US Bridges

I-5 over Northwest Ave

Fair

Whatcom County, Washington · 0.8 N JCT SR 539 · Structure no. 0005704B0000000

Built
1958
67 years old
Condition
Fair
inspected May 2024
Type
Slab
Concrete Continuous
Length
154 ft
3 main spans
Daily traffic
26,759
2023 count
Owner
State
State Highway Agency

About this bridge

I-5 over Northwest Ave is a concrete continuous slab carrying I-5 over Northwest Ave in Whatcom County, Washington. It was built in 1958, so it is 67 years old, older than the Washington average of 49.8 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 26,759 vehicles a day, roughly 7% of them trucks, projected to reach 39,851 by 2039. The structure is 154 ft (46.9 m) long and 33 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-5
CrossesNorthwest Ave
Location0.8 N JCT SR 539
RouteInterstate 5
CountyWhatcom County
StateWashington
Coordinates48.78386, -122.50261
Functional classUrban Principal Arterial - Interstate

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Last inspectionMay 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry2: Basically intolerable, requiring high priority of replacement
Approach roadway alignment8: Equal to present desirable criteria
Operating rating65 US tons
Inventory rating39 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length154 ft (46.9 m)
Longest span60 ft (18.3 m)
Deck width33 ft (10.1 m)
Roadway width31 ft (9.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic26,759 (2023)
Projected traffic39,851 by 2039
Trucks7%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$2.9 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-5 over Northwest Ave built?

It was built in 1958, making it 67 years old in 2025.

What condition is I-5 over Northwest Ave 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 May 2024.

How much traffic does I-5 over Northwest Ave carry?

About 26,759 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is I-5 over Northwest Ave?

The structure is 154 ft (46.9 m) long with a longest span of 60 ft (18.3 m) and a deck 33 ft wide.

Who owns I-5 over Northwest Ave?

It is owned by the State Highway Agency.