bridge contest

1. Construction criteria.

The bridge may only be made of wood and glue.

Any kind of wood or glue may be used.

No piece of wood may have a cross section greater than 1/4 by 1/8 of an inch.

There is no limit to the length of any piece.

The bridge may not be coated with any material (paint, glue, etc.).

You may laminate pieces of wood together as long as wood is not coated on the outside.

The bridge must have a roadbed 6 cm wide with a 1/4 inch hole in the center.

The roadbed must be no more than 1.5 inches above the edge of the opening.

2. Performance criteria.

The bridge must span a 12 inch opening.

At no time may any part of the bridge sag more than 1 inch below the edge of the support.

The maximum load for the bridge will be 20,000 grams.

The student will load the bridge with sand until it either fails, reaches the max. load, or the student stops loading to preserve the bridge.

3. Scoring

The score for each bridge will be calculated as follows:

Load (in grams) supported divided by mass of bridge plus 10% of mass supported

score =[(load)/(mass of bridge)] + (0.1)(load)

Lab score points are awarded as follows for each legal bridge:

lab points = 18 + (score)/220.