Structure 21 0005 · Napa County, CA

State Route 29 over Garnett Creek

Carries State Route 29 over Garnett Creek, 04-nap-029-39.08.

Overall conditionPoor

Set by its lowest-rated component: Substructure at 4 of 9.

How ratings work
Superstructure5/9 · Fair
Substructuresets the rating4/9 · Poor
Channelnot part of overall3/9 · Serious
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT76 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck not ratedSuperstructure 5/9Substructure 4/9 · sets the rating

76 ft end to end, longest span 29 ft. 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 deck arch.

Built1902rebuilt 1955
Length75.8 ft23.1 m
Daily traffic12,000counted 2017
Last inspectedApril 2023every 24 months

Location

StateCalifornia
CountyNapa
Location04-nap-029-39.08
CarriesState Route 29
CrossesGarnett Creek
Coordinates38.60334, -122.58878

Physical Characteristics

MaterialMasonry
DesignArch - Deck
Total Length75.8 ft (23.1 m)
Max Span28.9 ft (8.8 m)
Deck Width22.6 ft (6.9 m)
Deck Area159.4 sq m
Main Spans3
Year Built1902 (reconstructed 1955)

Traffic

Avg Daily Traffic12,000 (2017)
Truck Traffic6%
Lanes On Bridge2

Inspection & Ownership

Last InspectionApril 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is on the National Register of Historic Places
Scour Critical3 — Scour critical
Structure Number21 0005

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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