This is an issue that I've wondered about a lot. I've always worried that some of my favorite buildings will eventually not be able to stand up and will have to come down in some form.
I've always had faith in a good expectancy for bridges, but buildings is a whole other story.
I think that if maintained properly, a skyscraper could last well over 100 years.
This particular one in Birmingham has been standing for exactly 100 years now and is still in pretty good shape. It could use a renovation, but it's not gonna fall down anytime soon.
Glenfield Capital
This one is 93 years old, and just underwent a renovation, and I'm not expecting it to need replacing anytime soon either.
Jason's Blog
I've also wondered. Can we expect the modern skyscrapers, the newer ones, to last as long or longer than the older ones like the ones above or maybe the Empire State Building?