Hold On

When my group and I first started working on the bridge, we thought about how to make the bridge the sturdiest it could be.  One of our first thoughts was to make the top super durable so that it wouldn’t break.  We noticed that if you turned a popsicle stick so the side faced up, you couldn’t bend it.  We used this idea to make the bottom of the platform.  After that we added some straight supports on the ends to attach to the bottom later.  

Build 1

After attaching the top platform we decided it would be the best if we made the bottoms triangle shaped to ensure it could handle the load.  Then we thought if we made the top of these triangles flat, we could add side supports onto the top to make sure they didn’t separate under the weight.

Build 2

Lastly after observing the bridge started bowing at 20 pounds we added popsicle sticks in an arch formation from the sides to the platform on the top to add support to the top.

Final Bridge

Finished Bridge

Schematic

Schematic

Results

bridge smashed

When our bridge was complete, it weighed 397 grams and held 80 pounds.  The bridge held 92 times its weight.  The bridge failed after we took off some weights to put on a second 45 pound weight.  It was at this point that the bridge titled to its side and then the sides broke.  The top was left intact and didn’t break.  Overall the bridge held up quite well.  At first it started to bend under the pressure, but it settled into a more stable state.  It was a little unstable as we had to make sure the weights were in the middle because early into the test the bridge fell over.  If our supports were a bit sturdier we may have been able to hold much more.  This would have come in the form of adding a complete arch under the platform and extending the bottoms to hold the bridge stable.

smashed bridge

Who Did What

Dominic – Brought supplies. plan, build, blog, and pictures

Tom – Plan and build

Drew – Build, pictures, blog

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