Bridge Building Design Challenge Bridge Building Design Challenge

Bridge Building Design Challenge

Bridge Building Design Challenge • Bridge Building is a construction event that involves building and testing a bridge modeled to a design. • Your goal will be to design and build a bridge with the highest structural efficiency

Rules 1. 2. Must be a type of Truss Bridge Design Size Constraints 1. 2. 3. 4. Length- Minimum = 12” Maximum = 15” Width- Minimum = 3” Maximum = 4” Height- Minimum = 3” Maximum = 6” 1” minimum flat surface at top-middle of bridge.

What is a Truss Bridge? Here a couple different examples

Size Constraints This picture is an orthographic view of a bridge design showing you the length, width, and height size requirements. **Orthographic shows the Front, Top, and Side view of an object** 3” - 4” Width 4” - 6” Height 12” – 15” Length

What is Structural Efficiency? • Ratio of the maximum weight that a structure will hold to the weight of the structure itself. Structural Efficiency = Max Weight Held/ Weight of Structure Example: Johnny and Sam are in a competition to build the strongest bridge. After they finish building their bridges, they weigh them and test there strength. Here are there results: Name Bridge Weight Pounds Held Structural Efficiency Johnny . 5 lbs 150 lbs/. 5 lbs = 300 Sam . 7 lbs 165 lbs /. 7 lbs = 235 Results: Johnny had the highest structural efficiency even though his bridge did not hold as much weight as Sam’s did.

Design Process 1. 2. 3. 4. 5. Research Sketch Final Drawing Construction Test

Research 1. Lookup and read about the various types of Truss designs and purposes of each. 2. Find a couple of designs that you may be interested in building/modeling and put them in your Bridge Design Brief.

Sketches Sketch out 4 designs on graph paper provided. (Front, Top, Side View for each)

Final Drawing Choose one design from sketches to build. Draw final design full size on 11 x 17 graph.

Construction 1. 2. 3. 4. Tape final drawing down to foam board. Tape wax paper over final drawing. Cut out all pieces needed Glue pieces together and use pins to hold pieces in shape

Testing We will use a structural tester to get accurate testing conditions and results

Tips for Success • Strength and Stability is the goal – – – A well drawn bridge will yield a symmetrical bridge when built. Symmetrical = Stable + Strong Take your time when drawing the final copy Measure twice, cut once when assembling. Too much glue will add unnecessary weight to your bridge therefore decreasing your structural efficiency. General Rule: If you can see it, you are using to much.