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Norway Is Building The World's First 'Floating' Underwater Tunnels (thenextweb.com)
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.
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
moox. for a new generation.
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?
Inquiring minds want to know!
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.
In Soviet Washington the swamp drains you.
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].
Buoyancy making the tunnel 'want' to move towards the surface, but since it's secured to structures on the bottom it doesn't get to come all the way up.
-=This sig has nothing to do with my comment. Move along now=-
Do you also think that cruise liners and battleships and so on don't float because a portion of the structure is under water?
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.
As described in Harry Harrison's prophetic _Tunnel Through the Deeps_ (also published as _A Transatlantic Tunnel, Hurrah!_)
sPh
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.
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.
-The wise argue that there are few absolutes, the fool argues that there are no probabilities.
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.
ithinkthatwebsitecoulddowithsomedashesorunderscoresintheirpagenames.html
Floating doesn't necessarily mean floating on the surface, but it would be the most common usage of the word. I'd prefer if they said the bridges were buoyant.
Of course, they want to connect closer towns, but this conversation is reminding me of Norway. Norway is such a great place.
"First they came for the slanderers and i said nothing."
Here is Norwegian Public Roads Administration video of the proposals. The underwater tunnel is one of the four proposals https://www.youtube.com/watch?... (great watch)
There is no decision on which of those will be implemented yet. Article is simply running with the fanciest option.
The issue isn't about having some part below the water. It's about having none above it.
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
Why is this better than sitting the tubes on the bottom?
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
It can't be, since that isn't the case with the pontoon design mentioned.
What would engineers do without the smart people on Slashdot! I think you just single handidly averted a disaster.
I was talking about why "floating underwater" sounds wrong.
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
Submarines float underwater...
Yes it's an anecdote! Were you expecting original research in a Slashdot comment?
Here's another interesting project they're cooking up... a Ship tunnel which is, if anything, more impressive.
Picture
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.
I prefer the "u" in honour as it seems to be missing these days.
Much of the ferry traffic is tractor trailers full of heavy goods. Tunnels or bridges would provide much faster, more reliable, and lower cost transport.
Man, you really need that seminar!
Boy, can you imagine one of these springing a leak?
Those are my principles, and if you don't like them... well, I have others.
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.
How deep would the underwater section need to be? Hmmm, the record for keel depth is 28.5 meters.
https://en.wikipedia.org/wiki/Batillus-class_supertankers
Are we missing any other factors? http://ascelibrary.org/doi/abs/10.1061/9780784407707.ch06
Putting a hefty margin of error on it; go for a nominal 50 meter depth. What is the water depth in the proposed channel?
If you consider the depth of some of the fjords in Norway; it becomes patently obvious why you would consider floating subsurface tunnels. It is too bloody deep to put one on the floor of the ocean in many places.
"Norway's Hardangerfjord drops to 2,624 feet (800 m) below sea level, while the depth of Sogn Fjord (also Norway) measures 4,290 feet (1,308 m) deep, and Canal Messier in Chile is 4,167 feet (1,270 m). The great depth of these submerged valleys is due to their glacial origins.Oct 31, 2013"
http://www.newworldencyclopedia.org/entry/Fjord
A very interesting proposition. Very much a problem in dynamic engineering.
NRRPT/RCT
Do balloons float in the air? Floating doesn't imply that part is outside of the fluid, but that it isn't sitting on the bottom of the medium.
APK likes to ask for responses to the same things over and over. Maybe he just likes the responses?