20th Avenue NE Bridge

The 20th Avenue NE Bridge (also known as the Ravenna Park Bridge) is a three-hinged, steel, lattice-arched bridge that spans a ravine in Seattle, Washington, United States' Ravenna Park. It was designed by Frank M. Johnson under the direction of city engineer Arthur Dimock.^[2] Built in 1913, the structure is both listed in the National Register of Historic Places and is a designated city landmark.^[3][4]

20th Avenue NE Bridge
Coordinates	47°40′19″N 122°18′21″W
Other name(s)	Ravenna Park Bridge
Characteristics
Design	Deck Arch
Material	Steel
Total length	354 feet (108 m)
Width	18 feet (5.5 m)
Clearance below	41 feet (12 m)
History
Designer	Frank M. Johnson
Engineering design by	Arthur Dimock
Opened	1913
Closed	1975 (to vehicles only)
Ravenna Park Bridge
U.S. National Register of Historic Places
Seattle Landmark
Location	Seattle, Washington
Built	1913
Architect	Frank M. Johnson and J.R. Wood & Co
MPS	Historic Bridges/Tunnels in Washington State TR
NRHP reference No.	82004246
Significant dates
Added to NRHP	July 16, 1982
Designated SEATL	January 17, 1977[1]
Location

The structure is 354 ft (108 m) long. It has a 250 ft (76 m) arch that rises 41 ft (12 m) over the ravine. It supports an 18 ft (5.5 m) reinforced concrete roadway. Beginning on March 11, 1975, a four-month trial began wherein the bridge was closed to vehicular traffic. The bridge did not meet the standards for arterial roads at the time, and upgrading the bridge would have been cost prohibitive.^[5] The trial period was successful and the bridge has been closed to vehicle travel ever since,^[6] but it is accessible by pedestrians and cyclists.^[2]

• 
  The newly constructed 20th Avenue NE Bridge (now known as Ravenna Park Bridge), Seattle, Washington, U.S., 1914. Originally a bridge for automobiles, it was eventually pedestrianized.
• 
  A person rides a bike over the 20th Avenue NE Bridge.

References

1. "Landmarks and Designation". City of Seattle. Archived from the original on 2013-03-06. Retrieved 2013-03-05.
2. Long, Priscilla (July 23, 2008). "Seattle's Ravenna Park Bridge is constructed in 1913.". HistoryLink.org Online Encyclopedia of Washington State History. Archived from the original on 2011-10-03. Retrieved March 24, 2011.
3. National Register of Historic Places; Annual Listing of Historic Properties (Part II) (PDF). National Park Service. March 1, 1983. p. 8669. Archived from the original (PDF) on November 3, 2011. Retrieved March 25, 2011.
4. "Individual Landmarks". City of Seattle Department of Neighborhoods. Archived from the original on 2010-06-04. Retrieved March 25, 2011.
5. "Ravenna Span Closing to Cars". Seattle Post-Intelligencer. 1975-03-10.
6. "Old bridge being fixed". Seattle Daily Times. 1977-01-12.