Structure 21C0072 · Napa County, CA

Pratt Avenue over Napa River

Carries Pratt Avenue over Napa River, 0.1 Mi S Silverado Trail.

Overall conditionFair

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

How ratings work
Decksets the rating5/9 · Fair
Superstructure7/9 · Good
Substructure7/9 · Good
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT120 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 5/9 · sets the ratingSuperstructure 7/9Substructure 7/9

120 ft end to end, longest span 57 ft. Lengths and the semi-truck 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 girder bridge.

Built1921105 years old
Length120.1 ft36.6 m
Daily traffic1,106counted 1978
Last inspectedMay 2023every 24 months

Location

StateCalifornia
CountyNapa
Location0.1 Mi S Silverado Trail
CarriesPratt Avenue
CrossesNapa River
Coordinates38.52055, -122.47274

Physical Characteristics

MaterialConcrete Continuous
DesignGirder and Floorbeam
Total Length120.1 ft (36.6 m)
Max Span57.1 ft (17.4 m)
Deck Width23.0 ft (7 m)
Deck Area256.2 sq m
Main Spans2
Year Built1921

Traffic

Avg Daily Traffic1,106 (1978)
Truck Traffic10%
Lanes On Bridge2

Inspection & Ownership

Last InspectionMay 2023
Inspection FrequencyEvery 24 months
OwnerCounty Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number21C0072

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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