US Bridges

San BRUNO-N280 Onr over S280-E380 Connector Ramp

Fair

San Mateo County, California · 04-SM-280-R20.96-SBR · Structure no. 35 0218S

Built
1971
54 years old
Condition
Fair
inspected July 2023
Type
Box Beam or Girders - Multiple
Concrete Continuous
Length
378 ft
4 main spans
Daily traffic
7,400
1998 count
Owner
State
State Highway Agency

About this bridge

San BRUNO-N280 Onr over S280-E380 Connector Ramp is a concrete continuous box beam or girders - multiple carrying San BRUNO-N280 Onr over S280-E380 Connector Ramp in San Mateo County, California. It was built in 1971, so it is 54 years old, younger than the California average of 54.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 7,400 vehicles a day, roughly 2% of them trucks, projected to reach 9,299 by 2040. The structure is 378 ft (115.2 m) long and 40 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesSan BRUNO-N280 Onr
CrossesS280-E380 Connector Ramp
Location04-SM-280-R20.96-SBR
RouteInterstate 280
CountySan Mateo County
StateCalifornia
Coordinates37.62714, -122.43003
Functional classUrban Principal Arterial - Interstate

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating92.5 US tons
Inventory rating55.7 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20 + Mod
Structure length378 ft (115.2 m)
Longest span115 ft (35.1 m)
Deck width40 ft (12.1 m)
Roadway width36 ft (11 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic7,400 (1998)
Projected traffic9,299 by 2040
Trucks2%
Lanes on structure1
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed3.1 mi (5 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was San BRUNO-N280 Onr over S280-E380 Connector Ramp built?

It was built in 1971, making it 54 years old in 2025.

What condition is San BRUNO-N280 Onr over S280-E380 Connector Ramp in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in July 2023.

How much traffic does San BRUNO-N280 Onr over S280-E380 Connector Ramp carry?

About 7,400 vehicles per day (1998 count), of which roughly 2% are trucks.

How long is San BRUNO-N280 Onr over S280-E380 Connector Ramp?

The structure is 378 ft (115.2 m) long with a longest span of 115 ft (35.1 m) and a deck 40 ft wide.

Who owns San BRUNO-N280 Onr over S280-E380 Connector Ramp?

It is owned by the State Highway Agency.