Structure 55 1099 · Orange County, CA

Seal Beach BLVD over State Route 405

Carries Seal Beach BLVD over State Route 405, 12-ora-405-22.64-slb.

Overall conditionFair

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

How ratings work
Decksets the rating5/9 · Fair
Superstructure7/9 · Good
Substructure7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT472 FT OVERALL100 FT0ELEVATION · LENGTHS TO SCALE
Deck 5/9 · sets the ratingSuperstructure 7/9Substructure 7/9

472 ft end to end, longest span 258 ft: about 7 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.

Built201412 years old
Length472.4 ft144 m
Daily traffic20,000counted 2020
Last inspectedSeptember 2023every 24 months

Location

StateCalifornia
CountyOrange
Location12-ora-405-22.64-slb
CarriesSeal Beach BLVD
CrossesState Route 405
Coordinates33.77434, -118.07503

Physical Characteristics

MaterialPrestressed Concrete Continuous
DesignBox Beam - Multiple
Total Length472.4 ft (144 m)
Max Span257.5 ft (78.5 m)
Deck Width129.9 ft (39.6 m)
Deck Area5702.4 sq m
Main Spans2
Year Built2014

Traffic

Avg Daily Traffic20,000 (2020)
Truck Traffic3%
Lanes On Bridge7
Lanes Under Bridge18

Inspection & Ownership

Last InspectionSeptember 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number55 1099

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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