Idle question-World Trade Center

Discussion in 'Quackenbush's' started by BattleshipTexas, Feb 8, 2009.

  1. BattleshipTexas

    BattleshipTexas 1,000+ Posts

    Okay, I posted this on Quack's not the West Mall so no politics. Also no crackpot conspiracy theories, e.g. demolition in the buildings. Assume for this thread there is no massive conspiracy that happened and start your own thread if that interests you.

    What I want to know is this. What if the 2nd plane had not hit the WTC, like maybe the passengers managed to divert or crash it somewhere else. What would have happened? Would the first tower have still collapsed? Assuming so, what would that collapse have done to the 2nd tower that was not hit? Might the destruction even have been worse if it "knocked it over" instead of collapsing straight downward? Would the 2nd tower still have collapsed? Or just had one side ripped up badly?

    Any discussion appreciated, engineers encouraged to speculate.
     
  2. Dionysus

    Dionysus Cocky + Relaxed Admin

    I'm not an engineer but I would think that one tower's collapse would have rendered the surrounding area so unstable as to compromise the structural integrity of the other tower, or the foundation anyway. That's a heck of a lot of concrete and steel slamming into the ground at the base of another building.
     
  3. FondrenRoad

    FondrenRoad 1,000+ Posts

    I'm no engineer either, but I remember reading something shortly after 911 that claimed that they would not have collapsed. Don't remember where I read it now though. The 2nd tower collapsed first. It was said that its collapse caused the already damaged first tower to collapse. And the first tower may not have collapsed from the plane alone. I think the first plane did not hit the center of the structure, but I haven't read anything on 911 in years, so my memory is a little fuzzy.

    It would have been a hell of a lot worse if they fell over instead of going straight down. It could have been like dominoes and could have taken down nearly all of downtown.
     
  4. CTGA_Horn

    CTGA_Horn 250+ Posts

    I'm not an engineer but I play one on TV so I'll throw my two cents in.

    I think the chances of them toppling over sideways to any great extent were quite small. They were complex structures designed to flex in the wind. The force of the wind pushing them sideways (before the attatcks) was tremendous.

    They were also mostly air if you think about it. Anything pushing it from the side hard enough to knock it over would break through the outer skin and encounter air space and very bendable floors.

    I think due to the absolutely huge structural elements near the ground, they were quite bottom heavy. Far more than their appearance would make you believe.

    The first tower would have stood considerably longer (a few hours maybe) then would have fallen anyway. There were no actions being taken to actually put out the fire. It would not have gone out by itself.

    There would have been massive damage to the other tower. Not sure if it would have stood. Probably it would never have been occupied again. The first 15 floors would have been buried in rubble.

    In terms of "damage", there would have been a tremendous difference -- there would have been a lot less deaths. A lot less.
     
  5. OldHippie

    OldHippie 2,500+ Posts

    I'm not an engineer but I drove one of those little trains at the park once around the circuit. Seems that if one fell straight down and the other was not hit by a plane, there would have been no reason for the second to fall. Seems like it was the fire caused by the jet fuel that caused the structural weakness that caused the collapse. The second, theoretically fire free building would have certainly been damaged by the debris but without the heat, my guess, having driven a small park train once, is that it would have remained standing, been repaired and lived a long life as a surviving twin. Perhaps the idea of rebuilding the lost tower might even have been considered at some point in the future.
     
  6. madscientist

    madscientist 1,000+ Posts

    what was it that caused the 3rd building to fall? was it the damage caused by the other ones?
     
  7. AstroVol

    AstroVol 500+ Posts

    I am a structural engineer. In the winter of '01, just months after the attack, I was in attendance at the first public appearance of the structural engineer on the WTC, Les Robertson. A similar question was posed, and he did not believe the 2nd would have fallen had it not been hit. After watching the presentation, it's amazing they stood as long as they did. So much of the supporting infrastructure was destroyed, it looked like it was going to collapse under its own weight even without the fire.

    What's interesting to note is that each of the two WTC towers was actually designed to withstand the impact of a very large airplane traveling at high speed (I could swear he said B-52 bomber). What he did not count on was the thousands of gallons of burning jet fuel, burning at temperatures far greater than an average building fire. The impact destroyed the fireproofing, and the tremendous heat weakened the columns. His contention was that the buildings would have stood long enough to get everyone out if there were no fire.
     
  8. Macanudo

    Macanudo 2,500+ Posts


     
  9. 911_horn

    911_horn 500+ Posts

    The towers were built to withstand a Boeing 717 not a B52. a 717 would be the equivalent of a 727 or the more modern 737. The 757 that hit the thing was quite a bit bigger in addition to carrying much more fuel than a 717. as for if the other tower, etc I have no idea. not an engineer.
     
  10. UTIceberg

    UTIceberg 250+ Posts

    I'm a civil engineer (though not in structures) and AstroVol pretty much said it perfectly. I too have seen several presentations on the collapse and what caused the actual failure and that's pretty much the same explanation I got. The high temps caused by the burning gasoline changed the phase of the steel in the columns which correspondingly changed the physical properties of the material and causing failure. Unlike water which has three phases we are all familiar with: solid, liquid, gas each with distinct properties, steel has dozens of phases all with unique properties. In other words, the steel was still "solid" but went from solid phase "a" to solid phase "b" and as a result did not have the same properties as before, leading to the failure in the columns.

    So, it is unlikely that the second tower would have collapsed had it not been hit by a plane. And again echoing Astro here, it is pretty remarkable that the towers stood as long as they did considering what they went through.
     
  11. FondrenRoad

    FondrenRoad 1,000+ Posts

    Is it possible to build a building that could withstand that heat?
     
  12. UTIceberg

    UTIceberg 250+ Posts

    It's always possible, but practical is a different matter. Sufice it to say intentionally crashing loaded jumbo jets into sky scrapers wasn't something that was generally anticipated when most buildings were built prior to 9/11
     
  13. AstroVol

    AstroVol 500+ Posts


     
  14. Hornius Emeritus

    Hornius Emeritus 2,500+ Posts


     
  15. Dionysus

    Dionysus Cocky + Relaxed Admin


     
  16. chango

    chango 2,500+ Posts


     
  17. FondrenRoad

    FondrenRoad 1,000+ Posts

    Its amazing that B-52s are even capable of flight. They fly over my grandma's house in Bossier. They are ******* huge.
     
  18. MGS

    MGS 500+ Posts

    So by Boeing 717, do you mean DC-9?
     
  19. BattleshipTexas

    BattleshipTexas 1,000+ Posts


     
  20. HornBud

    HornBud 2,500+ Posts

    I think it was a B25 that hit the Empire. A few major differences: ESB has a lot more concrete than both WTC towers combined, B25 didn't carry jet fuel, and the speed and mass of the b25 was significantly less than the planes that struck the WTC.
     
  21. BattleshipTexas

    BattleshipTexas 1,000+ Posts

    [​IMG]


    They hung a newspaper photographer by his legs out a window to get this picture of the hole left by the B-25 in the Empire State Building. Not me.
     

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