How did the twin towers collapse at free-fall speed on 9/11?

Question

How come the undamaged, lower portion of the towers provided no resistance?

Isn't the bottom part of any tower intrinsically designed to withstand the weight of the top part?

If the floors collapsed onto each other, what happened to the internal support columns?

Answer 1

Thermate is the answer you seek. Dr. Steven Jones formerly of BYU tested several samples of melted steel recovered from the wreckage of 9/11. The steel support columns were cut in demolition fashion with what after careful scientific analysis appears to be Thermate, a form of Thermite with sulfur added for addiotional cutting power.

If you look at the image below you will see how the support colums have been sliced diagonally by a cutting charge of some sort. This is why the building had such a total collapse. Anyone who thinks jet fuel was sufficent to weaken steel that was tested to withstand 2000+ degree temps for over 6 hours is an idiot with no understanding of physics or chemistry.

Answer 2

It didn't fall at free-fall speed, the debris outpaced the collapse.

There was very little resistance (saying there was no resistance is incorrect) because unlike most everyother building in the world, the World Trade Centre had an open floor design. The weight of the building was supported by its central core and outer wall only. Most skyscrapers are constructed with a steel frame design consisting of interlocking columns and beams, where the weight is evenly distributed over the entire structure. Steel frame contruction WOULD provide more resistance to a collapse, unfortunately steel frame construction wasn't used on the WTC.

Here's how it worked:
1. Big planes filled with fuel hit the buildings.
2. The impact removed fireproofing on the steel trusses supporting the floors.
3. The impact also started fires with fuel and other combustible materials (desks, paper, plastics, etc.)
4. Heat from the fire weakened (NOT melted) the steel trusses, which causeed the floors to sag and eventually break off the brackets connecting the floors to the outer wall and central core.
5. With the floors no longer connecting to the outer wall and core, the wall lost its lateral support and buckled, which started the collapse.

Check the link below to hear what qualified scientists and engineers have to say about the collapse.

Answer 3

Lol...is your argument seriously that they should have fallen slowly? They were 100+ story buildings. Once they start to fall, they are not going to just lose a couple of floors at a time. That is beyond an idiotic thing to think. Do you have any idea what it takes for a controlled demolition of a building? You can't just throw a few sticks of dynamite in a few closets around the building. You need to place large amounts of explosives at very specific points on the structure and on certain supporting beams of the building. These aren't something you can sneak in in your pocket. Why don't you tell me... if your idea is that the twin towers were deliberately and systematically demolished, exactly WHEN the huge number of people it would have taken to set up the explosives all throughout the twin towers, at all the correct points, would have been able to get into the buildings and set up the explosives in order to CREATE a controlled demolition? And how they would have been able to DO this without being seen entering the building carrying multiple, gigantic packs of explosives by ANYONE, (there were people all throughout those buildings 24 hours a day) and done so without leaving any evidence behind like the gigantic holes they would have needed to make in the walls in order to place the explosives along the supporting beams? And how did they DO all of this without being captured on the thousands of surveillance cameras that were all throughout the twin towers? And how did they get into the building with thousands of pounds of explosives without also being captured by any of the multiple surveillance cameras that were all over the buildings OUTSIDE? (Not ONLY the twin towers themselves, but the buildings all around the twin towers?) I would be REALLY curious to hear you conspiracy theorist's explanation for that? Oooo...maybe the government has invented an INVISIBILITY potion, and they made themselves and the explosives INVISIBLE to get in! That must be it.

Answer 4

the towers were just floors surrounding a central tower of staircases and elevators. the floors were supported by trusses that were connected to the inside shaft and the outside walls. the trusses were covered in foam-like fireproofing. when the planes hit, the fireproofing was blown off of the trusses. when the fires started, the steel trusses expanded and began to sag. eventually the sagged so much that the broke the outer wall and all floors above the floor that broke fell straight down through all the bottom floors. so basically if the had invested in incredibly expensive fireproofing, the towers would have survived. but the chances of planes crashing into the towers were too unlikely to justify the spending.

Answer 5

It was the unique way (& a bad way also ) those 2 towers were built
they showed how on a tv show
it had a card stack type of fall that caused it
something to do with the weakened top support beams & it caused them to fall the way they did

Answer 6

Each floor collapsed because of the weight and force of the floors above it falling. Buildings are not designed to handle that. If they did, each floor lower to the ground would have to be sequentially stronger to maintain the downwards FALLING force of the floors above it combined.

Answer 7

there was too much weight on top of the bottom portion that was damaged and falling down, so much so that the small portion of the tower that was undamaged couldn't handle it.

Answer 8

911 seems to not go away. Demolition experts have stated over and over that the collapse was due to blasts placed around the lower gurter to weaken then and thus the collapse and that is why there were blast holes present on the site.

Answer 9

PLANES crashed into building eventually knocked the towers down and collapsed! i read that it was terrorists

Answer 10

They were designed not to be able to tip over so they went straight dow...