Thus, you have no proof WTC 1 and 2 were designed to support the weight of 500 acres of office building each.Thus, even if the fire had heated the steel to 550 degrees C (1022 F), that would not have been sufficient to cause the towers to collapse.....
Seriously Dan -- you are trying to say that WTC 1 and 2 were each designed support enough weight to make a structure that is 1.3 MILES tall.
That would seriously weaken his whole arguing strategy . . .
Astonishingly enough this is in the NIST report, if you had actually read it.
They do a whole technical subsection on it.
I don't watch crappy youtube conspiracy videos longer than two minutes.
Nothing I saw there said anybody actually saw any explosive devices.
My question remains unanswered. Yes or no.
ARE THERE ANY EYEWITNESS ACCOUNTS OF VISIBLE EXPLOSIVE DEVICES?
10th time this question has been asked and not given a straight answer. Is your case so weak that you can't answer ONE yes or no question?
Actually the two towers collpsed in 14 and 22+ seconds repsectively.
The 9 seconds of "free fall" used in your outdated physics lesson was arrived at through a very stilted and inaccurate analysis of video.
Do try to keep up.
Quite frankly the other starting assumption used by your outdated bit also was raised:
The collapse did not go from the top of the building height to ground level.
Both collapses started (gasp) where the planes and fires were, about 20-30 stories down the building, and the rubble pile was eventually about 4 stories above street level.
This means that the collapse of the building only really took 76-86 stories, not the full 110.
Shorter distance of collapse means less time for "free fall" than what is commonly put forth by the phsyics-challenged "twoofers".
If you actually go out to a calculator here:
http://hyperphysics.phy-astr.gsu.edu/hbase/flobi.html
You can get the free fall speed of an object dropped from, say, 86 stories or about 320 meters.
That ending velocity is about 79 m/s.
Stick that into the equation v= (g)(t) and you can easily solve, just as the professor did, for t.
79 = 9.8t
t = 7.95
So, the time that should be used for "free fall" is about 8 seconds, not 9.2.
This makes for an even bigger difference in the observed collapse times of 14 and 22+ seconds than 9 seconds.
Oops that must imply some resistance, because it took almost 2 and 3 times longer than "free fall".
Since the explosives theory DEPENDS on little to no resistance, and a large amount of resistance was observed, you MUST conclude that explosives were not used.
Please explain how thermite was attached to vertical columns long enough to cut them.
Do you have eyewitness accounts of the magically attached thermite charges?
Galileo was at least an entertaining truther troll. When dan gets involved, things just devolve into abject stupidity.
The blasts that blew out the core columns weren't thermite. Where are you getting your information?
Thermite does not blow multi-ton steel beams 500 feet horizontally through the air.
HAHAHAHAHAHAHA.
Argue with dan, dipstick.
Nope simple gravity will do that too, as you have inexpertly alluded to.
Oddly enough, you still haven't produced accounts of glass flying for any appreciable distance.
I guess the glass at the wtc towers was explosive resistant too?
Multi-ton steel beams flew 500 feet horizontally, but ounce size pieces of glass didn't fly for miles in all directions from the "explosives"?
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