Bridge Design Project

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To build a balsa wood bridge that will support the largest possible load.  The bridges will be loaded to the point of failure during an organized contest.

The following materials will be provided by the instructor.

  • one piece of 1/8 in x 1/8 in balsa wood 48 in long
  • one piece of 6/32 in x 1/8 in balsa wood 48 in long
  • one piece of 6 in x 3/32 in balsa wood 12 in long
  • one piece of string 18 feet long
  • one tube of glue
  • one wood loading plate with metal hook

10 in of transparent tape distributed on the day of the loading contest

You will also be given some material samples for testing purposes.  These samples may not be used in the final structure.

Each bridge must connect two sides of an 18 in span across two classroom tables.  The loading plate must fit in the center of the bridge in such a way that the mass holder can be attached to the metal hook.  The loading plate may not be permanently attached to or used as part of the structure of the bridge.  The transparent tape may only be used to attach the two ends of the bridge to the tables, not to reinforce the structure.

Each team will prepare a two-page written report describing their efforts.  Diagrams and sketches may be attached to the report.

You may use any general references you wish.  However, the bridge design and construction must be your own.

Loading Contest Guidelines:
Each team will receive a 1-kg mass holder that they must attach to the loading plate on their bridge.  Thereafter, each team will increase the load in 1 kg or 0.5 kg increments.  The bridge must support the load in static equilibrium in order to receive credit for it.  The builders of the last remaining bridge will decide whether or not to load their bridge to the point of failure.

The names of the loading contest winners and the maximum supported load will be added to the plaque in the hallway display.