US Bridges

US 20 (hwy 31) WB over Willamette River

Fair

Benton County, Oregon · In Albany · Structure no. 09806 031 01045

Built
1971
54 years old
Condition
Fair
inspected July 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
1,146 ft
7 main spans
Daily traffic
13,386
2022 count
Owner
State
State Highway Agency

About this bridge

US 20 (hwy 31) WB over Willamette River is a steel continuous stringer/multi-beam or girder carrying US 20 (hwy 31) WB over Willamette River in Benton County, Oregon. It was built in 1971, so it is 54 years old, older than the Oregon average of 49.9 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 13,386 vehicles a day, roughly 10% of them trucks, projected to reach 15,800 by 2042. The structure is 1,146 ft (349.3 m) long and 49 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesUS 20 (hwy 31) WB
CrossesWillamette River
LocationIn Albany
RouteU.S. Route 20
CountyBenton County
StateOregon
Coordinates44.63923, -123.10589
Functional classUrban Other Principal Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating24.3 US tons
Inventory rating18.5 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans7 (+3 approach)
Design loadHS 20
Structure length1,146 ft (349.3 m)
Longest span230 ft (70.1 m)
Deck width49 ft (14.8 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic13,386 (2022)
Projected traffic15,800 by 2042
Trucks10%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway and pedestrian
CrossesHighway, waterway and railroad
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedWidening of existing bridge without deck rehabilitation
Estimated improvement cost$5.9 million
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was US 20 (hwy 31) WB over Willamette River built?

It was built in 1971, making it 54 years old in 2025.

What condition is US 20 (hwy 31) WB over Willamette River in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in July 2023.

How much traffic does US 20 (hwy 31) WB over Willamette River carry?

About 13,386 vehicles per day (2022 count), of which roughly 10% are trucks.

How long is US 20 (hwy 31) WB over Willamette River?

The structure is 1,146 ft (349.3 m) long with a longest span of 230 ft (70.1 m) and a deck 49 ft wide.

Who owns US 20 (hwy 31) WB over Willamette River?

It is owned by the State Highway Agency.