Paper Bridge

We are trying to build a bridge made from paper, water based glue and cotton strings. The bridge must be able to hold 5kg; however, we would like it to hold more weight. The weight of the bridge should also be taken into consideration.

So we came up with numerous designs and we finally decided on a ring design one of my friends came up with which is able to hold 7-10 kg of weight when it is being stretched. I attached pictures of the ring design with where the deck would be placed ; note the real bridge would be 50cm long with numerous strings.

Now we cant decide on how to connect those ring structures holding the deck up to the table. A straight line attached to a pillar on the table is not strong enough ...

Any suggestions?
Pictures:
http://img6.imageshack.us/img6/5963/cimg1366.jpg [Broken]
http://img15.imageshack.us/img15/6438/cimg1365.jpg [Broken]
http://img6.imageshack.us/img6/9610/cimg1367e.jpg [Broken]
 
Last edited by a moderator:
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We've done a similar project as a team building excercise. Only we used tape and newspaper.

Remember the string is good in tension and the paper (rolled up) is decent in compression. So a suspension style bridge will more than likely give the best result.

If you want to carry on with the ring design, i'd make 2 small ones and 2 that are intermedieate in size (or more in needed). Then connect these with short rolls of paper as you want the bending to be supported by the compression in the paper. I dont really see any effective way of anchoring it to the table so it will need to be stiff enough so that it can support the bending when just rested on the table.
 

nvn

Science Advisor
Homework Helper
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Epsillon: That is a nice ring, but unfortunately, it serves no function, unless I am missing something.
 

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