Truss bridge
The objective of this project was to design and construct a bridge using a Truss formation of my choice out of coffee stirrers. Having given myself the constraint of not cutting any of the stirrers, I shifted my focus to reviewing several possible formations like the ‘K-truss’ and the ‘Bowstring’. Both of which inspired the final design.
Th Assembly of the bridge itself proved to be the most difficult part of the project. Only using PVA glue, the drying times when attaching members of the bridge were prolonged, meaning each part had to be held in place as it dried as any movement would alter the final shape. Due to the width of the individual stirrers and to ensure integrity, I doubled up the sticks in several areas.
To test the strength of the bridge, the bridge was suspended between two tables and weighted incrementally with bricks and slabs. My Bridge held up 7.1 kg before collapsing.
Analyzing the snapping point of the bridge, it was clear to see the reason for the structural failure; that area was not reinforced with multiple stirrers. However due to the constraint of 150 stirrers maximum, that area could not be reinforced at the time. Looking at the distribution of weight afterwards, going forward with this project, I would change the reinforced areas on the side of the bridge and focus them to the top and bottom of the structure.
Technical Skills:
Model Making; Construction
Analytical Thinking
Full analysis below: