Structure 34 0135G · San Francisco County, CA

Us101n-i 280s (wl) over 280/101 Interchange

Carries Us101n-i 280s (wl) over 280/101 Interchange, 04-sf-101-1.79-sf.

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 FT1,579 FT OVERALL250 FT0ELEVATION · LENGTHS TO SCALE
Deck 5/9 · sets the ratingSuperstructure 7/9Substructure 7/9

1,579 ft end to end, longest span 121 ft: about 4.4 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.

Built196066 years old
Length1579.4 ft481.4 m
Daily traffic—reported figure implausible
Last inspectedMarch 2024every 24 months

Location

StateCalifornia
CountySan Francisco
Location04-sf-101-1.79-sf
CarriesUs101n-i 280s (wl)
Crosses280/101 Interchange
Coordinates37.73297, -122.40499

Physical Characteristics

MaterialConcrete Continuous
DesignBox Beam - Multiple
Total Length1579.4 ft (481.4 m)
Max Span121.1 ft (36.9 m)
Deck Width37.4 ft (11.4 m)
Deck Area5488.0 sq m
Main Spans16
Year Built1960

Traffic

Avg Daily Traffic80,000 (2019)
That is about 80,000 vehicles per lane per day — beyond what any U.S. road carries (the busiest freeways run about 25,000–30,000). It is almost certainly a data-entry error in the National Bridge Inventory, so we leave this bridge out of traffic rankings.
Truck Traffic3%
Lanes On Bridge1
Lanes Under Bridge12

Inspection & Ownership

Last InspectionMarch 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number34 0135G

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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