Structure 53 1899 · Los Angeles County, CA

State Route 60 over Diamond Bar

Carries State Route 60 over Diamond Bar, 07-la-060-r25.56-dmbr.

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 FT156 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 5/9 · sets the ratingSuperstructure 7/9Substructure 7/9

156 ft end to end: about 2 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.

Built197056 years old
Length155.8 ft47.5 m
Daily traffic223,000counted 2015
Last inspectedFebruary 2025every 24 months

Location

StateCalifornia
CountyLos Angeles
Location07-la-060-r25.56-dmbr
CarriesState Route 60
CrossesDiamond Bar
Coordinates34.02300, -117.81177

Physical Characteristics

MaterialPrestressed Concrete
DesignBox Beam - Multiple
Total Length155.8 ft (47.5 m)
Max Span154.9 ft (47.2 m)
Deck Width148.0 ft (45.1 m)
Deck Area2142.2 sq m
Main Spans1
Year Built1970

Traffic

Avg Daily Traffic223,000 (2015)
Truck Traffic11%
Lanes On Bridge11
Lanes Under Bridge5

Inspection & Ownership

Last InspectionFebruary 2025
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number53 1899

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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