US Bridges

NB I-5 over Prairie Creek

Fair

Thurston County, Washington · 2.4 N Lewis CO · Structure no. 0017465A0000000

Built
2009
16 years old
Condition
Fair
inspected September 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
77 ft
1 main span
Daily traffic
34,754
2023 count
Owner
State
State Highway Agency

About this bridge

NB I-5 over Prairie Creek is a prestressed concrete stringer/multi-beam or girder carrying NB I-5 over Prairie Creek in Thurston County, Washington. It was built in 2009, so it is 16 years old, younger 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 34,754 vehicles a day, roughly 17% of them trucks, projected to reach 50,229 by 2039. The structure is 77 ft (23.5 m) long and 73 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesNB I-5
CrossesPrairie Creek
Location2.4 N Lewis CO
RouteInterstate 5
CountyThurston County
StateWashington
Coordinates46.79736, -123.01008
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.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionSeptember 2024
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation8: Equal to present desirable criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating73 US tons
Inventory rating44 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHL 93
Structure length77 ft (23.5 m)
Longest span74 ft (22.6 m)
Deck width73 ft (22.1 m)
Roadway width58 ft (17.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic34,754 (2023)
Projected traffic50,229 by 2039
Trucks17%
Lanes on structure3
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 statusHistorical significance not determinable at this time
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$2.1 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was NB I-5 over Prairie Creek built?

It was built in 2009, making it 16 years old in 2025.

What condition is NB I-5 over Prairie Creek 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 2024.

How much traffic does NB I-5 over Prairie Creek carry?

About 34,754 vehicles per day (2023 count), of which roughly 17% are trucks.

How long is NB I-5 over Prairie Creek?

The structure is 77 ft (23.5 m) long with a longest span of 74 ft (22.6 m) and a deck 73 ft wide.

Who owns NB I-5 over Prairie Creek?

It is owned by the State Highway Agency.