1. BRIDGES

2. BRIDGE EXPLORATIONS What makes bridges stay up
What makes bridges fall down
Different types of bridges
You will design and construct a bridge
You will test your bridge’s load capacity

3. Beam Bridges

4. The Tarr Steps – England
Circa 1000 B.C.

7. KOCHER VIADUCT, AUTOBAHN, GERMANY
185 m HIGH, m LONG

9. Top of beam is in compression and bottom is in tension.
The middle of the beam is neutral – the middle is in neither compression or tension.

10. Making a beam stiffer:
I Beams move most of the beams material away from the neutral axis which is underutilized.
This results in a stiffer beam.

11. Arch Bridges
PONT DU GARD, FRANCE, 63 BC-13 BC 47.4 m HIGH

13. Arches are made of wedge-shaped stones in compression
Arches are made of wedge-shaped stones in compression. Without the keystone the two sides of the arch will fail.
The wedged stones at the bottom must be prevented from moving outwards using abutments (stones anchored into the soil).

14. MOSTAR BRIDGE, YUGOSLAVIA 1566-1567
27.3 m SPAN, 19 m HIGH

15. Cabin John Bridge, Washington D.C.

16. RHINE RIVER, BONN- BUEL,

17. FRANCIS SCOTT KEY BRIDGE, WASHINGTON, DC

18. HEILBRONN, AUT0BAHN, GERMANY

19. A truss is a hinged triangle
Truss Bridges
A truss is a hinged triangle

21. TENMON BRIDGE, KUMAMOTO PREFECTURE, JAPAN
SPAN m 42 m CLEARANCE, 1966

22. Why are trusses so common?
The members are in either experiencing compression or tension; the members are not bending.
Trusses can be arranged into many shapes.

23. Truss Bridge with a moveable center section.

24. Cabin John Bridge, under construction
using timber false work

25. Cantilever Truss Bridge

26. Cantilever Bridges
Cantilever is a beam supported at only one end.

27. The Forth Rail Bridge – c.1882-1889
Scotland
One the worlds most massive bridges.

32. Suspension Bridges

35. Akashi-Kaikyo Bridge 3911 m

36. http://www. youtube. com/watch

37. Cable is made by running spools of smaller cable back and forth across the towers. This is called spinning the cable.

38. Cable Stay Bridges
Kaohsiung County, Taiwan

39. Øresund Bridge between Denmark and Sweden
Relatively inexpensive to construct – no large cables need to be spun over towers. Able to span large distances.

41. What kind of Bridges?

42. MARACAIBO BRIDGE, VENEZUELA, 1957

44. FEHMARNSUND BRIDGE, 248 m SPAN

46. Combination arch and beam.

48. GANTER BRIDGE DESIGNED BY CHR. MENN

49. Engineering Design Process
Problem Statement
Problem Analysis
Design Specifications
Brainstorming / Idea generation
Idea Selection
Implementation

50. Problem Statement
What is the maximum load a short paper bridge can carry?

51. Problem Analysis How will structure carry loads?
How is failure likely to occur?
What can be done to prevent failure?

52. Design Specifications
10” minimum span
1” max. bearing at abutment
Tape is connector only.
Bridge cannot be taped to the abutment.
Materials: Three 2”X12” strips (cut from heavy poster paper)

53. Idea Generation & Selection
Brainstorming
Minimize judgment
Combine ideas
Select final idea based on best fit for Design Specifications

54. Implementation
Construct bridge
Test bridge
Review and evaluate design