Umatilla Bridge
Encyclopedia
The Umatilla Bridge is the collective name for a pair of bridge
Bridge
A bridge is a structure built to span physical obstacles such as a body of water, valley, or road, for the purpose of providing passage over the obstacle...

s carrying Interstate 82
Interstate 82
Interstate 82 is a Interstate Highway that extends from I-90 in Ellensburg, Washington to I-84 near Umatilla, Oregon in the United States. In the state of Washington, it serves the cities of Ellensburg, Yakima, and the Tri Cities , and in Oregon, it serves Umatilla and Hermiston...

/U.S. Route 395
U.S. Route 395 in Washington
In the U.S. state of Washington, U.S. Route 395 is a major state highway in two parts, separated by a long overlap with Interstate 90 between Ritzville and Spokane. The southern piece, from I-82 near the Tri-Cities to I-90 near Ritzville, is a high-speed four-lane divided highway...

 across 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...

 at the Washington State/Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...

 border. The older bridge is a steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

 through truss
Truss bridge
A truss bridge is a bridge composed of connected elements which may be stressed from tension, compression, or sometimes both in response to dynamic loads. Truss bridges are one of the oldest types of modern bridges...

 cantilever bridge
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...

 and only carries southbound traffic, with northbound traffic going on the newer bridge, a concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...

 arch bridge
Arch bridge
An arch bridge is a bridge with abutments at each end shaped as a curved arch. Arch bridges work by transferring the weight of the bridge and its loads partially into a horizontal thrust restrained by the abutments at either side...

.

Construction

The old bridge was proposed by Umatilla County
Umatilla County, Oregon
Umatilla County is a county located in the U.S. state of Oregon. It is included in the 8 county definition of Eastern Oregon. The county is named for the Umatilla River. In 2010, its population was 75,889...

 judge James H. Sturgis and known as "Sturgis' folly" initially. The construction upstream of McNary Dam
McNary Dam
McNary Dam is a 1.4-mile long concrete gravity run-of-the-river dam which spans the Columbia River. It joins Umatilla County, Oregon with Benton County, Washington, 292 miles upriver from the mouth of the Columbia at Astoria, Oregon. It is operated by the U.S. Army Corps of Engineers' McNary...

 would create Lake Wallula
Lake Wallula
Lake Wallula is a reservoir on the Columbia River in the United States, between the U.S. states of Washington and Oregon. It was created in 1954 with the construction of McNary Dam. It reaches from McNary Dam near the city of Umatilla, Oregon, to the Tri-Cities of Washington.-See also:* Wallula...

 and submerge the old Wallula Highway. In the interim, traffic was carried across the newly formed lake via ferry
Ferry
A ferry is a form of transportation, usually a boat, but sometimes a ship, used to carry primarily passengers, and sometimes vehicles and cargo as well, across a body of water. Most ferries operate on regular, frequent, return services...

 service, with 178,576 vehicles transported in 1951. The bridge was financed by $10 million worth of bonds
Bond (finance)
In finance, a bond is a debt security, in which the authorized issuer owes the holders a debt and, depending on the terms of the bond, is obliged to pay interest to use and/or to repay the principal at a later date, termed maturity...

 and operated as a toll bridge
Toll bridge
A toll bridge is a bridge over which traffic may pass upon payment of a toll, or fee.- History :The practice of collecting tolls on bridges probably harks back to the days of ferry crossings where people paid a fee to be ferried across stretches of water. As boats became impractical to carry large...

 until 1974, when the bonds were fully repaid.

It is a five-span continuous Warren through truss design. The configuration of the span is unusual in the fact that it takes advantage of a submerged island near the middle of the Columbia River. With its two 600-foot spans, each constructed using the cantilever
Cantilever
A cantilever is a beam anchored at only one end. The beam carries the load to the support where it is resisted by moment and shear stress. Cantilever construction allows for overhanging structures without external bracing. Cantilevers can also be constructed with trusses or slabs.This is in...

 method, this is the only bridge in the state having two spans constructed using that method.

External links

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