Bridge Report Team Total Domination

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

References http://cee.carleton.ca/Exhibits/Tacoma_Narrows/ http://www.nwrain.com/~newtsuit/recoveries/narrows/narrows.htm http://www.bridgemeister.com/pic.php?pid=839 Introduction Prototype Final Conclusion

Any Questions?

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