US Bridges

Independence Road over Chehalis River

Fair

Thurston County, Washington · Over the Chehalis River · Structure no. 079721000000000

Built
1976
49 years old
Condition
Fair
inspected March 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
436 ft
5 main spans
Daily traffic
1,409
2021 count
Owner
County
County Highway Agency

About this bridge

Independence Road over Chehalis River is a prestressed concrete continuous stringer/multi-beam or girder carrying Independence Road over Chehalis River in Thurston County, Washington. It was built in 1976, so it is 49 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 1,409 vehicles a day, roughly 15% of them trucks, projected to reach 2,221 by 2043. The structure is 436 ft (132.9 m) long and 33 ft wide. If it were closed, the detour would be 13 mi (21 km).

Location

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CarriesIndependence Road
CrossesChehalis River
LocationOver the Chehalis River
RouteCounty Highway 12310
CountyThurston County
StateWashington
Coordinates46.80668, -123.12026
Functional classRural Minor Collector

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.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionMarch 2024
Inspection intervalevery 12 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment6: Equal to present minimum criteria
Operating rating77.9 US tons
Inventory rating47 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans5
Design loadHS 20
Structure length436 ft (132.9 m)
Longest span120 ft (36.6 m)
Deck width33 ft (10.2 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,409 (2021)
Projected traffic2,221 by 2043
Trucks15%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed13 mi (21 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedOther structural work, including hydraulic replacements
Estimated improvement cost$8.7 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Independence Road over Chehalis River built?

It was built in 1976, making it 49 years old in 2025.

What condition is Independence Road over Chehalis 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 March 2024.

How much traffic does Independence Road over Chehalis River carry?

About 1,409 vehicles per day (2021 count), of which roughly 15% are trucks.

How long is Independence Road over Chehalis River?

The structure is 436 ft (132.9 m) long with a longest span of 120 ft (36.6 m) and a deck 33 ft wide.

Who owns Independence Road over Chehalis River?

It is owned by the County Highway Agency.