Description:
This is a building event. Teams will design and build ahead of time an elevated bridge constructed from wood and glue capable of bearing a load. The official rules clearly define the minimum/maximum dimensions that the bridge must have. At the competition teams will place their bridge on the testing platform, and load sand into a bucket suspended and supported by the bridge. The bridge will be loaded until either the bridge breaks or 15 kg is held, whichever occurs first.
Materials:
Teams MUST bring safety spectacles with side shields and the elevated bridge.
Event Leaders will supply the testing apparatus (loading block/chain/bucket, sand, dispenser, rulers, scales, clearance block, testing platform) and official score sheet.
Scoring:
High score wins. Scoring for this event is based on efficiency. The following formula will be used:
Structural Efficiency = Load supported(g) / Mass of bridge(g)
Bridges that fail to meet one or more of the requirements will be ranked in a 2nd tier beneath those that do meet requirements. Bridges that cannot be tested at all will be ranked in a 3rd tier below those that can be tested. Ties will be broken first by whichever bridge is lightest, then by whichever bridge is shortest.
Common Mistakes:
Be very careful to abide by the given dimensions in the rules.
Elevated bridges are top heavy. When setting the loading block and hanging the bucket under the bridge, many teams have had their bridge fall over. Have one team member steady the bridge while the other hangs the bucket underneath to prevent unnecessary damage!
Recommendations:
Safety goggles (the chemical splash kind that most schools have) have a tendency to fog up, making it hard to see. This event only requires safety spectacles with side shields, meaning the kind that look like sunglasses will work as long as they have the piece on the sides to protect your eye from that angle. These are MUCH easier to see out of. Your local home improvement store carries cheap versions for under $4
