Calling all Civ Engs...How feasible would it be to build a trans-oceanic bridge?

[sao123]

Would it be possible to build a structurally safe trans oceanic bridge?
Lets say for example over the atlantic from N America to Europe. Or from Calicfornia to Hawaii.

Putting aside all environmental concerns....

What would be the ideal materials for such a project? To withstand both large weight and water erosion.
How far apart would the supports be lets say for 2-3 lanes in each direction.
How would you deal with wind, waves, storms etc?

How much max weight could the structure hold (useful for truck shipping?)
How long would it take to cross such bridge.
Could we build a few refueling stations along the way on platforms.

 

[ZeroNine8]

There are basically two types of bridge that are possible to accomplish this, either floating or on pillars. A floating bridge would probably be the easiest to construct, however it would have to expand and contract significantly due to tidal fluctuations, not to mention be able to resist lateral forces due to winds, currents, etc. This type of bridge is also more difficult to route shipping around as it would not have as much clearance over the water. The second type would be a bridge on pilings, and while the concept isn't all that difficult, the massive scale coupled with frequent undersea quakes near plate boundaries would make it not practical. Additionally, the plate expansion or contraction (depending on which ocean), although slow, is a significant factor in the lifespan of a bridge and would have to be accounted for. I believe all the technology exists today to be able to build such a bridge, however the scale and cost of such a project far outweigh the benefits. Over such a large span, you would have to have many facilities for fuel, rest stops, lodging, vehicle repair or towing, etc. I can't even imagine the cost of such an undertaking.

 

[djNickb]

It's cheaper to fly, hence why there aren't any bridges already.

 

[Pulsar]

The bridge is unfeasisble.

A bridge bedded in the sea bed would have to extend in some case MILES deep. The amount of resources need to move that much material for not one, but THOUSANDS of seabed supports would be physically impossible to manage in the next 500 years.

A floating bridge would have to be ANCHORED to the mainland in such a way that it could support the lateral forces on the middle of the bridge. Waves in the atlantic have been record at heights of 500+ feet. The bridge would have to be so thick and so strong by the time you reached the main land (because each successive bridge "portion" would have to support not only it's own forces, but the forces from the next in line) you would have a supports 10's of miles wide, incredibly strong... and still able to float.

To top it off, the bridge would have to be high enough that Tsunami's didn't hit it, and strong enough that hurricanes couldn't take it out.

No, No, No.

 

[Witling]

There is a story about a guy who found a magic lamp. He rubbed it and the genii gave him one wish. He asked for a bridge from California to Hawaii. The genii pointed out how hard that would be on the shipping and environment and begged the guy to make another wish.

The man made his new wish. "OK, I want to be able to understand women."

The genii replied, "How many lanes do you want on that bridge?"

 

[DrPizza]

I agree that it wouldn't be feasible to build such a bridge... The amount of materials needed would be simply incredible.

On the other hand...

How difficult would it be to build a tunnel *under* the ocean? Much like the tunnel under the English Channel linking England and France?

(not that I'd ever risk my life in such a tunnel)

Perhaps such a tunnel could simply be used for an unmanned supertrain carrying materials back and forth.

 

[BigPoppa]

I'd imagine the pressure would be um...high. The tunnel would have to be either damn deep or snake around all the miles deep trenches. Then you'd have to have an elevator bring up the materials, or make a train that could go both horizontal and vertical, which is definately possible with some forethought.

 

[PowerEngineer]

Tunnel

 

[Navi]

Originally posted by: PowerEngineer
Tunnel

Heh, you just summarized what everybody just said...to costly...way too costly. A '5' mile deep ancor! Just imagine the maintance costs if just '1' broke. Eep!

Lets say they could put '1' anchor in for a $1million. At a minimum of 10 anchors per section and 50000 anchors is a trivial 0.55 trillion dollars. That is just for the anchors. The average passenger pays approximately 50 cents a mile to fly. Lets just say somebody is actually wiling to pay 10x as much to get there 10x faster. So you are charging $5 a mile. Assume then you would want to pay this back in 50 years. Again assume 200 passengers per train. That means you would need to travel atlantic 10 million times a year to just pay it back...Even if it was 1 anchor a section it would still be 1 million times a year. Even if you got 1000 people on a train it would still be 200,000 times a year. Thatmeans a train would need to be leaving every 3 minutes. This is just for the anchors.

