Structure 35 0228R · San Mateo County, CA

Interstate 280 NB over Avalon Drive

Carries Interstate 280 NB over Avalon Drive, 04-sm-280-r22.04-ssf.

Overall conditionPoor

Set by its lowest-rated component: Deck at 4 of 9.

How ratings work
Decksets the rating4/9 · Poor
Superstructure5/9 · Fair
Substructure7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT143 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 4/9 · sets the ratingSuperstructure 5/9Substructure 7/9

143 ft end to end, longest span 80 ft. 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.

Built197155 years old
Length143.0 ft43.6 m
Daily traffic50,500counted 2009
Last inspectedFebruary 2025every 24 months

Location

StateCalifornia
CountySan Mateo
Location04-sm-280-r22.04-ssf
CarriesInterstate 280 NB
CrossesAvalon Drive
Coordinates37.63962, -122.44166

Physical Characteristics

MaterialConcrete Continuous
DesignBox Beam - Multiple
Total Length143.0 ft (43.6 m)
Max Span80.1 ft (24.4 m)
Deck Width69.6 ft (21.2 m)
Deck Area924.3 sq m
Main Spans2
Year Built1971

Traffic

Avg Daily Traffic50,500 (2009)
Truck Traffic2%
Lanes On Bridge4
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 Number35 0228R

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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