1. Structural Engineering: Bridges
Sergio F. Breña
STEM Education Institute
Saturday Workshop
September 30, 2006
University of Massachusetts Amherst

2. University of Massachusetts Amherst
Bridge Definition
Bridge, n. – a structure built to span and provide passage of vehicles or pedestrians over an obstacle (river, highway, railroad)
Passage, n. – movement from one place to another
Span, v. – to reach or extend over or from one side to the other…
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3. University of Massachusetts Amherst
Bridge Design Process
The challenge: provide passage (span) over an obstacle
Research/brainstorm
Other successful applications?
Materials available locally?
Available construction techniques/equipment?
Note: this presentation will primarily address this aspect of bridge design through the use of bridge examples that have been successful (or not!)
Testing/validation of design (build models if possible)
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4. Highway Bridge Overpass Load Testing
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5. Bridge Instrumentation
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6. Load Testing in Progress
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7. Earthquake Testing of Bridge Models
Bridge seismic testing conducted at U.Nevada - Reno
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Evolution of Bridge Design through Successful Use of Structural Forms and Development of New Materials
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9. University of Massachusetts Amherst
Arch Bridges
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10. Typical Structural Systems (1)
Arch
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11. Pont du Gard - Nimes, France
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12. Coalbrookdale, England (Severn River)
Built between 1777 and 1779 by Abraham Darby III (grandson of inventor of method to reduce coal to coke), and is reputed to be the first cast iron bridge. Bridge still in service for pedestrian loads only.
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13. Walnut Lane Bridge – Fairmount Park, Philadelphia, PA
Completed in Designer: George Webster and Henry Quimby. World’s longest and highest (147 ft) arch bridge when completed. Main span = 233 ft. Two-rib open spandrel design with minimum steel reinforcement (mostly for shrinkage cracking). Use of rubble concrete (concrete with large stones) to increase shear strength.
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14. University of Massachusetts Amherst
Walnut Lane Bridge
Pier design intended to simulate masonry construction. The designers took inspiration from a 1904 masonry arch bridge in Luxembourg (Historic American Engineering Record, HAER PA 51-Phila, 731)
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15. University of Massachusetts Amherst
Zuoz Bridge
Completed in Designed by Robert Maillart.
Main span = 125 ft.
Three-hinged arch; hollow box deck.
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Concrete Arch
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17. University of Massachusetts Amherst
Steel Arches
Roosevelt Lake Bridge – Arizona: Twin steel arches. Designer HNTB.
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18. Natchez Trace Parkway Bridge
Completed in 1994 near Nashville, Tennessee. Designer: Figg Engineering Group. First segmental post-tensioned concrete arch bridge in the U.S. Box section for arches, piers, and deck. Total length = 1648 ft.
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19. University of Massachusetts Amherst
Truss Bridges
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20. University of Massachusetts Amherst
Truss Behavior
Truss C T
Forces in Truss Members
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21. University of Massachusetts Amherst
Types of Trusses
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22. Common Truss Types in Bridges
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23. University of Massachusetts Amherst
Wood Covered Bridges
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24. University of Massachusetts Amherst
Roof Trusses
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25. University of Massachusetts Amherst
Truss Bridges
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26. Montpelier, VT (American Bridge Co.)
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27. Firth of Forth Bridge (Cantilever Construction)
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28. Cantilever Truss Bridge (Queensboro Bridge, NY)
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29. Bardwell’s Ferry Bridge
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30. University of Massachusetts Amherst
Hells Gate Bridge
Completed in 1916 for the NY connecting RR. Designed by Othmar Ammann (1912).
Largest arch bridge in the world when completed.
Main span = 1017 ft to face of abutments.
Materials used: concrete, steel, cast iron, reinforcement, granite.
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31. University of Massachusetts Amherst
Bayonne Bridge
Completed in 1931.Designed by Othmar Ammann (Chief Engineer). Architect Cass Gilbert (consulting). World’s longest steel bridge for almost half a century. First use of manganese steel (arch ribs and rivets).
