US Bridges

Fern RD over Marys River

Fair

Benton County, Oregon · 0.7 Mile S of Philomath · Structure no. 08815 262 00050

Built
1961
64 years old
Condition
Fair
inspected July 2024
Type
Tee Beam
Concrete Continuous
Length
161 ft
3 main spans
Daily traffic
2,060
2020 count
Owner
County
County Highway Agency

About this bridge

Fern RD over Marys River is a concrete continuous tee beam carrying Fern RD over Marys River in Benton County, Oregon. It was built in 1961, so it is 64 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.

It carries about 2,060 vehicles a day, roughly 10% of them trucks, projected to reach 2,884 by 2040. The structure is 161 ft (49.1 m) long and 31 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesFern RD
CrossesMarys River
Location0.7 Mile S of Philomath
RouteCounty Highway 0
CountyBenton County
StateOregon
Coordinates44.5297, -123.36854
Functional classUrban 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
Deck8 Very GoodNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
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 geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating72 US tons
Inventory rating43 US tons

Structure

Structure typeTee Beam
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length161 ft (49.1 m)
Longest span60 ft (18.3 m)
Deck width31 ft (9.5 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,060 (2020)
Projected traffic2,884 by 2040
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed3.7 mi (6 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 proposedWidening of existing bridge without deck rehabilitation
Estimated improvement cost$825,000
NavigationNo navigation control on waterway

Frequently asked questions

When was Fern RD over Marys River built?

It was built in 1961, making it 64 years old in 2025.

What condition is Fern RD over Marys 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 Fern RD over Marys River carry?

About 2,060 vehicles per day (2020 count), of which roughly 10% are trucks.

How long is Fern RD over Marys River?

The structure is 161 ft (49.1 m) long with a longest span of 60 ft (18.3 m) and a deck 31 ft wide.

Who owns Fern RD over Marys River?

It is owned by the County Highway Agency.