5 Steps to Building a Model Bridge

June 11th, 2007

Now you can download the 5 Steps to Building a Model Bridge PDF ebook. The ebook contains the expanded version of the outline below, plus a lot of helpful pictures. The ebook also contains 25 bonus tips.

#1: Know the rules!

  • Be able to define in your own words what the bridge must accomplish

#2: Design the bridge

  • “Center” the design around the loading point
    • Plan for extra bracing around loading point
  • Choose a truss to use
    • Warren
    • Pratt
    • Howe
    • Design your own
  • Draw the bridge to scale on graph paper
    • Forces you to choose sizes for everything
    • Label everything
    • Name the design and add a date

#2b: Before building

  • Get the wood
  • Tools
    • Glue
    • Saw/Exacto knife
    • Gram scale
    • Clamps/clothespins
  • Workspace
    • Good lighting
    • Good ventilation

#3: Build the bridge

  • Step 1
    • Tape down the top and bottom chords
    • Glue on remaining pieces
    • Make sure everything is held firmly in place and let dry
  • Step 2
    • Make two piles of books, spaced correctly apart
    • Tape trusses to piles
    • Glue bracing on top
    • Glue bracing on bottom
  • Double check for leaning
    • Glue on lateral bracing
    • Weigh the bridge
    • Record weight and all specs of the bridge

#4: Test the bridge

  • Test before competition if:
    • You have time to build another bridge
    • You are only testing your bridge to a certain point
  • Testing procedure
    • Bathroom scale (top loaded only)
    • Bucket and sand (top or bottom)
  • Time
    • Practice if you have a time limit
    • Don’t waste time loading, load the bridge quickly

#5: Evaluation of the bridge

  • Efficiency = mass that bridge held divided by mass of bridge
    • What is a good efficiency score?
  • What failed?
    • Video taping
    • Carefull examination of broken pieces
  • Improving
    • Design
    • Construction

If what you’re building is a home then general contracting is something to try to learn as much about as possible before hiring new home builders to work on your home. The process of building a home is something that still might involve the use of a remodeling contractor so that’s something to keep in mind.

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2 Responses to “5 Steps to Building a Model Bridge”

  1. Earl Says:

    can you build a mini bridge out of fosilised wood?

  2. Katarina Says:

    thanks so much i almost got grounded for not finding information for my science fair bridge project