1. A brief study of bridges

2. We build different bridges for different needs

3. Covered Bridge

4. In the 18th and 19th century many bridges were covered
Covered Bridges
In the 18th and 19th century many bridges were covered

5. Why do you think these bridges were covered?
Covered Bridges
Why do you think these bridges were covered?

6. Some say it was for protection from a sudden storm
Covered Bridges
Some say it was for protection from a sudden storm

7. Some say to keep horses from shying at the sight of rippling water
Covered Bridges
Some say to keep horses from shying at the sight of rippling water

8. Some say to provided a romantic setting for a hug or kiss
Covered Bridges
Some say to provided a romantic setting for a hug or kiss

9. Covered Bridges
However…

10. Covered Bridges
The real reason was to protect the timber from the affects of rain and snow 

11. Beam Bridge

12. Beam Bridge The simplest and least expensive
Beam Sometimes called a girder

13. Beam Bridge
Can be made of steel

14. Beam Bridge
Concrete

15. Beam Bridge
or even wood

16. Not the best for long or high spans
Beam Bridge
Not the best for long or high spans

17. Suspension Bridge

18. Suspension Bridge
Better for Long spans
More Majestic

19. First suspension bridge in America Newburyport, Mass.
Built around 1900

20. Why is it called the Golden Gate?
Golden Gate Bridge
Perhaps the most famous bridge in the world
Why is it called the Golden Gate?

21. It spans the Golden Gate Strait
Golden Gate Bridge
Perhaps the most famous bridge in the world
It spans the Golden Gate Strait

22. The worlds 10 longest spans are all suspension bridges
No.
Bridge
Span (m)
Country
year 1
Akashi-Kaikyo
1991
Japan
1998 2
Great Belt East
1624
Denmark 3
Runyang South
1490
China
2005 4
Humber
1410 UK
1981 5
Jiangyin
1385
1999 6
Tsing Ma
1377
1997 7
Verrazano-Narrows
1298
USA
1964 8
Golden Gate
1280
1937 9
Höga Kusten
1210
Sweden 10
Mackinac
1158
1957

23. Arch Bridge

24. Can last a very long time
Arch Bridge
Very strong
Can last a very long time

25. Arch Bridge
This is Pont du Gard a 2000 year old Roman aqueduct

26. Cable Stayed Bridge

27. Cable Stayed bridge
Long spans
Elegant structure

28. Sunshine Skyway Bridge St. Petersburg, FL
Requires Less labor
Requires less material

29. Sunshine Skyway Bridge St. Petersburg, FL
Similar to Clark bridge in Alton, IL

30. Lift Bridge

31. Do you know the name of this bridge?
Lifting Bridge
Do you know the name of this bridge?

32. Lifting Bridge
It is not London Bridge.

33. Lifting Bridge
Tower Bridge
It is over 100 years old

34. Truss Bridge

35. Truss Bridge
A truss can support from above

36. A truss can also support from below
Truss Bridge
A truss can also support from below

37. What do you know about this bridge?
Truss Bridge
What do you know about this bridge?

38. Eads Bridge St. Louis, MO
Completed in 1874
American masterpiece

39. A quick review

40. Covered Bridges Makes use of local building supplies
Covering the timbers makes them last longer

41. Least expensive design
Beam Bridge
Easiest to build
Least expensive design

42. Less expensive to build than suspension bridges
Cable Stay Bridge
Less expensive to build than suspension bridges

43. Cable Stay Bridges Uses less material than suspension bridge
Uses more modern materials

44. Longest unsupported spans
Suspension Bridges
Longest unsupported spans

45. Ancient/low tech building materials
Arched Bridges
Strong
Durable
Ancient/low tech building materials
Labor intensive

46. Stronger than beam bridge
Truss Bridge
Stronger than beam bridge
Think Vectors!

47. Can bridge longer unsupported spans than a beam bridge
Truss Bridge
Can bridge longer unsupported spans than a beam bridge

48. but allows the passage of ships
Lifting Bridge
Blocks traffic,
but allows the passage of ships

49. Subject to mechanical breakdown
Lifting Bridge
Rather expensive
Subject to mechanical breakdown