Popsicle Stick Bridge Lab

Build Strategy:

When designing and constructing the bridge, we knew that we wanted there to be an arch shape, so that the weight would be distributed evenly along the sticks. Additionally, we knew we wanted to use triangles because they are the strongest shape structurally.We also knew that the glue would be stronger than the wood itself, and we wanted as much overlap and places to glue as possible. To achieve this, we tried to make a gradual curve with lots of popsicle sticks overlapping each other, making the two main support pieces much thicker than the rest of the bridge. Then, we built the feet of the bridge, and built supports off of the feet and connected them to the arches with triangles. We made sure that all joints and connections were reinforced with other sticks as well, to distribute the weight evenly.

The Process:


Bridge Schematics:

thumbnail_bridge schematics

Final Bridge:

Video of Bridge Collapse:


The bridge was capable of holding of 115 lbs before it broke. It weighed 482 kg. This gives a ratio of 108 Kg/kg. The bridge overall was relatively sturdy. However, it suffered from human errors such as crooked arches and imbalance structures. This could have been fixed by avoiding an arch bridge to begin with. Building the arch was difficult and time consuming especially when both arches had to be as symmetrical as possible. Additionally, the bridge was overweight. This could have been avoided by removing some of the supports that we had underneath the deck. Unfortunately, we wanted to add towers to the end and connect rubber bands from the bottom of the deck to these towers to add more suspension however the bridge was already overweight.
Peer Reviews:
 Ethan: Ethan came up with the main design for the bridge and helped with the deck top and supports. He made the arch side pieces and main structural pieces, and was the main builder for the project. Ethan stayed over at Brad’s house for the whole time, and provided paper clamps to be used to help the sticks dry together. On the blog, Ethan wrote the “written strategy and build process” section as well as write the peer reviews.
Brad: Brad offered his house to be used for the construction of the bridge, and provided us dinner one night. He helped with the construction of the deck top, arches, and triangle supports seen throughout the project. He also purchased the popsicle sticks and provided some of the glue for the project. For the blog, Brad created the schematic, inserted and formatted all of the photos, and organized the sections together.
Ben: Ben stayed over at Brad’s house while the bridge was being constructed for the entire time. He helped in the constructing of the feet and deck of the bridge, and also worked on the triangle pattern. Ben also supplied some of the wood glue used in the project. For the blog, Ben wrote the data and analysis section. He also provided extensive moral support.

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