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Learning Activity #1:
Build a model of a truss bridge. Build a model bridge from
cardboard file folders. The bridge has already been designed, and accurate
drawings and fabrication instructions are provided. Through this activity,
students will learn bridge terminology, construction techniques, and some
basic concepts in physics and structural engineering.
Learning Activity #2:
Test the strength of structural members. Use experimental testing
to determine the strength of structural members made of file folder
cardboard—the same stuff we used to build our bridge model in Learning
Activity #1. The data obtained from these tests will be used extensively
in Learning Activities #3 and #5. This activity requires the use of
a simple wooden testing device.
Learning Activity #3:
Analyze and evaluate a truss. Calculate the internal member forces
in our model truss bridge. We will then evaluate the structural safety of
the truss by comparing these calculated forces to the member strengths we
determined experimentally in Learning Activity #2.
Learning Activity #4:
Design a truss bridge with a computer. Design a full-scale highway
truss bridge using the West
Point Bridge Designer software. The
design process includes working through multiple iterations to ensure that
the structure will carry the prescribed loads safely and at minimum
cost.
Why manila file
folders? Why not toothpicks or pasta?
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File folders are readily
available and very inexpensive
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Cardboard can be easily
folded, cut with a scissors, and glued with common household adhesives
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The behavior of
cardboard as a structural material is surprisingly predictable
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Cardboard provides the
capability to build two fundamentally different kinds of structural
members—hollow tubes and solid bars.
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Cardboard provides the
capability to build connections that are stronger than the members
they join together. If you’ve ever built and tested a truss
bridge made of balsa wood or Popsicle sticks, you know that these
structures almost always fail at the connections.
Learning Activity #5:
Design and build a model truss bridge. Here we will apply what we
have learned in the previous four activities to design, build, and test a
model truss bridge.
Also included is a Glossary
(Appendix D), which provides definitions for mathematical, scientific, and
engineering terms used throughout the book. The first appearance of any
Glossary term in the text is highlighted in bold type.
Bridge
Designer
Online
program to design truss bridges.
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Step
1. Measuring
and cutting the pieces
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Step 2. Building and
connecting trusses
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Step 3. Adding the floor beams
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Step
4. Completed bridge
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 FINAL
PRODUCTS
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