I do understand that they suffered a global collapse and that they were designed to withstand extreme wind loads. But as for being designed for a plane impact, they were designed for a much slower impact than they received on 9/11. Leslie Robertson, one of the designers, has stated that it was designed for a "slow flying" airplane impact.
WARNING!! LONG ASS REPLY POST.
Leslie E. Robertson, an engineer who helped design the WTC. He is currently a partner at Leslie E. Robertson Associates, a structural consulting firm that was under contract to the WTC at the time of the tragedy. In a keynote address Robertson reportedly told the Structural Engineers Association of Utah that: "...as of 21 days after the attack the fires were still burning and
molten steel still running."[3]
So how did the fires get hot enough to melt steel and continue to burn for months despite using thousands of gallons of Pyrocool?
Despite the strong possibility that combustibles like "paper, carpet and other combustibles packed down the elevator shafts by the tower floors as they 'pancaked' into the basement." And "that cars left in parking garages under the WTC contained gasoline that may have fueled the fires."
"none of these fires were hot enough to melt steel. Indeed, none of the combustibles in the wreckage burned anywhere near the melting point of construction grade steel beams (2800 °F). ...the smoldering fires for the most part were oxygen-starved.
There is no way to avoid the conclusion that the molten materials under the wreckage, as well as the smoldering fires, were a residual product of whatever caused the collapse of the WTC. Something on September 11, 2001 burned hot enough to melt steel in the basement of both towers."
Hint-It wasn't run of the mill office fires doing that melting, even NIST admitted that most of the Kerosene was consumed by the initial fireball after impact of the planes.
"But as serious as these explosions and fires were, jet fuel simply does not burn with sufficient energy to melt steel***not even close."
"The fact is that jet fuel, which is essentially kerosene, will not burn in air in excess of about 1,000°C (1,832°F)***nowhere near the 2,800°F melting point of steel. Even this 1,000°C upper limit is very difficult to achieve, since, as Thomas Eagar pointed out, it requires the optimal mixing of fuel with oxygen during combustion, which can only be achieved in a laboratory."
The difference in a 200mph impact versus a 500mph impact is considerable. And there is no question that those impacts caused severe structural damage.
Back to the design for plane impact-
"Although the WTC's soaring lines gave the impression of a relatively light frame, in fact, the towers were extremely rugged, engineered to withstand hurricane-force winds and to survive a direct hit by a Boeing 707, the largest commercial jetliner of the day. In a 1993 interview the WTC's principal structural engineer, John Skilling, stated that prior to construction he performed an impact analysis of a 600 mph Boeing 707 impact, and concluded "that the building structure would still be there."[28]
"Frank A. Demartini, onsite manager during the construction of the WTC, seconded this view during a January 25, 2001 interview, in which he noted that the study involved "a fully loaded 707." Demartini even declared that
"the building probably could sustain multiple impacts of jetliners because this structure is like the mosquito netting on your screen door, this intense grid, and the jet plane is just a pencil puncturing that screen netting."[30] Demartini kept an office in the North Tower and was last seen on 9/11 assisting evacuees on the 78th floor.[31] "
Sure there were multiple examples of erroneous reporting and speculation of how the steel turned into "licorice" or spaghetti or whatever but that has been shown to be false.
And you still don't comprehend that these fires were not hot enough to cause this huge tower to go from stable to instantaneous total descent ..fire does not work that way. Even FDNY firefighters radioed that they weren't that bad and in one instance called for 2 hoses to 'knock it down"
And explain the people standing in the gaping whole where the airliner entered? Were there fires? You bet your ass, but NOT enough to cause the rapid global descent in just a little over free fall acceleration.
So if the fires DID reach the temp point to cause this melting and pooling that burned for 3 months, it wasn't from normal office fire combustibles, and the melted steel Leslie Robertson and others talked about could not have come from that.
It seems people forget just how fucking massive they really were, and how the further down they went ..the bigger they got! Some people act like they should not have provided
some resistance, and forget they only provided minimal resistance that resulted in the towers falling way faster then, given the physics, should have.
