Slashdot Mirror

← Back to Stories (view on slashdot.org)

Structural Engineer On the Fallacies of Movie Bridge Destruction (hackaday.com)

Posted by samzenpus on from the falling-down dept.

szczys writes: Suspension bridges like the Golden Gate Bridge and the Brooklyn Bridge are favorite victims for movie makers but are almost always shown to perform in violation of the laws of physics. Structural Engineer Alex Weinberg couldn't stay silent any longer. He covers how bridge collapses in several major films should have looked. The biggest offender? Christopher Nolan's The Dark Knight Rises.

16 of 211 comments (clear)

  1. Parade of the Pedants! by Anonymous Coward · · Score: 4, Insightful

    Next they will be telling us that X-Wing fights can't really bank in space and don't make that "rrrrrrrrrrrrrraaaaaararrarrr" noise.

    1. Re:Parade of the Pedants! by fahrbot-bot · · Score: 3, Funny

      Fiction is about suspending disbelief, ...

      Or, in this case, "suspensioning" disbelief.

      --
      It must have been something you assimilated. . . .
    2. Re:Parade of the Pedants! by lgw · · Score: 4, Interesting

      ere are a number of explanations for the sound that you hear when a fighter flies near the camera in the documentaries you're watching

      The explanation in Babylon 5 was that the fighters are actually making noises in the cockpit when other fighters fly nearby, as an audible cue to the pilot about where in the sphere to look for that other fighter. Real world fighters use all sorts of audible cues, so that the pilot can keep his eyes on the target.

      --
      Socialism: a lie told by totalitarians and believed by fools.
    3. Re:Parade of the Pedants! by dbIII · · Score: 3, Insightful

      Even fantasy has a wizard stand up and wave things around to give a clue that there is some sort of cause to the unrealistic effect.

    4. Re:Parade of the Pedants! by gl4ss · · Score: 3, Informative

      well.. in case of star trek and star wars.. there was explanations before for why tie fighters did not fight in atmosphere(they would break up) and why xwings had closing wings(closing or opening them while in space serves little purpose). also once upon a time star trek writers bothered to come up with plot lines where they didn't place the huge saucer space ship in atmosphere/gravity as well.

      then came this one director who apparently was too stupid to understand backstories OR physics, so he made movies of both which seem just silly poorly informed fan flics. never mind the space phone.

      the point is, that such things can destroy a plot. if there is a teleporter and flying to klingon home planet takes 1 hour and there is a space phone that can operate anywhere then everything else done in the movie is totally pointless.

      with the batman, it doesn't really affect the plot how it looks when the bridge breaks - what matters for the plot is just that the bridge breaks. there's big plot holes around that sure about human behavior but that is hardly the point.

      --
      world was created 5 seconds before this post as it is.
  2. Well written and funny article by Radical+Moderate · · Score: 5, Insightful

    If you have a few minutes to waste, or are passionate about suspension bridge structural integrity, well worth a read.

    --
    Never let a lack of data get in the way of a good rant.
    1. Re:Well written and funny article by Anonymous Coward · · Score: 5, Informative

      You should have read further and into the comments as well. Catenary is indeed not a parabola, but the suspension cables are. The cables are not free-hanging, they carry a considerable mass, which makes them parabola-shaped. As soon as the bridge fails, the cables turn into catenary shape, which makes his usage of the words accurate.

    2. Re:Well written and funny article by Ol+Olsoc · · Score: 5, Funny

      I stopped reading when he described a catenary as a parabola

      Yeah, what a dumbass.

      Everyone knows a catenary is a little yellow bird.

      --
      The shepherds did so well protecting the flock that the sheep no longer believed that wolves existed.
  3. The Cartoon Laws Of Physics by sconeu · · Score: 5, Funny

    http://www.dgp.toronto.edu/~ka...

