6 ms·

Do you mean 50 years without maintenance? I would be shocked if major bridges weren't designed to last indefinitely.

by yosame 2y ago

onlyrealcuzzo 2y ago
Nothing lasts indefinitely...
mango7283 2y ago
I can think of at least 5 famous bridges that are way older than 50 years...
- Retric 2y ago
  Sure, and there's 100's of thousands of replaced bridges that don't immediately spring to mind. Though to be clear designed to last 50 years isn't the same as saying it will only last exactly 50 years, or that theirs nothing you can do to extend a bridges lifespan if it's replacement is running a little late.
- bee_rider 2y ago
  If it is a famous bridge, it seems possible that they’ve done some special extra maintenance, replace more wear-and-tear bits that would normally fail. Eventually you probably get the tourist attraction of Theseus.
deleted 2y ago
[deleted]
0xbadcafebee 2y ago
Depends on the bridge. Steel and concrete bridges can last for at least 100 years. But it depends on the environment, its expected use, the construction, design. Some famous major bridges failed early due to poor design or poor construction, but many still fail due to lack of maintenance. The average age of a bridge in the USA is 43 years. But we also have an epidemic of unmaintained bridges. No bridge made today is designed to last indefinitely. Many different forces will degrade the bridge over time, even with maintenance. Steel stresses weaken it over time. Concrete weathers over time due to salt, chemicals, water, wind, and the steel reinforcements tend to corrode eventually. Stone bridges may last for an exceptionally long time, but their weight and expense makes them only useful in limited applications, typically as small rail overpasses. Ones that were designed for horse and buggy end up slowly failing as heavier trucks and cars in traffic weaken them. The same fate lies for timber bridges. When well maintained they can last for 75 years, but it's expensive and requires certain skills. They were also mostly designed before heavier cars and trucks, and for less traffic. Most famous covered bridges today are being closed to traffic due to increased wear.
- btilly 2y ago
  According to https://www.fhwa.dot.gov/bridge/ https://www.fhwa.dot.gov/bridge/, the federal government oversees more than 610,000 bridges in the USA. There are a lot of unmaintained small bridges. But I'd hope that the major ones get more attention.
  - 0xbadcafebee 2y ago
    Here's a list of major bridges that need attention (& aren't getting it): https://artbabridgereport.org/state/ranking/top-bridges https://artbabridgereport.org/state/ranking/top-bridges FHWA provides up to $7 Billion in assistance in maintaining bridges. But it would take at least $125 Billion to begin dealing with the structurally deficient bridges in the USA, according to the ASCE Infrastructure Report Card[1]. Add to this the fact that many bridges in the US are privately owned, and it's the responsibility of the bridge owner to maintain them. But guess what's not profitable for a private enterprise? Maintaining bridges. Despite this, train derailments and property damage continue every year due to unmaintained bridge and train infrastructure. The executive has proposed funding for repairs, but as usual, it's not enough[2]. So far they've gotten almost half that number of bridges repaired, and pledged another $300M,[3] which is still just a drop in the bucket of what's needed of the backlog; it doesn't address all the new maintenance that will be needed each year. According to the American Road & Transportation Builders Association, there are 167 million crossings on 42,400 bridges rated in poor condition. [4] [1] https://infrastructurereportcard.org/cat-item/bridges-infrastructure/ https://infrastructurereportcard.org/cat-item/bridges-infras... [2] https://www.nbcnews.com/news/us-news/biden-has-plan-fix-america-s-broken-bridges-it-may-n1267445 https://www.nbcnews.com/news/us-news/biden-has-plan-fix-amer... [3] https://www.whitehouse.gov/briefing-room/statements-releases/2023/04/13/biden-harris-administration-announces-new-investments-repairing-bridges-across-america/ https://www.whitehouse.gov/briefing-room/statements-releases... [4] https://artbabridgereport.org/congressional/map https://artbabridgereport.org/congressional/map
    - ajb 2y ago
      Personally I'm in favour of government maintaining stuff, but https://en.m.wikipedia.org/wiki/City_Bridge_Foundation https://en.m.wikipedia.org/wiki/City_Bridge_Foundation has maintained most of London's bridges privately for nearly three quarters of a millennia so I wouldn't say it can't be done.

