US Bridges

N Fork Siuslaw RD over N Fork Siuslaw River

Fair

Lane County, Oregon · 061 NE of Florence · Structure no. 39C528507000560

Built
1978
47 years old
Condition
Fair
inspected September 2023
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
161 ft
1 main span
Daily traffic
1,037
2020 count
Owner
County
County Highway Agency

About this bridge

N Fork Siuslaw RD over N Fork Siuslaw River is a prestressed concrete box beam or girders - multiple carrying N Fork Siuslaw RD over N Fork Siuslaw River in Lane 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 1,037 vehicles a day, roughly 10% of them trucks, projected to reach 1,202 by 2025. The structure is 161 ft (49.1 m) long and 32 ft wide. If it were closed, the detour would be 9.3 mi (15 km).

CarriesN Fork Siuslaw RD
CrossesN Fork Siuslaw River
Location061 NE of Florence
RouteCounty Highway C5070
StateOregon
Coordinates44.02191, -124.0338
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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 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 adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating29.3 US tons
Inventory rating22.8 US tons

Structure

MaterialPrestressed Concrete
DeckOther
Main spans1 (+2 approach)
Design loadHS 20
Structure length161 ft (49.1 m)
Longest span90 ft (27.4 m)
Deck width32 ft (9.8 m)
Roadway width30 ft (9.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,037 (2020)
Projected traffic1,202 by 2025
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed9.3 mi (15 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 N Fork Siuslaw RD over N Fork Siuslaw River built?

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

What condition is N Fork Siuslaw RD over N Fork 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 September 2023.

How much traffic does N Fork Siuslaw RD over N Fork Siuslaw River carry?

About 1,037 vehicles per day (2020 count), of which roughly 10% are trucks.

How long is N Fork Siuslaw RD over N Fork Siuslaw River?

The structure is 161 ft (49.1 m) long with a longest span of 90 ft (27.4 m) and a deck 32 ft wide.

Who owns N Fork Siuslaw RD over N Fork Siuslaw River?

It is owned by the County Highway Agency.