Structure 20 0012 · Sonoma County, CA

State Route 116 over Austin Creek

Carries State Route 116 over Austin Creek, 04-son-116-4.93.

Overall conditionFair

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

How ratings work
Decksets the rating6/9 · Satisfactory
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 FT380 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9 · sets the ratingSuperstructure 7/9Substructure 7/9

380 ft end to end, longest span 118 ft: about 5 semi-trucks nose to tail. 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 box-beam bridge.

Built196264 years old
Length379.9 ft115.8 m
Daily traffic5,175counted 2016
Last inspectedJune 2024every 24 months

Location

StateCalifornia
CountySonoma
Location04-son-116-4.93
CarriesState Route 116
CrossesAustin Creek
Coordinates38.46719, -123.05003

Physical Characteristics

MaterialConcrete Continuous
DesignBox Beam - Multiple
Total Length379.9 ft (115.8 m)
Max Span118.1 ft (36 m)
Deck Width34.1 ft (10.4 m)
Deck Area1204.3 sq m
Main Spans4
Year Built1962

Traffic

Avg Daily Traffic5,175 (2016)
Lanes On Bridge2

Inspection & Ownership

Last InspectionJune 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical5 — Stable for scour
Structure Number20 0012

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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