Do you mean 50 years without maintenance? I would be shocked if major bridges weren't designed to last indefinitely.

by yosame 2y ago

Do you mean 50 years without maintenance? I would be shocked if major bridges weren't designed to last indefinitely.

onlyrealcuzzo 2y ago

Nothing lasts indefinitely...

mango7283 2y ago

I can think of at least 5 famous bridges that are way older than 50 years...

Retric 2y ago
Sure, and there's 100's of thousands of replaced bridges that don't immediately spring to mind. Though to be clear designed to last 50 years isn't the same as saying it will only last exactly 50 years, or that theirs nothing you can do to extend a bridges lifespan if it's replacement is running a little late.
bee_rider 2y ago
If it is a famous bridge, it seems possible that they’ve done some special extra maintenance, replace more wear-and-tear bits that would normally fail. Eventually you probably get the tourist attraction of Theseus.

deleted 2y ago

[deleted]

0xbadcafebee 2y ago

Depends on the bridge. Steel and concrete bridges can last for at least 100 years. But it depends on the environment, its expected use, the construction, design. Some famous major bridges failed early due to poor design or poor construction, but many still fail due to lack of maintenance. The average age of a bridge in the USA is 43 years. But we also have an epidemic of unmaintained bridges. No bridge made today is designed to last indefinitely. Many different forces will degrade the bridge over time, even with maintenance. Steel stresses weaken it over time. Concrete weathers over time due to salt, chemicals, water, wind, and the steel reinforcements tend to corrode eventually. Stone bridges may last for an exceptionally long time, but their weight and expense makes them only useful in limited applications, typically as small rail overpasses. Ones that were designed for horse and buggy end up slowly failing as heavier trucks and cars in traffic weaken them. The same fate lies for timber bridges. When well maintained they can last for 75 years, but it's expensive and requires certain skills. They were also mostly designed before heavier cars and trucks, and for less traffic. Most famous covered bridges today are being closed to traffic due to increased wear.

btilly 2y ago
According to https://www.fhwa.dot.gov/bridge/ https://www.fhwa.dot.gov/bridge/, the federal government oversees more than 610,000 bridges in the USA. There are a lot of unmaintained small bridges. But I'd hope that the major ones get more attention.
- 0xbadcafebee 2y ago
  Here's a list of major bridges that need attention (& aren't getting it): https://artbabridgereport.org/state/ranking/top-bridges https://artbabridgereport.org/state/ranking/top-bridges FHWA provides up to $7 Billion in assistance in maintaining bridges. But it would take at least $125 Billion to begin dealing with the structurally deficient bridges in the USA, according to the ASCE Infrastructure Report Card[1]. Add to this the fact that many bridges in the US are privately owned, and it's the responsibility of the bridge owner to maintain them. But guess what's not profitable for a private enterprise? Maintaining bridges. Despite this, train derailments and property damage continue every year due to unmaintained bridge and train infrastructure. The executive has proposed funding for repairs, but as usual, it's not enough[2]. So far they've gotten almost half that number of bridges repaired, and pledged another $300M,[3] which is still just a drop in the bucket of what's needed of the backlog; it doesn't address all the new maintenance that will be needed each year. According to the American Road & Transportation Builders Association, there are 167 million crossings on 42,400 bridges rated in poor condition. [4] [1] https://infrastructurereportcard.org/cat-item/bridges-infrastructure/ https://infrastructurereportcard.org/cat-item/bridges-infras... [2] https://www.nbcnews.com/news/us-news/biden-has-plan-fix-america-s-broken-bridges-it-may-n1267445 https://www.nbcnews.com/news/us-news/biden-has-plan-fix-amer... [3] https://www.whitehouse.gov/briefing-room/statements-releases/2023/04/13/biden-harris-administration-announces-new-investments-repairing-bridges-across-america/ https://www.whitehouse.gov/briefing-room/statements-releases... [4] https://artbabridgereport.org/congressional/map https://artbabridgereport.org/congressional/map
  - ajb 2y ago
    Personally I'm in favour of government maintaining stuff, but https://en.m.wikipedia.org/wiki/City_Bridge_Foundation https://en.m.wikipedia.org/wiki/City_Bridge_Foundation has maintained most of London's bridges privately for nearly three quarters of a millennia so I wouldn't say it can't be done.