US Bridges

Siuslaw RD over Siuslaw River

Fair

Lane County, Oregon · 061 MI W of Lorane · Structure no. 39C453439003721

Built
1984
41 years old
Condition
Fair
inspected July 2024
Type
Slab
Prestressed Concrete
Length
209 ft
3 main spans
Daily traffic
325
2020 count
Owner
County
County Highway Agency

About this bridge

Siuslaw RD over Siuslaw River is a prestressed concrete slab carrying Siuslaw RD over Siuslaw River in Lane County, Oregon. It was built in 1984, so it is 41 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.

It carries about 325 vehicles a day, roughly 10% of them trucks, projected to reach 380 by 2025. The structure is 209 ft (63.7 m) long and 32 ft wide. If it were closed, the detour would be 16.2 mi (26 km).

Location

Open in Google Maps
CarriesSiuslaw RD
CrossesSiuslaw River
Location061 MI W of Lorane
RouteCounty Highway C4390
CountyLane County
StateOregon
Coordinates43.83832, -123.35563
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
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 statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating60 US tons
Inventory rating30 US tons

Structure

Structure typeSlab
MaterialPrestressed Concrete
DeckOther
Main spans3
Design loadHS 20
Structure length209 ft (63.7 m)
Longest span70 ft (21.3 m)
Deck width32 ft (9.9 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 closed16.2 mi (26 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 Siuslaw RD over Siuslaw River built?

It was built in 1984, making it 41 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 209 ft (63.7 m) long with a longest span of 70 ft (21.3 m) and a deck 32 ft wide.

Who owns Siuslaw RD over Siuslaw River?

It is owned by the County Highway Agency.