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Water bridges

  • 04-06-2011 11:40AM
    #1
    Registered Users, Registered Users 2 Posts: 3,608 ✭✭✭


    Anyone know where I could go looking for information on water bridges?

    I'm talking about things like this: http://www.amusingplanet.com/2011/04/incredible-magdeburg-water-bridge-in.html

    But I'm looking for technical information like considerations for the design of the deck, rather than just pictures and newspaper articles.

    Thanks


Comments

  • Moderators, Science, Health & Environment Moderators Posts: 23,255 Mod ✭✭✭✭godtabh


    Anyone know where I could go looking for information on water bridges?

    I'm talking about things like this: http://www.amusingplanet.com/2011/04/incredible-magdeburg-water-bridge-in.html

    But I'm looking for technical information like considerations for the design of the deck, rather than just pictures and newspaper articles.

    Thanks

    The royal canal flows over the m50 like this. Maybe contact waterways Ireland. They can be very helpful


  • Closed Accounts Posts: 3 bridges


    You'll have to submit a Section 50 application to the OPW for the structure.

    The main design loads will be the selfweight of the water & deck. The parapets will also have to be sufficient enough to withstand water pressure.Waterproofing will also be important. Other than that it should be a standard bridge design.


  • Moderators, Science, Health & Environment Moderators Posts: 23,255 Mod ✭✭✭✭godtabh


    There is more than water pressure.

    If its a navigable waterway you have a lot more things to consider.


  • Registered Users, Registered Users 2 Posts: 5,165 ✭✭✭enda1


    Also there's an old one I think near the Lucan spa somewhere where the canal crosses the Liffey maybe? Its a very old childhood memory that's rekindled.

    How much extra force would a boat in the water cause to the bridge? I'd imagine its a highly dimensionally sensitive problem. The weight of the boat should be supported the bridge, but also by the body of water either end. I guess its a function of height of water, length of bridge, width of water, length of boat and mass of boat.


  • Closed Accounts Posts: 9,698 ✭✭✭tricky D


    Archimedes would be turning in his grave.


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  • Registered Users, Registered Users 2 Posts: 5,165 ✭✭✭enda1


    tricky D wrote: »
    Archimedes would be turning in his grave.

    Probably. It was a stab in the dark. I should leave this to the civil guys :o


  • Closed Accounts Posts: 9,698 ✭✭✭tricky D


    It's a very long time since my civil days but here's my take, which might well be wide open to correction.

    What I'm thinking is that the boat weight is displaced along the length of the whole waterway, not just the bridge. While the displacement might be slightly more in the local area, it is practically insignificant. So you don't really need to factor the boat weight in as safety factors would absorb that easily. The question I can't remember the answer to is whether the water load is live or dead? I'm thinking dead with live loads being impacts and the like.


  • Registered Users, Registered Users 2 Posts: 5,165 ✭✭✭enda1


    ^
    That sounds better alright. Sure I've swam under plenty of boats of various sizes and not been crushed :P


  • Registered Users, Registered Users 2 Posts: 3,608 ✭✭✭breadmonkey


    I think the water would be classified as "quasi-permanent live load", like the book shelves in a library, for example. It was quite an interesting project in the end anyway!


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