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Transportation Earth The Almighty Buck News Science Technology

Norway Is Building The World's First 'Floating' Underwater Tunnels (thenextweb.com) 84

Posted by BeauHD from the underwater-in-debt dept.
An anonymous reader writes from a report via The Next Web: Norway plans to build "submerged floating bridges" to allow drivers to cross its bodies of water. The Next Web reports: "The 'submerged floating bridges' would consist of large tubes suspended by pontoon-like support structures 100 feet below water. Each will be wide enough for two lanes of traffic, and the floating structures should ease the congestion on numerous ferries currently required to get commuters from Point A to Point B. Each support pontoon would then be secured to a truss or bolted to the bedrock below to keep things stable." A trip from Kristiansand to Trondheim is roughly 680 miles and could take as long as 21 hours due to the seven ferry trips required along the way. While building normal bridges would cost significantly less than the $25 billion in funds required for the tunnel project, the fjords and difficult terrain make them unsuitable candidates. The pricey tunnel project could cut the trip time to just 10 hours when it's expected to be finished in 2035.
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Norway Is Building The World's First 'Floating' Underwater Tunnels More

Norway Is Building The World's First 'Floating' Underwater Tunnels

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  • San Francisco's Transbay Tube (Score:4, Interesting)

    by Hadlock ( 143607 ) on Tuesday July 26, 2016 @06:57PM (#52585949) Homepage Journal

    San Francisco's Transbay Tube does this. It's a bunch of segments bolted together, and then it was weighted down with thousands of pounds of granite fill/gravel and they pumped all the water out of it. The bottom of the San Francisco bay is pretty flat and muddy compared to Norway, I suspect, so they just let it sit on the bottom, rather than precariously suspend it in the water(?!?)
     
      https://en.wikipedia.org/wiki/Transbay_Tube [wikipedia.org]

    • Re: (Score:3)

      by IrquiM ( 471313 )
      We already have what you're talking about in Norway as well, and that one is probably one of the busiest tunnels we've got. This is something completely different.

  • What sort of failsafes are in place for a tunnel section collapsing? Are there emergency bulkheads that can shut to keep the rest of the tube network from filling if a single segment/module fails?

    If not, have they factored in the cost for evacuating and repairing the tunnels in the event of a module failure? If not have they factored in the lost time and cost should they have to return to ferries for the months and/or years it would take to repair and empty one of these tunnels should it fail and flood?

    Inqu

    • Re: (Score:2)

      by trevc ( 1471197 )
      What would engineers do without the smart people on Slashdot! I think you just single handidly averted a disaster.

  • Easy target for enemies... (Score:5, Insightful)

    by mi ( 197448 ) <slashdot-2017q4@virtual-estates.net> on Tuesday July 26, 2016 @07:02PM (#52585969) Homepage Journal

    Such a tunnel seems to be an even easier target for a Russian submarine or a well-equipped terrorist, than a regular bridge or a tunnel in solid soil.

    And the results will be spectacular — once a wall is breached, everybody inside drowns... No escape, no rescue... Unless, maybe, individual segments can somehow be made to self-seal and automatically surface in an emergency.

    • Why is this any more risk-prone than immersed tube tunnels, which we've had for over a century now? I can't think of any good reason.

      • The only risk differential I could see is I would assume a floating structure would be more susceptible to torsion stress than one sitting on the bottom.

        • Re: (Score:2)

          by dbIII ( 701233 )
          Which means it would be a bad idea in the open sea. In a fjord it may as well be in a shallow pond as far as the stresses go.

          • I don't know what the tidal stresses would be in the fjords. I don't know how much they empty and fill and at what rate. That though is easy to calculate.

            I was more thinking along the lines of anchors dropped by ships though. Depending on how far off the bottom they are you could conceivably get a large torsional force applied by the chain.

            That said this was only to think what the difference was between an immersed tube tunnel being on the bottom vs suspended.

      • Re: (Score:2)

        by mi ( 197448 )

        Why is this any more risk-prone than immersed tube tunnels

        If they are to be suspended, they must be flexible. If they have to be flexible, the walls will inevitably be softer than what we've had 'till now...

        Unless, of course, some wonderful (and expensive) new material comes along... Like those nanotubes we keep thinking about for our space elevator.

    • No need to jump to the terrorism scenarios. Consider a ship riding lower than expected (sinking), a fishing net or other debris caught on a shipt, stormy seas moving heavy debris around, etc..

      A whole lot of bad can happen, but people will I assume be happy with the risk.

      • Re: (Score:2)

        by dbIII ( 701233 )
        It's not in a stormy sea it's a fjord a long way from anywhere with waves.
        Of course the government could fake a plane crash into it or set it on fire like with your other posts where you used your "engineer" title to pretend you knew about civil engineering.

        • Re: (Score:2)

          by dave420 ( 699308 )

          He is a senior engineer/architect/fruitloop, you dolt! Show him the respect he so obviously craves! Keep your knowledge of basic geography to yourself!

      • *Drops Anchor*

        OOPS

      • It says 100 feet below the surface. Is it possible for a ship to ride 100 feet below the surface?

