1. Tim Wyckoff David Cenidoza Sachin Narvekar Felix Liu Weston Wells
Teh Sl4ck0rz!!!1!1 (group 8)
Tim Wyckoff
David Cenidoza
Sachin Narvekar
Felix Liu
Weston Wells

2. Table of Contents Project Introduction Component Testing I-beams
Prototype Designs (pros and cons)
A-Frame design
Prototype Test Results
Final Design (changes)
Final Test Results
Evaluation of changes and recommendations
Conclusion

3. A Project Introduction “A-Frame” Bridge This PowerPoint will outline:
Why we chose this design
Different Ways it can be done
How effective it is

4. Component Testing Fish line Test Tension Testing Tongue Depressor Test
Torsion & Bending Test

5. Compression
The test is responsible for testing the integrities of different truss structures, finding it’s strong and weak points
Finding the best way to put it all together and maximize the efficiency of the bridges
Some of the tests on the tongue depressors involved compression, tension and bending/torsion.
To do this we just applied vertical pressure on the depressors with a scale underneath it and read of the weigh limit using visual confirmation at the first sign of bending
Box Structure

6. Torsion and Bending Testing
The testing involved building platforms that were different in design, and they were
Tested for their strength and flexibility by twisting and bending.
The testing was to find out which designs would excel in strength and flexibility, therefore ways that help maximize the strength and flexibility of the bridges can be known.
There are many platforms that were designed and it was easy to distinguish which designs provided more strength and flexibility
“X’s” into the designs helped with the strength and it wasn’t too flexible

7. Fish line Testing
The purpose of this test is to figure out the amount of tension 4 different
fishing lines could withstand.
Used four different types of fish lines; 10,20,30,65
65 lb line despite it’s in ability to hold its alleged weight, it still managed
to withstand the most tension under the least strain
65 l line is recommended

8. Tension Testing
The test is to determine the amount of tension two tongue
depressors could withstand before breaking
Three types of glue; super glue, Elmer’s glue and Elmer’s glue wood
Popsicles were glued together at three different overlap lengths,
which were ¼”, ½”, and ¾”.
Elmer’s glue

9. I-Beam Effective beams with I or H shaped cross-section
Commonly use in construction.
Strong is bending and Torsion.
Extremely Strong in compression (perfect for our side beams).

10. Prototype Designs: Cable-stay Bridge
Pros
Lightweight
Potential for high efficiency
Simple design
Cons
Not ideal for point loading
Weak design

11. Truss Bridge Pros Very symmetrical Strong Cons Heavy Difficult design
Too many meaningless pieces

12. A-frame Bridge Pros Ideal for point loading Strong Very symmetrical
Simple design
Cons
Pretty heavy
Great opportunity for torsion

13. Why the A-Frame?
The A-frame bridge has a very strong, supportive design.
It is ideal for point loading, which is how these bridges were being tested
The design is very simple and does not take long to assemble.
Picture of Prototype

14. Prototype After Testing
Prototype Results
Weight: lbs
Max. Load: 181 lbs
Score: 276
What went wrong?
Bridge was not built for point loading
Many unneeded beams or tongue depressors
Tongue depressors not placed in supportive places
Bridge failed mainly due to torsion.
Prototype After Testing

15. Final Design Changes we implemented
Making side beams touch in the middle by changing the angle
Turned all beams into I-beams
Added middle I-beam
Used fewer tongue depressors
Made bridge more stable (even sides, less wobbly)

16. notice the bottom right corner
Final Test Results
notice the bottom right corner
Weight: 0.58 lbs
Max. Load: 379 lbs
Efficiency: 654
What Went Wrong?
Some torsion along bottom beams
Weak base-side connection
Use of hot glue instead of Elmer’s.

17. Side by Side Comparison
Prototype Final Design
Before
After

18. Final Word Angling of side beams = Success
Omission of diagonal beams = Success
Addition of middle I-beam = Partial Success
Recommendations for more improvements
Maybe take out middle beam
Strengthen base-side connection

19. Conclusion Overall: Success Results: Efficiency: 276 -> 654
Did well on original goal of building a tongue depressor bridge that held maximum amount of force, with minimum weight.
Results:
It is important to give direct support to wherever the point loading is applied
It is extremely important to build your bridge precisely and carefully (make precise measurement, glue well, etc.)
Connecting Parallel beams gets rid of torsion
Don’t use pointless beams and tongue depressors. Having a lighter bridge really helps