US Bridges

I-5 over Allen ST / SR 4

Good

Cowlitz County, Washington · JCT SR 4 · Structure no. 0010902D0000000

Built
1981
44 years old
Condition
Good
inspected October 2023
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
132 ft
1 main span
Daily traffic
23,283
2023 count
Owner
State
State Highway Agency

About this bridge

I-5 over Allen ST / SR 4 is a prestressed concrete box beam or girders - multiple carrying I-5 over Allen ST / SR 4 in Cowlitz County, Washington. It was built in 1981, so it is 44 years old, younger than the Washington average of 49.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 23,283 vehicles a day, roughly 21% of them trucks, projected to reach 30,569 by 2039. The structure is 132 ft (40.2 m) long and 55 ft wide. If it were closed, the detour would be 8.7 mi (14 km).

Location

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CarriesI-5
CrossesAllen ST / SR 4
LocationJCT SR 4
RouteInterstate 5
CountyCowlitz County
StateWashington
Coordinates46.14453, -122.89742
Functional classUrban Principal Arterial - Interstate

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionOctober 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating85.3 US tons
Inventory rating60 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20 + Mod
Structure length132 ft (40.2 m)
Longest span127 ft (38.7 m)
Deck width55 ft (16.8 m)
Roadway width52 ft (15.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic23,283 (2023)
Projected traffic30,569 by 2039
Trucks21%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed8.7 mi (14 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$3.4 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-5 over Allen ST / SR 4 built?

It was built in 1981, making it 44 years old in 2025.

What condition is I-5 over Allen ST / SR 4 in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in October 2023.

How much traffic does I-5 over Allen ST / SR 4 carry?

About 23,283 vehicles per day (2023 count), of which roughly 21% are trucks.

How long is I-5 over Allen ST / SR 4?

The structure is 132 ft (40.2 m) long with a longest span of 127 ft (38.7 m) and a deck 55 ft wide.

Who owns I-5 over Allen ST / SR 4?

It is owned by the State Highway Agency.