US Bridges

SR 121 EB Imola Av over Napa River

Fair

Napa County, California · 04-NAP-121-R5.30-NAP · Structure no. 21 0108R

Built
2007
18 years old
Condition
Fair
inspected April 2024
Type
Box Beam or Girders - Multiple
Prestressed Concrete Continuous
Length
2,146 ft
13 main spans
Daily traffic
13,500
2009 count
Owner
State
State Highway Agency

About this bridge

SR 121 EB Imola Av over Napa River is a prestressed concrete continuous box beam or girders - multiple carrying SR 121 EB Imola Av over Napa River in Napa County, California. It was built in 2007, so it is 18 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 13,500 vehicles a day, roughly 2% of them trucks, projected to reach 32,344 by 2046. The structure is 2,146 ft (654 m) long and 45 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

Open in Google Maps
CarriesSR 121 EB Imola Av
CrossesNapa River
Location04-NAP-121-R5.30-NAP
RouteState Highway 121
CountyNapa County
StateCalifornia
Coordinates38.28153, -122.28786
Functional classUrban Other Principal Arterial

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionApril 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating59.6 US tons
Inventory rating35.7 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans13 (+13 approach)
Design loadHS 20 + Mod
Structure length2,146 ft (654 m)
Longest span148 ft (45 m)
Deck width45 ft (13.8 m)
Roadway width36 ft (11.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic13,500 (2009)
Projected traffic32,344 by 2046
Trucks2%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway and pedestrian
CrossesRailroad and waterway
Detour if closed8.1 mi (13 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—
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was SR 121 EB Imola Av over Napa River built?

It was built in 2007, making it 18 years old in 2025.

What condition is SR 121 EB Imola Av over Napa River 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 April 2024.

How much traffic does SR 121 EB Imola Av over Napa River carry?

About 13,500 vehicles per day (2009 count), of which roughly 2% are trucks.

How long is SR 121 EB Imola Av over Napa River?

The structure is 2,146 ft (654 m) long with a longest span of 148 ft (45 m) and a deck 45 ft wide.

Who owns SR 121 EB Imola Av over Napa River?

It is owned by the State Highway Agency.