    • So, all they have to do is take a sub up a very long fjord with a very narrow entrance and then spend hours getting out again during a time of war.
      There were anti-submarine measures like booms and nets at narrow inlets a century ago during World War One FFS!

      You may want to remove your "missing an idiot" sig for utterly stupid posts to avoid a truly epic failure.

    • Re: (Score:2)

      by IrquiM ( 471313 )
      The risk calculations have already been done, and it is negligible. There are a lot of better targets in Norway than this bridge/tunnel. There will also be passages between the two sections in an emergency.

    • Such a tunnel seems to be an even easier target for a Russian submarine or a well-equipped terrorist, than a regular bridge or a tunnel in solid soil.

      And I'm sure the couple of people affected by this will be devastated.

    • One you blow up a support pillar of a regular bridge, the whole bridge will collapse into the water and everybody on it will be dead. What's the practical difference?

      • Re: (Score:2)

        by mi ( 197448 )

        One you blow up a support pillar of a regular bridge, the whole bridge will collapse

        That is, actually, very hard to achieve. Possible, but very hard — ask any demolition/explosives expert.

        And a single pillar is unlikely to do it — you will make the bridge unusable, yes, but there will not be massive amount of deaths — most of the people on the affected section it will survive either on their own or thanks to rescuers. Whereas everyone in the entire flooded tunnel (except those right by th

  • Do you really have to link to some other news site that only repeated stuff? Can't you follow the chain and link to the original source?

    I tried: Slashdot quoted TheNextWeb who quoted Hackaday who quoted Wired who quoted [disable your adblocker to know the end of the story].

  • The road to Trondheim (Score:5, Funny)

    by tomhath ( 637240 ) on Tuesday July 26, 2016 @07:38PM (#52586181)

    A trip from Kristiansand to Trondheim is roughly 680 miles

    So the road to Trondheim will be a series of tubes? Ted would be proud.

  • Tunnel Through the Deeps (Score:3)

    by sphealey ( 2855 ) on Tuesday July 26, 2016 @07:42PM (#52586193)

    As described in Harry Harrison's prophetic _Tunnel Through the Deeps_ (also published as _A Transatlantic Tunnel, Hurrah!_)

    sPh

  • It only takes 10 hours to make this trip currently (Score:5, Informative)

    by Isca ( 550291 ) on Tuesday July 26, 2016 @07:50PM (#52586229)
    You can already make this trip on a highway that is 4 lanes for a large portion of it by going up through oslo and central Norway. The reason it would take so long with the path they are wanting to connect is that this path is along the coast. Even after getting rid of the ferries it's still going to be winding and longer mileage. I suppose the coast might be a bit warmer and less likely to have winter conditions, but a gale along the coast already shuts down the highway in quite a few parts as it is.

    They really just want to connect all the cities along the coast without having to take a ferry (down if bad weather) or having to drive a hundred kilometers or more inland and back out again.
    • Of course, they want to connect closer towns, but this conversation is reminding me of Norway. Norway is such a great place.

  • Misleading title, it is 1 of 4 proposals (Score:5, Informative)

    by ThatsMyNick ( 2004126 ) on Wednesday July 27, 2016 @01:52AM (#52587691)

    Here is Norwegian Public Roads Administration video of the proposals. The underwater tunnel is one of the four proposals https://www.youtube.com/watch?... [youtube.com] (great watch)

    There is no decision on which of those will be implemented yet. Article is simply running with the fanciest option.

  • Why is this better than sitting the tubes on the bottom?

    • Easy answer:

      Some of those fjords are 200+ meters deep at the narrowest points near the outlet, i.e. where you would want to build a bridge/tunnel/submerged tube.

      We already use tunnel crossings underneath a lot of shallower crossings, and several not so shallow, like the one about half an hour south of Oslo, near Drøbak:

      The tunnel is 7-8 km long even though the fjord is less than a km wide at that point, the extra distance was required in order to keep the incline at or below the (highway) maximum allow

  • Those crazy Norwegans. (Score:3)

    by Catmeat ( 20653 ) <mtm&sys,uea,ac,uk> on Wednesday July 27, 2016 @12:32PM (#52590487)
    Here's another interesting project they're cooking up... a Ship tunnel [wikipedia.org] which is, if anything, more impressive.

    Picture [norwegianamerican.com]
  • If you are driving from Kristiansand to Trondheim wouldn't you just take E18 over to Oslo and then Route 3 up to Trondheim?
  • If they do this right, they can convert these to hyperloop instead of slow cars.

  • Boy, can you imagine one of these springing a leak?

    • Re: (Score:1)

      by MercTech ( 46455 )

      Shhhhhh. You don't want people to realize that every tunnel system in existence leaks and requires pumping out so it doesn't fill up. And there are automatic traffic stop lights that trigger when the air flow in or the water pumping out stops.

  • The system of having an underwater roadway suspended from floating pontoons sounds a whole lot cheaper to install than extensive hyperbaric work in caissons to install a tunnel on the floor of a waterway. You would only need short sections of underwater tunnel anyway. Just enough to allow for a shipping channel. The rest of the transit could be floating pontoon roadway as has been used for decades. On the other hand, having the whole span underwater minimizes storm effects on the roadway.

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