Northport Bridge
Encyclopedia
The Northport Bridge spans the Columbia River
Columbia River
The Columbia River is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia, Canada, flows northwest and then south into the U.S. state of Washington, then turns west to form most of the border between Washington and the state...

 near Northport, Washington
Northport, Washington
Northport is a town in Stevens County, Washington, United States. The population was 295 at the 2010 census.-History:Northport was given its name since it was once the northernmost town on the Spokane Falls and Northern Railway...

, close to the border with Canada. The steel cantilever through-truss
Cantilever bridge
A cantilever bridge is a bridge built using cantilevers, structures that project horizontally into space, supported on only one end. For small footbridges, the cantilevers may be simple beams; however, large cantilever bridges designed to handle road or rail traffic use trusses built from...

 bridge replaced an 1897 timber bridge, and was completed in 1951. It carries Washington State Route 25
Washington State Route 25
State Route 25 , named the Coulee Reservoir Highway, is a long state highway serving communities in Lincoln and Stevens counties in the U.S. state of Washington. The highway begins at an intersection with east of Davenport and continues northwest to cross the Spokane River on the Spokane...

. It is one of a series of similar bridges built at about the same time, including the Grand Coulee Bridge
Grand Coulee Bridge
The Grand Coulee Bridge, or Columbia River Bridge at Grand Coulee Dam, is a thru-cantilever steel truss bridge built in 1935. It carries Washington State Route 155. It is near the city of Grand Coulee, Washington and the Grand Coulee Dam. In 1982, it was added to the National Register of Historic...

 and the Kettle Falls Bridges
Kettle Falls Bridges
The Kettle Falls Bridges is the collective name for a pair of steel cantilever bridges carrying State Route 20/U.S. Route 395 and the BNSF Railway across the Columbia River at Kettle Falls, Washington. The south bridge carries motor vehicle traffic while the similar northern span is used for...

.

The Northport Bridge's total length is 1542 feet (470 m). he main span consists of a central span of 224 feet (68.3 m) between 140 feet (42.7 m) cantilever spans, for a total span of 504 feet (153.6 m). The steel anchor spans are 168 feet (51.2 m) long, with additional concrete approach spans. The bridge opened to traffic on June 13, 1951, at a cost of $1,751,587.

The bridge was designed by George Stevens of the Washington State Highways, and the main span was built by the Midland Structural Steel Company. Work began in August 1946. Floods in 1948 undermined the south main pier of the steel structure, causing the design to be changed from a section of earth fill to five additional T-beam concrete approach spans. Underwater blasting was require to remove the south pier for the altered work, resulting in a 673 feet (205.1 m) series of concrete approach spans on the south.

The Northport Bridge was placed on the National Register of Historic Places
National Register of Historic Places
The National Register of Historic Places is the United States government's official list of districts, sites, buildings, structures, and objects deemed worthy of preservation...

on May 24, 1995.
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