US Bridges

US101 (hwy 9) over Trask River

Fair

Tillamook County, Oregon · 018 MI S Tillamook · Structure no. 07147 009 06798

Built
1949
76 years old
Condition
Fair
inspected March 2024
Type
Tee Beam
Concrete Continuous
Length
336 ft
3 main spans
Daily traffic
8,740
2022 count
Owner
State
State Highway Agency

About this bridge

US101 (hwy 9) over Trask River is a concrete continuous tee beam carrying US101 (hwy 9) over Trask River in Tillamook County, Oregon. It was built in 1949, so it is 76 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 8,740 vehicles a day, roughly 16% of them trucks, projected to reach 8,800 by 2042. The structure is 336 ft (102.4 m) long and 39 ft wide. If it were closed, the detour would be 6.8 mi (11 km).

Location

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CarriesUS101 (hwy 9)
CrossesTrask River
Location018 MI S Tillamook
RouteU.S. Route 101
CountyTillamook County
StateOregon
Coordinates45.42952, -123.82417
Functional classRural Principal Arterial - Other

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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection3 SeriousLoss of section, deterioration, spalling or scour have seriously affected primary structural components.
Last inspectionMarch 2024
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 geometry4: Meets minimum tolerable limits to be 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 rating22.5 US tons

Structure

Structure typeTee Beam
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3 (+8 approach)
Design loadHS 20
Structure length336 ft (102.4 m)
Longest span70 ft (21.3 m)
Deck width39 ft (11.9 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic8,740 (2022)
Projected traffic8,800 by 2042
Trucks16%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed6.8 mi (11 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkNon-Interstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
Maintained byState 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 US101 (hwy 9) over Trask River built?

It was built in 1949, making it 76 years old in 2025.

What condition is US101 (hwy 9) over Trask 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 March 2024.

How much traffic does US101 (hwy 9) over Trask River carry?

About 8,740 vehicles per day (2022 count), of which roughly 16% are trucks.

How long is US101 (hwy 9) over Trask River?

The structure is 336 ft (102.4 m) long with a longest span of 70 ft (21.3 m) and a deck 39 ft wide.

Who owns US101 (hwy 9) over Trask River?

It is owned by the State Highway Agency.