Structure 35 0040 · San Mateo County, CA

Bunker Hill Drive over Interstate 280

Carries Bunker Hill Drive over Interstate 280, 04-sm-280-r12.32.

Overall conditionFair

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

How ratings work
Decksets the rating6/9 · Satisfactory
Superstructure7/9 · Good
Substructure7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT260 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9 · sets the ratingSuperstructure 7/9Substructure 7/9

260 ft end to end, longest span 130 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.

Built196957 years old
Length260.2 ft79.3 m
Daily traffic3,300counted 1998
Last inspectedJuly 2023every 24 months

Location

StateCalifornia
CountySan Mateo
Location04-sm-280-r12.32
CarriesBunker Hill Drive
CrossesInterstate 280
Coordinates37.52306, -122.35642

Physical Characteristics

MaterialPrestressed Concrete Continuous
DesignBox Beam - Multiple
Total Length260.2 ft (79.3 m)
Max Span129.9 ft (39.6 m)
Deck Width43.6 ft (13.3 m)
Deck Area1054.7 sq m
Main Spans2
Year Built1969

Traffic

Avg Daily Traffic3,300 (1998)
Truck Traffic2%
Lanes On Bridge2
Lanes Under Bridge8

Inspection & Ownership

Last InspectionJuly 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number35 0040

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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