Bridge construction challenge with K'Nex

Wise related quote.

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.
  1. Tension - pull or stretch
  2. Compression - push together
  3. 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?

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.

C. Stading, K. Flanagan, L. Haisch, K. Dusatko, S. Simpson, A. Baumann, M. Tobias, Angie Simpson, M. Foster, and C. Mettler

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

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