US Bridges

Thomas Road over Samish River

Fair

Skagit County, Washington · 0.3 N JCT Allen West RD · Structure no. 081890000000000

Built
1973
52 years old
Condition
Fair
inspected June 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
91 ft
1 main span
Daily traffic
216
2021 count
Owner
County
County Highway Agency

About this bridge

Thomas Road over Samish River is a prestressed concrete stringer/multi-beam or girder carrying Thomas Road over Samish River in Skagit County, Washington. It was built in 1973, so it is 52 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 216 vehicles a day, roughly 23% of them trucks, projected to reach 321 by 2041. The structure is 91 ft (27.7 m) long and 30 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesThomas Road
CrossesSamish River
Location0.3 N JCT Allen West RD
RouteCounty Highway 21610
CountySkagit County
StateWashington
Coordinates48.52106, -122.41122
Functional classRural Local

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating67.1 US tons
Inventory rating40.3 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length91 ft (27.7 m)
Longest span89 ft (27.1 m)
Deck width30 ft (9.1 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic216 (2021)
Projected traffic321 by 2041
Trucks23%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 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 proposedDeck rehabilitation with only incidental widening
Estimated improvement cost$1.3 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Thomas Road over Samish River built?

It was built in 1973, making it 52 years old in 2025.

What condition is Thomas Road over Samish 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 June 2023.

How much traffic does Thomas Road over Samish River carry?

About 216 vehicles per day (2021 count), of which roughly 23% are trucks.

How long is Thomas Road over Samish River?

The structure is 91 ft (27.7 m) long with a longest span of 89 ft (27.1 m) and a deck 30 ft wide.

Who owns Thomas Road over Samish River?

It is owned by the County Highway Agency.