US Bridges

SR 4 over Cowlitz R / RR / SR 411

FairPosted for load

Cowlitz County, Washington · 0.1 E JCT SR 411 SP · Structure no. 0003717A0000000

Built
1951
74 years old
Condition
Fair
inspected September 2022
Type
Truss - Thru
Steel Continuous
Length
1,710 ft
3 main spans
Daily traffic
9,179
2023 count
Owner
State
State Highway Agency

About this bridge

SR 4 over Cowlitz R / RR / SR 411 is a steel continuous truss - thru carrying SR 4 over Cowlitz R / RR / SR 411 in Cowlitz County, Washington. It was built in 1951, so it is 74 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 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. Its operating status is: posted for load restriction.

It carries about 9,179 vehicles a day, roughly 2% of them trucks, projected to reach 12,128 by 2039. The structure is 1,710 ft (521.2 m) long and 58 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

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CarriesSR 4
CrossesCowlitz R / RR / SR 411
Location0.1 E JCT SR 411 SP
RouteState Highway 4
CountyCowlitz County
StateWashington
Coordinates46.14729, -122.91797
Functional classUrban Other Principal Arterial

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.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionSeptember 2022
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating37 US tons
Inventory rating22 US tons

Structure

Structure typeTruss - Thru
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3 (+20 approach)
Design loadHS 20
Structure length1,710 ft (521.2 m)
Longest span256 ft (78 m)
Deck width58 ft (17.7 m)
Roadway width56 ft (17.1 m)
Vertical clearance over deck15 ft (4.6 m)

Traffic and service

Average daily traffic9,179 (2023)
Projected traffic12,128 by 2039
Trucks2%
Lanes on structure4
Traffic directionOne-way traffic
CarriesHighway and pedestrian
CrossesHighway, waterway and railroad
Detour if closed6.2 mi (10 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusEligible for the National Register of Historic Places
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$47.1 million (2022 estimate)
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was SR 4 over Cowlitz R / RR / SR 411 built?

It was built in 1951, making it 74 years old in 2025.

What condition is SR 4 over Cowlitz R / RR / SR 411 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 September 2022.

How much traffic does SR 4 over Cowlitz R / RR / SR 411 carry?

About 9,179 vehicles per day (2023 count), of which roughly 2% are trucks.

How long is SR 4 over Cowlitz R / RR / SR 411?

The structure is 1,710 ft (521.2 m) long with a longest span of 256 ft (78 m) and a deck 58 ft wide.

Who owns SR 4 over Cowlitz R / RR / SR 411?

It is owned by the State Highway Agency.