Structure 6974A0000000 · Whatcom County, WA

SR 20 over Half Br Sta 155

Carries SR 20 over Half Br Sta 155, 5.9 E Skagit Co.

Overall conditionFair

Set by its lowest-rated component: Deck at 5 of 9.

How ratings work
Decksets the rating5/9 · Fair
Superstructure6/9 · Satisfactory
Substructure6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT63 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 5/9 · sets the ratingSuperstructure 6/9Substructure 6/9

63 ft end to end. Lengths and the car on the deck are drawn to the same scale. Each part is colored by its latest inspection rating. The inventory records lengths but not heights or the layout of the shorter spans, so those are drawn as typical for a multi-beam bridge.

Built1900rebuilt 1962
Length62.7 ft19.1 m
Daily traffic1,696counted 2023
Last inspectedMarch 2024every 24 months

Location

StateWashington
CountyWhatcom
Location5.9 E Skagit Co
CarriesSR 20
CrossesHalf Br Sta 155
Coordinates48.69081, -121.22578

Physical Characteristics

MaterialSteel
DesignStringer/Multi-beam
Total Length62.7 ft (19.1 m)
Max Span58.4 ft (17.8 m)
Deck Width19.7 ft (6 m)
Deck Area114.6 sq m
Main Spans1
Year Built1900 (reconstructed 1962)

Traffic

Avg Daily Traffic1,696 (2023)
Truck Traffic7%
Lanes On Bridge2

Inspection & Ownership

Last InspectionMarch 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number0006974A0000000

How Bridge Ratings Work

Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."

0Failed
1Imminent failure
2Critical
3Serious
4Poor
5Fair
6Satisfactory
7Good
8Very good
9Excellent
Good · lowest component 7–9
Fair · lowest component 5–6
Poor · lowest component 0–4

A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.

Nearby Bridges