Main Span = 1675 ft.; width 85 ft.
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32. University of Massachusetts Amherst
Suspension Bridges
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33. Anatomy of a Suspension Bridge
Suspension Cable
Deck
Tower
Anchorage
Hanger
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34. Verrazano Narrows Bridge
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35. Anchorage Detail – Verrazano Narrows
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36. Anchorage Detail – Verrazano Narrows
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37. Menai Strait Bridge (Thomas Telford)
Built by Thomas Telford; opened in 1826
Chain (wrought iron) suspension bridge with 580 ft main span (record at the time)
Suffered from aerodynamic vibrations after opening and chains were braced
Retrofitted repeatedly afterwards; wrought iron chains replaced by steel in 1939
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38. Menai Strait Bridge (Thomas Telford)
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39. Essex-Merrimac Bridge,Amesbury, MA
Spans Merrimack River between Newburyport & Deer Island. Designer – George Fillmore Swain. Constructed in Build at site of old arch timber bridge (Timothy Palmer – 1792) and wrought iron chain link suspension bridge (James Finley -1810). Chain link bridge collapsed into water in 1827 when a heavily loaded ox cart crossed over it. Single suspension span = 225 ft. Stone piers.
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40. University of Massachusetts Amherst
Brooklyn Bridge
Designed and built initially by John Roebling in 1867; completed by his son, Washington, after Roebling’s death in 1883.
Main suspension span = 1596 ft (record-holder for about 20 yrs.). 4 cables, 5358 wires/cable.
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41. Tacoma Narrows Bridge Collapse
We also learn from unsuccessful applications!
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42. George Washington Bridge – As Built
Designed by Othmar Ammann. Completed in 1931 over Hudson River.
Main suspension span = ft (longest in the world at time of construction).
Extremely low depth-to-span ratio. 4 cables, wires/cable.
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43. George Washington Bridge
Current view with second level added.
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44. University of Massachusetts Amherst
Golden Gate Bridge
Constructed from ; designed by J.B. Strauss and Charles Ellis.
Span = 4,200 ft.; 2 Cables, wires/cable (Roebling cable Co.)
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45. University of Massachusetts Amherst
Golden Gate Bridge
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46. University of Massachusetts Amherst
Cable-Stayed Bridges
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47. Anatomy of a Cable Stayed Bridge
(Fanned)
Deck
Pylon
Cable Stay
(Harped)
Deck
Pylon
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48. Albert Bridge – Thames River (London)
One of the earliest cable-stayed bridges, it opened in The spans are 147 ft, 384 ft, and 147 ft. Width of the bridge is a little over 41 ft. (London, England). (Source: NISEE:
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49. Sunshine Highway Bridge, Tampa FL
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50. Normandy Bridge (France)
Built in crossing the Seine River between Le Havre and Honfleur, France. Inverted-Y Pylons, multi-cable in fan arrangement. Materials: RC pylons, PC deck, and PC/steel deck. Designer Michel Virlogeux. Main span = 856 m; total length = 2141 m.
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51. Twin Diamond Shaped Pylons
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52. University of Massachusetts Amherst
Akashi Kaikyo Bridge
Completed in 1998
Main suspension span = 1991 m (6530 ft) - longest suspension span in the world.
Tower height 297 m. Stiffening girder depth = 14 m
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53. Harilaos Trikoupis Bridge (Greece)
Completed in 2004, connecting Rion and Antirrion, Greece. Longest cable-supported bridge in the world. Cables in fan arrangement. Four-column diamond shape pylons. Materials: RC pylons, composite steel-RC deck. Main span = 560 m. (1840 ft). Total length = 2880 m. (9450 ft.). Span arrangement: 286-3x m. Designer Ingerop. Olympic flame crossed over bridge at inauguration. (Source: Structurae:
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54. University of Massachusetts Amherst
Building Big Website
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55. Tufts University Bridge Site
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