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Bridge Building Contest

The contest is to build a model bridge in accordance with the contest rules which will hold the largest load in relation to its own weight.
1. Bridge span = 36 inches between supports
2. Maximum allowable dimensions
Length = 42.0 inches
Width = 7.0 inches
Height = 12.0 inches
3. Maximum bridge weight = 3.00 pounds (1362.2g)
4. Bridge must have a road way with atleast 4 inches of horizontal and vertical
clearance to allow for loading.
5. The bridge must be a self contained unit. No anchors will be provided for
suspension bridges. The edge of the tables may be used
horizontal supports for arch bridges.
6. Commercial grade cardboard may not be used as primary support members.

Only the following materials may be used in construction.

1. Soda straws, either paper or plastic
2. Plain-sheet cardboard or paper (maximum thickness = 1/16 inch)
(No cardboard tubes)
3. Corrugated cardboard (maximu thickness = 3/16 inch)
4. String, thread, or cloth cord (no wire or fishing line)
5. Toothpicks, matchsticks, popsicle sticks, tongue depressors
6. White glue, wood glue, hot glue (No epoxy cements)

Students may work in teams of two people. Each person in a team will receive 80% of the points the bridge earns.

The testing device needs the 4" x 4" opening to pull down on the bridge. If you excede any of the above bridge dimensions, then your device cannot be tested and you will receive the minimum points.


The testing device is a see-saw. In order for the 450 pounds to be balanced by 90 pounds a water, it side of the see-saw must be 5 times longer. Every pound of water poured out of bucket causes the clamp to pull down on the bridge with 5 pounds of force.

There are basically 2 ways to design you bridge for testing.


Go to the Contest Home Page

A special thanks to VASTfor hosting our web site.