Sir Wilfrid Laurier SS

Technological Design


Course Topics: TDJ1O | TDJ2O | TDJ3O | TDJ3M | TDJ4O | TDJ4M

BRIDGE CHALLENGE 2010



Problem Statement: to research, design, construct, test and report on a scale model of a basswood bridge that can hold the most mass based on the span.

Materials: The teams are provided with the following supplies:

  • 10 – 1/8” * 1/8” balsa sticks
  • 1 sheet of 18 x 24 wax paper, graph paper, cardboard
  • 1 box of pins

Design Criteria:
The bridge must be designed and constructed within the time limit.
It must be constructed of the provided materials only. Tools cannot form part of the design.
The specifications must be followed.


  • A maximum of 10 pieces of wood may be used.
  • The total length of the superstructure must measure 14 inches long at the roadbed.
  • The total width of the superstructure must measure 2 1/2 inches wide from side to side.
  • The total height of the superstructure must not measure more than 3 inches above the roadbed.
  • The distance between supports (span) must be 12 inches.
  • A substructure must not measure more than 12 inches long and 1inch high.

In the interest of fairness, it is essential that only the materials above be used. In particular, this means that the wood cannot be treated in any way to change its strength or appearance, and only the amount and type of materials specified should be used in construction of the bridge. Only water and/or steam treatment will be allowed in order to facilitate bending of the wood. Wood pieces may be bonded together with cement ONLY at joints, and may not be laminated together in parallel fashion. If two or more strips of wood are placed parallel to each other, they must be at least the thickness of this paper apart from each other. Splitting or laminating are not allowed.

“Bridge Breaking Day” is to test the strength and efficiency of the bridge. You must design your bridge leaving at least a 1inch square opening at the very center point of the roadbed of the bridge.




Hand-in for Evaluation:
Modified Technical Report
Model Bridge