What bridge design is best?

I need to design a bridge for a project but it has to be made out of MDF that is 20cm x 33cm x 3mm MDF that is 3mm x 3mm x anything hot glue and string. It has to be strong, span 60cm have a 30cm clearance and be 20cm wide. It can have no supports and not attach to the ground. The wide MDF can only be used for the road and you cannot layer it.

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kelseymh7 years ago
If you're building a completely unsupported bridge which doesn't attach to the ground, do you have to design the antigravity device, too?  Or is it included in your parts kit?
eggyeggyeggy (author)  kelseymh7 years ago
To the ground in between the gap
frollard7 years ago
Your materials list is a bit vague - I understand you have a 20x20x.3 sheet.  What is a 3mm x 3mm x anything?  a stick?

You need to span 60cm but you can't layer the road - how can you span a 60 cm gap with a 33cm piece if you can't layer to join it?  A butt joint would be extremely weak in this stuation.

How much can rest on the supports at the edge of the 'cliff'? 

Only thing you need to think:  Triangles.  Lots of small triangles.
eggyeggyeggy (author)  frollard7 years ago
Yeah It was pretty vague right up until the comp but we got best looking and second strongest. Ill post pics when i hook up my phone to my computer. The design was based on the worlds strongest paper bridge. (by the way that held 1076 kg!!!!! awesome!!!)
Acepilot427 years ago
make a truss bridge. they are made up of triangles. lots and lots of triangles.