Structure 20C0536 · Sonoma County, CA

River Road over Hillside

Carries River Road over Hillside, 1.7 Mi West Of Mirabel RD.

Overall conditionFair

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

How ratings work
Decksets the rating5/9 · Fair
Superstructuresets the rating5/9 · Fair
Substructuresets the rating5/9 · Fair
0 failed4 poor6 fair9 excellent

Elevation

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

78 ft end to end, longest span 27 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 multi-beam bridge.

Built200323 years old
Length78.1 ft23.8 m
Daily traffic13,450counted 2015
Last inspectedJune 2023every 24 months

Location

StateCalifornia
CountySonoma
Location1.7 Mi West Of Mirabel RD
CarriesRiver Road
CrossesHillside
Coordinates38.50947, -122.91985

Physical Characteristics

MaterialSteel Continuous
DesignStringer/Multi-beam
Total Length78.1 ft (23.8 m)
Max Span26.9 ft (8.2 m)
Deck Width14.1 ft (4.3 m)
Deck Area102.3 sq m
Main Spans3
Year Built2003

Traffic

Avg Daily Traffic13,450 (2015)
Truck Traffic2%
Lanes On Bridge2

Inspection & Ownership

Last InspectionJune 2023
Inspection FrequencyEvery 24 months
OwnerCounty Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number20C0536

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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