Name:
Period:
Date:
Design Scenario
A park needs a 24-meter pedestrian bridge across a drainage canal. The bridge must support people and small maintenance carts, remain open during heavy rain, and stay within budget.
| Design | Estimated cost | Material | Key characteristics |
|---|---|---|---|
| A: Beam bridge | $180,000 | Steel beams and concrete deck | Simple; few parts; requires a center pier |
| B: Truss bridge | $230,000 | Steel members | No center pier; many connected members; easy to inspect |
| C: Arch bridge | $285,000 | Concrete and steel | No center pier; strong abutments required; visually distinctive |
1. Understand Load Paths
A load path is the route force follows from the bridge deck to the supports and then into the ground.
- Describe the likely load path for each design.
- Which design places many members in tension and compression?
- Which design may experience large outward forces at its supports?
2. Decision Matrix
Score each design from 1 to 5. Multiply by the importance weight.
| Criterion | Weight | Beam | Truss | Arch |
|---|---|---|---|---|
| Cost | 3 | |||
| No obstruction in canal | 5 | |||
| Ease of inspection | 3 | |||
| Appearance | 1 | |||
| Construction simplicity | 2 | |||
| Weighted total |
3. Concept Sketch
Sketch your recommended bridge. Label the deck, supports, likely tension areas, likely compression areas, and the load path.
4. Engineering Recommendation
Recommend one design. Use at least three pieces of evidence and acknowledge one drawback.
Submission Checklist
- All analysis questions are answered.
- Required calculations, tables, sketches, or diagrams are complete.
- The final recommendation uses evidence from the lesson.
- Your name, class period, and date are included.
Closing Reflection
What was the most important engineering or manufacturing decision you made in this lesson? Explain why it mattered.