Below are the rules for the Bridge Competition.Please ask if you would like clarification of the intent of the rules. The general idea is that it needs to function as a bridge for a toy car, allowing the toy to cleanly traverse the entire length of the bridge, with a realistic maximum allowable grade.
If you plan to use a really exotic construction method, plan on providing detailed documentation or demonstrating the method.----Bridge:
May contain only balsa wood and Titebond 2 wood glue.Must fit within a 50 x 20 x 10 cm rectangular volume.May not contain more than 6oz of glue by wet volume.
Must have a smoothish road deck no less than 6cm in width. - suitable for a HotWheels-style car to easily roll overDeck ends must contact the upper surface of the test rig support planks.
Deck must have no more than a 10% grade (where grade = 100 * (rise/run))Deck must accommodate the load plate.Some part of the load plate must fall across the midpoint of the span.
There are no limits on construction tools or technique.Scoring:The load plate is 10 x 5 x 1 cm, and has a loading hook extending from the center of the bottom surface which requires 1 cm annular clearance through and below the bridge deck.
Bridges will be loaded progressively (w/ minimum shock load), starting at 5kg and progressing in 1Kg increments to 10Kg.Upon reaching the maximum load, the bridge must hold for 1 minute.
- Disputes as to whether a bridge 'held' will be resolved by voteBridges that fail will be ranked by the weight carried without failure and bridge mass.Bridges that do not fail will be ranked by the mass of the bridge.
Testing:The open span between the support planks is 30cm.The open span is between rectangular, fixed, smooth, level, coplanar planks with a thickness of ~2cm.
The bridge may touch the top or inner surfaces of the supporting planks, but may not touch any other surface, nor be affixed to any surface.The load plate will support a wire or rod from which the test load will be suspended.
Eric J. Kaplan