Alaskan Way Viaduct
Aerial View Of Alaskan Way Viaduct, Which Starts At Left Of Rail Yards, Becomes Double-Deck Viaduct Close To Coast Guard Yard Just Above Rail Yards, And Proceeds Along Shoreline Up Into Middle Of Picture.
Photo taken by Historic American Engineering Record
View photos at Library of Congress
BH Photo #197283
This concrete viaduct carries three lanes in each direction of WA 99 on two decks. It has widely been considered an ugly eyesore along the waterfront, but provides drivers with great views of Elliott Bay, Puget Sound and the Olympic Mountains.
It was significantly damaged in the 2001 Nisqually earthquake and is at risk of collapsing in another major earthquake. In 2009--after years of debate over the design of its replacement--an agreement was reached to replace it with a bored tunnel under Downtown Seattle, which is scheduled to be complete in 2015.
Part of the viaduct on the south end was demolished in 2011 to make way for construction of the south tunnel portal, with traffic temporarily re-routed around the construction site. The rest of the viaduct will be demolished in 2016.
- Double-deck stringer bridge running parallel to Alaskan Way along Seattle waterfront
- Seattle, King County, Washington
- Open to traffic
- Future prospects
- To be replaced with a bored tunnel
- Built 1953; rehabilitated 1957
- - George Stevens (Bridge Engineer - WSDOT)
- MacRae Brothers (Contractor)
- Morrison-Knudsen Co. of Boise, Idaho (Contractor)
- Ralph W. Finke of Olympia, Washington (City Engineer - Seattle)
- Ray M. Murray (Engineer)
- Concrete stringer
Length of largest span: 63.0 ft.
Total length: 10,704.6 ft. (2.0 mi.)
Deck width: 40.0 ft.
Posted to the National Register of Historic Places
- Approximate latitude, longitude
- +47.60127, -122.33593 (decimal degrees)
47°36'05" N, 122°20'09" W (degrees°minutes'seconds")
- Approximate UTM coordinates
- 10/549917/5272198 (zone/easting/northing)
- Quadrangle map:
- Seattle South
- Inventory number
- BH 48615 (Bridgehunter.com ID)
- Inspection (as of 03/2016)
- Deck condition rating: Poor (4 out of 9)
Superstructure condition rating: Poor (4 out of 9)
Substructure condition rating: Poor (4 out of 9)
Appraisal: Structurally deficient
Sufficiency rating: 9.0 (out of 100)
- Average daily traffic (as of 2014)
- January 13, 2014: Updated by Evin Fairchild: adding more info to the description
- January 12, 2014: Updated by Evin Fairchild: adding and correcting info
- April 12, 2011: Added by K. A. Erickson