Constraints/Problems
During this project many constraints to design the bridge were encountered. Firstly, we could only use 50 paddle pop sticks which meant we had to be efficient and not waste any. Our first design involved us using a majority of our sticks on the main beams, however, there were four beams plus the trusses so we easily would have surpassed the limit. On our second design we deducted one beam and made our bridge a triangle shape. This enabled us to keep using the majority of the sticks on the beams and still have enough to make the trusses. Once the paddle pop stick limit was increased to 100 we could simply add two extra beams for support either side of the triangle design.
Another constraint was the fact that the bridge could not touch the bottom of the 500mm gap. However, that was not too much of a problem as there were a lot of other bridge designs that we researched that didn't involve support pylons.
Another constraint was the fact that the bridge could not touch the bottom of the 500mm gap. However, that was not too much of a problem as there were a lot of other bridge designs that we researched that didn't involve support pylons.
Considerations
At first we considered making a simple k-truss deck bridge that would have been strong but not very efficient. It would have cost a lot of paddle pop sticks and we just did not have the adequate amount. After that, we thought we might try making a warren truss deck bridge instead, as it involved using less sticks for the trusses. However that design was soon adapted to what we eventually ended up making - a triangle shaped, warren truss deck bridge. The triangle shape resulted in us using less sticks as we only needed one lower centre beam and two upper beam rather than two lower beams and two upper.
In the end however, we put in extra beams on either side of the lower centre one as we had excess paddle pop sticks. This meant that our bridge was much more stable and strong.
In the end however, we put in extra beams on either side of the lower centre one as we had excess paddle pop sticks. This meant that our bridge was much more stable and strong.
Sketches
Computerized Sketches
This is an image of the bridge that we designed first however did not end up using.
This is a design that is similar to how the final bridge looked. However, due to the fact that we had excess paddle pop sticks after completing this design, two extra beams were added either side of the main centre beam. This added rigidity and strength. We also had excess tape so we wrapped the whole bridge up to make it more visually appealing.