Tensile & Compressive Strength: The Forces Behind Bridge Design

1. Tensile & Compressive Strength:The Forces Behind Bridge Design By, Mackenzie Moosbrugger EDU 505 Harrison Yang

2. Introduction Sometime during your life, maybe while taking a trip, many of you have crossed over a bridge. Whether large or small, bridges allow us to cross barriers that we may not have otherwise been able to. Have you ever wondered what holds such a strong structure up? It’s not just the cement or metal, it’s largely due to the physical nature of tensile and compressive strength! Through this WebQuest, you will learn what exactly these strengths are, and why they are so important to bridge design.

3. Task With a partner, you will navigate through the websites I will provide on the following pages. While reading through these pages, please answer the questions on your worksheet. Each group will be handing in one completed worksheet with both partners names. Once you complete your worksheet, you and your partner will be interactively designing and building a bridge online using the information about tensile and compressive strength that you have learned. *The lowest costing successful bridge will gain a 5 point bonus.

4. Process Step 1 – On the “Resources” page, there are various websites that you can use to answer the questions on your worksheet. Take your time and answer them completely and correctly. When you are finished, write both partners names at the top and hold onto it. Proceed to step 2. http://www.hellosanfrancisco. com/Images/Photos/972005 Golden_Gate_Bridge-s.jpg

5. Process Step 2 – After completing step 1, open the shortcut on your computer’s desktop named “West Point Bridge Designer.” This will open the program you will be using to design and build your bridge. At the start up screen, follow the parameters written on the board to setup your construction site. Using your knowledge of tensile and compressive strength, build the least expensive successful bridge possible. Proceed to step 3.

6. Process Step 3 – When you have built the best bridge you think you are capable of, print it out, and raise your hand. I will come over and you will show me whether or not the bridge is successful, and I will sign off on your printout. Staple your worksheet and printout together, and hand them in at the end of class. The bonus points will be awarded at the beginning of next class. !BONUS!

7. Resources Bridge Basics http://www.pbs.org/wgbh/buildingbig/bridge/basics.html How Bridges Work http://science.howstuffworks.com/bridge.htm Forces http://www.pbs.org/wgbh/buildingbig/lab/forces.html Building Stability http://www.polymorf.net/engineer.htm

8. Evaluation Students will be assessed on their correct answers on their worksheets, and their demonstration of understanding of tensile and compressive strengths through their application on their bridge designs. Your completed assignment will be graded based on a 25 point lab activity. 10 – Worksheet (Did you completely and correctly answer the questions given?) 10 – Bridge Design (Did you demonstrate your knowledge of tensile and compressive strength?) 5 – Work Ethic (Did you use your time wisely?)

9. Conclusion Hopefully now that you have completed research, answered questions, and practiced your comprehension of tensile and compressive strength, you have a better understanding of how structures such as bridges are supported. Feel free to work on more bridge designs at home and bring them in for extra credit!