Rebuilt HTML — PaddleOCR-VL (Baidu)

Bridge Building Challenge

Goal: Design and build a model bridge that spans a given distance and holds the maximum load possible using the provided materials. Your bridge must be strong, stable, and efficient!

Materials:

Popsicle sticks

Wood glue

• String or tape
• Cardboard base (supports)
• Small weights (for testing)
• Only the provided materials may be used.

Constraints:

The bridge must span 30 cm between the supports.

“I Only the provided materials may be used. 21

The bridge must be no wider than 10 cm.

Build time: 60 minutes.

Testing will be done by placing weights at the center of the bridge until it fails.

Think Like an Engineer!

A bridge must resist different types of forces and distribute the load to the supports.

Compression: squishing force

Tension: pulling force

Shear: forces sliding across each other

Bending: caused by the load pushing down on the bridge

Common Bridge Shapes

Triangular Truss

→ strong and stable

Howe Truss

→ good for heavy loads

Arch Bridge → compression only

Load and Strength (Algebra)

Load (L) is the total weight the bridge holds. If the bridge holds 5 weights and each weight is 20 g:

L = 5w

where w = weight of one mass L = 5(20) = 100 g

Stress (σ) is the force on a material

divided by the area (A) of the material.

σ = F/A

If a stick has a cross-sectional area of 0.2 cm2 and the force on it is 12 N:

σ = 12/0.2 = 60N/cm2

Stronger designs spread the load across more members, reducing stress.

Your goal is to MAXIMIZE L (the load) before failure!

Example Calculation:

If your bridge holds 8 weights (20 g each) and the span is 30 cm:

L = 8(20) = 160g

Convert to Newtons (1 g ≈ 0.0098 N)

P = 160g×0.0098 ≈ 1.57N

M = 7.5P = 7.5(1.57) ≈ 11.78N· cm

Bending Moment (M) at the center of a simply supported beam with a center load:

where P = load

M = PL/4

L = spanlength

For our bridge, L = 30 cm

Good design Balance of Strength, Stability, and Efficiency!

S0,M = (P(30))/4 = 7.5P(N· cm)

• Testing Procedure:
• Place the bridge on the supports.
• Add one weight at a time to the center.
• Record the total load.
• Continue until the bridge fails.
• The team with the highest load wins!

☆ Plan carefully. Build strong. Test fairly. Improve together! ☆