Structure 10C0159 · Mendocino County, CA

Orr Springs RD over Ackerman Creek

Carries Orr Springs RD over Ackerman Creek, 2.0 Mi W US 101.

Overall conditionFair

Set by its lowest-rated component: Substructure at 6 of 9.

How ratings work
Deck7/9 · Good
Superstructure7/9 · Good
Substructuresets the rating6/9 · Satisfactory
Channelnot part of overall6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT82 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 7/9Substructure 6/9 · sets the rating

82 ft end to end, longest span 38 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 tee-beam bridge.

Built195670 years old
Length82.3 ft25.1 m
Daily traffic3,101counted 2011
Last inspectedFebruary 2024every 24 months

Location

StateCalifornia
CountyMendocino
Location2.0 Mi W US 101
CarriesOrr Springs RD
CrossesAckerman Creek
Coordinates39.18067, -123.23398

Physical Characteristics

MaterialConcrete
DesignTee Beam
Total Length82.3 ft (25.1 m)
Max Span38.4 ft (11.7 m)
Deck Width27.9 ft (8.5 m)
Deck Area213.3 sq m
Main Spans2
Year Built1956

Traffic

Avg Daily Traffic3,101 (2011)
Truck Traffic10%
Lanes On Bridge2

Inspection & Ownership

Last InspectionFebruary 2024
Inspection FrequencyEvery 24 months
OwnerCounty Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical5 — Stable for scour
Structure Number10C0159

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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