1. Bridge Building Design Challenge

2. 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

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

4. What is a Truss Bridge?
Here are a couple different examples

5. 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

6. What is Structural Efficiency?
Commercial Frame Systems
Civil Engineering and Architecture
Unit 3 – Lesson 3.1 – Commercial Building Systems
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
150 lbs/ .5lbs = 300
Sam
.7 lbs
165
165 lbs / .7lbs = 235
Results: Johnny had the highest structural efficiency even though his bridge did not hold as much weight as Sam’s did.
Project Lead The Way, Inc.
Copyright 2010

7. Design Process
Research
Sketch
Final Drawing
Construction
Test

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

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

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

11. Construction 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

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

13. 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.