US Bridges

SR 6 over Chehalis River

Fair

Lewis County, Washington · 21.9 E Pacific CO · Structure no. 0008757A0000000

Built
1971
54 years old
Condition
Fair
inspected March 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
406 ft
3 main spans
Daily traffic
7,228
2023 count
Owner
State
State Highway Agency

About this bridge

SR 6 over Chehalis River is a steel continuous stringer/multi-beam or girder carrying SR 6 over Chehalis River in Lewis 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 7,228 vehicles a day, roughly 9% of them trucks, projected to reach 9,523 by 2039. The structure is 406 ft (123.7 m) long and 43 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

Open in Google Maps
CarriesSR 6
CrossesChehalis River
Location21.9 E Pacific CO
RouteState Highway 6
CountyLewis County
StateWashington
Coordinates46.62714, -123.06153
Functional classRural Minor 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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMarch 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating45 US tons
Inventory rating40 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length406 ft (123.7 m)
Longest span200 ft (61 m)
Deck width43 ft (13.1 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic7,228 (2023)
Projected traffic9,523 by 2039
Trucks9%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 km)
TollOn a free road
National Highway SystemNo

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$8.1 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was SR 6 over Chehalis River built?

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

What condition is SR 6 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 2023.

How much traffic does SR 6 over Chehalis River carry?

About 7,228 vehicles per day (2023 count), of which roughly 9% are trucks.

How long is SR 6 over Chehalis River?

The structure is 406 ft (123.7 m) long with a longest span of 200 ft (61 m) and a deck 43 ft wide.

Who owns SR 6 over Chehalis River?

It is owned by the State Highway Agency.