2. Bridge Report
Team Total Domination

3. Outline Introduction…………….. Zach Chaviers
Prototype……………….. Ali Nikkhah
Final Design……………. Bobby Schneider
Conclusion……………… Derrick Wang
Today our presentation will begin with an introduction of our problem and background information from Zach, who will hand it off to me to talk about the prototype design and test. Next, Bobby will address the details of the final design and test. Finally, Derrick will conclude the presentation with a summary. I will now hand it off to Zach. Zach?
Introduction Prototype Final Conclusion

4. Problem Build most efficient bridge Efficiency:
Limited to 125 tongue depressors
What efficiency equation variables mean
Materials- depressors, fishing line (not needed), and UNLIMITED glue
Introduction Prototype Final Conclusion

5. Background Warren Truss Component testing Four-step process
Process: initial design, test prototype, redesign, final test
Now that you know what you need to in order to follow along, I will hand the presentation off to Ali to discuss the first two parts of our four-step process.
Introduction Prototype Final Conclusion

6. Prototype Design 3 preliminary designs Criteria for design Simple
Triangle-based
Allow for easy layering
Thank you Zach. Our design process began with each of us creating a few designs from which we could choose. We narrowed our choices down to 3- an arch bridge, an A-frame bridge, and a Warren truss design. It was important to us to choose a design that would be simple and economical. We did not want to spend vast amounts of time building an overly intricate bridge, that is, one that would consume too many resources, i.e. time and materials. In order to keep our design simple, we decided it would be good to choose a triangle-based design. This would also be strong, as triangles distribute weight well. We also needed our bridge to be simple so that we could layer the sides of it. We wanted to make sure that we had thick sides that would not fall apart when even small loads were placed on the bridge.
Introduction Prototype Final Conclusion

7. Construction Warren Truss design used Built quickly
Main goal: test structure
We finally decided on a Warren truss design. This could be constructed easily and with little complication. We built the prototype quickly, as we were on a tight schedule. We also paid little attention to the construction method, as we felt it was most important to test the structure, as we already knew which materials would be best. Therefore we use hot glue in order to keep the construction process going quickly. We also made few measurements, shaping most pieces by fast fabrication. We completed the entire bridge in about 2 days.
Introduction Prototype Final Conclusion

8. Before Testing Introduction Prototype Final Conclusion
Here you can see our completed bridge. Note that the simple Warren truss contains many triangles. We tied the two sides of the truss together using beams at the top and bottom. Inside, you will note that there are 4 cross-supports. These were placed to keep the bridge from twisting and bending too much.
Introduction Prototype Final Conclusion

9. Test Stable load increase Bent at joint Support popped out
During the test, the load that the machine placed on the bridge increased steadily. This means that the structure had little give and was structurally sound. Once the load reached a certain magnitude, the bridge began to fail. The main failure was a joint that bent outward on the top of the truss. As a result of this, a support on the opposite side of the truss popped out, placing more load on the rest of the bridge.
Introduction Prototype Final Conclusion

10. Test Introduction Prototype Final Conclusion
As you can see from this photo, the joint bent out here (show them). This was the result of all three layers of the bridge having a joint between pieces in a close vicinity to one another. On the opposite side, this (point) support popped out of its joint.
Introduction Prototype Final Conclusion

11. Results Max load 397 pounds Efficiency: 630 Joints weak
In the end, our prototype performed well and showed promise. The maximum load that it could handle before completely failing was 397 pounds. Our goal had been 420 pounds, so we came close. Using the efficiency formula which Zach discussed earlier, we found that our bridge had an efficiency of 630, which was comparable to the best of all the teams. Our main weakness was the joints. Our design was solid, though, and we decided to keep it and make a few modifications for our final design, on which Bobby will now elaborate.
Introduction Prototype Final Conclusion

12. Final Design Fix weaknesses Joints Glue type Precision Symmetry
Thank you Ali. Based on the weaknesses………
Introduction Prototype Final Conclusion

13. Construction Graph paper Clamping Glue Coating
Thank you Ali. Based on the weaknesses………
Introduction Prototype Final Conclusion

14. Before Testing Completed Final Bridge
Thank you Ali. Based on the weaknesses………
Weighed .75 lb
Introduction Prototype Final Conclusion

15. Test Stable load increase Twisted Did not break
Thank you Ali. Based on the weaknesses………
Introduction Prototype Final Conclusion

16. Test Introduction Prototype Final Conclusion
Thank you Ali. Based on the weaknesses………
Introduction Prototype Final Conclusion

17. After Testing Dead Bridge Introduction Prototype Final Conclusion
Thank you Ali. Based on the weaknesses………
Introduction Prototype Final Conclusion

18. Results Max load 811 pounds Efficiency: 1080 71% more efficient
Held 811lb
I will now hand it off to Derrick to conclude the presentation.
Introduction Prototype Final Conclusion

19. Summary Truss Design Prototype performed well Minor changes made
Improved performance
Introduction Prototype Final Conclusion

20. Improving Final Design
Stabilizers created rectangles
Add triangles to prevent twisting
Introduction Prototype Final Conclusion

21. References http://cee.carleton.ca/Exhibits/Tacoma_Narrows/
Introduction Prototype Final Conclusion

22. Any Questions?

23. Team TOTAL DOMINATION Ali Nikkhah Zach Chaviers Derrick Wang
Bobby Schneider
Subject to your questions, that concludes our presentation.