Structure 23C0030 · Solano County, CA

Grizzly Island RD over Montezuma Slough

Carries Grizzly Island RD over Montezuma Slough, 5.5 Mi S SR 12.

Overall conditionFair

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

How ratings work
Decksets the rating6/9 · Satisfactory
Superstructuresets the rating6/9 · Satisfactory
Substructuresets the rating6/9 · Satisfactory
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT927 FT OVERALL200 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9Superstructure 6/9Substructure 6/9

927 ft end to end: about 2.6 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 multi-beam bridge.

Built195868 years old
Length926.8 ft282.5 m
Daily traffic606counted 2008
Last inspectedAugust 2024every 24 months

Location

StateCalifornia
CountySolano
Location5.5 Mi S SR 12
CarriesGrizzly Island RD
CrossesMontezuma Slough
Coordinates38.18575, -121.97689

Physical Characteristics

MaterialSteel
DesignStringer/Multi-beam
Total Length926.8 ft (282.5 m)
Max Span53.1 ft (16.2 m)
Deck Width26.6 ft (8.1 m)
Deck Area2288.2 sq m
Main Spans1
Year Built1958

Traffic

Avg Daily Traffic606 (2008)
Truck Traffic3%
Lanes On Bridge2

Inspection & Ownership

Last InspectionAugust 2024
Inspection FrequencyEvery 24 months
OwnerCounty Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical5 — Stable for scour
Structure Number23C0030

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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