1. A brief study of bridges

2. We build different bridges for different needs

3. Covered Bridge

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

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

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

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

8. 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 effects of rain and snow

11. Beam Bridge

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

17. Suspension Bridge

18. Better for Long spans More Majestic

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

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

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

22. No.BridgeSpan (m)Countryyear 1Akashi-Kaikyo1991Japan1998 2Great Belt East1624Denmark1998 3Runyang South1490China2005 4Humber1410UK1981 5Jiangyin1385China1999 6Tsing Ma1377China1997 7Verrazano-Narrows1298USA1964 8Golden Gate1280USA1937 9Höga Kusten1210Sweden1997 10Mackinac1158USA1957 The worlds 10 longest spans are all suspension bridges

23. Arch Bridge

24. Very strong Can last a very long time

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

26. Arch bridge This is a bridge built so that a stream of water could cross a stream of water

27. Cable Stayed Bridge

28. Cable Stayed bridge Elegant structure Long spans

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

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

31. Lift Bridge

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

33. Lifting Bridge It is not London Bridge.

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

35. Truss Bridge

36. A truss can support from above

37. Truss Bridge A truss can also support from below

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

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

40. A quick review

41. Covered Bridges Makes use of local building supplies

42. Covered Bridges Interior truss makes it stronger than wood beam bridge

43. Covered Bridges Covering the timbers makes them last longer

44. Beam Bridge Easiest to build Least expensive design

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

46. Cable Stay Bridges Uses less material than suspension bridge

47. Cable Stay Bridges They look cool!

48. Cable Stay Bridges Requires the use of more modern materials

49. Suspension Bridges Longest unsupported spans

50. Suspension Bridges They look pretty cool too!

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

52. Truss Bridge Stronger than beam bridge Think Vectors!

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

54. Lifting Bridge Blocks trafic

55. Lifting Bridge Allows the passage of ships

56. Lifting Bridge Rather expensive Subject to mechanical breakdown

57. Many different bridges for many different jobs

58. See these websites for more information on bridge design http://www.howstuffworks.com/bridge.htm http://www.pbs.org/wgbh/nova/bridge/ http://myron.sjsu.edu/romeweb/engineer/art2.htm http://www.bardaglea.org.uk/bridges/welcome.html http://education.sdsc.edu/enrich/downloadables/bridges.pdf http://www.tfhrc.gov/pubrds/summer95/p95su23.htm