    --
    General Relativity: Space-time tells matter where to go; Matter tells space-time what shape to be.
  4. James Bond physics by swm · · Score: 4, Interesting

    Heh. My brother and I grew up watching James Bond movies. And obviously, these movies are entertainment and fantasy, not documentary and physics lectures. We all knew that. We all accepted that. But one day my bother went to see a James Bond movie, and he came home positively spitting nails.

    It was the the movie where there is a chase scene on skis, so Bond skis down a mountain, and the bottom of the mountain delivers him to the roof of a chalet, and he skis down the roof, and off the edge, and lands on a picnic table, and skis across the table and then keeps on going. And when I say "picnic table", I don't mean a deserted, snow-covered table. The table was laid with a table-cloth and a picnic and people sitting all around. (I don't recall if Bond came off of it with a dinner roll stuffed in his mouth, like a Loony-Toons character).

    Anyway. The problem was that my bother skied. And he knew, from painful, first-hand experience, that if you are skiing down a mountain, and you hit just the tiniest bare spot--just the tiniest patch of dirt or rock--it feels like your ski has been grabbed by a bear trap, and you're lucky if you don't tumble right there. Skiing across a picnic table isn't a skill, or a stunt--it's just flat impossible.

    Bond movies are unrealistic, yes, but this one was unrealistic in a way that he couldn't accept. And it killed the movie for him.

  5. Re:It's a catenary curve by hondo77 · · Score: 5, Informative
    From your own citation:

    However, in a suspension bridge with a suspended roadway, the chains or cables support the weight of the bridge, and so do not hang freely. In most cases the roadway is flat, so when the weight of the cable is negligible compared with the weight being supported, the force exerted is uniform with respect to horizontal distance, and the result is a parabola...

    --
    I live ze unknown. I love ze unknown. I am ze unknown.
  6. OMG Pacific Rim by Solandri · · Score: 4, Informative

    Very fun movie to watch, but wow the bad physics. TFA mentions the Golden Gate Bridge standing in the background with the center span broken. Compared to all the other physics goofs, I didn't even notice that one.

    - Oil tanker swung like a baseball bat (it would buckle and snap in half just lifting it by one end).
    - Helicopters carrying gigantic armored robots (a C-5 Galaxy can carry a single M1A2 Abrams tank).
    - EMP-type event not affecting one robot because it's nuclear powered.
    - Nuclear reactor causing a nuclear explosion (they can't do that, their fuel isn't even the right type to attain uncontrolled criticality).
    - Giant monsters with exoskeletons (they would collapse under own weight). I let this one pass because of the Godzilla tradition, including the streets and buildings.

  7. Perhaps ... by PPH · · Score: 3, Informative

    ... Washington State can offer its consulting services for authentic bridge collapses.

    Always happy to share our vast quantity of experiences.

    --
    Have gnu, will travel.
  8. Yep, Pacific Rim was bad physics by Firethorn · · Score: 4, Informative

    I'm with you on all of those.

    For those that might be wondering about the oil tanker(and such). Consider how strong, proportionally, insects are compared to humans. This scaling continues. It's relatively easy to make a toy helicopter that can fall from several times it's height, ram it's blades into objects, and such and still come out without damage. A helicopter big enough for people? No way.

    Things like oil tankers are carefully balanced and strong where they need to be strong for their designed purpose. A tanker is designed to carry it's weight while supported on all sides by water.

    It's also why Superman's hands should tear through vehicles like paper instead of lifting them, much of the time. You don't jack up so much as 1/4 of a car without using specific points that are capable of holding the structure.

    --
    I don't read AC A human right
  9. Re:Suspend your disbelief by Anonymous Coward · · Score: 3, Funny

    > Umm, what HASN'T Neil DeGrasse Tyson whinged about?

    systemd ?

  10. Japanese disaster movies by dbIII · · Score: 3, Interesting

    It's been a bit of a shock to see that buildings in real disasters tend to fall apart just like some of the cheap and nasty models in some old low budget Japanese disaster movies. Something that initially looked very fake turned out to look just like real footage of earthquake and tsunami destruction.