carpenter patriot wrote:
Hey that was beautiful.I am a structural concrete form carpenter forman and in my career I have done steel beam construction enough to half assed keep up with you. If I may I think what your saying is. A floor or floors support structure failed,as the shock load slam down on the ones below, because of the shock loads from the weight above, witch there is only so much you can do about(3 hour stand time after compromised)crushed each floor below speeding up as it came down. With the weights we are talking about how fast it came down would be dependent on the amount of floors above and the weight of each floor above the
impact. At the most basic form of explanation. It was like how to a certain weight a aluminum can will let you slowly stand on it and not ccollapse.But lift your foot and stomp down it can easily be crushed. Above the planes impact is like your foot. When the planes hit it compromised a floor or floors and it dropped like your foot on a aluminum can. Because of the damage at impact the heat WAS enough to start the fall at a shorter than normal time because of the speed the heat was dispersed. That explains the explosions the people heard slow at first and increasing to a rumble the further down the collapse got. The explosions where the individual floors collapsing on each other. Now as long as the debris backs up what you say. All that would show up in the debris. One thing that looked suspicious was how the planes hit to the side of center. Not compromising the structure perfectly even. I would have thought from the impact up would have fallen to the side of the most damage. I understand after a certain speed and weight a near vertical fall would have happened. But at the start wouldn't you see a more pronounced fall in the direction of impact. Also as the floors above fell making contact with the floor below wouldn't a huge amount of material be ground off between the two structures. Further exaggerating the affect of a off center impact point. Also slowing the rate of collapse considerably because of lost material weight and again exaggerating even more a collapse to the side of impact. In the egg crate design you mentioned that's what I would have expected to see. You know kinda like that can you don't step down on perfectly centered. I think it was tower two that the plane was horribly off center. I am just a carpenter so I'm probably wrong. Again signs of that would show up in the debris.
Hey that was beautiful.I am a structural concrete ... (
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You're partially right, carpenter patriot. Imagine a bunk bed that is 150 beds tall. Each mattress is supported and held in place by the lip of each mattresses' bed-rails. The inward-angling lip of the mattress frame is taking on the roll of the "angle clips" used in building the WTC to support each of its floors. The mattresses will represent the floor(s). The 4 corner posts of each bunk bed simply hold the bed rails in place.
Now, suppose there's a fire in bed 100 (from the bottom). As the temperature from the flames rise and the flames grow closer to the corner posts and bed frame, the metal bed frames and the bed posts begin to bow/bend outward and downward, away from the mattress. The weight of the 50 upper beds act to add pressure on the heated bed frames and the corner posts, causing even more bending/bowing.
Eventually, the bending/bowing of the bed frame extends so far as to allow the mattress to slip through the space between the bed frames holding up the mattress. The mattress falls through, onto the bed below. With the burning mattress no longer in place, acting as an outward force against the bed rails and corner posts, the bed frame and posts fall inward, toward the inside of the bed structure. This occurs because the heated metal is weakest near the flames and strongest near the top. As such, the outward bowing would occur closer to the bottom of the mattress; allowing it to slip from place.
The "action" here is the weakened posts and rails have bowed OUTWARD & DOWNWARD at the bottom. The "reaction" is that the unheated portions of the rails and posts, close to the bed above, are now INSIDE the vertical line that used to exist between the top and bottom of the posts and frames. They are now off-center and the posts and frames are further apart at the bottom. Hence the mattress slipping through and falling onto the bed below it.
The beds above, without the vertical support of the bed that caught fire and collapsed, now lose their support and collapse into the space that the burning bed had occupied. As each bed above falls, its force and inertia causes a chain-reaction of the beds above to collapse on top of each other; in a sort of domino effect. The weight and rate of fall of each bed and frame, above the bed that caught fire, simply adds to the mass and energy being dropped on each subsequent bed below.
This "collapse-characteristic" was designed into the WTC by using the modular design. Without any overpowering outside forces (even the airliner(s) hitting the building(s) wasn't enough to force an outward fall of the building), the building would collapse inward.
My apologies if I'm still not making myself clear. If I'm not, let me know and I'll try a different analogy.