Structure 28 0137L · Contra Costa County, CA

State Route 24 over El Nido Ranch RD Aqueduc

Carries State Route 24 over El Nido Ranch RD Aqueduc, 04-cc-024-r4.90-lfyt.

Overall conditionFair

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

How ratings work
Decksets the rating5/9 · Fair
Superstructure6/9 · Satisfactory
Substructure7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT568 FT OVERALL100 FT0ELEVATION · LENGTHS TO SCALE
Deck 5/9 · sets the ratingSuperstructure 6/9Substructure 7/9

568 ft end to end, longest span 100 ft: about 1.6 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 box-beam bridge.

Built196957 years old
Length568.2 ft173.2 m
Daily traffic79,500counted 2019
Last inspectedJune 2023every 24 months

Location

StateCalifornia
CountyContra Costa
Location04-cc-024-r4.90-lfyt
CarriesState Route 24
CrossesEl Nido Ranch RD Aqueduc
Coordinates37.89137, -122.14608

Physical Characteristics

MaterialConcrete Continuous
DesignBox Beam - Multiple
Total Length568.2 ft (173.2 m)
Max Span100.1 ft (30.5 m)
Deck Width67.9 ft (20.7 m)
Deck Area3585.2 sq m
Main Spans9
Year Built1969

Traffic

Avg Daily Traffic79,500 (2019)
Truck Traffic3%
Lanes On Bridge4
Lanes Under Bridge2

Inspection & Ownership

Last InspectionJune 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number28 0137L

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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