US Bridges

Avenue U over Necanicum River

Fair

Clatsop County, Oregon · In City of Seaside · Structure no. 11150A111200001

Built
1957
68 years old
Condition
Fair
inspected April 2023
Type
Stringer/Multi-beam or Girder
Concrete Continuous
Length
165 ft
3 main spans
Daily traffic
5,250
2020 count
Owner
City
City or Municipal Highway Agency

About this bridge

Avenue U over Necanicum River is a concrete continuous stringer/multi-beam or girder carrying Avenue U over Necanicum River in Clatsop County, Oregon. It was built in 1957, so it is 68 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 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 5,250 vehicles a day, roughly 10% of them trucks, projected to reach 6,000 by 2025. The structure is 165 ft (50.3 m) long and 34 ft wide.

Location

Open in Google Maps
CarriesAvenue U
CrossesNecanicum River
LocationIn City of Seaside
RouteCity Street C0000
CountyClatsop County
StateOregon
Coordinates45.97929, -123.92727
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionApril 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 adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating34.6 US tons
Inventory rating26.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length165 ft (50.3 m)
Longest span62 ft (18.9 m)
Deck width34 ft (10.5 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,250 (2020)
Projected traffic6,000 by 2025
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed—
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedWidening of existing bridge without deck rehabilitation
Estimated improvement cost$845,000
NavigationNo navigation control on waterway

Frequently asked questions

When was Avenue U over Necanicum River built?

It was built in 1957, making it 68 years old in 2025.

What condition is Avenue U over Necanicum 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 April 2023.

How much traffic does Avenue U over Necanicum River carry?

About 5,250 vehicles per day (2020 count), of which roughly 10% are trucks.

How long is Avenue U over Necanicum River?

The structure is 165 ft (50.3 m) long with a longest span of 62 ft (18.9 m) and a deck 34 ft wide.

Who owns Avenue U over Necanicum River?

It is owned by the City or Municipal Highway Agency.