The Second Bridge

 

 Not only was the original Tacoma Narrows bridge aerodynamically unstable, it was too small. The replacement structure, which was the first 1,000 ft. span completed in the United States after World War II (the original was the last completed before the war), dealt with both problems. A series of wind tunnel tests conducted by Frederick Farquharson at the University of Washington was used to develop a deck structure with deep steel trusses and grating to allow the wind to pass through parts of the deck. The structure also had 4 lanes, making it less slender and doubling its traffic capacity. The bridge has never experienced and wind-related problems and now carries 80,000 vehicles a day.

 

  • built: 1950
  • carries SR 16 across Tacoma Narrows
  • engineers: Dexter Smith
  • total length 1.4 mi.
  • types (maximum span): suspension (truss deck) (2800 ft.)
  • visuals available: photos
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crosses: Tacoma Narrows

overall length: 5000 ft.
# of spans: 3
maximum span: 2800 ft.
# of maximum spans: 1

tower height: 483 ft.
clearance:  

type: suspension (truss deck)
structural material: steel
tower material: steel
deck material: steel
pier material: concrete
foundation type:  

carries: 4 highway lanes, sidewalk
The Tacoma Narrows suspension bridge, one of the largest suspension structures in the world, became toll free on May 14, 1965. It was followed a few months later by the removal of tolls on the Longview Bridge across the Columbia River; and in November, 1966, by the removal of tolls on the Vancouver-Portland Interstate Bridge.