Yes I've thought of this before -the pillars near the outside have half of the amount of building above them to hold up compared to the pillars near the middle, and the corners half as much as those on the sides. But the thing is, these pillars were nearer to the upper half of the building and not the complete bottom, so the stress wasn't as intense near the bottom floors. Also the plane hit from the side of the building and did not exit the other end, so a whole middle side, and interior were destroyed. This would in theory result in a building with a hole, and a fire. Nothing more. But if the building were to fall, it makes little sense that entire thing would collapse straight downward.
These bars im sure are extremely strong, and a fuel fire composed of hydrogen peroxide and diesel shouldn't be able to melt thick metal, or barely weaken it at all. As for explosions caused by the fuel, the fuel would need to be in a compressed environment to result in a devastating explosion, like a fuel tank truck, or fire hydrant. Yes fuel can cause an explosion from a plane, but not a plausible explosion to emit major damage to the structure. In my mind, the fires created had little to do with the building crashing.. So fires playing a major roll seems to be besides the point.
I'm not saying its impossible for a downward collapse, it just doesn't seem probable.
With these things in mind.. I still don't believe that this was planned purely by terrorists.
I have discussed everything you have mentioned in my previous posts. But i guess I'll recap on some crucial things people don't know as well as some other things:
1) People seem to believe that only when steel melts would it have a physical effect on a building. If fires burn at a hot enough temperature, it will create what's called a thermal misfit. According to research done, the fires burning in the buildings ranged somewhere between 600-1200 degrees Fahrenheit. This is way more than enough to create an elongation or a change in length in the members. A few inches may not seem alot, but this will create what's similar to "forcing a member into place" during construction. This will create a shear, axial, and torsional force/stress, which may push the bearing limits way past it's marginal safety factor. Few degree changes aren't going to do much, but raging fire spread throughout entire floors will start slowly fatiguing the members.
2) How would it not make sense for a building to not fall downward? Look at the basic physics here:

ss
The red squiggly line denotes the portion in which the airplane crashed into the building. Point C denotes the center of gravity of the portion of the building above the red squiggly line. This is called a centroid. Every object/body in this universe has a center of gravity which indicates the "center" of your weight. Now we'll treat point A as a joint which allows some form of rotation (because this is where the plane made a hole in the building).
There's this term we use called
moment. It can also be known as
torque. Take the moment/torque about point A, you'll see that the force is on the right side and that there will be a clockwise motion. And with this motion, this will create a downward collapse. The only way for a building to collapse sideways is for the top portion to rotate counterclockwise about point A. And in order for this to happen you have to either have:
- a REALLY strong horizontal force, like wind or something, so strong that it exceeds the clockwise moment created by the center of gravity (wind is a distributed force, so the centroid would be located at the mid point of the height of the building.)
- or have the top portion of the building tilted so that the center of gravity is ultimately located horizontally (in the x direction) to the left of point A. This will then create a counterclockwise moment about point A.
Now the building is actually a thousand times more complicated than this, but the general idea remains the same. Now if this building were super ass skinny like a tree, then yes it would be very plausible for it to topple sideways as just a slight angle change at one of the corners can easily shift the center of gravity to either side. Or if the airplane were to have crashed literally at a place like 5 or 10 stories above the ground, then a sideways topple would seem probable.
3) When you said this:
Also the plane hit from the side of the building and did not exit the other end, so a whole middle side, and interior were destroyed.
you were exactly right. I've said this many many times in my previous posts, but all members (columns, pillars, beams, girders, floor slabs, etc) are
dependent of each other. This network of members is a static system where they all support each other. Take out some members, all the others will be affected. And we both agree that the closer you are to the middle of the building, the more stresses, strains, and forces there will be right? Well now that the middle is gone, all the other members are even more affected, possibly pushing their bearing capacities past their ultimate strength.
Now you see, many structural engineers have pointed out that the plane crash itself won't cause the building to collapse. When you throw fire into the equation it will create enough damage.
You're probably thinking that because there's a hole in the side of the building that this gap will create a sideways collapse. Refer back to the picture i drew. Now this may be true for skinny things like trees but not for buildings. I could draw a picture to illustrate this but if you really insist that I prove this to you, i'll do it another time.
4) Take a few classes in Engineering mechanics of materials and Structural Analysis and you'll realize that the collapse of the towers were completely independent of controlled demolitions.
Post has been edited 1 time(s), last time on Sep 18 2008, 5:24 am by MillenniumArmy.
None.