How amazing is it that all the main supports collapse simultaneously?

Question

A truly remarkable coincidence! Especially for a building that had only been on fire and struck by some debris.

http://video.google.com/videoplay?docid=3898962504721899003

Answer 1

I suggest you visit rense.com. There's a lot of discussions there on your side.

Me? I'm a structural engineer and I don't see why the collapse can't happen. I was in front of the TV during the incident and watching the entire TV coverage. It was not simultaneous as you claimed. The collapse was sequential. From an upper level down. This only means that there was a build up of the impact energies from one floor down to the other.

Answer 2

It's not a coincidence at all. Suppose one support fails. Immediately, the stress on the rest of the already-weakened supports is increased and they fail. The process may be sequential and still look simultaneous to the casual observer.

Answer 3

Why WOULDN'T it collapse straight down?  The only force on it is gravitational, which is straight down.  I hate to state the obvious, but a building is not a tree, and there wasn't a lumberjack hacking away at the base with an axe to make it fall sideways.

Do you not expect that, with a group of supports which have similar load ratings, all with a similar amount of load, that when one support collapses, the sudden increase in downward force on the other similar supports would cause them all to collapse at virtually the same time?

Have you examined videos of other buildings of similar height and structure, that are known to collapse due to fire, and seen them to have a tendency to collapse in any other way?

You say you're a scientist, so do some research instead of just believing in a random conspiracy theory because of stupid internet videos.

Personally I'm a little surprised that people are still talking about this.  But I guess we still have Apollo moon landing deniers and Holocaust deniers, so I should have expected it.

edit: hmm... so your video of a 'gentleman from MIT' I thought suspicious for some reason.  Checked the MIT website and they don't have anyone listed under the name Jeff King in the civil or mech engineering sites, either as faculty or postdoc.

edit2:

"Apparently you have seen something I have not."

No, you're the one seeing things that aren't there.  Alright, awesome, you claim you've seen a 'litany of videos' involving OTHER steel frame, ~50 story buildings with trapezoidal footprints collapsing due to fire.  --show me--

"And apparently you have not bothered to view either of these posted videos."

Well gee, that's a reasonable conclusion for you to come to when I'm talking about things IN THE VIDEOS.  Are you implying that I'm a psychic?

"How do you explain that there was virtually no macroscopic pieces of concrete left? Not even pieces of office furniture? Everything was virtually atomized."

Why would I be surprised by that?  The material was heated to beyond it's structural limits, and then subjected to MASSIVE amounts of further energy in the collapse.

I'm glad that you've viewed a litany of videos of other similar buildings collapsing due to fire, that way it will be easy for you to show me one of these videos where all the material was left intact.

"What are jet engines made of that they're so much more resilient than trusses on an 80 story building? Wouldn't those melt too... or, I mean, lose 75% of their strength and occasionally explode in mid flight?"

You do realize that steel is not the most temperature resistant material in existence, right?  And that most of the energy that heated the steel in the ground came from the collapse, not the fire?  Jet engines don't typically deal with million ton collapses in mid-flight.

You knew that though, you're a 'scientist.'

Wait a minute, you said '80 story building.'  WTC 7 was 47 stories.

Are you SURE you've done your research here?

Watching videos on youtube does not constitute research.

Answer 4

If the WTC conspiracy theories are true, they'd be published in reputable peer-reviewed engineering journals.

EDIT: If I could be bothered I'd send a link to another engineer that says there's nothing abnormal about the collapse

Answer 5

If you were a scientist you would know that at the temperatures reached in the fire steel loses about 75% of its strength - buildings are designed with a 100% margin of error on stresses, so it was easily hot enough to surpass this.

You would also know that structural failures propogate - otherwise a scratch in a bit of glass would not enable it to be snapped and glaziers would be out of business. Its called Piers-Ingliss stress concentration.

So you are clearly not a scientist, or at least not a very good one.