Bridge experiments

 Mass Power Ratio
Apparatus [g] 
Loader 50 
Scale 235 
Bucket 498 
  
TOTAL 783 

Arch Bridge

Note: archlike, using straight lengths of balsa wood

Mass                         23 g
Rocks                      8670 g
Total mass load at failure 9453 g
Efficiency                  411

Separated Warren Truss

Note: had to modify the center to fit the prescribed loading device

Mass                         19 g
Total mass load at failure 4880 g
Total load                 5663 g
Efficiency                  298