Bridge Builder
Design and test bridges with wood, steel, and cables — watch your creation hold or collapse under a truck's weight. Learn about tension, compression, and why triangles are the strongest shape in engineering.
Frequently Asked Questions
What does this tool teach?
Bridge Builder teaches structural engineering fundamentals: tension vs compression, why triangles are the strongest shape, how different materials (wood, steel, cable) behave under load, and the engineering design process of build → test → improve.
How do I build a bridge?
Click on snap points to place joints, then click two joints to connect them with a beam. Choose your material (wood, steel, or cable) from the controls. Each material has a different cost and strength. Stay within budget, then click "Test Bridge" to see if a truck can cross!
Why do my bridges keep breaking?
Try using triangles! A triangle is the only shape that can't be deformed without changing the length of its sides, making it the strongest structural shape. Also consider using steel for high-stress areas and cables for long spans.
What are the different challenge levels?
There are 8 progressive challenges: starting with short gaps and big budgets (tutorial), advancing to wider gaps, tighter budgets, heavier loads, and eventually requiring cables and advanced truss designs.
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