1. Brian Brenner Aaron Levine Cindy Tran
Bridges
Brian Brenner
Aaron Levine
Cindy Tran

2. Some Uses of Bridges Walkways Highways/Roads Railways Pipelines
Connecting lands
Crossing rivers and canyons

3. What makes a bridge stay up?
Forces
Compression – a pushing or squeezing force
Tension – a pulling or stretching force
Let’s Try It!
With your neighbor…
View the types of forces involved in buildings

4. What kind of forces do bridges have to be prepared for?
Load – forces that act on structures
Structures must withstand loads or they’ll fall apart!
In order to build a structure, you need to know what kind of external forces will affect it.
View the types of loads that affect big structures

5. Types of Bridges
Arch
Truss
Cantilever
Cable-Stayed
Suspension
Beam

6. Arch Bridges
Keystone – the wedge-shaped stone of an arch that locks its parts together
Keeps the bridge from collapsing inward
Abutments – the structures that support the ends of the bridge
Keeps the bridge from collapsing outward

7. Arch Bridges
LIVE LOAD
Works by
Compression

8. Arch Bridges
Where have you seen these bridges?

9. Cold Spring Arch Bridge, Santa Barbara, CA

10. Marsh Rainbow Arch, Riverton, KS

11. Pont du Gard, Nimes, France

12. Beam Bridges Oldest known bridge and simplest to design and build
A horizontal beam is supported by vertical piers

13. Beam Bridges
Works by Tension and Compression
LIVE LOAD

14. Beam Bridges
Where have you seen these bridges?

15. Simple beam bridge Eagle County, Colorado

16. Continuous span beam bridge Chesapeake Bay Bridge-Tunnel Cape Charles and Virginia Beach, Virginia

17. Cable-Stayed Bridges Piers – the vertical supporting structures
Also known as columns
Cables – thick steel ropes from which the deck is suspended
Deck – the supported roadway on a bridge

18. Cable-Stayed Bridges
Works by Tension AND Compression
LIVE LOAD

19. Cable-Stayed Bridges
Where have you seen these bridges?

20. Zakim Bridge, Boston, MA

21. Sunshine Skyway Bridge, Tampa, FL

22. Sundial Bridge, Redding, CA

23. Suspension Bridges Similar to Cable-Stayed
Different construction method
Tower – holds up the cables
Anchorage - the ends of the cables are attached to these

24. Suspension Bridges
Works by Tension and Compression
LIVE LOAD

25. Suspension Bridges
Where have you seen these bridges?

26. Golden Gate Bridge, San Francisco, CA

27. Brooklyn Bridge, Brooklyn, NY

28. Verrazano-Narrows Bridge, New York, NY

29. Truss/Cantilever Bridges
Support comes from interlocking triangles
Cantilever bridges are a complex version of truss bridges (supported by balancing)

30. Truss/Cantilever Bridges
Works by Tension and Compression
LIVE LOAD

31. Truss/Cantilever Bridges
Where have you seen these bridges?

32. Truss
Southern Pacific Railroad Bridge, Tempe, AZ

33. Cantilever
Firth of Forth-Forth Rail Bridge, Edinburgh, Scotland

34. How long can a bridge be? Span – length of a bridge Beam Bridges
Rarely span more than 200 feet
Why? The farther apart its piers, the weaker the beam becomes.
Suspension Bridges
Can span 2,000 to 7,000 feet
Way farther than any other type of bridge!

35. Engineering
Engineering – the use of math and science to solve real world problems (like crossing a river)
Civil engineering – designing and building bridges, roadways, tunnels, buildings, dams, etc.
Architect – works with engineers to design bridges
Civil Engineer

36. Branches of Civil Engineering
Structural – bridges, roads, buildings
Geotechnical – foundations, excavations, and tunnels
Transportation – roads, traffic control, airports
Environmental – human impact on the environment

37. Other Types of Engineering
Mechanical – design machines and moving parts
Electrical – design electrical equipment
Chemical – design processes for mixing chemicals
Computer – design computer hardware and software

38. Questions?