-Navi

 

[Brucmack]

I'm sure it'd be possible for a bridge to be built between Alaska and Russia. Kind of a scenic route if you're driving from NY to Paris though

 

[martind1]

you gotta start watching more discovery channel and TLC. They do shows on things like this all the time. Actually not this, because its pretty much impossible(at least for now).

however they are always doing shows on a bering straight brdige and another in the mediterrianin somewhere.

so, (and you can quote me to your parents) watch more tv!

 

[Cuda1447]

A bridge that far, and that high... ya I wouldn't drive over it.

 

[Witling]

Then there is the fact that water transportation is the cheapest form of shipping goods known to man.

 

[sao123]

well ... flying is the best way right now...

but given the theory of how soon we could run out of oil and the ever increasing prices per barrel...and air transport may become no longer feasible as well.

That maglev train might just float after-all.

----
My conception for a bridge was also more for highspeed trains than automobiles as well, but my question is spurred by recently crossing the 9 mile bridge in that real big bay in delaware or maryland...somewhere down there.

Given the current research into lighter stronger materials...I think it may be possible soon to build a bridge. (like within 50-100 years)
someone in the PA DOT told me that some experimental bridges are currently being built made out of superstrong fiberglass like plastics, and they are 10x as strong and durable as concrete/steel bridges. So the material technology is approaching the levels we need to get to.

 

[glugglug]

Let's say you did build such a bridge. Can your car go 5000 miles on one tank? Didn't think so. Imagine the traffic jams with all the out-of-gas vehicles on that bridge and noplace to fill up.

 

[sao123]

I am aware of that problem...
it wouldnt be any more difficult to build a platform refueling station than it would to build a standard drilling rig platform.

 

[glugglug]

Originally posted by: sao123
I am aware of that problem...
it wouldnt be any more difficult to build a platform refueling station than it would to build a standard drilling rig platform.

Where does the gas station attendant live? Does he still get near minimum wage?

 

[sao123]

Self Service...pay by plastic only...
Vending machines....

Automation.

 

[sharq]

I say lets do it Who's got the first trillion to get us started? As soon as I make my first trillion I'll put it into this project, just need someone to hire a CS major fresh out of college. Any takers?
Sorry, I had to, couldn't resist. Good idea, but love the cost estimate.

 

[martind1]

Originally posted by: Witling
Then there is the fact that water transportation is the cheapest form of shipping goods known to man.

That is a fact? cause shipping isnt cheap.

got numbers?

 

[DrPizza]

Uh, I have a much better idea...

Why don't we get the lane dividers that go down the lengths of swimming pools... string a couple of them together across the ocean from NY to London, and call it a highway. Then, we just have to design "cars" that will drive on water. Compared to the trillion dollar figure for the tunnel floating in the ocean, I'd think this was a much more feasible idea.

 

[BigPoppa]

Originally posted by: DrPizza
Uh, I have a much better idea...

Why don't we get the lane dividers that go down the lengths of swimming pools... string a couple of them together across the ocean from NY to London, and call it a highway. Then, we just have to design "cars" that will drive on water. Compared to the trillion dollar figure for the tunnel floating in the ocean, I'd think this was a much more feasible idea.

When I get stuck behind an old couple going half the speed limit i'm coming after you.

 

[BigPoppa]

DP

 

[glugglug]

Just put a hundred thousand aircraft carriers end-to-end. Drive off the end of one aircraft carrier onto the next.

 

[martind1]

Originally posted by: DrPizza
Uh, I have a much better idea...

Why don't we get the lane dividers that go down the lengths of swimming pools... string a couple of them together across the ocean from NY to London, and call it a highway. Then, we just have to design "cars" that will drive on water. Compared to the trillion dollar figure for the tunnel floating in the ocean, I'd think this was a much more feasible idea.

This wouldn't work. There are a reason we have shipping lanes in the ocea. The use the currents to speed up their trips. going striaght across is nto neccessarily the best way.