US Bridges

Clatskanie Heights over Conyers Creek

Fair

Columbia County, Oregon · 020 M S City of Clatskani · Structure no. 13777B408900010

Built
1978
47 years old
Condition
Fair
inspected May 2023
Type
Slab
Prestressed Concrete
Length
56 ft
1 main span
Daily traffic
458
2020 count
Owner
County
County Highway Agency

About this bridge

Clatskanie Heights over Conyers Creek is a prestressed concrete slab carrying Clatskanie Heights over Conyers Creek in Columbia County, Oregon. It was built in 1978, so it is 47 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 5 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 458 vehicles a day, roughly 10% of them trucks, projected to reach 518 by 2025. The structure is 56 ft (17.1 m) long and 28 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

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CarriesClatskanie Heights
CrossesConyers Creek
Location020 M S City of Clatskani
RouteCounty Highway C4089
CountyColumbia County
StateOregon
Coordinates46.09497, -123.20874
Functional classRural Local

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating37.1 US tons
Inventory rating28.5 US tons

Structure

Structure typeSlab
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans1
Design loadHS 20
Structure length56 ft (17.1 m)
Longest span55 ft (16.8 m)
Deck width28 ft (8.5 m)
Roadway width28 ft (8.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic458 (2020)
Projected traffic518 by 2025
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed123.7 mi (199 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 Clatskanie Heights over Conyers Creek built?

It was built in 1978, making it 47 years old in 2025.

What condition is Clatskanie Heights over Conyers Creek 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 Clatskanie Heights over Conyers Creek carry?

About 458 vehicles per day (2020 count), of which roughly 10% are trucks.

How long is Clatskanie Heights over Conyers Creek?

The structure is 56 ft (17.1 m) long with a longest span of 55 ft (16.8 m) and a deck 28 ft wide.

Who owns Clatskanie Heights over Conyers Creek?

It is owned by the County Highway Agency.