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The spillway is 15" thick. http://www.mercurynews.com/2017/02/17/oroville-dam-what-made-the-spillway-collapse/ http://www.mercurynews.com/2017/02/17/oroville-d

• jessaustin 10y ago
  Great link. Haha, I wasn't even off by an order of magnitude!
• rsync 10y ago
  "The spillway is 15" thick." That is surprisingly thin. Plenty of concrete surface that you walk (not drive) on every single day is 6 or even 8 inches thick. I'm sure it's within spec and built to fulfill their design, etc., but ... I would hardly call it "burly".
  • lostlogin 10y ago
    6-8 inches is terribly wasteful and a bit of a nightmare for anyone following who wants to fix a pipe. Obviously a thick path is needed sometimes, but 8 inches will take a 10 ton truck just fine.
  • wiredfool 10y ago
    So how thick does it need to be?
    • dredmorbius 10y ago
      Cavitation at Glen Canyon Dam chewed through 3 feet of reinforced concrete and dug a 32' pit along with multiple cavitation gouges in a few minutes. https://m.youtube.com/watch?v=v98omCq1kRA https://m.youtube.com/watch?v=v98omCq1kRA http://www.popsci.com/scitech/article/2003-03/water-vapor-almost-busts-dam http://www.popsci.com/scitech/article/2003-03/water-vapor-al...
• fh973 10y ago
  Why is everybody talking abut thickness when the concrete did not break but "eroded?
  • wiredfool 10y ago
    Because they are arguing from being smart in a different field and experience with things that are several orders of magnitude off the scale of what they're dealing with. Things that work on a laptop with the dev server don't work at scale, and you won't even understand the problems till you've had some theory/experience with the problems that scale adds.
  • jacquesm 10y ago
    At a guess because they have no experience or knowledge on dimensioning something made out of concrete. You can land an A380 on a runway 17" thick... This was definitely strong enough, just not ready to withstand cavitation and given that bronze ship screws suffer from it it is hard to see what kind of liner would have solved this problem entirely. Solving it completely may ask for a totally different design, likely not a different material or thicker concrete.
• joezydeco 10y ago
  Previous images of the spillway were deceiving because of the scale involved. Here's a more recent photo with humans standing near the broken concrete. You can see how massive that structure actually is (was?). http://www.mercurynews.com/wp-content/uploads/2017/03/damageddam_2.jpg?w=620 http://www.mercurynews.com/wp-content/uploads/2017/03/damage...