1. Engineering Loads

2. Objectives Identify and explain the differences between tension and compression. Identify and provide examples of the 4 primary loads affecting structures. Design and test bridges using West Point software. Run simulations and manipulate bridge designs to optimize cost and strength.

3. Primary Structural Forces Tension- pulling or elongation of materials. Compression- pushing together or shortening of materials. What are the implications of a bridge that has excessive tension or compression? Talk with your neighbor about this (30 seconds)

4. Equilibrium The state in which there are no unbalanced forces acting on a body, balance of tension and compression. ©iStockphoto.com Balanced Unbalanced

5. Structural Loads The forces applied to a structure. -With your neighbors (3 or 4 people) discuss a few examples of loads that are applied to everyday structures such as bridges and schools in Minnesota? -Example loads on bridges and schools on the west coast of the United States?

6. Structures A few considerations… - size - shape - geographic location - materials - geotechnical - structural loads to support

7. Various Structures Designed dependent on their purpose Engineers and architects must consider weight requirements Must design around a structures safety factor

8. Safety Factor The ratio of the breaking stress of a structure to the estimated maximum stress in ordinary use A bridge may typically only carry passenger cars. Will it support a fully loaded cement truck? Most structures have a safety factor of 3.

9. Safety Factor Question The city of Plymouth is proposing a new 4 lane bridge to be built on Peony Lane with a safety factor of 10. What issues might homeowners and taxpayers have with this proposal? Take a minute and talk with someone nearby.

10. Dead Loads Stationary or permanent parts of a structure. Walls Floor Ceiling Essentially the weight of the structure with nothing on or in it.

11. Live Loads Weight that travels within or across a structure A high school hallway Cars on a bridge

12. Static Loads Accumulate over time It can become a dead load A steady rain or snow Cars backing up on a bridge due to an accident

13. Dynamic Loads A sudden exertion of force on a structure A strong gust of wind Earthquake Explosion Collision

14. Load Miscalculations Engineers must take all loads into account Consider…. - What will be in or on the structure - Who will use the structure - Where is it located geographically

15. Exit Question #1 This force shortens structural members. A. Equilibrium B. Tension C. Dynamics D. Compression

16. Question 2 This force lengthens or stretches structural members. A. Statics B. Tension C. Safety factors D. Compression

17. Question 3 This type of structural load occurs when there is a sudden exertion of force. A. Static B. Dynamic C. Dead D. Live -List an example

18. Question 4 This type of structural load accumulates over time. A. Static B. Dynamic C. Dead D. Live -List an example

19. Question 5 This type of structural load is a permanent part of the structure. A. Static B. Dynamic C. Dead D. Live -List an example

20. Question 6 This type of structural load moves across or within a structure. A. Static B. Dynamic C. Dead D. Live -List an example

21. Question 7 This type of structural load is applied during the west point bridge builder simulation. A. Static B. Dynamic C. Dead D. Live