CE 301Balsa Wood Bridge
Andrew Brownlow, Jamison Crowley, Johnson Baker, Chris Schultz
Bridge Design
Original Design
Truss
Deck with Girders
Cross Bracing
Final Design
Simple Girder Design
Two Main Girders
Cross Bracing
Construction
Why The Design Was Chosen
Simple Design
Cost Effective
Practicality of Construction
How it was built
Materials Used
Balsa Wood
Gorilla Glue
Various Tools
Testing and Failure Analysis
11.44 oz
Failed at 376.09 lbs
Strength-Weight Ratio 526
Started to Crack during testing
Wood, not glue, failed
Deflected 0.25 in
Improvements
Increase number of girders
Thinner and taller girders
Have curved girders
Reconsider number/position of cross bracings
Overall: Increase moment of inertia near the load
What We Learned
Simple design balances practical construction
with high SW ratio
To consider materials and tools available when
choosing the bridge design
How to incorporate the governing engineering
principles into design