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I'm not a civil engineer or even close, but I did note that some Roman concrete structures have lasted 2000 years, and nothing we're building now has any chance

I'm not a civil engineer or even close, but I did note that some Roman concrete structures have lasted 2000 years, and nothing we're building now has any chance of lasting that long. 100 years is not much, considering what infrastructure in developed countries costs nowadays.

hasmolo 5y ago
it's easy to forget that modern buildings have much more complex loads, higher stress weights, and the added benefit of us being able to calculate strength. it's kind of similar to the idea a 'craftsman' house used to cost the equivalent of 50k, and now a house is 500k. That's down to electrical service, having gas, appliances, modern codes, and more. shit, it's been so effective at reducing random fires that fire houses now have to include EMS for a reason to exist. it's cool as shit that a bridge over an ocean can last 100 years, do you have any classic examples of bridges or buildings in continuous use for thousands of years? of course not, it would wear out. the buildings that last are directly proportional to how used they are, unless maintained like a religious building.
- bondarchuk 5y ago
  Friendly inflation reminder: 50k in, say, 1950 dollars is roughly equivalent to 500k today. But of course one can argue that QoL improvements like you mention are exactly what makes up (some part of) inflation.
- yorwba 5y ago
  > do you have any classic examples of bridges or buildings in continuous use for thousands of years? of course not, it would wear out. The Pantheon in Rome is famous for having the world's largest unreinforced concrete dome: https://en.wikipedia.org/wiki/Pantheon,_Rome https://en.wikipedia.org/wiki/Pantheon,_Rome Various Roman bridges are still in use: https://en.wikipedia.org/wiki/Ponte_di_Tiberio_(Rimini) https://en.wikipedia.org/wiki/Ponte_di_Tiberio_(Rimini) Being in continuous use makes it more likely that a building will last long, since otherwise people might tear it down to use the stones elsewhere. (E.g. what happened to the Colosseum.)
  - Cupertino95014 5y ago
    If you read up on "Roman concrete" you find out that it used a volcanic sand "pozzolana" [1] which is difficult to find in some parts of the world. There was, supposedly, some American professor trying to find a recipe for concrete that was as good as the Roman type but used more available materials. I don't know the current status. [1] https://en.wikipedia.org/wiki/Pozzolana https://en.wikipedia.org/wiki/Pozzolana
- samatman 5y ago
  > do you have any classic examples of bridges or buildings in continuous use for thousands of years? of course not The Pond du Gard aqueduct is quite famous in fact.
alliao 5y ago
they get stronger over time, modern capital requirements probably would not consider funding buildings that are weakest when new and only operationally stable after couple of hundred years... https://www.science.org/content/article/why-modern-mortar-crumbles-roman-concrete-lasts-millennia https://www.science.org/content/article/why-modern-mortar-cr...
justin66 5y ago
I've seen estimates of the lifespan of the Hoover Dam on the order of 10,000 years. If you left it alone some exciting things would probably happen because it's not all just concrete, there's turbines and ducts and so on, but the concrete structure will last a long time.

hasmolo 5y ago

it's easy to forget that modern buildings have much more complex loads, higher stress weights, and the added benefit of us being able to calculate strength. it's kind of similar to the idea a 'craftsman' house used to cost the equivalent of 50k, and now a house is 500k. That's down to electrical service, having gas, appliances, modern codes, and more. shit, it's been so effective at reducing random fires that fire houses now have to include EMS for a reason to exist. it's cool as shit that a bridge over an ocean can last 100 years, do you have any classic examples of bridges or buildings in continuous use for thousands of years? of course not, it would wear out. the buildings that last are directly proportional to how used they are, unless maintained like a religious building.

bondarchuk 5y ago
Friendly inflation reminder: 50k in, say, 1950 dollars is roughly equivalent to 500k today. But of course one can argue that QoL improvements like you mention are exactly what makes up (some part of) inflation.
yorwba 5y ago
> do you have any classic examples of bridges or buildings in continuous use for thousands of years? of course not, it would wear out. The Pantheon in Rome is famous for having the world's largest unreinforced concrete dome: https://en.wikipedia.org/wiki/Pantheon,_Rome https://en.wikipedia.org/wiki/Pantheon,_Rome Various Roman bridges are still in use: https://en.wikipedia.org/wiki/Ponte_di_Tiberio_(Rimini) https://en.wikipedia.org/wiki/Ponte_di_Tiberio_(Rimini) Being in continuous use makes it more likely that a building will last long, since otherwise people might tear it down to use the stones elsewhere. (E.g. what happened to the Colosseum.)
- Cupertino95014 5y ago
  If you read up on "Roman concrete" you find out that it used a volcanic sand "pozzolana" [1] which is difficult to find in some parts of the world. There was, supposedly, some American professor trying to find a recipe for concrete that was as good as the Roman type but used more available materials. I don't know the current status. [1] https://en.wikipedia.org/wiki/Pozzolana https://en.wikipedia.org/wiki/Pozzolana
samatman 5y ago
> do you have any classic examples of bridges or buildings in continuous use for thousands of years? of course not The Pond du Gard aqueduct is quite famous in fact.

alliao 5y ago

they get stronger over time, modern capital requirements probably would not consider funding buildings that are weakest when new and only operationally stable after couple of hundred years... https://www.science.org/content/article/why-modern-mortar-crumbles-roman-concrete-lasts-millennia https://www.science.org/content/article/why-modern-mortar-cr...

justin66 5y ago

I've seen estimates of the lifespan of the Hoover Dam on the order of 10,000 years. If you left it alone some exciting things would probably happen because it's not all just concrete, there's turbines and ducts and so on, but the concrete structure will last a long time.