Spokane Street Bridge

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Spokane Street Bridge
Spokane Street Bridge - view from east approach of swing span turned (2009).jpg
One of the bridge's swing-span sections turned
Coordinates 47°34′17″N 122°21′12″W / 47.5714°N 122.3533°W / 47.5714; -122.3533Coordinates: 47°34′17″N 122°21′12″W / 47.5714°N 122.3533°W / 47.5714; -122.3533
CarriesSpokane Street
CrossesDuwamish River
LocaleSeattle, Washington, U.S.
DesignConcrete swing bridge
Longest span480 feet (150 m)

The Spokane Street Bridge, also known as the West Seattle Low-Level Bridge, is a concrete double-leaf swing bridge in Seattle, Washington. It carries Southwest Spokane Street over the Duwamish River, connecting Harbor Island to West Seattle. It has two separate end-to-end swing-span sections, each 480 feet (150 m) long. Its construction was finished in 1991, replacing an earlier bridge destroyed by a collision. It is named after Spokane Street, which itself is named after Spokane, Washington, which is named after the Spokane people.

Each 7,500-short-ton (6,800 t) leaf of the bridge floats on a 100-inch (2.5 m) steel barrel in hydraulic oil, situated in center piers at each side of the river. As the bridge intersects the river at an oblique angle, both leaves rotate only 45 degrees (one-eighth turn) to clear the shipping channel instead of the 90-degree turn of most swing spans.[1] It is claimed[2] to be the only bridge of its type in the world and it has received several awards for its innovation, including the Outstanding Engineering Achievement Award of the American Society of Civil Engineers in 1992.[3]

The bridge was featured in a 2007 episode of Really Big Things shown on the Discovery Channel.

The Spokane Street Bridge is the lower of the two bridges visible in this picture. Behind it is the higher West Seattle Bridge.


The original bridge at this location was a 1924 bascule bridge. This bridge was constructed to replace it after a long drawn out process to secure funding. Its construction was as part of the construction of the larger West Seattle Bridge next to it.


  1. ^ "West Seattle Connection: World's Only Hydraulically Operated Double-Leaf Concrete Swing Bridge" (PDF). City of Seattle Engineering Department. Retrieved 25 February 2014.
  2. ^ "Bridges and Roadway Structures" Seattle Department of Transportation. Retrieved September 3, 2017.
  3. ^ ASCE Honors and Awards: Outstanding Civil Engineering Achievement, 1992 [listed as West Seattle Low Level Bridge], American Society of Civil Engineers, retrieved June 9, 2013

External links[edit]

Media related to Spokane Street Bridge at Wikimedia Commons