Water BRIDGE... over a a RIVER: ??

from JoeUser Forums
When did this happen?? I got this in my email this morning and I'm just wondering how come I didnt hear about it earlier. It just looks like WOW.
So here's what we have:



(umm, do let me know if the picture doesnt come up please)

Even after you see it, it is still hard to believe !

Water Bridge in Germany.... What a feat!

Six years, 500 million euros, 918 meters long.......now this is engineering!

This is a channel-bridge over the River Elbe and joins the former East and West Germany, as part of the unification project. It is located in the city of Magdeburg, near Berlin. The photo was taken on the day of inauguration.

To those who appreciate engineering projects, here's a puzzle for you armchair engineers and physicists. Did that bridge have to be designed to withstand the additional weight of ship and barge traffic, or just the weight of the water?



Answer:

It only needs to be designed to withstand the weight of the water!

Why? A ship always displaces an amount of water that weighs the same as the ship, regardless of how heavily a ship may be loaded.

Remember your high school physics, and the fly in an enclosed bottle project? Similarly, the super sensitive scale proved that it didn't make any difference whether the fly was sitting on the bottom, walking up the side, or flying around. The bottle, air, and fly were a single unit of mass and always weighed the same.
misc
19,638 views 18 replies
Reply #1 from JoeUser Forums Top
I checked and it's not a hoax:
http://www.dw-world.de/dw/article/0,,990878,00.html
The massive water bridge over the Elbe river cost around €500 million.
Reply #2 from JoeUser Forums Top
No pic
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Reply #3 from JoeUser Forums Top
Looks like your linking to a picture in your mail box, which isn't viewable to the rest of us. The idea reminds me of the transatlantic train tunnel mentioned a while back. Definitely an accomplishment, but I hope they planned for a little extra weight. Otherwise rain could be a problem
Reply #4 from JoeUser Forums Top
Okay Picture again here:



Hehe, the transatlantic was a hoax, but this one not, the bridge was finished in 2003 And about the rain, i hope they thought about that!
Reply #5 from JoeUser Forums Top
Wow, I'd not heard about this either. What a great feat of engineering. Thanks for sharing.
Reply #6 from JoeUser Forums Top
Great trivia question too!  I would have failed that test.  But yea, I knew about it.  I think it is awesome.
Reply #7 from JoeUser Forums Top
That is so cool.
Reply #8 from JoeUser Forums Top
Dynamaso,
*Sigh of Relief* Thanks mate, I'm not the only one who didnt know about it! I think this is what happens when we live downunder, we never here the GOOD news, lol
Thanks for sharing.

You are very welcome my friend.

DrGuy:
The question was included in the email, I wouldnt have ever known the answer myself, lol! I think it's awesome too, scary what mankind builts though, a tunnel under the sea, a water bridge over a river, just sounds so unnatural, lol!

Tova7
That is so cool.

Totally dude, hehe
Reply #9 from JoeUser Forums Top
Does anybody actually have a link to an article about this bridge? You know, like, say, an original source for the picture? Some more detailed discussion of the engineering marvel?

IG, where did you find out about this bridge? Can we look in the same place, to find out more information for ourselves?
Reply #10 from JoeUser Forums Top
Very cool
Reply #11 from JoeUser Forums Top
Yep sure stutefish, sorry you have to copy and paste this because i dont know how to insert a link (oops!)

http://www.dw-world.de/dw/article/0,,990878,00.html

I found out of this through my email actually, a friend sent it to me. I was surprized coz i never even heard about it before!

Very cool

I know MM, makes you wanna see it with your own eyes, lol!
Reply #12 from JoeUser Forums Top
Wow, I lived in Germany from 2003 until just a couple months ago, and this is the first I heard of the water bridge. We were even in Berlin for a weekend. Not Magdeberg though.

Wish I could have seen it. Awesome!
Reply #13 from JoeUser Forums Top
I never heard about this too. That's quite a distance for people to walk too! This is really interesting Em, thanks for sharing!
Reply #14 from JoeUser Forums Top
Angela, sorry you missed that, that's too bad! Do you plan to go there anytime soon? Heh I think it's awesome too.

FS, you're welsome and well I'm glad this article was useful to some of us
Reply #15 from JoeUser Forums Top
Regarding the design weight for bridge: The weight of a container of water increases when a floating object is added to the water, because you are adding more mass to the previous single unit of mass. The water level rises in the container (an amount relative to the volume of the floating object); however, this results in an increased weight equal to that of the added floating object. Don’t believe this, then prove it to yourself by using a digital postal scale, placing on the scale a partially filled bowl of water, record the weight of the bowl and water, place a floating object in the bowl and notice that the weight will increase the exact weight of the floating object. The only way your theory works is if the water level does not rise by venting off the water (opening the ends of the bridge or container) to remove the excess volume of displaced water which resulted from introducing the floating object. So the old fly-in-the-bottle high school physics doesn't apply.... if the water rises in the bridge... it will weigh more!
Reply #16 from JoeUser Forums Top
The only way your theory works is if the water level does not rise by venting off the water (opening the ends of the bridge or container) to remove the excess volume of displaced water which resulted from introducing the floating object. So the old fly-in-the-bottle high school physics doesn't apply.... if the water rises in the bridge... it will weigh more!


Lets hope they have taken everything into consideration then.

It does look quite awesome doesn't it!
Reply #17 from JoeUser Forums Top
What Riggs says is true, but irrelevant. You don't just plop a 500,000 ton boat onto the water bridge. The bridge must be linked to other bodies of water. Obviously there must be a system of locks like in a canal to get the boats onto the bridge in the first place. These work by pumping water in to raise the water level inside the lock (with the boat) up to the bridge's water level. Once the two water levels are equal, the lock opens up and the boat enters the bridge. Thus, the water level doesn't rise. The water displaced by the boat is kept off the bridge before the boat even enters, So the original statement is true!
One other thing to consider. If the boat were magically just plopped onto the bridge (which can't happen in real life) and the water level did rise, the extra weight of the boat would be evenly distributed over the entire 1/2 mile-plus length of bridge which would make the weight increase negligible.
Reply #18 from JoeUser Forums Top
Oops. Typo. 500,000 tons is a bit large even for the largest cruise ships. Everything else I said is true, though.