Structure 6974C0000000 · Whatcom County, WA

SR 20 over Half Br Sta 163

Carries SR 20 over Half Br Sta 163, 6.1 E Skagit Co.

Overall conditionFair

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

How ratings work
Deck7/9 · Good
Superstructuresets the rating5/9 · Fair
Substructure7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT78 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 5/9 · sets the ratingSubstructure 7/9

78 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 slab bridge.

Built196264 years old
Length78.1 ft23.8 m
Daily traffic1,696counted 2023
Last inspectedJuly 2023every 24 months

Location

StateWashington
CountyWhatcom
Location6.1 E Skagit Co
CarriesSR 20
CrossesHalf Br Sta 163
Coordinates48.69230, -121.22348

Physical Characteristics

MaterialConcrete
DesignSlab
Total Length78.1 ft (23.8 m)
Max Span76.1 ft (23.2 m)
Deck Width11.8 ft (3.6 m)
Deck Area85.7 sq m
Main Spans1
Year Built1962

Traffic

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

Inspection & Ownership

Last InspectionJuly 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number0006974C0000000

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.

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