Quoth TV Tropes:
Is this claim factually correct? The average depth of the Pacific must be greater than 10,000 feet, yes? Do we have the engineering capability of sinking supports that far?
You could build a floating bridge.
You would have to have a hell of a gas tank to get across though.
Large waves and seismic activity are going to be hell on a floating bridge though. I don’t think it is possible for any type of useful bridge. There are so many extreme engineering challenges that those alone would guarantee failure no matter how much money or resources you put into the project.
I think we could do it, but it would be stupid, unnecessary, stupid, grotesquely expensive and stupid.
Ok, there is one real easy way to do it, build a bridge across a short stretch of the Pacific. Not from North America to Asia, just from one spit of land to another. It would be a bridge across the Pacific Ocean. That isn’t really the same thing as a bridge crossing the Pacific Ocean, which would likely be considered stretching from one continent to another. We could try the Bering Strait if that’s consided the Pacific and not the Arctic. We could also make a floating bridge as suggested, although it would be somewhat pointless. We build some kind of pylons, perhaps by disassembling Greenland, which isn’t doing anything useful otherwise. Or we could make a giant arch, which might even have to rise out of the atmosphere to be strong enough for that span, and solve a lot of space travel issues at the same time.
Or to put it more simply, what **Elendil’s Heir **said.
About 14000 feet is the average depth.
And yes…you can sink anything that far.
Seriously though, the deepest offshore rigs will be the Perdido Regional Hostoil rig with a height of 7,817ft . It probably costs well over $2 billion. So you would need something twice as tall spaced however far apart for whatever the distance across the Pacific.
Building a bridge across the Bearing Strait (average depth around 90 to 150 feet) might be more feasible.
If you did build it, what would be the average annual amount of bird shit that fell on it?
Possible? Probably
Stupid? Definitely
But think of the profits made by all the businesses that would be required to accommodate food, fuel and rooms for that drive!
Talk about some valuable rental space!
a pontoon bridge might work with high sides and vehicles with monster truck sided tires to make it over the gaps between sections. you would need a fleet of tenders working off of mother ships to repair the bridge, deliver fuel to fueling stations and repair (or retrieve dead monster trucks) and empty the seasickness collection systems in the monster trucks.
What about island-hopping across the Pacific? Maybe it would be less of an engineering challenge to build a bridge from San Diego to the Big Island of Hawaii, then have a series of shorter bridges up the island chain to Midway Island, then across to the Marshall Islands, the Caroline Islands, to Guam, then up the Mariana Islands, across to Japan, then across to South Korea or up the Japanese archipelago and across to Russia.
You could go San Diego to Hawaii and then island hop southward to Australia, maybe by stopping in Tokelau, Samoa, Fiji, and New Caledonia.
There’s a couple problems with either this plan or a single giant bridge.
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This thing is going to be a huge navigational hazard. Can we build it high enough so that it is unlikely ever to be too low for ships to pass? Is it going to have to be a drawbridge where ships get bottlenecked at certain draw points and they and road traffic have to wait?
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What about immigration and customs? There might be pressure to build right from Midway Island straight to Guam rather than stopping in a foreign country first in order to make immigration and customs easier and not make people show their passport five times to five different countries to cross the ocean, and where some people have visa difficulties with one of the island countries but can enter the rest and thus can’t drive the length. There could be a special transit agreement where there is a special highway running the length of the island where traffic entering the island from an interocean bridge can just stay on in transit to the next bridge without passing immigration and customs. Checkpoints could be placed on on/off ramps. People who were just crossing the Marshall Islands on their way across would just go through. People who wanted to stop and tour or otherwise do anything other than pass right across would get off at Exit 1 and pass Immigration and Customs.
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What about jurisdiction over events taking place on such a long bridge? If you commit a traffic offense halfway across the bridge between Kiribati and the Solomon Islands, who has jurisdiction? Would a bridge between San Diego and the Big Island of Hawaii be considered full US territory or would it be considered the High Seas under the law? Iirc high seas law is tied in with the national registration of your ship, so would you then go by where your car was registered? E.g. a person driving a car registered in South Korea trying to drive to California is subject to South Korean traffic, civil, and criminal law while on the bridge to Hawaii, becomes subject to Hawaiian and US law on entering Hawaii, then goes back to South Korean jurisdiction on the Arnold Schwartzenegger Memorial Bridge from Hawaii to California.
You could also imagine a bridge across the Atlantic. One idea that comes to mind is a series of bridges going from Cape Breton Island (which is already connected by land to the mainland of Canada iirc) to Newfoundland, then to Greenland, Iceland, the Shetland Islands, the main part of Scotland, then by road to southern England, then through the existing channel tunnel to mainland Europe.
Ahhh, that would be an advantage of pylons: make 'em big enough and you have your own rest area.
Not that any such thing would be built in the first place, but why are so many people presuming it would be a road bridge?! 
:rolleyes:
I would imagine its biggest traffic would be freight rather than passengers, and the long distances between islands – and especially between islands that are significant traffic generators in their own right – suggests rail rather than road. No “gas stations & motels in the middle of the ocean” issues, for one thing. 
IIRC, one of the significant costs in shipping freight is changing mode, hence the rise of containerization. A through rail route would avoid having to unload containers and other freight from trains or trucks to ships, then back from ships to trains. Closer to the real world people float the idea of an Alaska-Bering Strait-Siberia rail route for this reason.
I think what you’d want is a floating bridge, where the floats are anchored underwater by cables stretching to the sea floor.
Seems doable.
Why not a double-decker?
This statement is not just grandiose and overly optimistic, it’s flat out wrong. We most certainly do NOT have the technology to built any kind of a bridge hundreds (let alone thousands) of miles long across stormy ocean seas thousands of feet deep. Find me one credible engineer who would state otherwise.
It’s easy to say we have the technology. That doesn’t mean we have the resources to implement something in a practical manner.
A bridge across the Bering Strait is probably doable.
Getting to the bridge would be a challenge, but the bridge would sure be there, connecting vast nothingness to vast nothingness.
Well, to me that’s the exact same thing as not having the technology. The resources to build a practical, viable, real-world structure is part of ‘having the technology!’ It’s like saying we can now make carbon nanotubes in the lab, so we now have the technology to built a space elevator. No, we don’t.
I agree. I don’t think it could be done even if you gave a time-table of 20 years and all the possible resources in the world devoted to it. I believe building a practical and sustainable bridge across the Pacific would be harder than a moon base and probably harder than a manned Martian base.
The key attribute a bridge needs to have is that it has to stay unbroken throughout its entire length. Any temporary breaks in any section make the whole thing useless. With inevitable large rouge waves, random seismic activity and failures of whatever anchoring mechanism someone designs (even if they can come up with something that works twice as deep or much more as has ever been done), I don’t think you can say that we have the technology to do it either.
I agree that technology includes not just raw tech that works on a small scale but also the ability to scale up dramatically and also deal with inevitable failures in parts of the design. I am not seeing it for a bridge that big no matter how much money is spent. It is in the same realm as a space elevator except much less useful.
A floating vacuum tunnel for trains would be much more practicable (even tho it would have its own set of extreme engineering challenges).