US Bridges

SR 20 over Half Br Sta 155

Fair

Whatcom County, Washington · 5.9 E Skagit CO · Structure no. 0006974A0000000

Built
1900
125 years old, rebuilt 1962
Condition
Fair
inspected March 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
63 ft
1 main span
Daily traffic
1,696
2023 count
Owner
State
State Highway Agency

About this bridge

SR 20 over Half Br Sta 155 is a steel stringer/multi-beam or girder carrying SR 20 over Half Br Sta 155 in Whatcom County, Washington. It was built in 1900 and reconstructed in 1962, so it is 125 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 5 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 1,696 vehicles a day, roughly 7% of them trucks, projected to reach 2,442 by 2039. The structure is 63 ft (19.1 m) long and 20 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

Open in Google Maps
CarriesSR 20
CrossesHalf Br Sta 155
Location5.9 E Skagit CO
RouteState Highway 20
CountyWhatcom County
StateWashington
Coordinates48.69081, -121.22578
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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMarch 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating61.9 US tons
Inventory rating37 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckClosed grating
Main spans1
Design loadUnknown
Structure length63 ft (19.1 m)
Longest span58 ft (17.8 m)
Deck width20 ft (6 m)
Roadway width30 ft (9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,696 (2023)
Projected traffic2,442 by 2039
Trucks7%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesOther
Detour if closed98.8 mi (159 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$935,000 (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was SR 20 over Half Br Sta 155 built?

It was built in 1900, making it 125 years old in 2025. It was reconstructed in 1962.

What condition is SR 20 over Half Br Sta 155 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 SR 20 over Half Br Sta 155 carry?

About 1,696 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is SR 20 over Half Br Sta 155?

The structure is 63 ft (19.1 m) long with a longest span of 58 ft (17.8 m) and a deck 20 ft wide.

Who owns SR 20 over Half Br Sta 155?

It is owned by the State Highway Agency.