Re WTC collapse.
I understand the idea that the rigid steel structures were strong enough to withstand the initial impact. The only real explanation to the collapse being the structural steel became hot enough to buckle on one or more floors.
There might be some useful pointers to look into. Now that the rubble has been cleared away, what was the condition of wreckage of the aircraft? If the aluminum alloy skin had not melted (Al melting point 1220 degrees F), I would certainly wonder how a floors mass of structural steel got up to these kind of temperatures (page 4 from my earlier link)
sciam.com
"At about 800 degrees Fahrenheit structural steel starts to lose its strength; at 1,500 degrees F, all bets are off as steel members become significantly weakened," he explained.
If there was evidence that the aircraft aluminuim alloy burned
"Aluminum melts into burning 'goblet puddles' that would pool around depressions, [such as] beam joints, service openings in the floor, stair wells and so forth...The goblets are white hot, burning at an estimated 1800 degrees Celsius. At this temperature, the water of hydration in the concrete is vaporized and consumed by the aluminum. This evolves hydrogen gas that burns. Aluminum burning in concrete produces a calcium oxide/silicate slag covered by a white aluminum oxide ash, all of which serve to insulate and contain the aluminum puddle. This keeps the metal hot and burning. If you look at pictures of Iraqi aircraft destroyed in their concrete shelters [during the Persian Gulf war], you will notice a deep imprint of the burned aircraft on the concrete floor.
I would say there may well be good evidence that some of the vital steel structure on a given set of floors failed in the heat. One set of floors collapsing and the dynamics of the falling building take over.
Now... they did find remains of several of the passengers so one wonders.
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OK turning the matter on it's head.
Lets say a structural engineer is hired by a black op group looking to "pearl harbor" the USA into a war with Afghanistan and Iraq.(there are still some lingering doubts about the code breaking and advanced warning of pearl harbor I understand) You are told the cover story that some planes are going to be flown into WTC buildings and they are going to collapse. With the help of demolition experts how is it going to look convincing?
I know nothing of architecture and demolition except what I have seen on TV. From what I have seen though, large amounts of structural material is removed to weaken the building first. Then charges are laid and fired in a given sequence.
The WTC building, being strong structures as they are, would need a lot of work to sufficiently weaken them to be sure of success. A hard thing to achieve while the buildings are still being used. Some very unusual maintenance would have been going on. The firing patterns would probably have been recognisable to demolition experts too. |
