US Bridges

Siuslaw RD over Siuslaw River

FairPosted for load

Lane County, Oregon · 064 MI W of Lorane · Structure no. 39C452439003589

Built
1975
50 years old
Condition
Fair
inspected July 2024
Type
Tee Beam
Prestressed Concrete
Length
132 ft
1 main span
Daily traffic
325
2020 count
Owner
County
County Highway Agency

About this bridge

Siuslaw RD over Siuslaw River is a prestressed concrete tee beam carrying Siuslaw RD over Siuslaw River in Lane County, Oregon. It was built in 1975, so it is 50 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. Its operating status is: posted for load restriction.

It carries about 325 vehicles a day, roughly 10% of them trucks, projected to reach 380 by 2025. The structure is 132 ft (40.2 m) long and 33 ft wide. If it were closed, the detour would be 14.3 mi (23 km).

Location

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CarriesSiuslaw RD
CrossesSiuslaw River
Location064 MI W of Lorane
RouteCounty Highway C4390
CountyLane County
StateOregon
Coordinates43.84878, -123.36803
Functional classRural Major 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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2024
Inspection intervalevery 24 months
Operating statusPosted for load 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 geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating26.6 US tons
Inventory rating20.5 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length132 ft (40.2 m)
Longest span130 ft (39.6 m)
Deck width33 ft (10.1 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic325 (2020)
Projected traffic380 by 2025
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed14.3 mi (23 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Siuslaw RD over Siuslaw River built?

It was built in 1975, making it 50 years old in 2025.

What condition is Siuslaw RD over Siuslaw 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 2024.

How much traffic does Siuslaw RD over Siuslaw River carry?

About 325 vehicles per day (2020 count), of which roughly 10% are trucks.

How long is Siuslaw RD over Siuslaw River?

The structure is 132 ft (40.2 m) long with a longest span of 130 ft (39.6 m) and a deck 33 ft wide.

Who owns Siuslaw RD over Siuslaw River?

It is owned by the County Highway Agency.