US Bridges

SR 6 over Chehalis R

Fair

Lewis County, Washington · 3.4 E Pacific CO · Structure no. 0001558A0000000

Built
1931
94 years old
Condition
Fair
inspected June 2023
Type
Arch - Deck
Concrete
Length
324 ft
1 main span
Daily traffic
1,846
2023 count
Owner
State
State Highway Agency

About this bridge

SR 6 over Chehalis R is a concrete arch - deck carrying SR 6 over Chehalis R in Lewis County, Washington. It was built in 1931, so it is 94 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 1,846 vehicles a day, roughly 13% of them trucks, projected to reach 1,899 by 2039. The structure is 324 ft (98.8 m) long and 34 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesSR 6
CrossesChehalis R
Location3.4 E Pacific CO
RouteState Highway 6
CountyLewis County
StateWashington
Coordinates46.56947, -123.30439
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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating23.9 US tons
Inventory rating18.5 US tons

Structure

Structure typeArch - Deck
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1 (+10 approach)
Design loadH 15
Structure length324 ft (98.8 m)
Longest span184 ft (56.1 m)
Deck width34 ft (10.5 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,846 (2023)
Projected traffic1,899 by 2039
Trucks13%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$6.2 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was SR 6 over Chehalis R built?

It was built in 1931, making it 94 years old in 2025.

What condition is SR 6 over Chehalis R 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 June 2023.

How much traffic does SR 6 over Chehalis R carry?

About 1,846 vehicles per day (2023 count), of which roughly 13% are trucks.

How long is SR 6 over Chehalis R?

The structure is 324 ft (98.8 m) long with a longest span of 184 ft (56.1 m) and a deck 34 ft wide.

Who owns SR 6 over Chehalis R?

It is owned by the State Highway Agency.