A stable paper-bridge for a maths/physics/chemistry contest

[Kaimon]

This topic actually is off the origami-topic, so if necessary, it can be moved ...
sorry for that.

The school that I go to has taken part in a maths/physics/chemistry contest and there is a challenge to build a bridge from 50 sheets of Dina4-sized paper (about 21 cm x 29 cm / 8,3 in x 11,4 in). It has to bridgeover a distance of 30 cm (11,8 in) and should be as stable as possible. Then it will be laid stress on.

(The record was established by another school some years ago with a maximum weight of 250kg, but they were allowed to use strings.)

I'd be really happy to hear some suggestions of -how to build the bridge- from you!

[GreyGeese]

Try starting with a modular polyhedron, and try modifying it to make an arch.

[JeossMayhem]

Exactly. What I would consider is making strong trapezoidal units that make your arch. 30cm really is a short distance, so you can make plenty of units, making stronger arches. (5 trapezoids per arch?) Then add pieces between arches to help disperse weight.

What other guidelines are there? Can you cut your paper into a different size? Are adhesives allowed?

This sounds like a fun project... I wish I could do this instead of homework... but I suggest doing some more research on making a stronger structure.

[origamimasterjared]

Tips: If you can, use a ton of glue. Remember, the more joints, the more weak spots. Square joints are structurally awful. Triangles and circles are much better. Look into using paper tension; ie. bending in one area might make another (more integral) area much stronger.

And yeah, take a look at some real bridges, and maybe try to approximate them using paper.

[wolf]

A corrugated arch might be your best bet.

Remember also that you can use the grain direction of the paper to your advantage.