US Bridges

HWY 603 over Chehalis River

Fair

Lewis County, Washington · 0.15 S.E. SR 6 · Structure no. 085987000000000

Built
1991
34 years old
Condition
Fair
inspected January 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
377 ft
1 main span
Daily traffic
1,697
2022 count
Owner
County
County Highway Agency

About this bridge

HWY 603 over Chehalis River is a prestressed concrete continuous stringer/multi-beam or girder carrying HWY 603 over Chehalis River in Lewis County, Washington. It was built in 1991, so it is 34 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 1,697 vehicles a day, roughly 18% of them trucks, projected to reach 3,065 by 2042. The structure is 377 ft (114.9 m) long and 31 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

Open in Google Maps
CarriesHWY 603
CrossesChehalis River
Location0.15 S.E. SR 6
RouteCounty Highway 92008
CountyLewis County
StateWashington
Coordinates46.64167, -123.01333
Functional classRural Major 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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJanuary 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 alignment8: Equal to present desirable criteria
Operating rating106.8 US tons
Inventory rating35.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans1 (+2 approach)
Design loadHS 20
Structure length377 ft (114.9 m)
Longest span165 ft (50.3 m)
Deck width31 ft (9.5 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,697 (2022)
Projected traffic3,065 by 2042
Trucks18%
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

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of relocation of road
Estimated improvement cost$14 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was HWY 603 over Chehalis River built?

It was built in 1991, making it 34 years old in 2025.

What condition is HWY 603 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 January 2023.

How much traffic does HWY 603 over Chehalis River carry?

About 1,697 vehicles per day (2022 count), of which roughly 18% are trucks.

How long is HWY 603 over Chehalis River?

The structure is 377 ft (114.9 m) long with a longest span of 165 ft (50.3 m) and a deck 31 ft wide.

Who owns HWY 603 over Chehalis River?

It is owned by the County Highway Agency.