4 ms·

The idea of sealing each section and then floating it into position seems so elegant and simple. Is this a common technique for a project of this style, or a ne

The idea of sealing each section and then floating it into position seems so elegant and simple. Is this a common technique for a project of this style, or a new innovation?

baud147258 5y ago
looking at videos YT is suggesting, which are mostly about construction of underwater tunnels, it seems it's common
brnt 5y ago
All tunnels in the Netherlands are built this way. You can't drill through mud.
- ghostly_s 5y ago
  I think OP is referring to using the interior space of the segment for buoyancy rather than hauling it on a barge, not prefabrication in general.
  - brnt 5y ago
    The caisson technique is not new.
    - jamiek88 5y ago
      It’s not caisson either. How about understanding the conversation and questions being asked before jumping in with dismissive (incorrect) answers?
    - ghostly_s 5y ago
      ? This is not caisson construction.
      - brnt 5y ago
        It's what the construction consortium writes they are doing [1]. Looks like it too? [1] https://www.betoningenieure.de/dateien/FT2018/Seiten/fehmarn.html https://www.betoningenieure.de/dateien/FT2018/Seiten/fehmarn...
        sitkack 5y ago
        What that shows is the mold that is used to make the tunnel segments. A Caisson is like an upside down boat turned into a diving bell that is used to get access to the seafloor. https://en.wikipedia.org/wiki/Caisson_(engineering) https://en.wikipedia.org/wiki/Caisson_(engineering) Famously used in the construction of the Brooklyn Bridge https://fromthepublicdomain.com/2020/08/26/the-brooklyn-bridge/ https://fromthepublicdomain.com/2020/08/26/the-brooklyn-brid... 10 minute documentary on Brooklyn Bride https://www.youtube.com/watch?v=Ct_-0GC_QfM https://www.youtube.com/watch?v=Ct_-0GC_QfM The Ken Burns' documentary is really worth a watch, https://en.wikipedia.org/wiki/Brooklyn_Bridge_(film) https://en.wikipedia.org/wiki/Brooklyn_Bridge_(film) https://www.pbs.org/kenburns/brooklyn-bridge/ https://www.pbs.org/kenburns/brooklyn-bridge/
        ghostly_s 5y ago
        I think this might be a translation issue - the German Senkkasten is literally "sinking-box," so maybe it does apply to structures like these segments too? But the English caisson only means the diving-bell things.
        jaclaz 5y ago
        Yes it must be lost in translation somehow, in Italian also "cassone" is both the "diving bell" thingy and the "sinking box". The Mose in Venice (though it is a sort of foldable dam) has inside a tunnel for maintenance and it was built in a similar way: https://www.mosevenezia.eu/cassoni/ https://www.mosevenezia.eu/cassoni/
        Someone 5y ago
        > But the English caisson only means the diving-bell things. https://en.wikipedia.org/wiki/Caisson_(engineering) https://en.wikipedia.org/wiki/Caisson_(engineering) disagrees. It distinguishes between box caissons and open caissons.
BurningFrog 5y ago
I think it's the only way to do it: https://en.wikipedia.org/wiki/Immersed_tube#Construction https://en.wikipedia.org/wiki/Immersed_tube#Construction
asdfman123 5y ago
It can't possibly be new. Multi-billion dollar construction projects are fairly common and that kind of capital investment makes people very clever. Oil rigs definitely follow the prefabrication and then float-into-position approach, and have been doing that for a long time. I'm sure there's a good reason why it's more cost effective or feasible to do this instead of drilling a tunnel under the seabed.
- Taniwha 5y ago
  Not new - as mentioned above the BART trans-bay tube was built this way back in the '70s
- mstade 5y ago
  To your point of this technique not being new: the mulberry harbors the allies built following the d-day invasion of operation overlord made use of prefabricated sections code named phoenix, that were towed into place and then sunk to form the structure of the harbor. They were so named, I think, because after being built they were sunk off the coast of England before being refloated in preparation of the operation, i.e. like the phoenix the rose, or something poetic like that. If you're ever in or around Normandy I highly recommend a visit to the beaches. They're much bigger than I had imagined, and it really hit home then what a massive operation it was. Anyway – no, the technique is not new.
ianburrell 5y ago
The immersed tube technique is used for the BART Transbay Tube, Chesapeake Bay Bridge Tunnel, and Øresund Bridge Tunnel between Denmark and Sweden. The Fehmarn Belt will be the longest when it opens. I think the technique is mainly used for shallow tunnels in flat areas.
Someone 5y ago
The scale is different, but it’s far from a new idea. https://en.wikipedia.org/wiki/Immersed_tube#Examples https://en.wikipedia.org/wiki/Immersed_tube#Examples: The first tunnel constructed with this method was the Shirley Gut Siphon, a six-foot sewer main laid in Boston, Massachusetts in 1893. The first example built to carry traffic was the Michigan Central Railway Tunnel constructed in 1910 under the Detroit River, and the first to carry road traffic is the Posey Tube, linking the cities of Alameda and Oakland, California in 1928. The oldest immersed tube in Europe is the Maastunnel in Rotterdam, which opened in 1942.

