zlacker

>>hrl+(OP)
I don't know if it is really a problem, more like a tradeoff. Reinforced concrete costs less and enables shapes that are impossible without it, with the downside that the buildings last 50 years instead of 100+ years. The present value of a building that lasts 50 years is not that much different that the same one that lasts 100 years.

With that in mind, it makes perfect sense to make an office building out of reinforced concrete.

>>idoh+S8
It will become a very big problem if/when buildings start collapsing with people in them.

I grew up partly in an 18 story reinforced concrete building built in the 1920s. The apartment I lived in was recently sold for several million dollars.

Once, when there was a leak and the plaster came off, the underlying concrete was exposed and it scraped away like very weak sandstone.

How strong is the building and when will it collapse? Does anyone know? Is anyone testing?

I think the answer to both of those questions is "no". Everyone seems to assume they will stand forever. They won't.

>>raylad+Dc
Unless you are living in a developing country, the answer to the second question should be "yes".

>>diegoc+Hd
It should be but is it? I don't think anyone ever tested this building, which has a combined market value of probably close to $200M.

None of the owners want to know that their investments are worthless. So nothing will be checked unless its required by law.

>>raylad+ef
In Spain buildings older than 50 years are required to be inspected and mandated to make reforms if necessary. I doubt it's much different in the rest of Europe/north America

Also, buildings don't fall all of sudden. You would get a lot of cracks and problems before your building collapses

>>diegoc+xh
... buildings don't fall all of sudden...

False.

Large structural failures can be catastrophic and unexpected.

Buildings can and do collapse quite suddenly. The examples here are not necessarily caused by reinforced concrete failures (though several cases make use of reinforced concrete --- generally other failures lead to the collapse). But the final failure of a system under load and near its structural limits can be quite sudden.

Taiwan bridge: https://youtube.com/watch?v=OSCPUGHUyIs https://youtube.com/watch?v=WqHXMswLwPM

Minnesota I35W bridge collapse: https://youtube.com/watch?v=CMdv2wRaqo4

Jerusalem dance floor: https://youtube.com/watch?v=5UOb7RBWlak

Morandi bridge, Italy: https://youtube.com/watch?v=V479srTBlAk

Hard Rock Hotel New Orleans (under construction): https://youtube.com/watch?v=WC8k5unvyfU

Sampoong Department Store, Korea (visualisation): https://youtube.com/watch?v=aQXTSR9koCg

The Kansas City Hyatt Regency skywalk collapse (1981) would be another instance. I don't believe there's video of the failure itself, though Grady from Practical Engineering has a great explainer of what went wrong: https://youtube.com/watch?v=VnvGwFegbC8