Structure 27 0007 · Marin County, CA

U.s. Highway 101 over Ggt Bellam Andersen

Carries U.s. Highway 101 over Ggt Bellam Andersen, 04-mrn-101-9.63-srf.

Overall conditionGood

Set by its lowest-rated component: Deck and Superstructure and Substructure at 7 of 9.

How ratings work
Decksets the rating7/9 · Good
Superstructuresets the rating7/9 · Good
Substructuresets the rating7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT1,024 FT OVERALL200 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 7/9Substructure 7/9

1,024 ft end to end, longest span 108 ft: about 2.8 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.

Built1958rebuilt 2003
Length1024.0 ft312.1 m
Daily traffic172,000counted 2009
Last inspectedMay 2024every 24 months

Location

StateCalifornia
CountyMarin
Location04-mrn-101-9.63-srf
CarriesU.s. Highway 101
CrossesGgt Bellam Andersen
Coordinates37.95708, -122.50873

Physical Characteristics

MaterialConcrete Continuous
DesignBox Beam - Multiple
Total Length1024.0 ft (312.1 m)
Max Span107.9 ft (32.9 m)
Deck Width122.7 ft (37.4 m)
Deck Area11672.5 sq m
Main Spans12
Year Built1958 (reconstructed 2003)

Traffic

Avg Daily Traffic172,000 (2009)
Truck Traffic2%
Lanes On Bridge8
Lanes Under Bridge7

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 0007

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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