Structure 35 0009K · San Mateo County, CA

I-280 SB Onramp over Los Trancos Creek

Carries I-280 SB Onramp over Los Trancos Creek, 04-sm-280-r0.01.

Overall conditionGood

Set by its lowest-rated component: Deck and Superstructure and Substructure at 7 of 9.

How ratings work
Decksets the rating7/9 · Good
Superstructuresets the rating7/9 · Good
Substructuresets the rating7/9 · Good
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT75 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 7/9Substructure 7/9

75 ft end to end. Lengths and the car 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
Length75.1 ft22.9 m
Daily traffic2,100counted 1998
Last inspectedOctober 2021every 48 months

Location

StateCalifornia
CountySan Mateo
Location04-sm-280-r0.01
CarriesI-280 SB Onramp
CrossesLos Trancos Creek
Coordinates37.40820, -122.19423

Physical Characteristics

MaterialConcrete
DesignBox Beam - Multiple
Total Length75.1 ft (22.9 m)
Max Span73.2 ft (22.3 m)
Deck Width30.5 ft (9.3 m)
Deck Area213.0 sq m
Main Spans1
Year Built1969

Traffic

Avg Daily Traffic2,100 (1998)
Truck Traffic2%
Lanes On Bridge1

Inspection & Ownership

Last InspectionOctober 2021
Inspection FrequencyEvery 48 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number35 0009K

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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