Carnegie Mellon University

Lesson title:  2D to 3D Truss Bridge Building

 High School: Bridge Building Constraints

[NOTE: A pdf version of this page is available; see navigation box on the right.]

Truss Bridges

Figure 1: From page 64 of Noyce, Pendred E, Engineering Bridges Connecting the World, Boston: Tumblehome, Inc., 2019


Must be freestanding
  1. Bridge must not weigh more than __________*
  2. Bridge must have a road that spans 8 inches long, 3 inches wide, and has guardrails on both side of the bridge
  3. May only use the provided resources
  4. Budget must not exceed $500,000
  5. Must be able to support the weight of one or more of the following for 10 seconds without buckling
    1. Ten toy cars
    2. Four block erasers

*Must be as close to the chosen patented design as possible*

Budget Sheet:  Please see file

Materials Fees

  • Construction Paper: $10,255 per sheet  
  • Scissors: $15,000 per scissors
  • Tape: $50,000 per roll 9 (2 meters)
  • Ruler: $10,000


Construction Fees

  • Labor Cost: 45,000 per person in group + $65.87 per minute worked


Disposal Fee:

  • Construction Paper: $5,127.50 per sheet returned
  • Construction Paper: $2,563.75 per sheet; portion of sheet returned practices fee
  • Tape: $25,000 per roll returned