Structure 27 0030 · Marin County, CA

U.s. Highway 101 over Lincoln Ave-n101 On Ramp

Carries U.s. Highway 101 over Lincoln Ave-n101 On Ramp, 04-mrn-101-12.19-srf.

Overall conditionFair

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

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

Elevation

Side view, colored by inspection rating
CAR · 15 FT93 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 5/9 · sets the ratingSuperstructure 5/9 · sets the ratingSubstructure 7/9

93 ft end to end, longest span 51 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 slab bridge.

Built1938rebuilt 2009
Length92.5 ft28.2 m
Daily traffic180,000counted 2009
Last inspectedApril 2023every 24 months

Location

StateCalifornia
CountyMarin
Location04-mrn-101-12.19-srf
CarriesU.s. Highway 101
CrossesLincoln Ave-n101 On Ramp
Coordinates37.98836, -122.52683

Physical Characteristics

MaterialPrestressed Concrete Continuous
DesignSlab
Total Length92.5 ft (28.2 m)
Max Span50.5 ft (15.4 m)
Deck Width127.0 ft (38.7 m)
Deck Area1091.3 sq m
Main Spans3
Year Built1938 (reconstructed 2009)

Traffic

Avg Daily Traffic180,000 (2009)
Lanes On Bridge9
Lanes Under Bridge2

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 Number27 0030

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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