6.4 BRIDGE BUILDING COMPETITION
Objective: To use simple materials to construct a bridge with the highest strength to weight ratio.
1. The materials that may be used are listed below. If there are any questions regarding acceptable materials the course instructor can be consulted. Any questions must be resolved before the judging. The total weight must be below 500g. Use,
- common toothpicks, such as the tapered wooden or round variety (< 1/16”).
- white glue, balsa glue, 5 minute epoxy, super-glue, or a similar adhesive is to be used only for joining the toothpicks or thread.
- common sewing thread that can be used on a common sewing machine or serger.
2. The bridge will be mounted between two flat surfaces 8” apart, assume the maximum length of the edges will be 24 inches or less.
3. The bridge will be loaded on the upper surface until failure. The loading area must be at least 8” by 8” square.
1. The bridge will be weighed and checked for conformance to the rules.
2. A water vessel will be placed on top, and slowly filled with water until the bridge fails. Failure will be determined by the P.Eng. judges to be when the structure is no longer operating as originally anticipated, or 1cm below the original height of the load.
3. The water container, with water, will be measured to give the failure load.
4. A ratio of failure load to weight ratio of the bridge will be used to rank the performance.
1. Heavy is not necessarily better (an ant would outperform a human with the characteristics used here)
2. Equilateral triangles form good supports in a solid structures.
3. Consider the Golden Gate Bridge in San Francisco for support structures.
4. Try building prototypes first to test the structure.