Structure 20C0435 · Sonoma County, CA

Bohan Dillon RD over South Fork Gualala River

Carries Bohan Dillon RD over South Fork Gualala River, 0.1 Mi N Fort Ross RD.

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
Channelnot part of overall6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT77 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 5/9 · sets the ratingSubstructure 7/9

77 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 deck truss.

Built195076 years old
Length77.1 ft23.5 m
Daily traffic50counted 2015
Last inspectedJune 2023every 24 months

Location

StateCalifornia
CountySonoma
Location0.1 Mi N Fort Ross RD
CarriesBohan Dillon RD
CrossesSouth Fork Gualala River
Coordinates38.52698, -123.19238

Physical Characteristics

MaterialSteel
DesignTruss - Deck
Total Length77.1 ft (23.5 m)
Max Span71.9 ft (21.9 m)
Deck Width12.8 ft (3.9 m)
Deck Area91.7 sq m
Main Spans1
Year Built1950

Traffic

Avg Daily Traffic50 (2015)
Truck Traffic1%
Lanes On Bridge1

Inspection & Ownership

Last InspectionJune 2023
Inspection FrequencyEvery 24 months
OwnerCounty Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalUnknown
Structure Number20C0435

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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