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> In August, the Italian government revived long-standing plans to build a vast €13.5bn (£11.7bn) suspension bridge over the strait – one of the world's most am

by kibwen 1y ago

> In August, the Italian government revived long-standing plans to build a vast €13.5bn (£11.7bn) suspension bridge over the strait – one of the world's most ambitious engineering projects. What makes it particularly ambitious? The strait of Messina is two miles across, and I don't think that even cracks the top 100 of the world's longest bridges.

comrade1234 1y ago
I don't really know but looking at a depth map at the narrowest part it's pretty deep at 200+ meters. At another section where it's wider it's about 100m. Not sure where they're planning to build it.
agos 1y ago
it's geologically and seismically challenging. The project is a single span for 3300 meters, which would make it one of the longest in the world of the kind. The strong presence of organized crime in the area also makes a lot of people uneasy about the whole deal, but that's not a technical issue.
arethuza 1y ago
If you sort the list on Wikipedia by "main span length" rather than overall bridge length then the longest span is just over 2km? https://en.wikipedia.org/wiki/List_of_longest_bridges https://en.wikipedia.org/wiki/List_of_longest_bridges
- myself248 1y ago
  Apples to appleseeds. The main span doesn't cross the entire gap. The main span is just the middle part, typically a small fraction of the overall length between endpoints or shorelines, however those are defined.
  - arethuza 1y ago
    The current design for the Strait of Messina bridge has a main span of 3.3km - which is quite a bit more than the current longest span? https://en.wikipedia.org/wiki/Strait_of_Messina_Bridge https://en.wikipedia.org/wiki/Strait_of_Messina_Bridge
  - rob74 1y ago
    Well, in this case, the main span will cross the entire gap (or at least it's planned to do it). This BBC article has a rendering which is higher resolution than the one in the Wikipedia article: https://www.bbc.com/news/articles/c80d74v0e4lo https://www.bbc.com/news/articles/c80d74v0e4lo
  - IAmBroom 1y ago
    Nice adaptation of the metaphor. Golf clap.
easyThrowaway 1y ago
A tunnel would be massively easier to build, but there's strong political hubris and greed in keeping the original single-span bridge project from the early '60s.
- fph 1y ago
  The strait is unusually deep, 250 m. That seems quite a slope.
  - bobthepanda 1y ago
    Apparently we already have underwater tunnels 292 meters below sea level https://en.wikipedia.org/wiki/Ryfylke_Tunnel#:~:text=The%20Ryfylke%20Tunnel%20(Norwegian:%20Ryfylketunnelen,Hundv%C3%A5g%20island%20in%20Stavanger%20municipality. https://en.wikipedia.org/wiki/Ryfylke_Tunnel#:~:text=The%20R...
    - fph 1y ago
      It's also a question of length though. If you go down 292 m and then back up over 14.4 km, that is a 4% slope on average. But to go down 250 m and then back up over 3.3 km, it requires a 15% average slope.
      - bobthepanda 1y ago
        I mean both Sicily and mainland Italy have more than 7km of land on either side to ascend into.
joakleaf 1y ago
It will be by far the longest span of a suspension bridge at 3300 meter. The current longest is in Turkey at 2023 meter. Each of the pylons of the Messina Bridge will be around 400 meters tall. Which is taller than the Empire State Building. The strait is too deep, with too much current and seismic activity to place the pylons in the water. So they have to be on the shore, as I understand it.
antonvs 1y ago
Shortest summary I could quickly find: > "...building a suspension bridge of this scale poses significant engineering challenges. The Strait of Messina is known for strong winds, seismic activity, and deep waters, all of which complicate construction and long-term stability. Engineers will need to ensure the structure can withstand earthquakes, which aren't unheard of in the region, while addressing corrosion from the salty marine environment." -- https://www.iflscience.com/worlds-longest-suspension-bridge-between-sicily-and-italys-boot-gets-go-ahead-80385 https://www.iflscience.com/worlds-longest-suspension-bridge-... I remember reading an article, posted here on HN, that went into much more depth about why this was all unusually challenging, but I haven't found it again.

by kibwen 1y ago

comrade1234 1y ago

I don't really know but looking at a depth map at the narrowest part it's pretty deep at 200+ meters. At another section where it's wider it's about 100m. Not sure where they're planning to build it.

agos 1y ago

it's geologically and seismically challenging. The project is a single span for 3300 meters, which would make it one of the longest in the world of the kind. The strong presence of organized crime in the area also makes a lot of people uneasy about the whole deal, but that's not a technical issue.

arethuza 1y ago

If you sort the list on Wikipedia by "main span length" rather than overall bridge length then the longest span is just over 2km? https://en.wikipedia.org/wiki/List_of_longest_bridges https://en.wikipedia.org/wiki/List_of_longest_bridges

myself248 1y ago
Apples to appleseeds. The main span doesn't cross the entire gap. The main span is just the middle part, typically a small fraction of the overall length between endpoints or shorelines, however those are defined.
- arethuza 1y ago
  The current design for the Strait of Messina bridge has a main span of 3.3km - which is quite a bit more than the current longest span? https://en.wikipedia.org/wiki/Strait_of_Messina_Bridge https://en.wikipedia.org/wiki/Strait_of_Messina_Bridge
- rob74 1y ago
  Well, in this case, the main span will cross the entire gap (or at least it's planned to do it). This BBC article has a rendering which is higher resolution than the one in the Wikipedia article: https://www.bbc.com/news/articles/c80d74v0e4lo https://www.bbc.com/news/articles/c80d74v0e4lo
- IAmBroom 1y ago
  Nice adaptation of the metaphor. Golf clap.

easyThrowaway 1y ago

A tunnel would be massively easier to build, but there's strong political hubris and greed in keeping the original single-span bridge project from the early '60s.

fph 1y ago
The strait is unusually deep, 250 m. That seems quite a slope.
- bobthepanda 1y ago
  Apparently we already have underwater tunnels 292 meters below sea level https://en.wikipedia.org/wiki/Ryfylke_Tunnel#:~:text=The%20Ryfylke%20Tunnel%20(Norwegian:%20Ryfylketunnelen,Hundv%C3%A5g%20island%20in%20Stavanger%20municipality. https://en.wikipedia.org/wiki/Ryfylke_Tunnel#:~:text=The%20R...
  - fph 1y ago
    It's also a question of length though. If you go down 292 m and then back up over 14.4 km, that is a 4% slope on average. But to go down 250 m and then back up over 3.3 km, it requires a 15% average slope.
    - bobthepanda 1y ago
      I mean both Sicily and mainland Italy have more than 7km of land on either side to ascend into.

joakleaf 1y ago

It will be by far the longest span of a suspension bridge at 3300 meter. The current longest is in Turkey at 2023 meter. Each of the pylons of the Messina Bridge will be around 400 meters tall. Which is taller than the Empire State Building. The strait is too deep, with too much current and seismic activity to place the pylons in the water. So they have to be on the shore, as I understand it.

antonvs 1y ago

Shortest summary I could quickly find: > "...building a suspension bridge of this scale poses significant engineering challenges. The Strait of Messina is known for strong winds, seismic activity, and deep waters, all of which complicate construction and long-term stability. Engineers will need to ensure the structure can withstand earthquakes, which aren't unheard of in the region, while addressing corrosion from the salty marine environment." -- https://www.iflscience.com/worlds-longest-suspension-bridge-between-sicily-and-italys-boot-gets-go-ahead-80385 https://www.iflscience.com/worlds-longest-suspension-bridge-... I remember reading an article, posted here on HN, that went into much more depth about why this was all unusually challenging, but I haven't found it again.