"In fact, the WTC had tremendous reserve capacity. An early article about the project in the Engineering News-Record declared that "live loads on these [perimeter] columns can be increased more than 2,000 percent before failure occurs."[33]"
The top structure descending into the lower portion would have been met with equal force initially, thus slowing the descent, and there was none! It collapsed just short of freefall.
The top portion fell right through the more robust lower portion almost unimpeded. Even a lowly high school physics teacher called NIST out on that.
"Because the NIST did not have the necessary facilities, it contracted Underwriter Laboratories to conduct a series of fire endurance tests on trusses like those in the WTC. (The recovered truss samples were too badly deformed during the collapse to test them directly, so NIST fabricated new trusses identical in design.) The purpose of the tests was to establish a baseline, and the results were surprising. Not one of the truss assemblies failed during a series of four tests, not even the truss sprayed with the minimum amount of fireproofing. "The floors continued to support the full design load without collapse for over two hours."[52]
The UL tests not only laid to rest the theory that the trusses were the cause of the collapse on 9/11, if anything, the tests demonstrated the fundamental soundness of the WTC truss design."
Even if they could not withstand that, you must still take into account the resistance the lower floors that were not structurally compromised at the time, and take into account the time it should have taken to achieve this total global collapse, compared to what we witnessed.
Each truss assembly-concrete floor behaved as a single unit.
NIST has neglected the law of conservation of momentum by not explaining how the huge mass of the building provided virtually no resistance at all to the upper part of the building.
Also the problem with the puny truss theory is that one can clearly see "that during each collapse, perimeter columns and other structural members didn't simply fall to the ground. In many cases they were ejected up and out of the disintegrating structure at nearly a 45 degree angle: a cascade that hurled steel beams weighing 20 tons or more as much as 600 feet from the base of the buildings."
You can't even add those massive pieces of the towers that were ejected and PULVERIZED and claim they contributed to the weight smashing down on the lower portion..because they were...ejected away from them and fucking turned to dust!
Have you bothered to watch any videos of the WTC7 before it fell down in a heap? Seriously "multiple fires" on " multiple floors"?
"Enough to cause such an implosion like collapse? BS.
Besides omitting and otherwise falsifying evidence, NIST also committed the type of scientific fraud called fabrication, which means simply making up results.[49]
They lied about the shear studs, and the fires and what floors they were on and what time the 12th floor fire went OUT. They also lied about the lack of freefall acceleration until called out on it and still haven't had the balls to come back and try to explain THAT, nor give up their computer data for others to try and replicate!
And by what I have seen, fires can cause buildings to fail. I think the Delft building is a good example of that. As is the building in Madrid that is usually used to show that buildings don't collapse in a fire. But if you look at all the photos of that, you'll see that the unprotected structural steel collapsed while the steel reinforced concrete was left supporting the building.
Of course fires can cause buildings to fail, but not fucking implode in on themselves producing 2.25 secs of fucking freefall!
Have you read about the Madrid fire? Do you realize how long the motherfucker burned? And yet..still DID NOT IMPLODE OR COLLAPSE TOTALLY TO THE FUCKING GROUND.
NIST has not explained anything, in fact they lied their asses off and distorted facts, and data. Have you not read ANY rebuttals that counter NISTS claims?
So, as far as WTC7 goes, until there is proof that something other than fires did it, that's what I am going to believe. If evidence ever comes to light that something else occurred, I'll change my stance.
The people that were charged with finding out let you me and everyone else down miserably. I'm not out to convince you only to recommend that you seriously read with an open mind and some courage what many credible experts, FDNY and other witnesses say about the events of that day, in particular the physics experts explain the various laws that NIST did not take into account, and how steel loses its strength and how long it takes.
Dead On Arrival
Official theory of 9/11 WTC tower near-free-fall collapses violates Laws of Physics - a knol by Michael Fullerton
Building What? How SCADs Can Be Hidden in Plain Sight: The 9/11 "Official Story" and the Collapse of WTC Building Seven
http://www.journalof911studies.com/volume/2008/TheMissingJolt7.pdf
See how he always fails and desperatly starts grasping at straws when getting his ass handed to him on a platter?
