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I've been hearing a lot of conspiracy theories on this matter lately, and I was just wondering what some scientists/structural engineers thought about it. Ive heard some say that the heat of the airplane crash would not be hot enough to melt the steel beams, and also that it looked like there were placed explosives.

2006-07-21 20:24:26 · 9 answers · asked by eddster08 2 in Science & Mathematics Engineering

9 answers

The steel did not have to melt, heating beyond a few hundred degrees would cause it to lose "temper" that is to say that the atomic strucure of the steel would change to a more amorphous state causing it to lose a great deal of strength.

Steel comes in many forms but basically it is a combination of carbon and iron, This makes steel stronger than iron alone. there are ways of causing the atoms in steel to line up giving it even more strength, such as cold rolled steel etc. heating to high temperatures will undo most of this hardening.
Try heating a paper clip at one spot with a lighter, you don't have to get it very hot! Let it cool off now bend it and see how much weaker the steel is where you heated it!

Also the strength of the building is a combination of many materials most of which are even more sensitive to heating (concrete for example).

I do wonder about all the organizational "failures" that allowed those planes to get to their targets.

2006-07-21 20:34:23 · answer #1 · answered by Sleeping Troll 5 · 1 0

None whatsoever. It is a base canard perpetrated by Muslim extremists who are attempting to deflect responsibility for the disaster. To maintain the explosive thesis, one would have to suppose that people ran into the building to plant explosives in the 90 minutes from the time the planes hit until the buildings collapsed. It is a distinct understatement to call this notion silly.

What happened is that the fires, fueled by thousands of gallons of jet fuel, burned hot enough, not to melt the steel, but to eventually heat through the fireproofing surrounding the vertical beams and soften them so that they could no longer sustain the weight of the floors above. (This softening is known to anyone who has ever watched a blacksmith adjusting a shoe for a horse.) When the upper floors fell, the momentum overloaded the beams below, which also collapsed, and this process continued until the buildings were completely destroyed.

2006-07-21 20:38:10 · answer #2 · answered by Anonymous · 0 0

It is foolish to discuss this subject. Those who wish to believe in conspiracies will always believe in them and those smart enough to know the truth will always know that the planes and the burning fuel weakened the structure sufficiently for it to fail.

As to the question of jet fuel being sufficient to weaken the steel structural members. I know it is sufficient.

I have personally reconstructed portions of chemical plants after a fire. I have seen lightly loaded steel structures fail when exposed to the fire from hydrocarbon liquids similar to jet fuel for fairly brief periods of time.

The steel does not have to melt but only get hot enough to have its strength lowered to the point where the stresses on it exceed the lowered strength of the steel. This does not take hours but can happen in 5 to 15 minutes.

2006-07-22 03:52:27 · answer #3 · answered by oil field trash 7 · 0 0

In the structural design of buildings, the total weight of the structure should be supported by the soil pressure, otherwise, any building structure will collapse.

The top most floor level is supported by the floor level below it, notice the decreasing size of the girders, beams and columns as you go up.

There are wind load (wind pressure above) and seismic load (considering earthquake factor on certain regions), which are applied in the design after all the loads have been transmitted to the corresponding structures.

The dead load (the weights of concrete, steel and all materials used), live load (the people who occupy the rooms/floors), moving loads (if there's a machinery like a crane that moves from one end to the other), point load (a temporary load that is placed in a certain point, which could be removed or placed again), uniform load (such as a train or vehicle moving along a bridge), impact loads (dropping a heavy object on the floor is impacting the floor!) and other loads are then considered to determine specific loads or forces acting on the structures.

Floor level by floor level, all the loads except for the seismic and wind loads, are considered and distributed (by design) in each floor level's structures. Therefore, floor by floor, the loads differ from each floor depending on the use or function of a floor.

After the design loads have been distributed to the structures, (the flooring structures weight is then transmitted to the concrete or steel joists , then to the girders, then to the columns.

