The Arizona STEM Acceleration Project

Truss Bridge

Truss Bridge

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A 11-12’th grade Lesson STEM lesson

Sreevelmurugan Vamadevan

02/21/2023

Notes for teachers

• Context: This lesson takes place in a classroom for one or more hours
• Students may work in small groups of 3-4
• An emphasis on the target product (Components of a truss bridge and types of truss bridge)
• Creative solutions should be encouraged
• Facilitate student reflection on why and how Ocean to Ocean bridge constructed and which are the Math and Science concepts used.

Materials Using:

Craft sticks

Hot glue and extra glue sticks

Cable Ties

Sheets and Cardboard

Truss bridge pattern Handouts

Weights to test the capacity

Hanging scale

3 Foot length of nylon cord

Handle with nylon cord

Truss Bridge Questions

Truss Bridge Handout

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Arizona State Standards

• HS.P3U2.7
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• Use mathematics and computational thinking to explain how Newton’s laws are used in engineering and technologies to create products to serve human ends

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Next Generation Standards

HS-ETS 1-2,HS-ETS-1-3,HS-ETS-1-4

Discussing truss bridge

Analysis of force-basic concepts

The joints method

(i)Identify the corresponding forces acting on each of the truss elements

(ii)Find the value of reaction forces on the end bottom of the truss.

(iii) Analysis of forces on nodes using FBD and the equilibrium condition

(iv)Solve the system of equations using matrices

Objective(s):

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1. Identify the components of a truss bridge
2. Identify different types of trusses
3. Perform the analysis of forces at a truss’ nodes using free body diagram
4. Use trigonometric ratios to find force magnitudes at a truss nodes.
5. Use the method of joints to set up a system of linear equations to calculate the tensions and compressions on the truss elements.
6. Use substitution method to solve systems of linear equations larger than

3x3.

Agenda (lesson time)

What is the most efficient path to move to one point to another point, and why?

What is a Truss bridge and what is the purpose of it.

Bridges are more important structures in the modern world. Discuss

Design process of Bridges.

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Intro/Driving Question/Opening

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Bridges allow you to keep your wallet safe: Discuss.

What is a Truss bridge

Different forms

Hands-On Activity Instructions

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Truss Bridge Questions

Truss Bridge Handout

Assessment

1. Pre-Assessment to check their ability to model system of equations
2. Solve angles using Trig ratios test

Lesson summary Assessment: Check students’ Note Taking sheet and give a grade for completeness,Clarity and Neatness

Differentiation

One way to differentiate in this lesson is to provide some groups a template for their first design and analysis. This can help students who struggle with the “getting started” phase.

Another option is to provide a Truss bridge construction process video, that will enable them to visualize it and will be helpful for the visual learners.

Remediation

Extension/Enrichment

Students who are successful right away can plan how they would use a truss bridge construction process knowledge to accomplish a real-world task (reconstructing a collapsed bridge in front of your house).