Six Weeks 5 · Week 2 · Wednesday

Day 3: Bridge Constraints and Design Evidence

Students will compare bridge systems, create two options, and select a design from evidence.

Daily Learning Contract

  • Topic: Bridge Design Evidence
  • Objective: Students will compare bridge systems, create two options, and select a design from evidence.
  • TEKS: d(1)(C)
  • Demonstration of Learning: Two-view options + critique + individual career-role decision.

Lesson Overview

Time 50 minutes
Target Compare bridge systems, create two options, and select a design from evidence.
TEKS d(1)(C)
Evidence Two-view options + critique + individual career-role decision

Before Class

Provide one Canvas-capable device or one four-page landscape design packet per student, plus pencil and ruler. Students use one route. Work is individual; pairs may give the brief critique, with self-review or a teacher conference as equal routes. Project packet page 1 and the supplied two-option model in the Teacher Guide. No physical materials or build station are required.

50-Minute Flow

1. Shape investigation — 5 minutes

Demonstrate a pin-jointed square and triangulated frame. Say that triangulation can make an idealized frame geometrically stable; joints, material, span, loading, and failure mode still matter.

2. Constraints and evidence cycle — 10 minutes

The classroom comparison uses a 12-inch span, one marked load point, and standardized fictional results. The goal is a comparable result and justified revision, not a winner. Real infrastructure also requires licensed analysis, codes, geotechnical evidence, public review, and long-duration validation.

3. Compare bridge systems — 10 minutes

Use teacher-curated beam, truss, and arch visuals. Explain that performance depends on the complete system; do not force every team toward a predetermined truss answer.

4. Draw two options and critique — 20 minutes

The packet gives Option A and B a landscape drawing page with separate top and side fields. Students label the 12-inch span, supports, members, joints, load point, expected load path, and predicted weak point. Each student records one critique and the evidence behind the final choice.

5. Exit — 5 minutes

Name the civil/structural/technician role responsible for the next project step, what evidence that worker needs, and what the worker would produce.

Access and Absence Route

Use tactile or large-print geometry, verbal description, typing, dictation, or a teacher scribe. Absent students complete both options and use the same sample data on Day 4.

Monitor at minutes 10, 25, 38, and 45 for constraints, Option A, a meaningfully different Option B, and the supported choice/role response. If one-third changed only color or decoration, reshow the model. Accept clean labeled line diagrams and concise strengths when time is short; protect both distinct options, the supported choice, and the individual career-role evidence. Collect one annotation/upload or packet and stack rulers.