Structure 55 0650 · Orange County, CA

Fourth Street over State Route 55

Carries Fourth Street over State Route 55, 12-ora-055-10.98-sa.

Overall conditionFair

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

How ratings work
Deck7/9 · Good
Superstructuresets the rating6/9 · Satisfactory
Substructure7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT290 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 6/9 · sets the ratingSubstructure 7/9

290 ft end to end, longest span 123 ft: about 4 semi-trucks nose to tail. 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.

Built199234 years old
Length290.0 ft88.4 m
Daily traffic39,000counted 2020
Last inspectedMarch 2024every 24 months

Location

StateCalifornia
CountyOrange
Location12-ora-055-10.98-sa
CarriesFourth Street
CrossesState Route 55
Coordinates33.74806, -117.83284

Physical Characteristics

MaterialPrestressed Concrete Continuous
DesignBox Beam - Multiple
Total Length290.0 ft (88.4 m)
Max Span123.0 ft (37.5 m)
Deck Width113.8 ft (34.7 m)
Deck Area3067.5 sq m
Main Spans3
Year Built1992

Traffic

Avg Daily Traffic39,000 (2020)
Truck Traffic4%
Lanes On Bridge8
Lanes Under Bridge12

Inspection & Ownership

Last InspectionMarch 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number55 0650

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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