Bridge construction challenge with K'Nex
Wise related quote.
Overview
Introduction
A variety of challenges, investigations, and problems can be created related to bridges. This one used K'Nex as building materials. You may substitute other materials. I have also used oaktag, straws, thread, and straight pins.
Bridge vocabulary
- Beam
- Deck
- Load
- Pier
- Span
Source for the definitions of these and more bridge terms.
Investigation notes
Procedure
- Learners are shown photos of bridges.
- Ask. Can you build a sturdy bridge with K'Nex?
- Build bridges
- Share constructed bridge designs
- Introduce the three kinds of forces that affect the stability of bridges.
- Tension - pull or stretch
- Compression - push together
- Torsion - twist
- Tell. A simple way to test a bridge for compresion, tension, or torsion forces is to tie a piece of thread or string between two connectors that are connected with a girder and remove the girder. You can tell if the thread gets tighter, looser, or twists what kind of forces there are at different places on your bridge.
- Test bridges
- Share results.
Compression - capacity test
Who would have thought a bridge could win awards? Does that make this bridge the GOAT?
Pictures of bridge tests
Test with thread added and rod removed
Test with thread added and two piers removed
Test with thread added and grey rod removed
Test with thread added and white rod removed
Statements made when testing bridges:
- When the weight shifted, one side displayed tension while the opposite side showed compression.
- Once we removed 2 girders, there was some slight compression at the point of removal.
- When we removed two girders, force was applied which caused compression.
- When we removed a smaller girder and a larger girder, force was applied which caused tension.
Test bridges
Piers & beam
Piers, beam, & rails
Trusses, pier, & deck
Bridge photo album
Suspension bridge with stone piers
Beam bridge with piers
Trestle below road bridge
Beam bridge with piers
Tressle & beam bridge
Tressle above deck bridge with piers and some tressle below
Arch below deck bridge
Many stone arches bridge
Swinging bridge Rock City
Stone bridge with culverts
Beams and piers bridge
First Sunshine skyway bridge in Florida 1977
Suspension plus pier & beam bridge
Suspension above & arch below bridge - Pittsburgh Monogahala River
Arch bridge in Point Park Pittsburgh
Three rivers bridges in Pittsburgh
Tressel bridge above road
Large and small arches bridge
K'Nex suspension bridges