# Bridges

## Bridges

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##### Presentation Transcript

1. Bridges

2. 5. Construction Technologies Construction technology involves building structures in order to contain, shelter, manufacture, transport, communicate, and provide recreation.5.2 Identify and describe three major types of bridges (e.g., arch, beam, and suspension) and their appropriate uses (e.g., site, span, resources, and load). 5.3Explain how the forces of tension, compression, torsion, bending, and shear affect the performance of bridges.5.4 Describe and explain the effects of loads and structural shapes on bridges. Learning Standards

3. At the conclusion of the lesson students will be able to: Learning Objectives • Define Bridge • 2) Identify & describe 5 major parts of a bridge • 3) Identify & describe 5 forces that affect bridges • 4) Identify & describe 7 types of bridges

4. Bridge A structure built to span a physical obstacle Ex: Road, Valley, Railroad Track, River, etc.

5. Parts of a Bridge Thick wire that supports the deck of the bridge Cables Heavy column above the bridge that supports cables Surface on which traffic moves Tower Deck Heavy column that holds up a bridge Abutments Pier Span Distance between 2 supports or towers Heavy supports at the end of a bridge

6. Parts of a Bridge Truss Triangular framework used to support the bridge

7. Early Bridges The first bridges were: Stepping Stones Log Over a Stream

8. Early Bridges Later people used large flat rocks connect the stepping stones allowing them to cross over the bridge with small carts

9. Forces Upon Bridges Forces must be considered when building bridges A force that pushes Compression A force that pulls Tension A force that twists Torsion What happens when something heavy crosses a structure Bending A force acting across any structure Shear Click here to learn more about the forces that affect bridges

10. Beam Bridge Most common & oldest type of bridge Example: Highway overpasses

11. Beam Bridge Unsupported beams can span distances only up to 250 feet Longer Beam Bridges need piers for support along the span

12. Beam Bridge Top of Beam Bridges are under COMPRESSION Bottom of Beam Bridges are under TENSION

13. Drawbridge Also known as a Bascule Bridge A Beam Bridge that has surfaces that can be raised or lowered to allow the passage of boats

14. Arch Bridge First designed & created by the Romans First Arch Bridges were made of wedge shaped stones locked in a curve (Keystone)

15. Arch Bridge Arch bridges distribute weight sideways & down around the curve Arch bridges rely on the force of compression to work effectively Arch bridges typically span distances of 200 – 800 feet (can span longer distances)

16. Suspension Bridge Bridge is suspended (hangs) from large vertical cables Used to cross very wide spans (2000 - 7000 ft)

17. Suspension Bridge Cables & abutments (anchorages) are under the force of tension Towers are under the force of compression

18. Cable Stayed Bridge Cheaper & easier to construct than traditional Suspension Bridge Cables connected to towers stretch down diagonally to support beam Typically span distances of 500 – 2800 feet (can be longer)

19. Cable Stayed Bridge Cables are under the force of tension Towers are under the force of compression

20. Cable Stayed Bridge Different styles of Cable Stayed Bridges Fan Style Harp Style

21. Truss Bridge Made of steel beams constructed into rigid triangle shapes called trusses The trusses can be above or below the bridge Why triangles??? Triangles are considered one of the strongest shapes

22. Truss Bridge Forces affecting Truss Bridges Blue Arrows represent TENSION COMPRESSION Red Arrows represent

23. Cantilever Bridge (using trusses) Cantilever: Self supporting beam that is fastened to the ground at one end 2 cantilevers meet in the middle & are connected by trusses The strong design of these bridges resist high winds

24. Types of Bridges Beam Bridge CantileverBridge Types of Bridges Drawbridge Arch Bridge Cable StayedBridge Truss Bridge SuspensionBridge

25. Notable Bridges

26. Braga Bridge 5780 ft long Opened in 1965 Cantilever Bridge (using trusses)

27. Tappan Zee Bridge Crosses the Hudson River 25 miles north of NYC Cantilever Bridge (using trusses)

28. Washington BridgeProvidence, RI Opened 9/25/1930 Bridge consisting of a series of arches

29. Glen Canyon Bridge & Dam Lake Powell, Az Crosses Colorado River Opened in 1966 1560 ft long Steel Arch Bridge

30. Eads Bridge 1st major all steel bridge was built in 1874 Crosses the Mississippi River - Connects St. Louis, Missouri & East St. Louis, Illinois

31. Brooklyn Bridge Crosses East River in New York City Connects Manhattan & Brooklyn Opened May 24, 1883 – it took 13 years to build Longest Suspension Bridge in the world when it was built 5989 Feet

32. Golden Gate Bridge Crosses SF Bay Connects SF & Marin County Opened May 27, 1937 Longest Suspension Bridge in the world when it was built 8981 Feet

33. Manhattan Bridge Suspension Bridge Crosses the East River – Connects Manhattan & Brooklyn

34. Akashi Kaikyo Bridge OpenedApril 5, 1998 Connects Kobe & Awaji Island Also known as the Pearl Bridge Built to withstand 178 MPH winds, earthquakes measuring 8.5 on the Richter Scale & harsh sea currents Currently the world’s longest Suspension Bridge 12,831 Feet Center Span 6,532 Feet

35. Mt. Hope Bridge Opened October 24, 1929 Crosses Mt. Hope Bay Connects Bristol & Portsmouth Rhode Island 6,130 Feet Center Span 1,200 Feet Suspension Bridge

36. Crosses the Narragansett Bay – Connects Newport & Jamestown Claiborne Pell Newport Bridge Suspension Bridge

37. Leonard P. Zakim Bunker Hill Memorial Bridge Crosses the Charles River Opened in 2003 Widest Cable Stayed Bridge in the world: 183 feet wide 1432 feet long

38. Sunshine Skyway - St. Petersburg, Fla Crosses Tampa Bay Opened 4/20/87 5 1/2 miles long Cable Stayed Bridge

40. Millau Viaduct Spans the valley of the River Tarn near Millau, France Tallest bridge in the world – one of the masts has a summit of 1,125 ft Taller than the Eiffel Tower & just shorter (125 ft) than the Empire State Building Opened December 14, 2004 (ahead of schedule) – work began in October 2001 Total length: 8,071 ft

42. Brightman Street Bridge Opened 10/10/1908 Closed October 2011 922 ft long

43. Brightman Street Bridge Somerset, Mass.

44. Veterans Memorial Bridge Somerset, Mass.

45. London Tower Bridge Drawbridge with Suspension