Part of the shorter lifespan is that our cities grow much faster. Why build infrastructure that last 200 years if it needs to be ripped up in 50 due to no longer meeting population demands?
When they transported 100% of the output of a spring there’s no need to update the infrared as a city grows there was no way to go past 100%. Dams have the same kind of limits and are regularly designed for 150+ year lifetimes. The Hoover Dam is just about to turn 90 and it’s likely to last another 100 years.
Quite a lot of the built environment is designed for 100+ year lifespans. When it isn’t there’s often very good reasons. It’s kind of amazing we get road bridges to last as long as they do when you consider the physical and chemical assault they’re constantly under all while trying to minimize weight and cost.
Building a bridge that spans a wide road or river is extremely expensive without using iron or steel. If you do, that limits the lifespan because they corrode.
We never forgot how to build stone bridges, we stopped doing it most of the time because nobody wants to pay for it.
Iron bridges can easily last 100+ years with maintenance, faster replacement is generally cheaper which is why you see exposed metal on so many highway bridges.
Traffic on traditional stone bridge designs would quickly destroy them.
This is true. I was thinking of things like roads, water mains, sewer pipes, and even homes.
Yeah a house that lasts 200 years sounds good in principle, until you think about the kind of material and energy efficiency advances we’ve had in just the last 25.
