Structure 35 0175S · San Mateo County, CA

Junipero Serra-nb1 over Interstate 280

Carries Junipero Serra-nb1 over Interstate 280, 04-sm-001-r48.38-dlc.

Overall conditionFair

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

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

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT610 FT OVERALL100 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9 · sets the ratingSuperstructure 7/9Substructure 6/9 · sets the rating

610 ft end to end, longest span 111 ft: about 1.7 football fields. 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.

Built196561 years old
Length609.9 ft185.9 m
Daily traffic6,600counted 1998
Last inspectedOctober 2024every 48 months

Location

StateCalifornia
CountySan Mateo
Location04-sm-001-r48.38-dlc
CarriesJunipero Serra-nb1
CrossesInterstate 280
Coordinates37.70556, -122.47075

Physical Characteristics

MaterialConcrete Continuous
DesignBox Beam - Multiple
Total Length609.9 ft (185.9 m)
Max Span110.6 ft (33.7 m)
Deck Width34.1 ft (10.4 m)
Deck Area1933.4 sq m
Main Spans7
Year Built1965

Traffic

Avg Daily Traffic6,600 (1998)
Truck Traffic2%
Lanes On Bridge2
Lanes Under Bridge8

Inspection & Ownership

Last InspectionOctober 2024
Inspection FrequencyEvery 48 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number35 0175S

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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