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Thanks, that's really informative. So what's the trick with something like the Hoover Dam, where (I'm assuming) major reworking every 100 years isn't acceptabl

Thanks, that's really informative. So what's the trick with something like the Hoover Dam, where (I'm assuming) major reworking every 100 years isn't acceptable? Did they find some way to avoid steel, or maybe make it piece-wise replaceable?

lmm 5y ago
I think they did it all with non-reinforced concrete, which can last more or less forever. It has good compressive strength but hardly any tensile strength, so they'll have had to design the dam in a way that doesn't depend on that.
- jacobolus 5y ago
  Yes, 2.5 million cubic meters of unreinforced concrete. According to Wikipedia they took some core samples in 1995 and found the concrete to be stronger than when it was poured. "Last more or less forever" sounds about right. There is some steel involved, in embedded cooling pipes that were used to speed the concrete curing process and later filled with grout.
- abduhl 5y ago
  Large concrete dams like Hoover are almost invariably arch dams which are shaped so that the entire dam goes into compression as the water load comes on, so there is no real need for tensile steel. These dams can take decades to cure and just get stronger over time. The connections to the rock are usually reinforced - steel that's encased in concrete is generally thought to be relatively immune to most corrosion effects for the design life of any particular structure (plus a lot longer if it's maintained).