Straw Bridges
Working as engineering teams, students design and create model beam bridges using plastic drinking straws and tape as their construction materials. Their goal is to build the strongest bridge with a truss pattern of their own design, while meeting the design criteria and constraints. They experiment with different geometric shapes and determine how shapes affect the strength of materials. Let the competition begin!
Students create beam bridges.Copyright 2003 Denise W. Carlson. Used with permission.
Beam bridges are the most common type of bridge designed by engineers and relatively easy to imagine and build. Yet, with truss designs, the possibilities are unlimited. To design bridges, engineers perform careful analysis of bridge geometries and the anticipated applied loads so they can determine the exact place of the reaction forces. Engineers also consider the most effective materials to achieve a balance of tension and compression. Engineers determine the bridge type, design and materials; analyze site conditions, geologic and environmental factors; and establish detailed design plans and budget/funding schedules.
After this activity, students should be able to:
- Describe and design model truss bridges.
- Identify effective geometric shapes used in bridge design.
- Identify several factors that engineers consider when designing bridges.