Structure 20 0085L · Sonoma County, CA

US Highway 101 SB over Healdsburg Av-s101 On-rp

Carries US Highway 101 SB over Healdsburg Av-s101 On-rp, 04-son-101-34.55-hlbg.

Overall conditionFair

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

How ratings work
Decksets the rating5/9 · Fair
Superstructure7/9 · Good
Substructure7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT124 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 5/9 · sets the ratingSuperstructure 7/9Substructure 7/9

124 ft end to end, longest span 54 ft. 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 tee-beam bridge.

Built196066 years old
Length124.0 ft37.8 m
Daily traffic22,500counted 2015
Last inspectedApril 2023every 24 months

Location

StateCalifornia
CountySonoma
Location04-son-101-34.55-hlbg
CarriesUS Highway 101 SB
CrossesHealdsburg Av-s101 On-rp
Coordinates38.60391, -122.86843

Physical Characteristics

MaterialConcrete Continuous
DesignTee Beam
Total Length124.0 ft (37.8 m)
Max Span54.1 ft (16.5 m)
Deck Width41.7 ft (12.7 m)
Deck Area480.1 sq m
Main Spans3
Year Built1960

Traffic

Avg Daily Traffic22,500 (2015)
Truck Traffic13%
Lanes On Bridge2
Lanes Under Bridge1

Inspection & Ownership

Last InspectionApril 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number20 0085L

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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