Lesson 1: The Great Span: Engineering the 7 Bridge Types

1. How does the shape of a bridge determine how it handles a heavy load?

2. Why would an engineer choose a suspension bridge over a beam bridge for a long span?

3. Where are the points of "failure" in a bridge under extreme stress?

Tension: A pulling/stretching force.

Compression: A pushing/squeezing force.

Abutment: The substructure supporting the ends of a bridge.

Bascule: A bridge that opens (drawbridge) using a counterweight.

Load: The weight or force applied to a structure (Live load vs. Dead load).

Symmetry: The quality of being made up of exactly similar parts facing each other or around an axis.

ENG.05.01: Identify and describe the components of a structural system (e.g., beams, columns, trusses).

ENG.05.02: Analyze the effects of loads on structures (Tension, Compression, Shear, Torsion).

Working in teams of 2–3, students use K’Nex to build one assigned bridge type. They must measure the span, ensure symmetry, and then "tag" their model with colored string (Red for Compression, Blue for Tension).

Purpose: To provide a tactile understanding of civil engineering and the importance of geometric stability in design.

DOK Level: Level 3 (Strategic Thinking). Students must interpret their building instructions, troubleshoot structural weaknesses, and justify their design choices in their journals.

For Visual/Tactile Learners: Provide 1:1 scale templates of the bridge designs so students can "overlay" their K'Nex pieces to ensure accuracy.

For Advanced Learners: Introduce "Economic Constraints." Each K'Nex piece has a hypothetical cost; students must build the strongest bridge for the lowest price.

For ELL/ESL: Use a "Force Anchor Chart" with visual arrows showing push (compression) and pull (tension).

The Engineering Journal: Each student must record a sketch of their bridge, its measurements, and a "Stress Map" showing where the bridge is most likely to break.

Peer Evaluation: Teams rotate to other bridges and use a checklist to evaluate the symmetry and "build quality" of their classmates' work.

K’Nex Education: Real Bridge Building sets.

Student Engineering Journals.

Small weights (fishing weights or washers) and buckets for load testing.

Text: "Bridges and Tunnels: Investigate Feats of Engineering" by Donna Latham.

Potential Speaker: A Civil Engineer from the Connecticut DOT to discuss the construction of the Pearl Harbor Memorial Bridge (Q Bridge).