US Bridges

US 30 (hwy 92) over Gnat Creek

Fair

Clatsop County, Oregon · 180 MI W of Astoria · Structure no. 00921 02W 07725

Built
1929
96 years old
Condition
Fair
inspected March 2023
Type
Tee Beam
Concrete Continuous
Length
165 ft
4 main spans
Daily traffic
6,811
2022 count
Owner
State
State Highway Agency

About this bridge

US 30 (hwy 92) over Gnat Creek is a concrete continuous tee beam carrying US 30 (hwy 92) over Gnat Creek in Clatsop County, Oregon. It was built in 1929, so it is 96 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 6,811 vehicles a day, roughly 18% of them trucks, projected to reach 6,900 by 2042. The structure is 165 ft (50.3 m) long and 30 ft wide. If it were closed, the detour would be 19.9 mi (32 km).

Location

Open in Google Maps
CarriesUS 30 (hwy 92)
CrossesGnat Creek
Location180 MI W of Astoria
RouteU.S. Route 30
CountyClatsop County
StateOregon
Coordinates46.16951, -123.48667
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 protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMarch 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 geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating28.2 US tons
Inventory rating21.8 US tons

Structure

Structure typeTee Beam
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadH 15
Structure length165 ft (50.3 m)
Longest span50 ft (15.2 m)
Deck width30 ft (9.2 m)
Roadway width27 ft (8.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,811 (2022)
Projected traffic6,900 by 2042
Trucks18%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed19.9 mi (32 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 proposedWidening of existing bridge without deck rehabilitation
Estimated improvement cost$845,000
NavigationNo navigation control on waterway

Frequently asked questions

When was US 30 (hwy 92) over Gnat Creek built?

It was built in 1929, making it 96 years old in 2025.

What condition is US 30 (hwy 92) over Gnat Creek 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 2023.

How much traffic does US 30 (hwy 92) over Gnat Creek carry?

About 6,811 vehicles per day (2022 count), of which roughly 18% are trucks.

How long is US 30 (hwy 92) over Gnat Creek?

The structure is 165 ft (50.3 m) long with a longest span of 50 ft (15.2 m) and a deck 30 ft wide.

Who owns US 30 (hwy 92) over Gnat Creek?

It is owned by the State Highway Agency.