For the 13th year in a row, Nicole Baer, P.E., of Hope Furrer Associates, helped to judge the Maryland Wood Bridge competition held at the Baltimore Museum of Industry. It is a fun and challenging event open to any high school student in Maryland. The participants are given a set of rules which have to be met before their balsa-wood-and-glue bridges are tested for efficiency.
The parameters are specific and pragmatic: the bridges have to be a certain length, width, and height in order to fit on the testing equipment, and they must have the ability to support a plate in the middle. This is where the bridge is loaded by the equipment. When all these geometric properties are satisfied, the bridge is weighed. No bridge can be more than 25 grams!
Students have time to modify their bridges in order to meet the demands. Prior to testing, they can be found adding or removing support bracing, shaving off bits of glue and wood, and in some cases, making some major revisions to their creations.
When they are done, Nicole enters their information into the official spreadsheet, where she has a chance to chat with them about their design. Students from Johns Hopkins University help to load the bridges onto the testing equipment, and everyone gets to watch as the bridges twist and buckle under pressure, sometimes exploding splinters as they suffer from catastrophic failures. Nicole records the results on the spreadsheet and calculates the efficiency rating by dividing the weight held by the bridge weight. This year’s winning bridge had an efficiency rating of 1357 – so a 25 gram bridge held nearly 75 pounds!
It is fun to see the results, but even more fun to see the students become engaged in the creativity of engineering. The exercise mimics what real engineers do –before they run the calculations to validate their designs – and many students really enjoy it. This year, Nicole had the chance to talk to two girls who seem to have found a niche through this event. One will be graduating this year, and she is deciding which engineering college to attend from the four that have accepted her so far. (Go Penn State!) Another has a few years to go until college, but she is definitely hooked. She has come as the only representative from her school for the second year in a row, which means has made her bridge for the fun of it, as a completely extracurricular activity. She placed second this year and will be a contender to watch for Wood Bridge 2018!