Math Bridge Project
A group of triangles can be joined together to form a truss. There are many different truss designs, including the Pratt, Whipple, and Fink. Although truss bridges are not as good for spanning great distances as other bridge designs, they are extremely
strong,. Steel trusses, for example, are often used in railroad bridges. To build
your own truss bridge, you need a steady hand and a bit of patience.
Material Needed:
Toothpicks (flat, round, square) wood only.
Low heat glue gun or Elmer’s Grade school glue
Finger-nail clippers to cut toothpicks to create a flat neat cut
Ruler (centimeter)
Grid paper
Wax paper(used to lay over your grid design as you glue pieces together. You can see through it and glue will peel off it)
Make a day to day journal of the steps you take to create your bridge. (This
can be done on the computer) don’t forget dates.
You may NOT COAT toothpicks with anything, NO paint, glue, hardener of any
kind.
Instructions for your board must be exact not exceptions(visual
at the bottom of this page).
- Cut a piece of cardboard so
it is 35 cm long and 15 cm wide.
- Draw a 15 cm “river”
in the middle of the cardboard.
- Cut a 4 cm by 4 cm hole in
the middle of the river.
- Draw two 5 cm ssquares on
the cardboard, as shown.
- Design and build a truss bridge
using the toothpicks and glue /glue-gun. (Get an adult to help you with the glue gun if necessary.) The actural design of the bridge is up to you, but your finished bridge must meet the following specifications:
The
bridge can only touch the cardboard inside 5cm gray squares.
The
bridge must be at least 4 cm above the river.
The
bridge must use triangles only (or it’s not a truss bridge.)
Testing:
The bridges be tested to see how much weight they can hold before breaking. Each
student will test their own bridge. Sand will be used and measured.
I encourage you to look at truss designs.
Make searches online and discover the vast variety of types of bridges around the world.
http://www.toothpickdesign.com/
