US Bridges

I-5 over Nooksack River

Fair

Whatcom County, Washington · 6.9 N JCT SR 539 · Structure no. 0008655A0000000

Built
1971
54 years old
Condition
Fair
inspected April 2024
Type
Truss - Thru
Steel
Length
897 ft
1 main span
Daily traffic
25,301
2023 count
Owner
State
State Highway Agency

About this bridge

I-5 over Nooksack River is a steel truss - thru carrying I-5 over Nooksack River in Whatcom County, Washington. It was built in 1971, so it is 54 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 25,301 vehicles a day, roughly 7% of them trucks, projected to reach 37,061 by 2039. The structure is 897 ft (273.4 m) long and 42 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-5
CrossesNooksack River
Location6.9 N JCT SR 539
RouteInterstate 5
CountyWhatcom County
StateWashington
Coordinates48.85267, -122.58187
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionApril 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating52 US tons
Inventory rating31 US tons

Structure

Structure typeTruss - Thru
MaterialSteel
DeckConcrete, cast-in-place
Main spans1 (+17 approach)
Design loadHS 20 + Mod
Structure length897 ft (273.4 m)
Longest span220 ft (67.1 m)
Deck width42 ft (12.7 m)
Roadway width38 ft (11.6 m)
Vertical clearance over deck17 ft (5.3 m)

Traffic and service

Average daily traffic25,301 (2023)
Projected traffic37,061 by 2039
Trucks7%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
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$17.9 million (2022 estimate)
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was I-5 over Nooksack River built?

It was built in 1971, making it 54 years old in 2025.

What condition is I-5 over Nooksack 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 2024.

How much traffic does I-5 over Nooksack River carry?

About 25,301 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is I-5 over Nooksack River?

The structure is 897 ft (273.4 m) long with a longest span of 220 ft (67.1 m) and a deck 42 ft wide.

Who owns I-5 over Nooksack River?

It is owned by the State Highway Agency.