4. Creation and Evaluation

Block H needs to put their data here for the bridge testing.

Here's a vid where I show how I made rails and cylindrical beams with paper and glue.

How you test your bridge is somewhat up to you, and based on the physical structure of your creation.

You'll need to use something with a mass you can estimate. I would recommend something like soda cans.

Here's probably the easiest way to test it. Put a rigid board on top. I used a small cutting board from our kitchen. Carefully stack soda cans on it. Soda cans can also stack on each other.

I wanted to put the load on the BOTTOM (or roadway) of my bridge. So I used big Lego-type pieces to support the cans above the bridge top. The lego pieces (and hence the cans) rest on the roadway.

This is trickier. It also allows the roadway to support the weight, and allows loading from beneath the bridge. I used a big Lego block to support a drumstick, and then hung an open back from the drumstick. I then placed the cans inside the bag.

Here is a standard isometric viewpoint of the finished bridge.

End view of bridge showing cross bracing as you pass through the bridge. Note the roadway which is a homemade corrugated cardboard.

Here is a timelapse video of me loading my bridge. It got up to a load of 2 soda water cans, 1 Liter of milk, and the loading hardware (legos + breadboard). The masses should add up something like this.

345 g x 2 = 690 g

1 L of milk = 1050 g

loading hardware = 340 g

Total mass held = 2080 g = 2100 g (rounded)

I did not load the bridge until it broke. So I believe it can hold more.

Evaluation of Bridge

I was overall quite pleased by the performance and aesthetics of my bridge. It held 2100 g and used 21 sheets of paper. This gave it a ratio of 100 g held per sheets of paper used. I believe it could have actually held a great deal more weight, as I never saw it deform at all under 2100 g.

I was most pleased by the corrugated cardboard roadway that I made. It helped me understand why manufactured corrugated cardboard is such an important invention. If gives a great deal of strength to a material made solely out of paper and glue. The triangular sleeves on my cylindrical beams were also a source of pride. They gave me more surface area to stick the beams onto the rails.

If I were to improve on this bridge, I would add a second corrugated cardboard roof. This could keep the beams from compressing. Aesthetically, I would print the paper with pieces with pictures of frogs on it. I've never seen a bridge with frogs on it before, and I feel the world is long overdue for such a thing.

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