US Bridges

Woodson Road over Westport Slough

FairPosted for load

Columbia County, Oregon · 001 N of Woodson · Structure no. 13821A450400010

Built
1982
43 years old
Condition
Fair
inspected May 2023
Type
Slab
Prestressed Concrete
Length
315 ft
11 main spans
Daily traffic
330
2020 count
Owner
County
County Highway Agency

About this bridge

Woodson Road over Westport Slough is a prestressed concrete slab carrying Woodson Road over Westport Slough in Columbia County, Oregon. It was built in 1982, so it is 43 years old, younger 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. Its operating status is: posted for other load-capacity restriction.

It carries about 330 vehicles a day, roughly 10% of them trucks, projected to reach 364 by 2025. The structure is 315 ft (96 m) long and 28 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

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CarriesWoodson Road
CrossesWestport Slough
Location001 N of Woodson
RouteCounty Highway C4504
CountyColumbia County
StateOregon
Coordinates46.11603, -123.32555
Functional classRural Minor Collector

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.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusPosted for other load-capacity restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating50.7 US tons
Inventory rating30.8 US tons

Structure

Structure typeSlab
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans11
Design loadHS 20
Structure length315 ft (96 m)
Longest span30 ft (9.1 m)
Deck width28 ft (8.5 m)
Roadway width28 ft (8.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic330 (2020)
Projected traffic364 by 2025
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Woodson Road over Westport Slough built?

It was built in 1982, making it 43 years old in 2025.

What condition is Woodson Road over Westport Slough 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 May 2023.

How much traffic does Woodson Road over Westport Slough carry?

About 330 vehicles per day (2020 count), of which roughly 10% are trucks.

How long is Woodson Road over Westport Slough?

The structure is 315 ft (96 m) long with a longest span of 30 ft (9.1 m) and a deck 28 ft wide.

Who owns Woodson Road over Westport Slough?

It is owned by the County Highway Agency.