Engineering challenge: design a safe footbridge over a stream

🎯 Aim

To design a footbridge using weight, bending moments, the principle of moments and a safety factor, and to compare materials by safety and cost.

You will learn to

• Calculate loads with W = mg.
• Use M = wL²/8 to size beams with a safety factor.
• Find support forces with the principle of moments.
• Compare timber, steel and bamboo by cost and life.

🧭 What to do

1. Step 1: set the span and the number of people on the bridge.
2. Work through each numbered step: move the sliders and choose the options.
3. Watch the drawing and the results change after every choice.
4. Compare the options and their costs in the table and the chart.
5. Answer the questions below, using 💡 Hint before the method.
6. Justify your design in the last step, then download your design report.