After considering all the loads in each floor level, the wind load or wind pressure is applied horizontally by design, to the walls which then transfer it to the girders/columns. The design of loads calls only for half of the floor level, meaning, for each floor, half of the walls' height above is considered and half of the walls' height below is considered to evenly distribute the wind pressure pounding on the walls.

Therefore, what remains is the flooring structure consisting of floor slabs, joists, girders, half of the columns, too (above and below). This shows, that for each floor level, the lower floor level supports the upper floor level.

Myth 1: The aircrafts' fuels'(considering a full load of fuel) heat
is enough to melt the steel structures and therefore
paved the way for the total collapse. (You may gather
data on the temperature created by burning such
specific jet fuel and the melting point of the particular
part of the structure when the plane/s impacted
horizontally against the walls of the WTC.)

Considering the heat created by the jet's fuel blast
was not enough to melt the steel structures, the
plane/s impact made it penetrate the building, thereby
destroying the structural members esp the structural
columns. This destruction cut the floor levels structural
connection to the above floors, therefore, from the
level where the plane/s impacted, up to the top most
floor created one whole load, including the weight of
the jet! (if the weight is minimal, then it can be
neglected, but check the weight of a jet calling for
such specifics.)

Therefore, the total weight of the structure above the
jet in the building cannot be structurally supported by
the floor level structure below it! When this happens,
the structure below it collapses, adding another
weight, and so on.

Conclusion:

Therefore, since the airplane/s impacted/penetrated the structure of the building and even without considering the melting of the steel columns by the high temperature of the fuel,
the building will stiil collapse.
Now, if the high temperature of the burning jet fuel is more than enough to melt the specific steel structures of the WTC, or alter the steel's temperature property, the same scenario will happen and will hasten the collapse instead.

Questions:

1. If explosives were used (intentionally?), do you think the
hijackers would be able to target the exact point in the building
so as to ignite the explosives?

Remember, if not for a small degree of tilting of the wings,
hundreds would have been saved. The total wing span, as it
tilts, will occupy more floor levels thereby increasing the
number of victims.

2. Did the hijackers knowingly tilt the plane so as to have a wider
span in order to affect a bigger floor level for them to
successfully collapse the building? Osama bin Laden, must
be a civil engineer!

It could be further calculated from the jet/s impact until the
collapse (time), the property of steel to fully melt (enough to
render it structurally weak), the total load above the jetplane/s
and the dead load of the jet/s, will give us answers if or not,
the steel structures was affected by the tremendous
heat/temperature. Also, a change in the temperature property
of steel is enough to render the structures unsound (even
there is no melting of the steel) and therefore, prone to
structural collapse, considering again, the structural theory
behind the design of buildings.

Notes:

I was glued on TV that morning and when I saw those NYC firemen getting inside the building, I was shouting and started to cry, saying: "Don't go," for I know that the buildings have the possibility of collapsing, seeing the plane/s were able to penetrate and destroy the colcumns inside those floor levels. I wasn't even thinking of the high temperature of the burning jet/s fuels.
However, the death of the brave NYC firemen was a sacrifice to those they saved.

2006-07-21 21:57:51 · answer #4 · answered by Gala 3 · 0 0

No, the steel core of the towers which were the main structural component melted due to the excessive heat of burning jet fuel and it collapsed.

Bin Laden was an Oxford graduate, he claimed that he himself calculated the exact position of collision to maximise damage.

2006-07-21 20:37:54 · answer #5 · answered by ag_iitkgp 7 · 0 0

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2016-11-25 01:20:54 · answer #6 · answered by headlee 4 · 0 0

yes....the collapse had all the traits of a controlled explosion and theres only one in a million chance that it can happen otherwise

2006-07-21 20:33:47 · answer #7 · answered by Anonymous · 0 0

I agree with rhsaunders. I don't see where to vote anymore.

2006-07-21 21:03:37 · answer #8 · answered by Christopher D 2 · 0 0

Short answer: No.

2006-07-22 11:15:25 · answer #9 · answered by Prof. Frink 3 · 0 0

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