[jfengel]

There also a saying that "Anybody can build a bridge that stands up, but it takes an engineer to build a bridge that barely stands up". The 2,000 year old aqueducts were massively overbuilt, not because they wanted them to stay up forever but because they didn't know how to make them stand up for 20 years without building in a factor of 100 safety margin.

Our aqueducts won't last 2,000 years, but we built them for a fraction of the cost. They'll fall down in 100 years, but we'll rebuild them with something even stronger and even cheaper.

[Jon_Lowtek]

Tell that to the cities who see their infrastructure fall apart after 20 years and can't finance rebuilding it stronger and cheaper.

[lallysingh]

How little infrastructure works they have if they had to pay for it to be 1000x overbuilt?

[Jon_Lowtek]

there probably is a middle ground. Just because i disagree with the rather radical opinion that claims it's most efficient to just barely fulfill minimum requirement and that throw-away & buy-new should be considered for civil engineering doesn't automatically mean i favor the radical extreme opposite opinion.

I am just stating the very obvious problem.

[lallysingh]

I think ultimately the problem is that infra is an investment in future growth, but the decision makers aren't accountable on failure.

[_liww]

Got any evidence/examples for that, where the cost of building for 100 vs 1000 years has been worked out?

[jfengel]

I don't; I'm just spitballing the numbers. What really happens is that they'd rather tear down a building after 100 years and build a completely different thing. Even skyscrapers generally get torn down in less than that.

There is some infrastructure (bridges, sewer systems, dams) that are supposed to last longer than that. Bridges are often torn down and replaced, and it's probably more expensive than spending twice as much and having it last five times as long (again, spitballed numbers), but that's what fits in budgets. They don't want to discover that traffic patterns have changed and they need a different bridge, or no bridge at all and have to take it down.

That's becoming a real problem for sewer systems, which in a lot of places are reaching expected lifespan, and it's going to be ludicrously expensive to replace.

Incidentally, there are also reports that the Brutalist buildings are so overbuilt that they're hard to get rid of, even when they're bad (such as having insufficient ventilation). Gigantic piles of concrete will be there in 2,000 years, whether we want them or not.

[na85]

One of the pyramids at Giza was built over the course of 20 years by tens of thousands of slaves.

Taking the (shamefully low) minimum wage in the USA of $7.25/hr and assuming your employees work 40-hour weeks with 2 weeks vacation, that's $14,500 (again, shamefully low but let's roll with it).

Ten thousand of those workers costs you $145 million per year, and for twenty years that's some $2.9 Billion.

It's pretty obvious we could build a pyramid, which is basically just a hill of rubble with worked sides, for a lot less today if we only needed it to stay up for a few years.

[Rebelgecko]

For reference, the Bass Pro Shop pyramid in Memphis cost around $100m. The largest pyramid in the UK cost the government of Qatar over half a billion dollars