Structure 28C0425 · Contra Costa County, CA

James Donlon BLVD over Contra Costa Canal

Carries James Donlon BLVD over Contra Costa Canal, 1.5 Mi E Somerville RD.

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
Channelnot part of overall8/9 · Very Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT36 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 7/9Substructure 7/9

36 ft end to end. 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 tee-beam bridge.

Built1950rebuilt 1978
Length35.8 ft10.9 m
Daily traffic1,873counted 2020
Last inspectedJanuary 2025every 24 months

Location

StateCalifornia
CountyContra Costa
Location1.5 Mi E Somerville RD
CarriesJames Donlon BLVD
CrossesContra Costa Canal
Coordinates37.98300, -121.82950

Physical Characteristics

MaterialConcrete
DesignTee Beam
Total Length35.8 ft (10.9 m)
Max Span34.1 ft (10.4 m)
Deck Width94.5 ft (28.8 m)
Deck Area313.9 sq m
Main Spans1
Year Built1950 (reconstructed 1978)

Traffic

Avg Daily Traffic1,873 (2020)
Truck Traffic2%
Lanes On Bridge4

Inspection & Ownership

Last InspectionJanuary 2025
Inspection FrequencyEvery 24 months
OwnerCity/Municipal Highway Agency
Historical SignificanceHistorical significance is not determined
Scour Critical8 — Stable, low risk
Structure Number28C0425

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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