Structure 27 0081H · Marin County, CA

W37-s101&n101 Off over County RD US 101 Nwprr

Carries W37-s101&n101 Off over County RD US 101 Nwprr, 04-mrn-037-r11.20-nvto.

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 FT1,059 FT OVERALL200 FT0ELEVATION · LENGTHS TO SCALE
Deck 5/9 · sets the ratingSuperstructure 7/9Substructure 7/9

1,059 ft end to end, longest span 102 ft: about 2.9 football fields. 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.

Built196462 years old
Length1059.1 ft322.8 m
Daily traffic18,000counted 2004
Last inspectedMay 2024every 24 months

Location

StateCalifornia
CountyMarin
Location04-mrn-037-r11.20-nvto
CarriesW37-s101&n101 Off
CrossesCounty RD US 101 Nwprr
Coordinates38.07953, -122.54635

Physical Characteristics

MaterialConcrete Continuous
DesignBox Beam - Multiple
Total Length1059.1 ft (322.8 m)
Max Span102.0 ft (31.1 m)
Deck Width36.1 ft (11 m)
Deck Area3550.8 sq m
Main Spans13
Year Built1964

Traffic

Avg Daily Traffic18,000 (2004)
Truck Traffic2%
Lanes On Bridge2
Lanes Under Bridge13

Inspection & Ownership

Last InspectionMay 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number27 0081H

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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