The idea of sealing each section and then floating it into position seems so elegant and simple. Is this a common technique for a project of this style, or a new innovation?

baud147258 5y ago

looking at videos YT is suggesting, which are mostly about construction of underwater tunnels, it seems it's common

brnt 5y ago

All tunnels in the Netherlands are built this way. You can't drill through mud.

ghostly_s 5y ago
I think OP is referring to using the interior space of the segment for buoyancy rather than hauling it on a barge, not prefabrication in general.
- brnt 5y ago
  The caisson technique is not new.
  - jamiek88 5y ago
    It’s not caisson either. How about understanding the conversation and questions being asked before jumping in with dismissive (incorrect) answers?
  - ghostly_s 5y ago
    ? This is not caisson construction.
    - brnt 5y ago
      It's what the construction consortium writes they are doing [1]. Looks like it too? [1] https://www.betoningenieure.de/dateien/FT2018/Seiten/fehmarn.html https://www.betoningenieure.de/dateien/FT2018/Seiten/fehmarn...
      - sitkack 5y ago
        What that shows is the mold that is used to make the tunnel segments. A Caisson is like an upside down boat turned into a diving bell that is used to get access to the seafloor. https://en.wikipedia.org/wiki/Caisson_(engineering) https://en.wikipedia.org/wiki/Caisson_(engineering) Famously used in the construction of the Brooklyn Bridge https://fromthepublicdomain.com/2020/08/26/the-brooklyn-bridge/ https://fromthepublicdomain.com/2020/08/26/the-brooklyn-brid... 10 minute documentary on Brooklyn Bride https://www.youtube.com/watch?v=Ct_-0GC_QfM https://www.youtube.com/watch?v=Ct_-0GC_QfM The Ken Burns' documentary is really worth a watch, https://en.wikipedia.org/wiki/Brooklyn_Bridge_(film) https://en.wikipedia.org/wiki/Brooklyn_Bridge_(film) https://www.pbs.org/kenburns/brooklyn-bridge/ https://www.pbs.org/kenburns/brooklyn-bridge/
      - ghostly_s 5y ago
        I think this might be a translation issue - the German Senkkasten is literally "sinking-box," so maybe it does apply to structures like these segments too? But the English caisson only means the diving-bell things.
        jaclaz 5y ago
        Yes it must be lost in translation somehow, in Italian also "cassone" is both the "diving bell" thingy and the "sinking box". The Mose in Venice (though it is a sort of foldable dam) has inside a tunnel for maintenance and it was built in a similar way: https://www.mosevenezia.eu/cassoni/ https://www.mosevenezia.eu/cassoni/
        Someone 5y ago
        > But the English caisson only means the diving-bell things. https://en.wikipedia.org/wiki/Caisson_(engineering) https://en.wikipedia.org/wiki/Caisson_(engineering) disagrees. It distinguishes between box caissons and open caissons.

BurningFrog 5y ago

I think it's the only way to do it: https://en.wikipedia.org/wiki/Immersed_tube#Construction https://en.wikipedia.org/wiki/Immersed_tube#Construction

asdfman123 5y ago

It can't possibly be new. Multi-billion dollar construction projects are fairly common and that kind of capital investment makes people very clever. Oil rigs definitely follow the prefabrication and then float-into-position approach, and have been doing that for a long time. I'm sure there's a good reason why it's more cost effective or feasible to do this instead of drilling a tunnel under the seabed.

Taniwha 5y ago
Not new - as mentioned above the BART trans-bay tube was built this way back in the '70s
mstade 5y ago
To your point of this technique not being new: the mulberry harbors the allies built following the d-day invasion of operation overlord made use of prefabricated sections code named phoenix, that were towed into place and then sunk to form the structure of the harbor. They were so named, I think, because after being built they were sunk off the coast of England before being refloated in preparation of the operation, i.e. like the phoenix the rose, or something poetic like that. If you're ever in or around Normandy I highly recommend a visit to the beaches. They're much bigger than I had imagined, and it really hit home then what a massive operation it was. Anyway – no, the technique is not new.

ianburrell 5y ago

The immersed tube technique is used for the BART Transbay Tube, Chesapeake Bay Bridge Tunnel, and Øresund Bridge Tunnel between Denmark and Sweden. The Fehmarn Belt will be the longest when it opens. I think the technique is mainly used for shallow tunnels in flat areas.

Someone 5y ago

The scale is different, but it’s far from a new idea. https://en.wikipedia.org/wiki/Immersed_tube#Examples https://en.wikipedia.org/wiki/Immersed_tube#Examples: The first tunnel constructed with this method was the Shirley Gut Siphon, a six-foot sewer main laid in Boston, Massachusetts in 1893. The first example built to carry traffic was the Michigan Central Railway Tunnel constructed in 1910 under the Detroit River, and the first to carry road traffic is the Posey Tube, linking the cities of Alameda and Oakland, California in 1928. The oldest immersed tube in Europe is the Maastunnel in Rotterdam, which opened in 1942.